Do fruit and vegetables prevent cancer?

Apple doctor fruit cancer

For the last couple of decades we have been bombarded with messages to eat more fruit and vegetables. One of the main arguments for this, and indeed the entire motivation behind the “5-a-day” campaign that started in the early 90’s, is that fruit and vegetables protect against cancer. But do they really?

The European Prospective Investigation in to Cancer and Nutrition, otherwise known as the EPIC study (I guess “EPICN” didn’t sound quite as, well, epic) was a large cohort study that looked in to this question. A cohort study is a type of observational study that recruits people and then follows them over time to see what happens to them. The study was funded by the European Commission and the International Agency for Research on Cancer.

The results were published in the Journal of the National Cancer Institute in 2010. The study followed roughly 500,000 people in ten European countries. Participants filled in a questionnaire about what they ate when they were recruited in to the study, and they were then followed over time to see if they developed cancer, with a median length of follow-up of nine years. Intake of fruit and vegetable at the beginning of the study was then compared with risk of developing cancer over the following years, to see if there was any correlation.

Many readers will probably immediately notice one big problem with the study. They’ve interviewed people at one time about their fruit and vegetable intake, and then simply assumed that this stays stable over time. If a lot of people had a low intake of fruit and vegetables at the beginning of the study, and then a year in to the study switched to a high intake, that could seriously mess up the results. So the study builds to a large extent on the assumption that people overall don’t change their fruit and vegetable intake very much over the course of a decade. Is that assumption correct? I have no idea. This problem is very common in observational studies of diet.

A second issue stems from the fact that this was an observational study. Observational studies always have one big problem, and that is confounding. Confounding is caused by the fact that people are not randomized in to a high-fruit-and-vegetable and a low-fruit-and-vegetable group. They’re getting to choose for themselves which group they’re in. Since we’ve all been told for decades that fruit and vegetables are healthy, people who care about their health will generally have a higher intake than people who don’t care. They will also exercise more, smoke less, drink less alcohol, and so on.

If a difference in cancer incidence is found in this study, which of all those different variables is actually causing the difference? The authors of the study have attempted to correct for the most obvious potential confounders, like smoking, alcohol intake, and exercise habits. They have also corrected for educational level, and in women they corrected for menopausal status, age at which menstruation started, and contraceptive use (factors that correlate strongly with risk of breast cancer, which is by far the most common cancer in women). They also initially corrected for intake of red meat, processed meat, and fibre, but then decided not to bother when they realized that these things had zero effect on the results (as we’ve discussed previously, red meat consumption does not increase your risk of cancer).

In other words, they attempted to correct for a bunch of possible confounders. Of course, that leaves about five billion other confounders that they didn’t correct for. That’s the problem with observational studies. No matter how hard you try to correct for confounding variables, you’re never going to catch them all. That’s why observational studies cannot generally be used to prove the existence of a cause-and-effect relationship. The best they can do is suggest that such a relationship exists (in the language of medicine, we say that they are “hypothesis generating”). As a general rule, anything less than a halving or doubling of risk in observational studies should be assumed to be entirely due to confounding, at least until someone proves otherwise.

Let’s get to the results.

Average intake of fruit and vegetables in the study was 335 grams per day. The lowest intake was seen in Sweden, where average intake was 231 grams per day, and the highest was seen in Spain, where average intake was 511 grams per day. Intake of fruit and vegetables correlated positively with female gender, higher education, increased physical activity, lower alcohol intake and lower rates of smoking. This is as we would expect – people who care about their health also eat more fruit and vegetables.

Over the course of the nine years of follow-up, 6,4% of participants developed cancer. Now to the interesting part. The group with the highest intake of fruit and vegetables (more than 650 grams per day) had an 11% lower relative risk of cancer than the group with the lowest intake (less than 230 grams per day). Overall, the researchers found that an increase in consumption of fruit and vegetables of 200 grams per day (equivalent to two and a half servings) was correlated with a 3% reduction in the relative risk of getting cancer.

If we for one second assume that there is a real cause and effect relationship here, and that this reduction isn’t due to confounding, that would mean that someone who increases their intake of fruit and vegetables by two and a half servings per day, perhaps to get up to the recommended “five-a-day”, would decrease their risk of getting cancer over the coming nine years from 6,4% to 6,2%. In other words, the absolute risk reduction over nine years is 0,2%. That’s an effect size that makes even statins seem impressive.

Even if we take the more extreme example of someone who goes from eating no fruit and vegetables at all to eating eight servings per day, the absolute reduction in risk of cancer over nine years would still only be 0,7% (if you’re confused about the difference between absolute risk and relative risk, I recommend you read this).

And that’s assuming there is a causal relationship. As I think I’ve already made clear, there is no reason to think that an effect this small in an observational study is due to a cause-and-effect relationship. In fact, considering the enormous number of possible confounders, it’s almost certainly due to confounding. In other words, the best evidence that exists at this point in time suggests that an increased consumption of fruit and vegetables won’t decrease your risk of cancer.

Please provide your e-mail address below and you will get all future articles delivered straight to your inbox the moment they are released.

Join 23.6K other subscribers

106 thoughts on “Do fruit and vegetables prevent cancer?”

  1. Thank you for your work! In my opinion this study is utterly meaningless. If you REALLY want to know if fruit and vegetables reduce the risk of cancer, you should – as you suggest – monitor the people much more closely and follow-up their intake over the years AND have a look at which kind of fruit and vegetables people eat (some people consider eating french fries or crisps is eating vegetables and there is assumably a big difference between eating 200 g ecological fresh berries and 200 g apples sprayed with pesticides that have been stored in a cellar over the whole winter with constantly decreasing vitamin content) and also have a group of people with a very high intake of fruit and vegetables (they exist!). If I remember correctly there is more than one scientist thinking that even 5-a-day is far from enough in terms of fruit and vegetables.

    1. Would you be able to point me toward the individual who recommends more? Even if more fruit and veggie intake has miniscule impact on preventing cancer there are so many other good health reasons to increase our intake. Thank you!

      1. Hi Joshua, I read about it at different sources all of which I was not able to find right now, but this article here could be interesting in this regard: There are also researchers who have had a closer look at the health potential of certain fruit and vegetables, such as Prof. Béliveau from Montréal who found out that certain berries like raspberries seem to kill cancer cells at least in vitro. I also have read about the impressive potential of aronia berries recently. Maybe you would like to search a bit around these keywords on google scholar. This is why I said it would be desirable for a good study to have a closer look at what kind of fruit and vegetables is eaten. Anyway, I meant my comment above not to criticise Sebastian Rushworth (I hope it did not come across like that), I really like his/your way to look at things and studies. Thank you!

      2. I took a look. Their about page says it all. There’s not a doctor among them and most of them don’t seem to have any training in any health related discipline whatsoever. As far as I can tell, the website is a front for vegan propaganda.

    2. The best cure healing cancer is fasting and fever.

      When you live on fruit and vegetables, its more or less the same as fasting, because there is hardly any nutrition for the body in it.

      The body temperature must be limited to 43 degrees C and the head to 41 degrees C by external cooling.

      1. Wait a minute. Nutritional is Dr. Gregor’s website. He is a doctor. Look past the team and realize he has written some bestselling books like ” How Not To Die”. True he is a vegetarian advocate. However, his videos shows and cites his research. Don’t be so quick to judge Dr. Rushworth because I am aware you are a meat eater and might have some bias yourself. I do love this (your) website and your articles and your take on things. . They are thought provoking to say the least.We should all keep an open mind as you well know. After all Amazon tried to ban your book which was definitely in poor judgement and narrow mindedness on their part.

  2. Hi Sebastian,
    I loved you’re earlier studies and articles.

    However I know find they are moving away from being useful.

    I’m no medic, Mathematician, no anything that would produce meaningful input into this argument. But, I do try to use my intuition, common sense, and question the world around me. Hence how I found you in the early days of Covid. You were one of a very very few voices of reason.

    On to fruit and veg. You may be unable to find much causal relationship between eating more fruit and veg , and cancer.
    However, intuition, common sense, and ones own habits tell you that increasing your intake of fruit and veg is far better than increasing your intake of pizza, or McDonalds.

    Just comparing with incidence of cancer does not seem to be very helpful here. I’m guessing, but I would very much believe it to be true, that increasing your fruit and veg would have a very substantial positive improvement on your immune system. Which would have the knock on effect of protecting you against all kinds of diseases.

    So I guess the study you are really looking for is correlation between fruit and veg intake and age of mortality.

    As I say I’m just an everyday layman, but I won’t be lessening my intake of fruit and veg based on your article.

    1. I never said you should. And the alternative to fruit and veg doesn’t have to be pizza and Mcdonalds. My main point with these articles is that most dietary recommendations are not supported by the evidence. What I would love to see is fewer diet recommendations that are better supported by evidence. The main point of this article is that the ”five-a-day” recommendation has no scientific basis.

      1. I once tried to find the scientific origin of “five-a-day”. I failed but found a blogger who had looked harder. She said that the policy emanated from a conference of Californian “produce” growers. Clearly the almond growers hadn’t attended or nuts would have been included in the five-a-day.

        Later I found an observational study – for what it’s worth – that concluded that three-a-day is enough.

        Beyond the need for enough calories and for vitamins and certain minerals, is there anything scientific known about diet?

  3. Hi Sebastian, thanks for this, enlightening as usual. The relative importance of eating different types of foods etc is evidently exceedingly hard to study. I have a couple of questions. First, do you think (which is indicated, it seems to me) that the number of possible confounders is a reason for rejecting a causal relationship or that it merely undercuts the idea that the data supports positing one? Second, have any (attention-worthy) studies been conducted which have compared people who have a generally (so-called) healthy life-style (exercise, sleep, stress reduction, eating, etc) with those who only to a limited extent live up to those aims? Best wishes, Folke

    1. I would say that from a probabilistic perspective, if a beneficial difference is small, specially in a situation where people have been encouraged to engage in a behaviour because it’s supposedly healthy, then it’s more likely the effect is due to confounding than not. Say there are a hundred different factors that could be responsible for the difference, then the odds that any one factor is responsible is a hundred to one. So the difference shouldn’t be assumed to be due to any one factor until there is higher quality evidence to support that belief.
      Yes, those types of studies have been done, but they are virtually always observational. Basically, the most important thing people can do for their health is not smoke, which results in something like a 7 year improvement in average life expectancy. Everything else produces at best a smaller improvement than that.

      1. Even there I wonder. Don’t smoke cigarettes? Certainly.

        But does smoking a pipe do much harm? I have in view a light smoker, not the sort of chap who used to have a pipe in his mouth the whole day long.

  4. But I think you would say also that veggies are super healthy in that you can eat a lot of them without getting fat?

    1. Veggies yes. Fruit no. I actually think it’s a bit problematic to combine the two in to one category. It’s very easy to consume a huge amount of carbohydrates by eating fruit, and since the main thing driving the obesity epidemic is overconsumption of carbohydrates, I think fruit should be limited in the same way bread, pasta, rice, cereals, and sweets should be.

      1. “It’s very easy to consume a huge amount of carbohydrates by eating fruit, and since the main thing driving the obesity epidemic is overconsumption of carbohydrates, I think fruit should be limited…”
        —Sebastian Rushworth, M.D.

        I think you’d be very hard pressed to find people who can get obese from only adding fruit to their diet. Fruit might be energy dense compared to OTHER vegetables (Fruit is technically just another vegetable coming from vegetation.) However, fruit is still easily considered a low energy-density food by weight. Despite energy density, it’s very hard to get obese bodies to keep their weight, even if you let them consume the highest energy-density foods among WHOLE vegetable foods (e.g. beans, sweet potatoes, fruits, nuts), not processed foods (white flour, white rice, etc.).

      2. “since the main thing driving the obesity epidemic is overconsumption of carbohydrates” please provide really strong evidence for that. and please also see the difference between refined carbohydrates and complex carbohydrates.

  5. Dr Rushworth is opening our minds to question information presented to us .He has put a lot of time and effort into his correspondence.
    Wouldn’t it be wonderful if we could read it and let the information sit for a while, and be less critical and judgmental, Just Be .
    Best Wishes to all and thank you Dr Rushworth for offering us alternative information based on your research

  6. We have approx. since 200 years access to fruit and vegetables the year around. Genetic we are still in the dark ages in where the eating of meat is what we must do to be productive for reproduction of the kind.

    Our stomach and intestines are still not able to break the cells of vegetables when they are not really cooked and that is also for the large cells of European fruits.

    Our brains needs approx. 50 grams animal grease each day and therefore most fanatic vegetarians get during their lives heavy brain and nerve cladding related illnesses.

    A lot of vegetarian pregnant woman creating a kind of pregnant dementia because the unborn parasite on moms brains and her nerve cladding.

    If you like to be healthy and smart old, try to avoid fresh fruit and vegetables, take only cooked stuff.

    1. Fish! You forgot fish. Every week some sardines, some smoked salmon, some white fish. I know fish-eating is healthy because (i) it’s what we do and we are still alive, and (ii) Jeeves recommended it.

      If you can’t take dietary advice from a fictional valet who can you take it from?

      1. I did not forget fish, raw Herrings with chopped unions and also kibbelling (small pieces of Tilapia, covered with a beer sauce, baked in arachnid oil (brrr) covered with a mix of dried krauts)

        I eat weekly a mixed halve a kilo of it on the week market.

        It tast hummy but it smells very nasty (says my lady), not good for kissing hahaha.

        In the Netherlands they say: Herring in the land, doctors on the side.

  7. We need to only look at internal carcinomas and not all cancers. We need to correct for hereditary cancer syndromes.
    After that the epidemiology is quite straightforward and the the fruits and vegetable theory is nonsense. The epidemiological findings and mechanistic findings overwhelming indicate that endodermal cancers (stomach, colon, uterine) correspond to sugar consumption. The Warburg paradigm that indicted only cancers use aerobic glycolysis is wrong. All cells use aerobic glycolysis and proliferate in the presence of high glucose content as is found in high sugar diets as glucose both supplies energy and the building blocks for cellular elements (via the PPP shunt). Although the Krebs cycle is more efficient at producing quantity of ATP, aerobic glycolysis produces easily obtainable ATP (but in low volume).

    Is there benefit in fruits and vegetables? Yes in that they supply trace minerals and some essential vitamins that we cannot make; but that is it unless they also contain complex carbohydrates. Complex carbohydrates are necessary for butyrate production by gut bacteria. Butyrate is essential for suppressing excessive colonic proliferation and maintaining the gut lumen. Sugar consumption, in particular fructose, promotes non-butyrate forming bacteria and inhibits production of butyrate from butyrate forming bacteria. The rising epidemic of colo-rectal cancers in young people (less than 50) and the shift from left sided colon cancer to right sided colon cancer is totally explained (both epidemiologically and mechanistically) by the increase in sugar/fructose in the younger population; some who have been on high sugared diets from before birth.

  8. Please let me know where I can get one of your 36 hour days. There’s not enough time in 24 hours for a day job and everything else. Thanks.

      1. I suggest a nice Phillipino day-and-night lady.

        We have had them for approx 2 years over 20 years period.

  9. I suppose we also have to consider the fact that many non-organically grown fruits and vegetables may actually contribute to cancer, due to the toxic remnants of pesticides etc and the fact that, over the decades, modern farming methods have led to a decrease in micronutrients in these foods! (Just to add a couple more confounders to the debate 🙂 )

  10. Thank you Sebastian!

    Good to know that eating fruit does not lead to cancer.
    Fruits are delicious!

  11. Very interesting. However, I will continue to eat fruits and some veg because I like the flavor not because I believe doing so will decrease my chances of getting cancer.

    So much of what we are told to do by government and other interested parties that have a profit motive are actually harmful. It’s good to know that their admonition to eat more fruit and veg won’t really hurt us. Now if they would start promoting meat, butter, cheese, and eggs over sugar, simple carbs, and vegetable oil everyone could feel better about eating bacon and roast beef.

  12. Dr. Rushworth, something has been on my mind recently and perhaps you can provide some enlightenment. Were Roman gladiators vegetarians or did they eat a more normal diet? It just doesn’t make sense to me that they were able to do the things they did on a diet of lentils and greens. I understand that there is some archeological evidence for this diet among gladiators but find it really hard to believe such a diet would provide the energy for their life of combat.

    1. I’ve read that gladiators ate a high carb diet specifically in order to put on weight, because a good thich layer of fat was a good protection against slashing wounds.

  13. Keep up the excellent work. I’m reading your book on Covid and more than anything it provides information about how trials should be conducted and their pitfalls. We want to have trust in medical experts and consequently we are too ready to believe anything. It is the job of the media to assess trials but they mostly don’t seem to have a clue about them, or are being paid not to.

  14. I wonder if there is any study looking at fibres, preferably distinguishing between the different types of fibres.

    Also fats, looking at PUFA, MUFA, SFA. I think we know that one. But what about PUFA that is not industrially extracted?

    Also, diets that include bones/marrow/cartilage.

    And what about fermented foods.

    Perhaps a good way to limit confounders is to cover as wide a variety of countries, cultures, regions, continents, time periods as possible?

  15. I am a dietitian who is continuing my education as a functional nutritionist so this is a topic I have some interest in. Also over the past year I have explored the healing power of food with Covid potentially affecting our health which has led me to even more areas of interest.

    There is a man, Chris Wark, who cured himself of stage IIIc Colin cancer about 15 years ago using extreme diet and lifestyle changes. He began juicing vegetables (because it’s almost impossible to chew effectively to get out maximum nutrients in large quantities of organic, raw produce in only 24 hours a day). He removed all animal products from his diet, cut out fat, began selective and science-backed supplements…. he also worked on movement, hydration and peace. He has now helped thousands to also heal. It so happens that his kids go to my kids’ school and his wife is in my book club; and he is as kind and genuine as the day is long. It is absolutely not a hoax. So based on this I do think food can be medicine and can decrease risk of cancer. The questions up for study in my estimation are the details (how much is enough). He consumed and continues to consume massive amounts of vegetables and fruit and has now added back occasional meat (organic grass fed only) and small amounts of healthy fat. Studies have not been completed using his approach, but there are many testimonies of people following his recommendations who heal from even stage 4 cancers. I mention this because I thought you might want to explore this more but also one never knows who may be reading this and who wants to check it out for prevention or healing purposes. I am attaching the link to his website and support materials. Occasionally he will release his 10video modules for free along with a discount of half off, but his book Chris Beat Cancer may be an inexpensive way to get your feet wet. I would enjoy your opinion after you have taken it all in.

      1. Pamela Matlack-Klein: Pardon my butting in, but my view is this: A healthy fat is the fat of any ruminant animal raised entirely on pasture, and the fats of wild-caught sea creatures . An unhealthy fat is (usually an oil) produced in a factory. Olive oil, and other cold-pressed oils are probably OK in small amounts, but animal fats contain crucial fat-soluble vitamins in greater abundance (and they taste really good!).

      2. Pamela Matlack-Klein
        I can’t seem to get my response to match up with your question. I apologize and hope you see this. You asked which fats I consider to be healthy fats. First I would say minimally processed, organic fats are ideal. This would include olive oil, avocado oil, coconut oil from plants and grass fed organically grown animal fats. Of course cooking methods are important. Olive oil should not be used with high heat due to a lower smoke point. Avoid seed oils which are largely found in processed food and used in restaurants.

        Chris Wark, from Chris Beat Cancer, however, limits animal fats further. He says no fat (or animal product) for first 90 days then can add about a tablespoon per day of olive oil. He notes that bovine leukemia virus, that can be found in 80%+ small dairy farms and 100% large farms, is associated with cancer (strongly associated- 37% breast cancer may be caused by consuming undercooked beef). If your immune system is strong you can protect yourself but best to limit to reduce toxic exposure. Now to be clear, Chris had advanced colon cancer and did Herculean changes to his diet and lifestyle to become cured. These same changes have helped many others who have chosen to use food as medicine according to his reports. He backs up all of his recommendations with research and reasonable rationale along with personal and shared experience. In other words he’s not off the deep end. His healing journey was like a full time job. He found success 15 years ago but promises nothing, yet he is empowering and supportive for those who choose to follow his lead. He provides all of the support and education needed to boost the immune system including comprehensive information on herbs, micronutrients, nutraceuticals, recipes, daily scheduling, as well as how to find peace, sleep, movement that supports healing. It is really comprehensive. Not everyone would want to follow his program Square One but for those who do for prevention or for healing you will appreciate all that he includes.

        That’s more than you asked but I wanted to reiterate in case someone missed my previous comment yet would benefit from exploring more.

  16. Sebastian perhaps you would be interested in evaluating the China Study and doing a post on it. It is old but still considered by many to be the best evidence that we have that vegetarian/vegan diet reduces cancer risk. There is a book by the same name, written by Colin Campbell that comments in the study and presents additional related studies.

      1. Mark N: Thanks for posting the link. Most everything we’ve been told about food and health is simply wrong, and Denise Minger rips The China Study to shreds in her ever-charming way. Long read, but so worth it!

  17. Thank you, Dr. Rushworth. Another thorough and complete waste of time (EPIC). On a personal level, switching to the carnivore diet about eleven months ago has led to so many wonderful improvements at 72! I sleep like a rock, seven hours, and never get up to pee. I have better mental clarity. My digestion is more normal than I can ever recall. I have more stamina for my weekly (strenuous) hikes in the woods. I feel a sense of calmness throughout the day. Tinnitus is reduced. I still don’t get sick (and haven’t in fifteen years). I did need to adjust the diet about three months in, adding back some carbs in the form of dates, figs, prunes, and honey, and having three meals a day rather than two (between about 10:00 a.m. and 6:00 p.m.). There is simply no physiological need for fruits and vegetables in the diet, in my view.

    1. Gary, one thing that needs mentioning is that men need fairly high testosterone levels, which requires some sort of physical work. Even lifting weights will help with that. This is especially necessary as we age.

      Men’s bodies are designed to run with high testosterone levels. What we take in in our diets can sabotage that–especially raw soy elements, although I try to avoid cooked soy protein. Watch out for soy lecithin and soybean oil. Soy sauce is no problem, being fermented. 😊

  18. Science is religion; scientists are priests; studies are His word revealed. You can’t reason away faith: all these “nutrients” and “foods” are angels dancing on pinheads. This is theology: one trusts Authority. The end.

    I may be wrong, and I’d defer to your training, but I don’t know how to discuss “health” with those lined up for a Happy Meal in $100k cars during a “pandemic” that has been ravaging the earth for over a year now.

    Again. In the time Before Science™ (BS), Homo Sapiens Sapiens ate what was in the immediate environment, varied (I’d imagine) as the environment might be. I’m typing this, so that/those diets(s) was/were ipso facto a proper diet.

  19. “Published by The Journal of the National Cancer Institute”. I will bet that large organisation such as the above is sponsored by Big Pharma and therefore would like the statistics to prove there is little difference in the low or high consumption of fruit and vegetables.

    Also to say that red meat does not cause cancer, I beg to differ, Sebastian. Too many people with their high intake of red meat have died prematurely. On the contrary, the people of Okinawa live quite long with little or no cancer by eating fish, sea vegetables a some fruit.

    1. E Grant Goodwin, but what were the other lifestyle factors of the meat eaters? Were they smokers? Did they eat bread with added sugar, a la American bread, etc? Cancer is a metabolic disease, so excessive carbohydrates can cause cells to malfunction. A cause is not always easy to determine.

      1. AhNotepad: And cancer cells have defective mitochondria which require glucose or glutamine to produce energy.

  20. Gary Ogden, I totally agree, and only use animal fats from pigs, sheep, and cows with olive oil and coconut oil for sauteing. All those vegetable oils that have been foisted on us by profit-hungry companies are not fit for human consumption. At the risk of offending the vegans/vegetarians on this list, it is my honest belief that humans need animal protein and fat to be truly healthy.

  21. Right Simon. I’ve always scoffed at the five a day advice on other grounds. If I followed it I would have no room left in my stomach for any other food!
    I’ve always thought the smoking causes cancer claims were grossly exaggerated too. It is perfectly obvious that there are all sorts of other hazards in our modern lifestyle contributing to deaths from cancer.
    You are quite right to point out the logical flaws in much of the research that is rammed down our throats. Unfortunately it always leads to interference into our lives and infringement of our liberties.
    As it happens, at present I’m eating many bananas per day now. They take little chewing by my elderly teeth/gums. Reasonably high calorie content to gain weight and the fibre helps to keep me regular. They need no preparation either, and no plates to wash!
    Perhaps monkeys have more sense than us.

  22. I think if you are eating fruits and vegetables than you are perhaps not eating something worse like junk food or processed foods with chemicals and high salt and sugar content that may be a cancer culprit. So perhaps if the fruit is not in itself magical perhaps its because you are not eating worse stuff.
    Being Italian I can tell you most of my relatives on both sides in Italy are living well into their nineties and no signs of cancer. They die of old age. Their diet has minimal meat and lots of fruits and vegetables and olive oil. Not as much availability to junk food or fast food. But they also walk more and are thinner.
    I hope we can solve the mystery of cancer. I think its a multi facetted , complex problem not associated with just one factor.

    1. That’s exactly my view. It’s not that fruit and vegetables (and also seeds, pulses etc) prevent cancer; it’s
      that a diet of highly processed foods introduces elements that lead to cancer. If you eat lots of the former you have no appetite for the latter.

    1. I agree anglosvizzera, Zoe Harcombe is a fountain of knowledge and has a great presentation on YouTube on fiber, as does Paul Mason, a physician from Sydney, both active in the low carb movement. They completely refute that fiber is necessary in our diets, both well worth checking out!

  23. Studies of this type, as a lot of studies, ignore the dynamic aspect of the change being measured. The instant one item changes, the basic parameters are different. In this case if an individual’s fruit intake increases or decreases it is almost certainly offset with a corresponding change in his intake of another food type like bread or meat, etc while the total quantity of food consumed may remain fairly constant. So the presumed effect could be as much or more the result of the change in intake of alternate foods, as of the subject of the study.

  24. But, Sebastian, people must internalize responsibility for their cancer. Otherwise, they might focus on environmental contaminants.

    It must be in their genes. Or something. I should write grant applications.

  25. Excellent read thanks. If you ever had time to have a look on the evidence of tumeric and cancer it would be awesome. 👍

  26. It’s not surprising fruit and veg consumption was higher in Spain than in Sweden as they are much easier to grow, and of more variety, in a warm, sunny climate. Yet humans have made Scandinavia their home since shortly after the Ice Age and I doubt fruit and veg were plentiful then. However, people would have been more active and consumed less food overall. In any of the studies, was weight taken into account? We know that being overweight increases the risk of all kinds of diseases. I imagine people who habitually eat lots of fruit + veg and little full-fat dairy probably have a lower BMI. Is it not more likely that this has a protective factor than the fruit and veg themselves?

  27. Dr Rushworth

    To change the topic and offer a suggestion,I would like your next topic to be on H Pylori Bacteria and if it should or should not it be eradicated for our stomachs. So many bad things are associated with it that it makes me wonder what the truth is. Plus the strong combo antibiotics they give people to eradicate it causes problems for some making things worse. It would be an interesting topic as some doctors claim it’s beneficial and should be left alone. I would love to read your take on it.

  28. To Sebastian: “How not to die” is a funny titly on one of the best and most well documented books I have read. It deals with nutrition and gives nutritional advice based on science and scientific evidence. There are 130 pages of references in the book with a total of 2600 references to research, often peer reviewed and published in established medical journals. Dr Greger brings forward overwhelming evidence of how “whole plant food” (includes also fruit) helps you to get or keep a healthy life. Our current western life style, where what the food is an important ingredience, brings plenty of diseases, which today primarily is cured with pills. NutritionFacts have thousands of private donors, including a number of MDs. If you turn to you will get similar advice as those from Dr Greger. A number of Swedish M.D.s are more or less active in this association. Happy reading Sebastian and everyone else on this forum. (The book is also translated to Swedish, which is helpful for those of you who are not familiar with medical english language.)

    1. Thanks, I checked out their web site. The first article that pops up shows that they don’t understand basic scientific concepts like the difference between absolute and relative risk or the difference between clinical and statistical significance (or for that matter how statistical significance is determined), nor are they aware of the fact that observational studies can only show correlation, not causation. If the ”How not to die” book is similar to ”Läkare för framtidens” web site, then I would be very skeptical of any claims made in it.

  29. Hello agaion Sebastina,
    I can assure you that Dr Greger knows the difference beteen relative and absolute risks. In his book he always points out if a study is observational (without cause and effect) or it it is a blind study or double blind. Dr Greger is not a dummy. Don´t underestimate him.
    And by the way: Are the doctors connected to Läkare för framtiden dummies?
    David Stenholtz, överläkare onkologi
    (ordförande och kassör)
    Veronica Hedberg, specialistläkare kirurgi (vice ordförande)
    Jakob Rosén, läkarstuderande (sekreterare)
    Sandra Isaksson, specialistläkare anestesi
    Rådgivande kommitté
    Gunnar Johansson, professor i hälsovetenskap
    Peter Nygren, professor i onkologi
    Jerzy Leppert, professor i allmänmedicin
    Yvonne Wettergren, docent i molekylär medicin
    Theo Wikström, allmänläkare
    Karl-Otto Aly, allmänläkare
    Stella Cizinsky, överläkare kardiologi
    Ylva Gefvert, dietist
    Viktor Watz, nutritionist
    Petra Rönnholm, PhD Kemi, spec kemisk riskanalys

    1. I don’t know any of them personally, so I can’t say. Most medical doctors have a poor understanding of scientific method and statistics, which is why pharmaceutical companies find them so easy to fool.

      1. A physician I know well has told me that most physicians only read the abstract of papers and said that the section on limitations ought to be read as well.

    1. Goran, Yes you are correct about Dr Gregor. he is definitely on to something. I liked the book. I read it years ago.However, like so many others he does often cherry pick his studies. Having said that I am a firm believer that vegetable consumption in higher consumption amounts does extend health and life and perhaps reduces cancer risk when other factors are incorporated like no smoking and limited alcohol consumption and good exercising.. But then I know a heavy meat eater who hated vegetables, never ate them never exercised, was obese who lived to 95. I also know a person, a vegetarian who had many many health issues including cancer despite his healthy eating. Dr Gregor claims in the book if I remember correctly to curing an older woman in a wheel chair destined to die by feeding her an all plant diet. I think he said he got her walking again. Interesting. Truly though, what are we supposed to believe these days? Perhaps the truth is somewhere in the middle. Dr Rushworth’s website is my favorite reading these days. I hope he continues with his though provoking topics.

      1. Hi Tony,

        He probably cherry picks in the sense that he chooses his topics, and ,who knows, he may not publish reports that are favorable to non-vegan food. On the other hand, the number of reports, often based on either doubel blind tests, are huge and long observational studies are so many that the multitude in itself is a type of general evidence. Dr Greger´s conlusions are nowadays not so controversial among the medical profession. Many or most doctors agree, I tink. The problem is that people don´t want to change their habits. Many people like to continue to eat hamburgers and other fast food and drink coke or other pops. However, some of these people may, as you pointed out, despite everything, live until they are 100 years. We talk about probablities. What Greger( and others say) is that you increase your probablities for a sound and healthy life if you primarily eat whole plantfood. It may no be a whole lot longer, but you may feel a whole lot better while you live.

      2. Some plant food causes me problems, like jalapenos and sweet potatoes. A diet must be tailored to the individual tastes. If some food makes you nauseous, you ought not eat it because the nausea is your body’s way of telling you that a food is poison to you.

  30. Gosh, I eat meat, a lot of meat, but I don’t eat fast food or drink pop, and all my food is cooked from scratch by me. Humans evolved their big brains only after they started hunting and eating concentrated protein and animal fat. The human body has evolved to eat mostly meat with whatever was growing and edible at the time.

    It is impossible to get all the nutrients necessary for life from a strictly plant-based diet without major supplementation. How many and what kinds of supplements do you take daily? I take D3 and only because I can’t always get out in the sun enough to synthesize my own. I understand that it is harder to make D from the sun as one ages, so that is another consideration for me.

    If you choose to only eat plants, that is perfectly ok with me. Is it ok with you if I keep on with my meat-centered diet?

  31. Hi Pamela,
    I think everyone should make their own decisions on what to eat. if you like to eat meat, that is fine. If you like a lot of hamburgers that is also fine. It is up to each individual on what basis they chose what type of the food to eat. However, after carefulley reading Dr Greger´s “How not to die”, I found it hard to continue eating plenty of animal based food. So if you read this book , you take a risk of changing your diet. I am not convinced that our ancestors primarily ate meat. I dont think anybody knows what homo sapiens actually ate during our 200 000 years of history. And it may have varied in place and in time and among individuals. The argument that you need to eat a lot of animal protein to grow body and brain may not be true. One of our closest relative, the gorilla, is a vegan.
    My guess is that the base food for homo sapiens was whole plant food, but now and then when the hunting was successful people had meat. But that we primarily lived on mammuts, bears or other big animals is for a number of reasons not my guess. As a vegan with plenty of sunshine all year around,my conclusion is that the only thing I am missing in my diet is vitamin B12. So I eat B12 as a supplement. This matter also tells me that our ancestors must have had a certain intake of meat. Exactly how gorillas do with B12, if they need it, I don´t know. But that is perhaps something which someone may have looked into on this forum.
    The only truly negative I have to say about meat, fish or dairy food, is that evertime I eat such food I obstain from what I think is a healthier food, i.e. whole plant food.

    1. Well I think gorilla B12 levels are the least of their problems as they are going extinct as their territory continues to be infringed upon. But that is an interesting observation about them being vegetarians.

      I guess since you brought up fish, I must admit that while my beef/turkey/chicken meat consumption is an occasional treat, I do eat plenty of fish for the Omega 3 and protein benefit. I do worry about the pollution factor however. But Fruits and vegetables have their own contamination risk.
      I do recall Dr. Gregor being against fish consumption as well and telling us “Not to take the bait” which I guess I am doing. I have to wonder if the best answer to all of this takes us right back to eating everything in moderation and not obsessing over any one category of food. Perhaps variety truly is the spice of life . This whole topic just leaves me scratching my head as to what the truth really is.

      1. Göran and tony, poor gorillas and pigs, only one stomach but with long gut designed for sallad (longer than gut of the white ape). But you can always recirculate food and multiply your stomach by eating your poo. Refining the b12 this way… just an idea to cope without supplementing.

        You do not have to make guesses what white ape ate. Go find some carbon isotope 13 studies on antropolgy and you shall be disappointed; white ape was the apex predator, even compared to wolfes.

        Läkare för framtiden links to similar minded u.s. physicians for responsible medicine. You can never know what kind of “seventh day adventists” or similar faith groups are behind these pompous words -my life is too short to get in their bs.

        Läkare links to two eggs bashing studies and one read meat bashing, to begin with and for me, to end with. The italian egg study abstract claims causality “the egg contribution to dietary cholesterol”… even the goodfather of this brain excrement of” dietary cholesterol affecting plasma chol.” admitted he was wrong, if the eater was not a rabbit (cholesterol is found in animal products; rabbits live on sallad). His name was keys, ancel keys.

        Så, this confirms my confirmation bias. There is not so stupid idea in the world, that a couple of Dr and PhD would not support it. I know this from my home country as well, from science papers to blogs to usual care nutritional advice. The last profession I take eating advice is cardiologists; the official crisco trans fats sales organisation AHA and their cousin associations promoting “heart emblem ” in some countries.

        Greger is a good performer and writer, and even better in cherry picking. Plant based evidently works for him. However, I am looking for more robust everything.

        So please check your facts, otherwise you are simply promoting misguided beliefs.

  32. Gorillas have a different digestive system from humans. They spend a lot of the day eating. This is common with other herbivores, ie most of the time is spent eating. Some spend so much time, the day is not long enough, and they eat all night too.

  33. AhNotepad, very true, herbivores do eat continually, when not sleeping they are grazing. I raised horses and cattle for many years and keeping pastures in top condition is a necessary part of animal farming.

  34. Valda, eating carbs to put on fat makes excellent sense. I just hope they also ate meat so they would have enough energy to battle it out in the arena! I question the assertion that all the gladiators were vegan and did find a reference that claims this. I need to do a lot more research but this is a little outside my field of Geology….

  35. Really and Truly, what an extraordinary Doctor you are!
    The whole world believes Sweden is some terrifying killing fields. The sheer depravity of not Locking Down the entire society as every other nation has. Sweden laid low by the dreaded third wave of the covid 19 pandemic…….
    And you write about food….
    What we should eat….
    in the context of the famous 5 a day study….
    ……..quite extraordinary
    ….perhaps it is not that busy in the A&E at Södersjukhus in Stockholm after all…

  36. There are many scientific reports that say the industrialized coked food is much healthier than self cooked food.

    We, my wife and I, eat never self cooked food at home since we are married in 1956.

    My blood pressure is 130/90 since puber age and my wife is approx 115/75 since decades.

    We are still both without medicines for decades, we only use a chlor dioxide preparate of 6 drops a day, we don’t go for a covid vaccine and we both still working at least 8 hours a day, 7 days a week in our publisher/print factory.

    1. I am full of awe for you life riddle solving abilities; your marriage is older than I and blood pressure less than mine; you + wife made it over 80…
      the theme of this writing was fruit vegetables; do they play any role in your longevity?

      1. We eat vegetals a lot but always good cooked and eat fruit for the taste if it.

        When we have an inhouse anniversery we offer all kinds of snacks to our gasts, meat, fried potatos, fish , hering, fruits, cumcomber and carrots and of course big humps of cheescakes.

        We dont go for healthy snacks, we only tell our 7 kids, 13 grand- and 23 grand-grand children never take anti-biotics because they kill the gut bacterias, better take chlordioxide when your body feel itself unpleasant.

        Most do that, I am the only one in the family with a BMI of 31, we all eat by the kilo’s sweets and fats.

        Cancer is not an issue in the family, also not from the cold site.

        When I was 18 at my militairy duty I weight 88 kilo’s (to heavey to become an infanterist, so they make me a truck driver, hahaha) and now, more than 70 years later I weight 99-101 kilo’s and I am still feel myself not older than 40-50.

  37. Interesting article. I’m going off on a bit of a tangent.

    “That’s the problem with observational studies. No matter how hard you try to correct for confounding variables, you’re never going to catch them all. That’s why observational studies cannot generally be used to prove the existence of a cause-and-effect relationship.”

    No, that’s the problem with _all_ studies, including RCTs. RCTs correct for one thing–bias due to personal choice. Observational studies of mentally incompetent persons test just as well as RCTs when compared with some baseline like community statistics of mortality from a disease. You might run some such study on nursing home patients who are mentally incompetent.

    Here are a couple of other papers which look at the value and limitations of RCTs…

    “Understanding and misunderstanding randomized controlled trials”


    Randomization does not balance confounders in any single trial.
    Unbiasedness is of limited practical value compared with precision.
    Asymmetric distributions of treatment effects pose threats to significance testing.
    The best method depends on hypothesis tested, what’s known, and cost of mistakes.
    RCT results can serve science but are weak ground for inferring ‘what works’.

    “Randomized controlled trials (RCTs) have well-known problems with realism or validity (a problem that researchers try to fix using field experiments, but it’s not always possible to have a realistic field experiment either), and cost/ethics/feasibility (which pushes researchers toward smaller experiments in more artificial settings, which in turn can lead to statistical problems)”

    RCTs on hydroxychloroquine cannot be done by physician advocates of HCQ for ethical reasons. That leaves the task to HCQ skeptics who have no reason to conduct such a test. Catch-22

    When an observational study produces a 400% benefit over baseline (80% reduction in hospitalizations), that pretty much overwhelms any problem with confounders. We have several studies of this sort. Only people who are die-hard RCT fundamentalists would ignore such overwhelming evidence. Such people are potentially dangerous neurotics if they treat outpatients.

    Let’s consider looking for evidence against HCQ. What is there?

    1. late treatment studies…and some which claimed to be early treatment, but turned out to not be…they proved that giving an antiviral late didn’t help…no surprise, but the hypothesis that should be tested is whether antivirals work when given early after symptom onset

    2. doctors who tried HCQ and found it didn’t work, so they discontinued it…these were either emergency physicians or ICU doctors and only tried using HCQ long after symptom onset…we can find _no_ family medicine doctors who say that they have tried using HCQ and found it doesn’t work

    What we have here are some pictures of grey waterfowl (ducks, geese), but no black swans.

    Here’s the million dollar question to find out the game being played. Why did the CDC mandate that HCQ be restricted to late treatment?

  38. So red and processed meat doesn’t cause cancer and fruit and veg don’t stop it. That leaves genetic hand-me-downs, ageing and bad luck, unless anyone has any brighter ideas?

  39. Seamus: I would recommend you to read “How not to die” before you draw your conclusions.

  40. dearieme: We have only epidemiological evidence regarding smoking and lung cancer. Cigarettes give about a five-fold greater risk, cigars a slightly increased risk, and pipe smoking no increased risk. I was once, long ago, a pipe-smoker, and found it a pleasant pastime (cigars, too).

    1. Dear Gary,

      Sorry to say so, but pressing heeps of adult spiders to make enough fish baking oil is hard work, so I had to go from arachnid to arachide (groundnut) oil.


  41. You def need to expand your scope of research and educate yourself on the role of Sulforaphane along with a plethora of other biochemical reactions that take place within our bodies when one eats a mostly raw plant based diet versus a carnivorous diet, or even a omnivorous diet.
    Here’s a deep dive into some research by a PHD who specializing in this kinda thing.

    Also your referenced study is extremely flawed in a few ways, doesn’t take into account a few things you mentioned but also doesn’t look at the individuals consumption of all or any animal products, just “meat,” no mention of dairy, eggs, ect… They also don’t look at a group that abstains from consuming any animal products. You also state in one of your previous hyperlinked articles that, “I’m inherently skeptical of the idea that red meat is unhealthy, for the simple reason that it has constituted a major part of our diets for at least the last couple of million years. Evolution generally doesn’t produce animals that become sick from the main components of their diets.” First off that statement is pretty flawed as there’s so much evidence that for millions of years we did not evolve consuming an animal product centrist diet but one that was centered on consuming plants and that the increase of animal products in our diets started around the time of the neolithic revolution. So based on your own logic and the historical data we ate mostly a plant centrist diet for millions of years, versus the drop in the bucket of the last 12k for an animal centrist diet. Of course they consumed animal flesh before the neolithic revolution, but it was much harder/riskier and scarcer to obtain than edible plants, and the fossil record shows that. You probs didn’t have to take too many anthropology course in med school but I could send you a few of my old anthro text books if you’re interested in reading them, and learning about the mainstay of our ancestral diets.
    Also your referenced study only compares a “reduction of red meat consumed” not an elimination of it and all other animal products. Its pretty flawed. Do you think a person who drinks only one 750ml bottle of vodka a day has less a chance of health issues than one who drinks 2 750ml bottles of vodka a day?

    The evidence is overwhelming that a mostly raw plant based whole food diet reduces the risk of a variety of cancers and in many cases can even reverse them when a strict protocol is followed. If you aren’t familiar with who Dr. Max Gerson MD is I suggest you do some research into him and the Gerson Therapy.

    Its clear you have an inherent biases for meat consumption, but as a MD who is influential and projecting their ideas for the world to read you really should look at all the evidence and research out there and at least write in a unbiased manner.
    I dare you to try and commit to a carnivorous/animal product only diet for a month or two and see how that goes for you. Then compare it to a proper well balanced raw whole food plant based diet. You’ll probs see the drastic difference if you do them both for a month or two each. Or you could look at any diagram of the gi track of a lion vs a wolf vs an orangutan. Our gi tracks are those of primates, not carnivores or omnivores, but that of frugivores. Sad to see how keenly aware you are of our global political society yet so clueless on our own biological make up and the biochemistry that occurs within, but that’s what personal biased does it blinds and creates tunnel vision. Please expand your perspective.

    1. We are carnivors for 100%, eating fruit and plants is second choice for our body.

      As human we have a very complex brain and nerve system with a lot of nerves and brain cells close to each other.

      All these cels and nerves must be isolated with fat to avoid short circuits and neuropathy in the brain and body.

      Vegetal oils dont isolate, they are soluble in water, therefor most humans who avoid animal products have all kinds of behavior and fysical problems.

      We follow our staff in the company cantines and during pauses and look what they eat and drink. We sack vegetairians a.s.a.p. by offering them an upgrade to a fellow company.

      We keep health records of our approx. 400 K staff WW and therefore we know why we do that.

      Not only vegetariands destroy themselves, they also make a kind of zombies from their children and normally we employ since 1884 also their children and their children and ….

  42. I tend pretty much to agree with Andy. I doubt that Sebastian has taken very much interest in medical studies regarding fiber rich food. Or in other studies found among serious, evidens based vegetarians, like Dr Greger.
    Here is a link to what our grand-grand forefathers may have eaten
    I must admit that I have not made a deep dive in various studies of human fecal from the last hundred thousand years or so, but I equally doubt that people on this forum have studied reports claiming that we primarily fed ourselves with meat over a hundred thousand years. Which are these reports by the way?
    I hope I can avoid an employment with Peter Sr´s company and be one of the 400K persons in his register. My perception is that it is illegal within EU to keep registers of which of your employees are vegetarian, (until Peter sacks them) which are omnivores and which are LCHFs (people inte the latter group are next for promotions, I guess? 😀. )If not illegat, utterly unsympathetic. Most people including myself prefer to read literature which either supports your belief, or alternatively, in a convincing way explain why you are wrong.
    If Peter Sr really wants to know why he -most likely – is wrong regarding healthiness of food (I am not taking abour taste or the fun of frying or grilling meat) he should read “How not to die. Good luck.

    1. We are a serious company and we feel ourself obligated to be in all aspects a father for our employees and customers.

      There is a lot of evidence in our registers that the quality of the food we offer in the cantines WW is the best for a healthy live, so we offer our Chinese emploiees also western food with a chinese twist and meat and animal fat is a big part of it.

      We try to avoid WW all food produced with vegetal grease because it is poison for brain and nerves.

    2. I looked up Michael Greger. He is a vegan animal rights activist, and was so long before he started studying medicine. He has repeatedly been criticised for misrepresenting scientific data to further a vegan agenda. In other words, he is not even remotely evidence based, and nothing he says about nutrition can be trusted.

      As to the prior comment – no, the human gastrointestinal tract does not even remotely resemble the dietary tracts of herbivores or heavily fruit-eating species. Humans are omnivores, and the human diet has to a very large extent been meat based for at least the last few hundred thousand years before the agricultural revolution. This is well established. Claims to the contrary, such as those found on nutritionfacts, are misinformation.

      1. “I looked up Michael Greger. He is a vegan animal rights activist, and was so long before he started studying medicine. He has repeatedly been criticised for misrepresenting scientific data to further a vegan agenda. In other words, he is not even remotely evidence based, and nothing he says about nutrition can be trusted.”
        maybe. what I think is worth looking at is his talks about factory farming and pandemic risk, for example this:
        unless you know don’t want to believe anything that comes out of his mouth, which I consider very judgmental

  43. Hi Sebastian – wondered what you thought of this paper that looked at fruit and vegetable consumption in smokers over a 8.7 year period to see if they were protected from cancer by a higher fruit and vegetable intake. The study found that it was the variety of fruit and vegetable intake, not the amount that was protective against cancer.

  44. Fruit and vegetables is a rather wide field. I read of benefits of carotenoids and similar properties in the fruit and vegetables like carrots, pumpkin, apricots, mango, tomatoes, and green leafy vegetables. Sugar is also reported as a fuel for cancer so fruit that is high in sugar may be counter-productive for avoiding cancer. Surely it is important to differentiate the food and nutritional properties.

  45. YES! Thank you for sharing the bias of this man. So much of what we find online is biased towards the author’s own agenda and too many do not take the trouble to ask pertinent questions just blindly follow the biased advice.

    Entertainment media is also full of lies and misinformation. Temperance Brennan of Bones was a vegetarian for health reasons, she claimed. And I constantly hear TV characters speak about Global Warming and catastrophic Sea Level change as if it actually was an “Existential” problem. Climate always changes as part of natural cycles and humans can not do anything to alter this simple fact of nature. Carbon Dioxide (CO2) is on of the most important gases in our atmosphere. It is not a pollutant and without it all life on Earth perishes.

  46. You are right. Misinformation is everywhere. But so is bias. You might be showing some yourself. Don’t you think? So what and who are we to believe anymore? What studies? What scientists? What Doctors? Who has an agenda? Are vegetarians healthier than meat eaters? Maybe , maybe not, possibly. Do heavy meat eaters have a proportionally higher lever of heart disease and cancer? Maybe, maybe not, possibly. Do you see the problem? Our biases, money interests, and political agendas are making it impossible to know the truth as fact. The problem is we are flooded with opinions based on biases and sometimes ulterior motives. That is our problem first and foremost.

  47. Sebastian, you might want to consult. T. Colin Campbell, PhD, The Future of Nutrition, which deals with the relationship of nutrition and cancer in an in-depth way. Becoming pretty much the go-to book in cancer. His conclusion: Cancer therapy in general needs to focus on nutrition first. This was all part of his original research published in The China Study, but he has gone a lot further since then.

Leave a Reply

Your email address will not be published. Required fields are marked *