Vitamin D and covid-19, with Dr. David Grimes

David Grimes is a physician in the UK who developed an interest in vitamin D decades ago, after he realized that his darker skinned and less sun exposed patients were especially prone to illness. He’s written multiple books on vitamin D and its central role in immune function. He believes that the main thing predisposing people to severe outcomes when they become infected with covid-19 … Read more

Covid-19: a new look at vitamin D

I’ve written about vitamin D as a potential treatment for covid-19 a couple of times before. In September of 2020 I wrote about a Spanish randomized trial that showed a massive reduction in ICU admissions in hospitalized patients treated with 25-hydroxyvitamin D (a part-activated form of vitamin D). However, that study had some major weaknesses – it was completely unblinded and it was small. In … Read more

Is potassium effective against high blood pressure?

I’ve written previously about how salt (sodium) only marginally raises blood pressure, and how the evidence that there is any benefit to reducing salt intake in the diet is weak at best. Now it’s time to look at that other salt, potassium. While sodium raises blood pressure, potassium supposedly lowers blood pressure, and many people have been given the recommendation to replace their table … Read more

Does omega-3 prevent heart disease?

I have a confession to make. For at least the last ten years, I’ve taken an omega-3 supplement every day. Religiously. Why? I literally have no idea. I don’t remember exactly when or why I started taking it. Presumably I read somewhere that it was a good idea. This was before I started studying medicine, and the decision certainly wasn’t based on any thorough evaluation … Read more

Do vitamin D supplements decrease the risk of depression?

A new study has just been published in JAMA (the Journal of the American Medical Association) that seeks to answer this question definitively. This subject has been somewhat controversial, because observational studies have tended to show a positive effect, while randomised clinical trials have failed to show any effect. Usually you would trust the trial data more than the observational data, but these trials were … Read more

Do vitamin D supplements protect against respiratory infections?

This question has actually been pretty thoroughly researched, so it should be possible to come up with a conclusive answer. A systematic review and meta-analysis of the collected data was published in the British Journal of Medicine in 2017. The review was funded by the National Institutes of Health (NIH). No companies standing to benefit from the sale of vitamin D supplements were involved in … Read more