Many of us have heard that vitamin D might protect us from COVID, but is there real science behind these claims? Yesterday, I received a very thoughtful message from Dr. Peter Attia on the subject. Dr. Attia cites a randomized controlled trial from Spain that found the following:

patients not treated with vitamin D had 33.3 times the risk of ICU admission compared to patients treated with vitamin D

Vitamin D seems to help with disease severity even if it doesn’t prevent you from catching COVID in the first place. Dr. Attia also provides some good perspective on dosing.

there is virtually no risk to supplementing, say, 5,000 IU/day

I had heard that too much vitamin D could cause kidney stones, but Dr. Attia put those concerns to rest as well:

Too much vitamin D results in hypercalcemia, most commonly due to an overproduction of calcium that can result in kidney stones. However, vitamin D toxicity is not easy to come by: a review article noted that all published cases involved an intake of at least 40,000 IU/day. Even though the Food and Nutrition Board established a conservative dose threshold of 2,000 IU/day, some studies suggest that doses of up to 10,000 IU/day is safe for most adults.

I’ve taken 5,000 IU of Vitamin D for nearly 3 years with no ill effects that I can discern. I based that decision on information from this book that it may boost testosterone levels. I was also informed by this book, which noted that those who live in the north struggle to get sufficient vitamin D in the winter, regardless of the amount of sun exposure. The next step I need to take is to get blood levels of vitamin D taken to confirm the supplementation is getting me into the healthy range.

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