This latest episode of the Barbell Medicine Podcast features Dr. Austin Baraki sharing his current understanding about the accumulated research on the relationships between vitamin D and health and the value (or not) of vitamin D supplementation. And if I were to summarize his main point, it is that reduced vitamin D is associated with many diseases states, but there’s little data suggesting that increasing vitamin D improves those disease states. Basically, it’s a practical lesson in the old Stats 101 chestnut “correlation does not necessarily mean causation.”
Throughout the conversation, Dr. Baraki talks about the research and the limits of the research which fails to show that healthy people have significantly better outcomes for supplementing with vitamin D. He also says that unless there is a disease state that reduces vitamin D absorption or availability in the body, supplementation does not seem to improve health outcomes.
Many times in these conversations with experts there’s advice to us lay-folk on how to interpret data, and I think that’s not really a reasonable expectation. I read, listen and think about this stuff all the time for fun, and I’m not reading studies. I don’t feel qualified. Instead, I seek information from the best interpreters of data out there that I can find and put my trust them to do their jobs. Over time, I have gotten better at learning who to trust. But as they point out, ten years ago the general consensus was that most people have insufficient vitamin D and would benefit from supplementation. But I don’t think it’s reasonable to expect an everyday human to keep up as that recommendation has evolved in the last decade.
Unfortunately, my experience of medical doctors suggests it may not be reasonable to expect all of them to keep up on such details, either. The same doctor who suggested I cut out carbs to treat my autoimmune diseases also ordered all sorts of tests, including vitamin D. I questioned her about all the tests at the time–are these appropriate and necessary for the condition I was there to have treated? I was generally aware that we have a culture of increased, potentially unnecessary screening, but I didn’t have a particular reason to question the vitamin D test except that I already supplemented with vitamin D. And now, in this podcast, I hear another reason, as Dr. Baraki said that many autoimmune diseases are associated with decreased amounts of vitamin D, and I have multiple autoimmune conditions. It sounds like it is reasonable to expect that my vitamin D levels may be lower sometimes, but there’s little reason to assume supplementation would improve my conditions.
So now what? My pill box right now includes a daily dose of 2000 IU(1) of vitamin D. I began taking it because I live in a state with one of the greyest skies in the US (although climate change may be changing our status), and I’m certain I don’t get either enough daily sunlight nor enough fatty fish or supplemented dairy to get the recommended amount. However, I acknowledge it’s a “reassurance” supplement for me. There’s no evidence it’s making anything better, although I feel that way about nearly all supplementation! My other daily supplements include chaste tree/vitex (an ancient remedy for “female problems” that has decreased my PMS-related migraine symptoms) and creatine monohydrate. I also take 4-6 medications a day. The day to day evidence that these are doing what I want them to do can be pretty slim. And when we add in the known confounders of anecdotal data like the placebo effect, I’m somewhat having to take it on faith.
And I feel like that’s what each of us are likely doing when we take on a preventative supplement like vitamin D. Of course, science is a great tool for helping us weed through the anecdata and to give it context. I’m open to the possibility that I could stop taking vitamin D and have no ill effects. I will keep my ear open for further conversations on the topic, and in time, maybe I won’t replace the bottle when I run out.
Do you supplement with vitamin D? How do you decide which preventative supplements to take and which aren’t worth the bother? I’d love to hear from you! Please leave a comment below or find and follow the conversation over at Progressive Strength on Facebook!
(1) I will happily acknowledge that this amount is excessive. If I recall correctly, I was looking to purchase 1000IU last time I was low, and they were out of stock, so I bought the next-smallest amount. I don’t believe there’s much risk of toxicity at this amount, especially since I don’t live off of fatty fish and egg yolks, but next time around, I will look for a smaller dosage.