Doesn't it seem like when it comes to nutrition or more opinions than facts to go around?

Every day we hear new theories about diets, supplements, best foods, my role is to take

them mystery out of good nutrition and look at the science.

Welcome to the Nutrition Facts Podcast.

I'm your host and Dr. Michael Greger.

And I'm here to bring you an evidence-based approach to the best way to live a healthier

longer life.

Today we ask, is it necessary to take vitamin D supplements, vitamin D, which is made

mostly by animals, including ourselves when we're exposed to sunlight, may help us enjoy

a longer life based on randomized controlled studies, which has also been shown to improve

pain from menstrual periods and help prevent respiratory infections?

In our first story, we ask, how much vitamin D should we take?

In my nine-part video series on vitamin D back in 2011, I noted that the relationship between

vitamin D levels and mortality appeared to be a U-shaped curve, meaning low vitamin D levels

were associated with increased mortality, but so were levels that were too high with

your parents' sweet spot around 75 or 80, and animals per liter.

Based on individual studies, why might higher D levels be associated with higher risk?

Well, this was a population study, so you can't be sure which came first.

Maybe the vitamin D led to higher risk, or maybe higher risk led to the vitamin D, meaning

maybe those who weren't doing as well were prescribed vitamin D.

Maybe, because these were Scandinavian studies where they tend to take a lot of cod liver

oil, as the vitamin D supplement, one spoonful of which could exceed the tolerable upper daily

...