To D or Not to (Vitamin) D

There is a link between vitamin D and depression. That seems clear. What that link looks like, though, is still somewhat uncertain. This raises three important issues.
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The year before last you couldn't go more than one winter week without a headline or news anchor telling you that your winter blues may be due to vitamin D deficiency, at which point vitamin manufacturers and sellers everywhere littered your grocery store aisles with vitamin D bottles. We all took loads of vitamin D.

Jump two years forward. A recent study came out saying that vitamin D deficiency does not cause depression, but the reverse. Depression causes vitamin D deficiency. Right.

There is a link between vitamin D and depression. That seems clear. What that link looks like, though, is still somewhat uncertain. This raises three important issues.

1) Medical and science reporting in the news. We all love a nutrition discovery. And a good many of us are eager to improve our health to maximum levels. So, if an uptick in a certain vitamin is all it takes to do that, we will oblige. Biological science is rarely this simple, though.

In the case of vitamin D, we seem to be looking at the difference between causality and correlation. This is a common wall to run into in biology, because it is very hard to get real-time information about a closed system.

This is to say, it is quite difficult to go look inside of your body while you are processing vitamin D and depressive thoughts in order to know, exactly, how one is affecting the other. So, experiments are designed that can hopefully isolate these issues and give some direction about which is the chicken or the egg.

While science is sorting this out, our job as consumers is to exercise some caution about news stories that pin something as complex as mental health on a single vitamin. The wise reaction is to be skeptical but alert and willing to investigate. If the correlation is there, that may be enough for you to act on it, but find out precisely how best to act first.

2) Possible dangers in nutrition -- fat soluble vitamins can reach toxic levels. You do need vitamin D. Sunlight helps you manufacture it. You generally get less sun exposure in the winter. This may not cause your winter blues, but you might look into having your vitamin D levels checked to see if you should get supplements.

The key concept here is getting tested. It takes a lot of vitamin D to reach toxicity, but you can do it, and the consequences are very real. So, find out definitively how much you have in your body before putting more in it.

By contrast, vitamin C, for example, is "water soluble." If you have too much, you will excrete the excess in your urine. (Much too much vitamin C will even give you diarrhea.) Your body has an easy way to get rid of excess C.

Vitamins A, D, E and K are all "fat-soluble." They are not as easily eliminated and therefore all have toxic levels. Get tested before ingesting large amounts of any of these.

3) The complexity of mental health. The brain and its processes are about as complicated as science gets. It will be a very rare thing indeed to find one thing -- a vitamin, a pill, a surgery -- that can explain something as multifaceted as depression, anxiety or even happiness. If it sounds too good to be true, it probably is.

So what are you to do with conflicting data? Understand that science is a discovery process. It is terrifically useful and gets better every day at explaining our world and our bodies. But the internet and TV have made us witnesses to that discovery process, which means we sometimes get data in a bit of a raw form.

When you see these conflicts, the safe bet is to assume there is a correlation at play rather than causality. But then investigate what that correlation may mean for your health.

A greater understanding for the discovery aspect of science -- where it gets to update itself to greater levels of accuracy on an ongoing basis -- may empower you to take medical certainty about things like how much salt you should eat with a grain of salt.

A greater understanding of your own health will help you decide these things wisely.

For more by Amy M. FitzPatrick, MS, L.Ac., click here.

For more on mental health, click here.