Map of life expectancy at birth from Global Education Project.

Tuesday, February 05, 2013

Why you are wasting your money

A couple of days ago I posted about the uselessness of dietary supplements for most people. Right on cue, some folks writing in JAMA Internal Medicine let us know what people think they are doing when they take the snake oil.

It turns out that 45% of all U.S. adults say they take dietary supplements -- mostly multivitamins -- "to improve overall health," while about 1/3 say they do it "to maintain health." Other prevalent reasons include "to prevent health problems" (20%), for heart health (15%) to "boost immunity" or prevent colds (14.5%), for healthy joints or to prevent arthritis, (12.4%), for enhanced energy, skin health, eye health, mental health, weight loss . . .

Reality check: it is all bullshit. Dietary supplements for the general public do none of the above. These authors are a bit coy about that conclusion. They review evidence, all of which is negative, and then call it mixed or unconvincing. It's convincing, folks. What has happened to you is that people on teevee lied to you, and you fell for it. Unless your doctor has identified a specific condition for which you require a nutritional supplement, there is no reason to take vitamin pills, or iron (which can actually be quite bad for you in excess!), or fish oil, or even calcium. (I delayed mention of the bone health motivation, which 1/4 of people, mostly women, give because some women have been told by their physicians that they should take calcium supplements. I doubt this really applies to 1/4 of all people, or 40% of women, however, and it's somewhat controversial anyway.)

There are a couple of other gray areas or open questions. Some people, those with dark skin in particular, might benefit from vitamin D, although this has been questioned. There is maybe a little bit of a fuzzy zone between some specific foods and dietary supplementation, olive oil, very high fiber foods like bran, there are other examples. Some foods are routinely supplemented -- e.g. folic acid and iron in refined wheat, vitamin D in milk -- which replaces what otherwise might be supplements that might reasonably be indicated for more people. But really folks. Talk to your physician, and unless there's something specific going on, you should probably save your money.

1 comment:

Anonymous said...

The only supplement I found helpful has been Calcium/Magnesium when I've done a lot of exercise and sweat a lot. I understand both calcium and magnesium are important for muscle function and you do loose them when sweating. Being depleted does lead to muscle cramps. The results can be very dramatic: the difference between barely being able to walk and being able to run hard in two days. Other athletes I know have had similar experiences.
Granted the typical person doesn't regularly do 5 hour bike rides in 90 degree weather.
I thought that some people who swear about feeling better with supplements probably had a low level deficiency point and the supplements helped. They then assume because a supplement helped they always need them.