August 31, 2011

Good Advice on Multivitamins in Particular and Supplements in General

I subscribe to several health newsletters, but the one that probably gives me the most immediately useful info is Nutrition Action, published by the nonprofit Center for Science in the Public Interest. (More on this newsletter at the end of this posting.)

The current (September) issue is a good example. The cover story is entitled "What you need to know about multivitamins." Written by David Schardt, it's full of good advice.

While study after study finds little or no long-lasting benefit from taking a daily multivitamin, Schardt says, "a little insurance against something that may be missing from your diet couldn't hurt." But he advises not to waste your money on a multivitamin that has more than you need or should get.

Even if multivitamins won't prolong your life or keep you from getting sick, "they can still fill in the gaps if you get too little vitamins and minerals from your food," says Susan Roberts, professor of nutrition at Tufts University.

Nutrients Often in Short Supply
Last year the U.S. Dietary Guidelines Advisory Committee listed seven nutrients that many Americans do not get in sufficient quantity. Two of them -- fiber and potassium -- aren't available in significant amounts from multivitamins, Schardt says. Here are the other five:
  • Vitamin D.  A majority of us don't get enough from our food, and the recommended use of sun screens may keep us from getting enough from sunlight.
  • Folic acid.  This nutrient helps protect against birth defects that can occur before a woman knows she is pregnant. About one in five women of child-bearing age don't get enough folic acid.
  • Vitamin B-12.  Adults over 50 have too little stomach acid to absorb the B-12 that naturally occurs in foods and therefore should look to fortified foods or supplements.
  • Iron.  About 15 percent of women 50 and younger are iron deficient.
  • Calcium.  Adults need 1,000 to 1,200 milligrams of calcium a day, and most of us don't get that much from food. Multivitamins typically have 100 to 200mg, which can help.
Three Risky Nutrients
For most nutrients, there's no downside to taking a multivitamin every day, Schardt says, But researchers are concerned about the safety of these three nutrients:

Folic acid.  Folate is a B vitamin that helps cells divide and grow. That's why too little can cause anemia and birth defects. But too much may spur the growth of precancerous colorectal adenomas, according to Joel Mason, director of Tuft University's Vitamin and Carcinogenesis Laboratory. A third to a half of Americans over age 50 have colorectal adenomas. But the danger of getting to much folate probably only exists if you take more than 800 to 1,000mcg a day from fortified foods or supplements. Most multivitamins contain 400mcg, and you probably get 250mcg from fortified foods, for a total of 650 mcg, which is probably safe, Mason says. 

Here's CSPI's advice:
If you take a multivitamin, avoid cereals, energy bars, or other foods or supplements that contain  400mcg of folic acid per serving. (If they have that much, the Nutrition Facts panel on the label will list the amount of folic acid as "100% DV."
And if you're still nervous about excess folic acid (and are not at risk of becoming pregnant), take your multivitamin every other day. 
Selenium.  I took selenium for awhile years ago for my prostate cancer based on studies showing that it could prevent some tumors in laboratory animals. But CSPI notes that "its results in people has been disappointing." And it may increase the risk of being diagnosed with diabetes. CSPI's advice: "don't take a multivitamin with more than 100mcg of selenium.

Vitamin A.  In 2002, Harvard researchers found that women who consumed a lot of Vitamin A from food and supplements had an increased risk of hip fractures. But subsequent studies have cast doubt on this finding. Here's what Sarah Morgan, director of the Osteoporosis Prevention and Treatment Clinic at the University of Alabama, concludes based on these studies:
We are finding that vitamin A is not as big a concern as earlier studies suggested. We tell our patients not to get more than 100% of the Daily Value for vitamin A from supplements, and to make sure that at least some of their vitamin A is in the form of beta carotene, which gives people some protection.
So What Multivitamin Should I Buy?
"Multivitamins vary widely in quality," says Ted Cooperman of ConsumerLab.com, a website that analyzes dietary supplements. They conducted a study recently of popular multivitamins, results of which only subscribers ($33 a year) can see. I subscribe and just checked the website. From the list of approved multivitamins, I checked only those marketed for seniors or mature adults.  And from those, I picked out three of the more popular. All three meet the CSPI recommendations on what a multivitamin should contain.

Here they are and their cost per day:
  • Centrium Silver (11 cents)
  • CVS Spectravite Senior (9 cents)
  • Costco's Kirkland Signature Mature for Adults 50+  (3 cents)
Other Advice from CSPI
  • Men: Your multi should have no more than 200mg of calcium.
  • Premenopausal Women: Your multi should have 18mg of iron.
About CSPI
The Center for Science in the Public Interest, founded in 1921, is an independent nonprofit consumer health group that advocates honest food labeling and advertising, and safer and more nutritious foods. It accepts no government or industry funding. It is supported by foundation grants and subscribers to The Nutrition Action Healthletter, which accepts no advertising.

2 comments:

AccuNurse said...

Great article! Thanks for sharing this info. 

Dafpax said...

Did it say anything about the difference between a liquid multi-vitamin and a pill?  I've been told that the bulk of a pill passes through your system without being injested properly.  One friend of mine takes his pill and smashes it up and lets it dissolve under his tongue.  I went with GNC's liquid multivitamin (probably a little pricier per dose)

UA-20519487-1