Should you take a multivitamin? And which one?
For: Wellness Made Easy, June 2002
As more and more Americans take multivitamin/mineral pills, marketing hype and consumer confusion have increased. Of course, it's possible—and usually preferable—to get your nutrients from a healthy, balanced diet (vitamin E is an exception, see below). But surveys consistently show that large groups of Americans tend to fall short in a variety of key vitamins and minerals.
Here are some reasons to consider taking a multi:
• Many, if not most, people over 60 don't get the nutrients they need, for a variety of reasons (see Wellness Letter, February 1998). For instance, aging itself may make it more difficult to absorb and utilize certain nutrients. The major problem nutrients for older people are vitamins D, C, B-6, and B-12, and folic acid, as well as minerals such as zinc.• All women who might become pregnant—that is 70 million Americans—should take 400 IU of folic acid daily. This B vitamin helps prevent neural tube birth defects that affect thousands of babies every year in the U.S. The surest way to get that much folic acid is with a multi. The folic acid in supplements (and in fortified grain products) is better absorbed by the body than the vitamin found naturally in food.
• Many premenopausal women do not consume enough iron. The amount found in most basic multivitamins can help prevent a decline in women's iron stores.
• Vegans, who consume no animal products, may not be consuming enough vitamin B-12, zinc, or calcium.
• People on low-calorie diets, as well as heavy drinkers, are likely to have a shortfall of vitamins and minerals.
• Poor people tend to have the poorest diets and would thus benefit from a multivitamin.
• Anyone else not eating a balanced diet (at least five fruits and vegetables a day, as well as whole grains, low-fat dairy, and small servings of lean meat, poultry, or fish) may not be getting enough folic acid, B-6, and B-12. In recent years evidence has grown about the role these B vitamins play in lowering homocysteine levels in the blood and thus reducing the risk of heart disease. Folic acid may also help prevent cervical and colon cancer. Most multivitamin supplements have 100% of the daily recommended intake of these Bs.
• Pregnant women should probably take a multi, but should discuss their nutritional needs with their doctors.
Not everyone needs a multivitamin/mineral. But the above list includes more than half of all Americans, for whom a basic multi makes sense.
Your buying guide
The labels on supplements list the amount of each nutrient and the percentage of the "Daily Value" (the FDA's reference values used on foods and supplements) that represents. Here's what you need to know:
• A multivitamin/mineral need not cost more than a few cents a day. Most store-brand and generic products are fine.• Look for "USP" on the label. This means that the product meets the standards of the U.S. Pharmacopeia, including one for disintegration, and has been tested under controlled laboratory conditions. Most brand-name vitamins aren't labeled USP, because the manufacturers either don't want to do the tests, or prefer to guarantee the products via the brand names. Generic or store brands are more often labeled USP, and are cheaper anyway.
• Most important: Look for 100% of the Daily Value of the following vitamins: A (some from beta carotene), B1 (thiamin), B2 (riboflavin), B3 (niacin), B-6, B-12, folic acid, and D.
• Look for up to 100% of the Daily Value of the following minerals: copper, zinc, magnesium, iron, iodine, selenium (not more than 200 mcg), and chromium (not more than 200 mcg). Most multis also contain tiny amounts of trace minerals such as boron, manganese, and molybdenum.
• Least important: Most contain some potassium, phosphorus, pantothenic acid, and biotin, but you can ignore these since they are easily found in food.
• Most multis contain 100%, or even 200%, of the Daily Value of vitamins C and E, but this is not enough to provide the full antioxidant effects and other potential benefits of these vitamins. We recommend that everyone consume 200 to 800 IU of E and 250 to 500 milligrams of C a day.You'll definitely need a pill to get that much E (that's the amount in a pound or two of sunflower seeds or two quarts of corn oil). And unless you eat lots of broccoli, peppers, kiwifruit, and oranges, you'll probably need a pill to get that much C.
• Calcium is bulky, so a multi will contain only a small amount of it. Unless you consume enough dairy products, broccoli, and salmon or sardines (with bones), you should take separate calcium supplements. Everyone needs at least 1,000 milligrams of calcium a day, from food and/or supplements. Women over 50 and men over 65 need 1,200 to 1,500 milligrams a day.
• Premenopausal women should look for 100% of the Daily Value of iron. In contrast, people with the genetic disorder hemochromatosis (who absorb too much iron) should avoid supplemental iron.
• More than 100% of the Daily Value isn't necessarily better. Up to 200% of the B vitamins is okay, but large doses of copper, for instance, can interfere with the absorption of zinc, and vice versa. And large doses of vitamin A or D can be dangerous.
• Take your multi with food. If it contains iron, don't take a calcium supplement at the same time, since iron interferes with calcium absorption.
• Words you don't need to see listed on the bottle: "stress formula," "sugar-free," "starch-free," "natural," "super-potency," "senior formula," "slow-release," enzymes, hormones, amino acids, PABA, or ginseng and other herbs. These serve no purpose and add to the price.
But keep in mind: Even if you take a multi, you still need to have a balanced, healthy diet. These pills are not magic bullets. Foods—particularly fruits, vegetables, and whole grains—provide fiber as well as countless beneficial phytochemicals not found in any pill.
UC Berkeley Wellness Letter, July 1999
