Pill Power

What do you get when you add a supplement to a poor diet?

A good diet

A poor diet plus a supplement

The correct answer, of course, is b. Popping a rainbow of pills can’t make up for a four food-group diet of fat, sugar, salt, and alcohol. But what about adding a supplement to a healthy diet? Dietitians and nutritionists have long maintained that if you eat well, only the municipal sewer system benefits from the extra nutrients in supplements.

That may still be true in many cases, but in recent years, authorities such as the Food and Nutrition Board of the National Academy of Sciences—who bring you guidelines for the RDA, or Recommended Daily Allowance—have recommended supplements for certain groups of people. And many people take a supplement to provide extra insurance that they’re getting what they need.

How do you know if you need a supplement? And if you decide you do, how should you choose it? Use these guidelines to determine whether you need to take supplements, and if so, what to take.

Are you:	What, and what dose, you might need	How much is too much?	Why it might be important
A woman capable of becoming pregnant?	Folic acid 400 micrograms, which equals 0.4 milligrams (mg)	The tolerable upper intake level is 1,000 micrograms per day. With intakes above this level, safety cannot be assured	Adequate folic acid in the first few weeks of pregnancy, before most women know they’re pregnant, helps prevent birth defects such as spina bifida Because only about 50% of pregnancies are planned, it’s recommended that all women who could become pregnant take supplemental folic acid
A strict vegetarian or an adult older than 50?	Vitamin B12 The RDA is 2.4 micrograms (mcg)	For now, no toxic level of vitamin B12 has been identified	Vitamin B12 is important for maintaining red blood cells, and also plays a role in nerve conduction It’s found only in animal foods, so those on strict vegan diets need to use a supplement
Someone who avoids dairy products?	Calcium About 1,000 mg up to age 50; 1,200 mg for those older than 50	The tolerable upper intake level is 2,500 mg per day	Strictly speaking, it’s possible to get enough calcium from a diet that excludes dairy products, but it doesn’t happen often. Even conscientious vegans rarely get more than 500 mg per day, unless they rely on fortified foods (i.e., calcium-fortified orange juice, calcium-fortified soy or rice beverages) If you don’t use dairy products, look carefully at your diet and read nutrition labels. If you’re not getting close to 1,000 mg, consider a supplement
An adult older than 50, or an excessive user of sunscreen?	Vitamin D The RDA for adults younger than 50 is 200 IU. For those aged 51 to 70, it’s 400 IU, and for those 71 and older, it’s 600 IU	The tolerable upper intake level is 2,000 IU per day	More and more studies are pointing out the importance of vitamin D, along with calcium, to keep bones healthy As we age, the amount of vitamin D produced in our skin from sunlight exposure decreases. And sunscreen use effectively prevents any synthesis from the sun. So if you’re older than 50 or if you use sunscreen conscientiously, you’ll have to depend on your diet to provide what you need Vitamin D isn’t found in many foods (good sources include fatty fish such as salmon, and fortified milk or margarine). Fortified milk has about 100 IU per glass, so even avid milk drinkers aren’t likely to get enough if they’re older than 50

How should I choose a supplement?
Here are a few things to look out for if you decide to take a supplement.

For healthy people, a “one-a-day” type multivitamin and mineral supplement is usually recommended instead of taking many “single” supplements. The reason is that nutrients can interact with each other—take an iron supplement and you’ll interfere with zinc, take a zinc supplement and you’ll interfere with copper, and so on. The amounts provided in multiple vitamin and mineral supplements are usually balanced so negative interactions won’t occur. (However, if your doctor has prescribed a “single supplement” to treat a deficiency—e.g., iron for anemia—use it until your deficiency is corrected.)

Calcium is one supplement you may need to take separately if your diet is inadequate. Because relatively large amounts are recommended (about 1,000 mg versus 0.4 mg of folic acid, for example) there just isn’t enough space in most pills to provide more than about 200 mg of calcium—and even those capsules are horse-sized. Calcium-containing antacids such as Tums provide 200–300 mg per tablet. Check the label for the specific amount.

Look for supplements that stay at or below 100% of the daily value (DV). This will be listed on the supplement facts label. Most multivitamin and mineral supplements would provide the 2.4 micrograms of vitamin B12, 400 IU of vitamin D, and 400 micrograms of folic acid recommended for some groups in the chart above.

Choose a reputable brand.

For most nutrients, natural and synthetic forms don’t differ in their effectiveness. Possible exceptions are vitamin E (natural sources are better absorbed) and folic acid and vitamin B12 (synthetic forms are actually absorbed better than natural forms).

Keep all supplements out of reach of children. Accidental overdoses of supplements, especially those containing iron, is a leading cause of fatal poisoning in children.