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| Fitness Tip #1 |
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| Each fitness tip contains powerful strategies to help
you achieve your health and fitness goals. |
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Eating for Vitamins: Do You Need Supplements?
Nancy Clark, MS, RD
Confusion abounds about vitamin supplements for active people:
Should you take them? Which ones are best? When should you
take them? Will they enhance sports performance? Here is
information to help clear up any confusion and show you
how to meet your vitamin needs without wasting money on
unnecessary supplements.
What Are Vitamins?
Vitamins are food substances that assist essential biochemical
reactions within your body. There are 13 known vitamins:
• Four fat-soluble vitamins-- A, D, E, and K--
which your body stores in amounts large enough to last for
months; and
• Nine water-soluble vitamins: C
(ascorbic acid), and the B-complex vitamins--B1 (thiamin),
B2 (riboflavin), B6 (pyridoxine), B12, niacin, folic acid,
biotin, and pantothenic acid. Your body is able to store
enough of these vitamins to last for several weeks.
The Best Source: Food
Most people can get an adequate supply of vitamins from
a 1,200- to 1,500-calorie-per-day diet consisting of a variety
of wholesome foods. For athletes who get 2,500 to 4,000
or more calories a day, the task is relatively simple. For
example, a thirsty teenage athlete who needs over 4,000
calories per day can easily get almost three times the recommended
60 milligrams (mg) of vitamin C from 16 ounces of orange
juice. And that's just from one beverage there's even more
in food.
The trick to getting enough vitamins is to choose foods
that are nutritional powerhouses. Fresh fruits and vegetables
are the ultimate natural vitamin sources. Unlike supplements,
fruits and vegetables offer far more than just the vitamins--they
also contain fiber and various other compounds that are
important to health. If you eat a balanced diet you'll get
these important nutrients and you won't need vitamin supplements
to correct nutritional deficiencies. Unfortunately, most
Americans eat fewer than the recommended 5 servings of fruits
and vegetables per day.
Who Needs Supplements?
To date, no evidence suggests that extra vitamins will enhance
athletic performance, increase strength or endurance, increase
energy, or build muscles. Certainly, a vitamin deficiency
can impair performance, but deficiencies are generally related
to conditions such as anorexia, unhealthy weight loss, malabsorption,
or poor eating habits. Deficiencies are unlikely in active
people with robust appetites.
For very active people, vitamin E is a possible exception
to the "eat your vitamins" rule, because even
though a hungry athlete eats a lot of food, diet is unlikely
to provide large enough amounts of this nutrient. Vitamin
E is an antioxidant, which means it helps fight damage to
body cells. It may help reduce the tissue damage associated
with intense exercise. Researchers are still trying to determine
if extra vitamin E offers benefits for athletes.
Although outright vitamin deficiencies are rare, some people
are at risk for marginal vitamin shortages. Supplements
can be appropriate for:
• Dieters. People who
restrict their food intake to less than 1,200 calories per
day may miss out on important nutrients. This also includes
people who eat only a few types of foods or have anorexia.
• People who are lactose intolerant. Active people
who are unable to digest the milk sugar found in dairy foods
commonly eliminate milk and other dairy foods from their
diets. Lack of dairy foods can result in a deficiency of
riboflavin (as well as calcium, a mineral).
•
People who have food allergies. If you can't eat certain
types of foods, such as wheat or fruit, you may have a harder
time getting certain nutrients.
• Vegans. Active
people who eat no animal foods may become deficient in vitamins
B12, D, and riboflavin (as well as the minerals iron and
zinc).
• Women who might become pregnant or are
already pregnant. Before becoming pregnant, women should
eat a diet that is rich in folic acid. This means eating
generous amounts of spinach, broccoli, oranges, and lentils,
and also taking 400 micrograms of folic acid daily. This
vitamin, when taken at the time of conception, helps to
prevent neurologic problems in the fetus, and can reduce
certain types of birth defects.
• Active people
who are at risk for heart disease and cancer. Although the
evidence is preliminary and controversial, 100 to 400 international
units (IUs) of vitamin E is unlikely to cause harm, and
its antioxidant properties may be beneficial (1).
Some people simply like to take a multiple vitamin pill
for health insurance. This is practical as long as the pill
just supplements healthy eating. People who take handfuls
of pills in hopes of finding a cure-all are likely to feel
better if they improve their diet instead. No amount of
pills can compensate for a deficient diet.
Choosing Supplements
Prompted by persuasive advertising, many active people have
developed a big appetite for vitamin pills. Here are some
tips to help you sort through the hype and get the most
from a vitamin supplement:
• Choose a multiple
vitamin with approximately 100% of the daily values (or
DV--formerly known as the recommended dietary allowance,
or USRDA); this will provide a safe and adequate balance
of vitamins. It is highly unlikely that you need more. "High
potency" vitamins enhance manufacturers' profits more
than they enhance your health.
• Because a person
is rarely deficient in just one vitamin, a multiple vitamin
is preferable to large doses of single vitamins (unless
the vitamin is prescribed by a physician for a medical condition).
• Claims about "natural" vitamins in
pills tend to be false, given the prohibitive costs of extracting
vitamins from natural sources. In reality, almost all vitamins
in supplements are synthetic. Besides, naturally occurring
and manufactured vitamins have identical chemical structures.
The one exception is vitamin E, which, in its natural form,
is slightly better absorbed and used. But for long-term
use--and people generally take vitamin E for chronic conditions--the
price of natural vitamin E may be too high to justify the
slight advantage.
• Store brands are likely to
be identical to name brands, only much lower in price. Ten
dollars a month is more than enough for vitamin supplements.
• The label "stress tablets" is a marketing
ploy. There is little evidence that the stresses of daily
living deplete the body of vitamins. Evidence about the
connection between stress and vitamin depletion pertains
mostly to physical stress from surgery, burns, or fever,
not psychological stress.
• Supplements made
without sugar or starch offer no advantages.
•
Taking beta-carotene is better than taking vitamin A, which
is described on labels as palmitate, acetate, or fish oil.
Beta-carotene, from which the body makes vitamin A, acts
as an antioxidant and is safer than vitamin A. If taken
for several months in doses greater than 25,000 IUs per
day, vitamin A can be toxic.
• Taking a supplement
with or after meals optimizes absorption. Vitamins tend
to work together with other nutrients.
Many active people are already getting abundant vitamins
from fortified foods such as breakfast cereals, energy bars,
sports drinks, and snack foods. You don't even need to take
a vitamin pill if, for example, you eat a big bowl of a
cereal fortified with 100% of the DVs for breakfast or as
a snack.
Invest in Nutrition
If you don't know whether you're getting adequate vitamins
in your food, consult with a registered dietitian who specializes
in sports nutrition. He or she can evaluate your diet and
teach you how to optimize your food intake. To find a local
sports nutritionist, you can call the American Dietetic
Association's referral network (800-366-1655). Investing
in personalized nutrition education is better than buying
myriad mysterious pills.
Reference
1. Greenberg ER, Sporn MB: Antioxidant vitamins, cancer,
and cardiovascular disease. N Engl J Med 1996;334(18):1189-1190
Remember: You, your physician, and your nutritionist need
to work together to discuss nutrition concerns. The above
information is not intended as a substitute for appropriate
medical treatment.
Ms Clark is director of Nutrition Services at SportsMedicine
Brookline in the Boston area. She is a fellow of the American
College of Sports Medicine, a fellow of the American Dietetic
Association, and a member of its practice group, Sports
and Cardiovascular Nutritionists (SCAN). |
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