Vitamin Essentials as We Age
As we age, our dietary requirements change, and we're also more focused
on the diseases and disorders that accompany aging -- conditions that
getting the right nutrients may help to prevent.
By Gina Shaw
WebMD Feature Reviewed By Charlotte Grayson, MD
Mom may have worried about you getting the vitamins you needed when you
were a child (remember those Flintstone's chewables?), but who's
keeping track of your essential vitamins and other nutrients now that
you're getting older? As we age, our dietary requirements change, and
we're also more focused on the diseases and disorders that accompany
aging -- conditions that getting the right nutrients may help to
prevent.
So if you're in your 40s, 50s, or 60s, with things like menopause,
retirement, and creaky bones looming a little larger in your daily life
than they did in your 20s and 30s, what vitamins should you be getting
to make the most of your health? And how should you be getting them --
on your plate or in a handy supplement?
Concentrating on Calcium
Osteo****osis, the bone-thinning disease that most commonly affects
postmenopausal women, results from bones that have lost calcium and
thickness.
"Osteo****osis has reached epidemic pro****tions in the U.S.," says Wendy
Demark-Wahnefried, PhD, RD, associate professor of surgery and director
of the Cancer Prevention, Detection and Control Research Program at
Duke University. "There's a variety of reasons for that: We get too
little calcium in our diets, for one, and we don't get enough
weight-bearing exercise."
If you're over 55 -- and especially if you're a woman -- you're likely
to be at risk for osteo****osis, since 55% of people in this age group
have low bone mass - a thinning of the bones. Men shouldn't ignore
their calcium intake either: 20% of osteo****osis sufferers are male.
"Getting sufficient calcium as we age is critical, especially for women
but also for men," Demark-Wahnefried says.
"Over the age of 50, women have an escalated rate of bone loss," says
Marianne Smith Edge, RD, president of the American Dietetic
Association. "The recommended daily value of calcium jumps to 1,200 mg
daily for women and men over 50. Obviously, first you should focus on
calcium sources within your diet, but calcium supplementation may be
necessary to meet your increased needs and prevent bone loss."
You can get your daily dose of calcium from milk and milk products like
yogurt; fish with bones that are eaten, like canned salmon or sardines;
broccoli; and juices and cereals that are fortified with calcium.
Don't Forget Your D
Vitamin D is calcium's indispensable partner. It's essential for proper
absorption of the calcium you get in your diet. But as we get older,
our ability to synthesize vitamin D in sunlight through our skin
diminishes, says Irwin Rosenberg, MD, professor and dean of the
Friedman School of Nutrition Science and Policy at Tufts University.
"Therefore, our dependence on dietary sources of Vitamin D goes up. We
either have to get it through our food, especially in the winter, or we
have to get it through supplements."
Adults between 50 and 70 should be getting 400 IU (international units,
the measurement usually used on vitamin D labels) of D per day. Once
you're over 70, the recommendation goes up to 600 IU daily. That's not
always easy to get through dietary sources, which are primarily
fortified milk and cereals, liver, and fish. "As we age, D is one of
those vitamins I think we're unlikely to meet our needs for through
diet alone, especially during the winter months," says Rosenberg.
B-12 Basics
Another vitamin that we tend to get less of as we age is B-12, which is
naturally found in animal foods and proteins including meat, eggs,
milk, fish, and poultry, as well as in fortified cereals. Adults of all
ages should get 2.4 micrograms of B-12 daily (pregnant and
breastfeeding women need a little more).
"Research has shown that as we grow older, we tend to make less stomach
acid, and stomach acid is required for the efficient absorption of
vitamin B-12," says Rosenberg. That's because B-12 needs to be
separated from the protein it's bound to in your food before you can
start making use of it." The Institute of Medicine recommends that
adults over 50 get most of their vitamin B-12 from supplements or
fortified food because of impaired B-12 absorption.
So what can B-12 do for you? Quite a lot, if you're concerned about
your memory and cognitive (mental) function. "This vitamin is one of
the im****tant requirements for the maintenance of healthy central
nervous system function [brain and spinal cord]," says Rosenberg. "In
the absence of that vitamin, you're likely to see some decline in
memory and cognitive function as well as other neurologic
abnormalities."
Folate: Not Just for Pregnancy
Almost every pregnant woman knows that a daily dose of folate is
essential for preventing neural tube defects in the developing fetus.
More and more, research is indicating that folate may be just as
im****tant as we age as it is during pregnancy.
"Folic acid helps to metabolize a substance called homocysteine, which
has been clearly associated with the risk of heart disease and stroke,"
says Rosenberg. "If you don't have enough folate, you're likely to have
high homocysteine levels. In recent years, there's been increasing
evidence that these levels are also associated with an increased risk
of cognitive decline and dementia."
Folate may have cancer-fighting properties as well. "Harvard studies
suggest that folate can play an im****tant role in cancer prevention;
the evidence is strongest for colorectal cancer," says Demark. "The
Harvard group has reached the point of suggesting that all adults ought
to be taking folate supplements; other groups are a little less
emphatic about how much we should use folate. There's no real consensus
yet."
The current recommended daily allowance of folate for adults is 400 mcg
per day, raised to 600 mcg if you're pregnant. Many fortified grain
products like pasta, bread, breakfast cereals, and rice contain folate,
as do dark green leafy vegetables like spinach and citrus juices and
fruits.
Vitamin E and Vitamin C
Vitamin E and vitamin C are both powerful antioxidants; studies have
suggested that they may help protect against diseases of aging as
varied as cancer, Alzheimer's, and cataracts. But other studies have
found that increased E and C intake does nothing to prevent these
diseases. "We still don't have really strong evidence from randomized,
controlled trials," says Demark.
"It's been suggested that E and C, as antioxidant nutrients, are
associated with countering the oxidative events that occur with age
that are likely to lead to some of these conditions," says Rosenberg.
"Those effects appear to be well demonstrated in test tubes, but in
some of the clinical studies they're not so well borne out. The jury is
out on whether we need to be supplementing with E and C, but there is
certainly a theoretical basis for wanting to make sure we have an
adequate intake of both of these as we get older."
We get most of our vitamin C (RDA 60 mg for adults) from citrus fruits,
tomatoes, and vegetables like peppers, broccoli, and asparagus. Vitamin
E (RDA 15 mg for adults) is found most commonly in nuts, seeds, and
oils. You can boost your daily dosage of both with fortified cereals.
The (Vitamin) A Team
Found primarily in animal products like liver and eggs, vitamin A has a
number of health-promoting functions particularly im****tant as we get
older: It plays an im****tant role in vision, bone growth, reproduction,
cell division, and cell differentiation; helps to regulate the immune
system; and promotes eyesight.
Can it also help prevent cancer? Researchers had theorized that dietary
vitamin A, in the form of beta-carotene (an antioxidant) might well be
a cancer-fighter, but clinical trials showed just the opposite. The
Carotene and Retinol Efficacy Trial, a lung cancer chemoprevention
trial that provided randomly selected patients with supplements of
beta-carotene and vitamin A, was stopped after researchers discovered
that subjects receiving beta-carotene had a 46% higher risk of dying
from lung cancer than those who did not receive beta-carotene. "We'd
done a lot of studies on beta-carotene in animal models and cell
culture, but we found that when we gave it as a supplement to high-risk
people, their risk of cancer actually increased," says Demark.
So while it's im****tant to get your recommended daily intake of vitamin
A (3,000 IU for men and 2,330 for women) for all its known benefits,
the Institute of Medicine does not recommend beta-carotene supplements
for the general population.
Supplementing Wisely
Of course, you can get too much of a good thing. "There is no
substance, including water, that is safe at any dose," says Rosenberg.
Vitamin D, for example, in too-large doses can lead to side effects
like vomiting and diarrhea, and long-term consequences like kidney
damage. Too much folate can mask the damage being done by a vitamin
B-12 deficiency. Researchers are now investigating evidence that an
excess intake of vitamin A may contribute to osteo****osis, although the
evidence remains inconclusive. Some vitamins, like B-12, don't have
much potential for toxicity in high doses, but it's generally safest to
avoid supplementing with more than 100% of the recommended daily intake
of any vitamin.
"To get the vitamins and other nutrients we need, food should always be
first, and in a balanced diet that includes fruits and vegetables,
whole-grain bread, and cereals -- especially those that are enriched,"
says Smith Edge. "Any decision to supplement ideally should be based on
professional input from a health professional."
Originally published January 2004.
Medically updated Jan. 24, 2005.
SOURCES: Wendy Demark-Wahnefried, PhD, RD, associate professor of
surgery and director, Cancer Prevention, Detection and Control Research
Program, Duke University, Durham, N.C. Marianne Smith Edge, RD,
president, American Dietetic Association, Owensboro, Ky. Irwin
Rosenberg, MD, professor and dean, Friedman School of Nutrition Science
and Policy, Tufts University, Boston. Facts About Dietary Supplements,
NIH Office of Dietary Supplements.
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