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
Reviewed By Charlotte Grayson
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
"Osteoporosis has reached epidemic proportions 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 osteoporosis, 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 osteoporosis 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.
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 important 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 important 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 important 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 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 important as we get older: It plays an important 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 important 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.
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 osteoporosis, 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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