Dr. Andrew Weil, founder of the University of Arizona's Program in Integrative Medicine, recommends the following supplements as part of a program for healthy aging. They provide important nutrients, prevent inflammation, bolster your immune system, support your liver, and increase your energy levels.

Dr. Weil recommends selecting one that fits the following criteria:

Does not contain preformed vitamin A, often indicated as retinol.

Gives you a mixture of carotenoids (lutein, lycopene, as well as other members of this family of antioxidant pigments), not just beta-carotene.

Provides vitamin E as mixed, natural tocopherols (or mixed tocotrienols), not just as d-alpha-tocopherol or, worse, synthetic dl-alpha-tocopherol.

Provides 50 milligrams each of most B vitamins, except folic acid (at least 400 mcg) and vitamin B12 (at least 50 mcg).

Does not contain much more than 200 milligrams of vitamin C, which is all the human body can use in a day.

Provides at least 400 IU of vitamin D (but you'll need to take additional vitamin D to get Dr. Weil's recommended daily intake of 1,000 IU).

Does not contain iron, unless you are menstruating, pregnant, or have documented iron-deficiency anemia.

Contains no more than 200 mcg of selenium, a key antioxidant mineral.

Provides some calcium, preferably as calcium citrate (although most women and some men need to take additional calcium to maintain bone health).

In addition to the antioxidants you get from food (such as fruits, vegetables, tea, and olive oil) and from your multivitamin, consider a few well-researched natural products that provide additional antioxidant support.

Coenzyme Q10 increases oxygen use at the cellular level, improves the function of heart-muscle cells, and boosts the capacity for aerobic exercise. The main problem with it is its bioavailability -- how much gets into your system and used. New softgel and emulsified forms are much better than other forms in this respect but still need to be taken with a meal that contains fat. Recommendation: 60 milligrams a day of CoQ10.

Grape-seed extract helps prevent and treat age-related diseases, including cardiovascular disease, cataracts, and macular degeneration. If you're generally healthy, Dr. Weil suggest 100 milligrams a day.

Alpha-lipoic acid (with or without acetyl-l-carnitine) decreases insulin resistance while augmenting the body's antioxidant defenses. If you have any degree of metabolic syndrome (low HDL cholesterol, high serum triglycerides, a tendency to gain weight in the abdomen, a tendency toward high blood pressure) or have a personal or family history of obesity or type 2 diabetes, consider taking ALA. Start with 100 milligrams a day; take up to 400 milligrams a day.

Abnormal inflammation is a common root of many chronic diseases, including autoimmune conditions such as type 1 diabetes and rheumatoid arthritis. It can be a component of other diseases such as multiple sclerosis and inflammatory bowel disease. Besides eating an anti-inflammatory diet, you might want to give your body additional support with a few key anti-inflammatory herbs and over-the-counter drugs.

Ginger and turmeric can, of course, be added to food but are most effective taken in supplement form. You can take a starting dose of 1 gram a day of ginger (after a meal) and 1 gram of whole extract of turmeric (rather than a preparation of curcumin, only one of the spice's active components). Many people find their musculo-skeletal and other ailments disappeared after using ginger, while extract of turmeric may have a preventive effect against Alzheimer's disease and may also reduce the risk of cancer.

Aspirin offers many health benefits, including its influence on the same hormones that mediate inflammation -- an influence that offers a reduction of cancer risk as well. Aspirin can cause irritation and bleeding of the stomach and lower GI tract, but in general, the health benefits of low-dose aspirin regimens outweigh the risks. Dr. Weil takes two baby aspirins a day, the equivalent of half an adult tablet.

These include ibuprofen (sold as Motrin and Advil) and other products. Ibuprofen reduces the risk of Alzheimer's disease but, like aspirin, can cause GI irritation and bleeding. Dr. Weil recommends its daily use only for those with symptomatic inflammation (such as arthritis) or a significant family history of Alzheimer's.

Our immune systems weaken as we age, making us more susceptible to infections and cancer and slowing our healing responses. And our immune systems are under constant assault from toxins in the environment, both natural and man-made. It's worth experimenting with natural products that enhance immune function.

Astragalus has a long history in Chinese medicine, where it's used to ward off colds and flu. Dr. Weil often recommends it to people who "get whatever's going around," to cancer patients undergoing chemotherapy, to those with immune deficiencies, and to everyone during flu season. Look for standardized extracts in capsules and take them as the label directs.

These include edible species such as shiitake, maitake, and oyster mushrooms as well as purely medicinal ones like reishi that are too bitter and woody to be used as food. Dr. Weil believes it's better to take a number of these mushrooms together, since their effects are synergistic. Liquid, powder, and encapsulated forms are available, some providing extracts of seven or more species.

Protection from toxins begins with minimizing your exposure to them -- drinking purified water, eating lower on the food chain and pesticide-free food when possible, not ingesting toxic substances, not smoking, and not living near hazardous sites such as toxic-waste dumps. You also can help support the liver, the organ responsible for processing toxins.

Milk thistle is an herbal remedy with an excellent reputation for protecting and enhancing liver function. Anyone who drinks alcohol heavily, who takes drugs or medications that can harm the liver, who has abnormal liver function for any reason, or who works with solvents or has a history of toxic exposures should take milk thistle. Look for extracts standardized to 70 percent to 80 percent silymarin, and take two capsules twice a day or as the label directs.

A common complaint among older people is waning energy. Tonic herbs and mushrooms are especially helpful in addressing this issue. Experiment with these favorites to find out which ones work best for you, trying each one daily for two months. If you like the effects, you can stay on these herbs indefinitely, perhaps giving yourself occasional breaks -- say, two or three weeks off every four months.

Asian ginseng is esteemed as a sexual energizer for men. American ginseng (Panax quinquefolius) is valued for its stress-protective properties. Buy products standardized for ginsenoside content, follow dosage recommendations, and don't expect to notice results until after six to eight weeks of regular use.

Formerly called Siberian ginseng, eleuthero ginseng has a long history of use by athletes, military personnel, and cosmonauts of the former Soviet Union due to its energy-enhancing properties. Buy products standardized for eleutheroside content, follow dosage recommendations, and wait six to eight weeks to evaluate the effect.

Arctic root, or rhodiola, can enhance endurance, reduce harmful effects of stress, and improve mood and memory. It may increase sexual energy as well. Buy products standardized to 3 percent rosavins and 1 percent salidroside, and follow dosage recommendations.

Cordyceps is a mushroom long used in China as an energizing tonic for people debilitated by age, illness, or injury. Here, you'll find extracts of cordyceps in either liquid or capsule form.