Why should I take a vitamin for my health?
In a special three-part series, the “Today” show tries to clear up some of the confusion surrounding vitamins. We know they're important to our health, but what's the best way to get vitamins and which ones do we really need? Dr. Andrew Weil, author and director of the program in integrative medicine at the University of Arizona in Tucson, was invited on the “Today” show to navigate through the nutrition maze.
When it comes to obtaining the micronutrients your body needs, your best possible source is food, especially fruits and vegetables. But circumstances may prevent you from eating optimally every day. The main reason I take supplements is for insurance against gaps in my diet. Also, researchers are finding that some important vitamins (D and E particularly) and minerals are protective against disease in amounts that may be difficult to obtain through diet alone, no matter how conscientious you are. This is another reason I take supplements faithfully and encourage my patients to do so as well.
I recommend a comprehensive antioxidant and multivitamin for women and men as the basic foundation for nutritional insurance. My recommended daily antioxidant regimen includes 200 mg of vitamin C, 400 to 800 IU of natural vitamin E (or 80 mg of mixed tocopherols and tocotrienols), 200 mcg of selenium, 15,000 to 20,000 IU of mixed carotenoids, and 30 to 100 mg of coenzyme Q10.
Supplementation to cover dietary gaps is only one aspect of optimum health, which also includes the following lifestyle approaches:
For optimum health, I recommend walking every day.
Eat a diet rich in antioxidants and omega-3 fatty acids
Vegetables and fruits are the best sources of antioxidants, although tea and dark chocolate contribute as well. Cold-water fish, freshly ground flaxseed and walnuts all provide omega-3 fatty acids.
Do not smoke and avoid secondhand smoke
Smoking is the single greatest cause of preventable major illness. The best defense against the harmful effects of tobacco is to never use it.
Practice breathing exercises and explore other relaxation techniques such as yoga and meditation to find ones that work for you.
Question and answer
Q. What is the optimum time of day to take vitamin and mineral supplements? Are there certain foods that interfere with absorption?
A. There are no rules about the best time of day to take supplements. My advice is to take them when they agree with you most. Many people find taking pills of any kind as part of a morning routine makes it easier to remember, so taking them with breakfast is a popular option. Vitamin and mineral supplements can cause nausea, heartburn, and other gastric disturbances, especially when taken on an empty stomach. For best absorption and the least irritation to the stomach, I generally suggest taking your supplements with a meal containing fat. This is particularly important for the fat-soluble vitamins (A, D and E). Experiment with taking your supplements with lunch or dinner if they cause you problems with breakfast.
Foods — or an empty stomach — can also interfere with absorption of some vitamins and minerals. With calcium, for instance, you need enough stomach acid to assimilate it, so you’re better off taking it after you’ve eaten, because food in the stomach stimulates acid secretion. Tannins in tea can block absorption of iron, while vitamin C enhances iron absorption, as do fermented soy foods such as miso and the lactic acid in both yogurt and sauerkraut. Foods that interfere with iron absorption include caffeinated beverages, eggs, milk and bran. (You shouldn’t be taking iron supplements or a multivitamin/mineral containing iron unless you’re a premenopausal woman with a heavy menstrual flow or your doctor has recommended an iron supplement because a test has shown you’re iron deficient). In addition to these foods, excess consumption of alcohol can interfere with absorption of several vitamins and minerals.
If you’re eating a healthy, balanced diet, however, you have no reason to worry about foods interfering with the absorption of your vitamin and mineral supplements.
Q. I cannot take a multivitamin or any supplements. I become nauseated and, sometimes, vomit — even if I take it with a meal. Any suggestions?
A. I’ve come across a number of accounts like yours, but without exception they are from pregnant women or women trying to get pregnant who were taking prenatal vitamins. The culprit seems to be the iron the supplements contain, which can cause nausea or worsen morning sickness during early pregnancy. Check your multi to see if it contains iron. If so, consider whether you really need that mineral. If you’re pregnant, you do need iron, but probably can postpone taking it until your second trimester when you probably won’t be suffering from morning sickness.
If you’re not pregnant, you probably shouldn’t be taking a vitamin/mineral supplement that contains iron. In fact, the only people who need extra iron are women of reproductive age who have heavy menstrual bleeding, which can lead to loss of iron, and people who have been medically diagnosed with iron deficiency, or anemia. No one else should take a supplement containing iron because excess amounts can accumulate in the body and increase the risk of cancer and cardiovascular disease.
If iron is not an issue in your case, I would suggest trying alternative forms of vitamin and mineral supplements designed for people who gag or become nauseated when taking pills. You can get supplements in both spray and liquid form. With spray vitamins, you simply spritz the supplements into your mouth, where they’re directly absorbed by the oral tissues, bypassing the stomach.
With liquid vitamins, you can swallow your daily doses straight or mix the liquid with juice or water. The downside to these alternative forms of vitamin/mineral supplement is cost — a month’s supply may run up to $50 or more for only basic formulations.
Q. I’m curious about interactions between herbs and drugs. Are there many that we should worry about?
A. For the most part, I think warnings about interactions between herbs and drugs are overstated. For example, a few years ago the American Society of Anesthesiologists warned that certain herbs and supplements could pose a hazard to patients undergoing surgery. The group claimed that several herbs have anti-blood-clotting activity and conceivably could interfere with clotting during and after surgery. St. John’s wort was also singled out in 2003 as an agent that could diminish the effectiveness of certain drugs because of its effect on enzyme systems involved in drug metabolism. (Many pharmaceutical drugs have the same effect.)
In general, I think you’re pretty safe taking most supplements, but you certainly should tell your doctor about anything you’re taking regularly, particularly if you’re also taking either prescription or over-the-counter drugs. Here’s a quick rundown of some commonly used supplements and drugs that could interact to your detriment:
St. John’s wort: May affect metabolism of antidepressants; HIV protease inhibitors used to treat HIV/AIDS; digoxin, a heart medication; theophylline, used to treat asthma; cyclosporine, an immunosuppressant; chemotherapy; birth control pills (it may reduce their effectiveness); the blood pressure and heart disease medications nifedipine and diltiazem; Coumadin, a blood-thinner; and non-nucleoside reverse transcriptase inhibitors for HIV/AIDS treatment.
Co-enzyme Q10, dong quai, feverfew, garlic, ginger, ginkgo, ginseng, vitamin E and St. John’s wort: May increase the risk of bleeding if you’re taking prescription anticoagulants such as Coumadin.
Echinacea: May increase levels of HIV protease inhibitors used to treat HIV/AIDS, calcium channel blockers used to treat high blood pressure, and anti-anxiety drugs.
Capsicum (red pepper, cayenne pepper): May increase the absorption and effect of ACE inhibitors used to treat high blood pressure, heart failure and kidney disease; theophylline (for asthma); sedatives; and antidepressants.
Garlic: May decrease the effectiveness of immunosuppressant drugs and HIV protease inhibitors. It also may reduce the need for insulin among diabetics (by lowering blood sugar).
Ginkgo: May increase the amount of antidepressant drugs in your blood; may cause seizures when combined with anti-psychotic drugs.
Ginseng: Can cause headache, trembling and manic behavior when combined with the antidepressant Nardil; may interfere with the action of the heart medication digoxin; may reduce blood sugar levels in people with Type II diabetes, thus affecting the need for insulin or other medication for diabetes.
Q. I read that a big, new study just found that taking vitamin E and low-dose aspirin doesn’t protect women from cancer or heart disease. Your thoughts?
A. The study you’re referring to is part of the Women’s Health Study (WHS) conducted between September 1992 and March 2004. It included 39,876 women and was a randomized, double-blind, placebo-controlled trial to evaluate the benefits and risks of taking 100 mg of aspirin every other day and 600 IU of vitamin E (as alpha tocopherol) every other day. Approximately half of the women took the aspirin/vitamin E combination and half took a placebo.
Results showed that taking the aspirin had no observed effect on the women’s risk of all types of cancer — including breast and colon cancer — with the exception of lung cancer. The study found a 22 percent reduced risk of lung cancer among the women taking the aspirin/vitamin E combination. Over the years, a number of observational studies have suggested that taking aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) reduced the risk of various types of cancer by 20 to 50 percent. However, another randomized control trial, the Physician’s Health Study, found no reduced risk of colon cancer among participants who took 325 mg of aspirin every other day for five years. And a large study from California published in the June 1, 2005 issue of the Journal of the National Cancer Institute found no protection from breast cancer among women who regularly took aspirin or ibuprofen, both of which are NSAIDs.
As far as vitamin E is concerned, the WHS was looking for a protective effect against cancers of all types and against cardiovascular disease. The study did find a 24 percent reduction in cardiovascular deaths among women in the vitamin E group. Earlier observational studies have suggested that vitamin E reduces the risk of heart disease and that its antioxidant activity lowers cancer rates. Apart from the reduction in heart disease deaths, this study showed no such benefits. The results were published in the July 6, 2005 issue of the Journal of the American Medical Association.
I still recommend taking 400 IU of vitamin E in the form of mixed tocopherols and tocotrienols for general antioxidant and health-protective effects. I would like to see more research assessing the health benefits of the whole, natural vitamin E-complex. As for low-dose aspirin, it offers many benefits, especially in lowering risk of heart attacks. I continue to take both of these myself.
Q. I’ve heard that you’re changing your vitamin D recommendation. Why? And how much do you now recommend?
A. Yes, I am raising my recommendation for vitamin D from 400 IU to 1,000 IU per day. That may sound like quite a leap, but evidence has been accumulating to suggest that the 400 IU now recommended for adults isn’t enough for optimum health. We need vitamin D to facilitate calcium absorption and to promote bone mineralization as well as for protection from a number of serious diseases. I recently reviewed a series of studies on vitamin D and bone health with Walter Willett, MD, professor of epidemiology and medicine at Harvard Medical School. Dr. Willett has assembled a compelling review of clinical evidence suggesting that current vitamin D recommendations, including my own, are too low.
To sum up, most adults are simply not getting enough vitamin D for good bone health. We get vitamin D from such foods as fortified milk and cereals as well as from eggs, salmon, tuna, mackerel and sardines, and our bodies make vitamin D with exposure to sunlight. Unfortunately, many people don’t spend enough time in the sun to get optimal exposure, particularly in northern latitudes during the gray winter months. In addition, sunscreen blocks vitamin D synthesis in the skin, and dermatologists have made people so paranoid about sun exposure that many people in lower latitudes and in summer don’t get enough either.
And, clearly, many people are falling short of their vitamin D needs. A study published in the February 2001 issue of the American Journal of Clinical Nutrition showed that even while taking a 1,000 IU supplement, fewer than half of the participants in a Canadian study were getting enough to achieve optimal blood levels of vitamin D. And research published in the January 2003 issue of the American Journal of Clinical Nutrition showed that 1,700 IU was needed to bring blood levels of vitamin D to optimal levels during winter months in Nebraska. Dr. Willett told me that other studies have shown that an intake of 400 IU of vitamin D per day has no impact on the risk of fractures, but that 700 to 800 IU per day, with or without calcium supplements, does seem to reduce fracture incidence. He noted that some evidence further suggests that a higher intake of vitamin D may reduce the risk of prostate cancer, colon cancer, other malignancies, and multiple sclerosis.
Don’t be concerned that 1,000 IU will give you too much vitamin D — exposure to sunlight in the summer can generate between 10,000 and 20,000 IU of vitamin D per day with no ill effects. What’s more, no adverse effects have been seen with supplemental vitamin D intakes up to 10,000 IU daily.
Increasing my vitamin D recommendation to 1,000 IU daily may not be the last word on this subject. Depending on the amount of sunshine available where you live, you may need to take even more. Stay tuned.
Q. I just bought some supplements, and the clerk at the health food store told me I needed to take 6,000 mg of vitamin C per day. That sounds like an awful lot. What do you recommend?
A. I used to recommend taking 2,000 to 6,000 mg of vitamin C daily (divided into three doses). However, I changed my recommendation in 1999 to 200 to 500 mg (divided into two doses) after examining two well-designed studies showing that lower levels of vitamin C more than saturate the body's tissues, and thus are sufficient to protect against cancer, heart disease and other chronic illnesses. One of the studies that influenced my decision was a review of clinical trials published in the April 21, 1999, issue of the Journal of the American Medical Association. It concluded that 200 mg a day is the maximum amount of vitamin C that human cells can absorb, making higher doses a waste.
The second study came from the Linus Pauling Institute (Pauling himself took 18,000 mg of C per day) and was published in the June 1999 issue of the American Journal of Clinical Nutrition. It identified a similar dose, 120 to 200 mg, as the optimal amount for reducing the risk of cardiovascular disease, cancer, cataracts and other chronic conditions.
I wouldn't worry if you've been taking higher doses. Vitamin C is water soluble and anything not used by the body quickly passes out. In fact, I still recommend higher dosages to those under extra stress, living in smoke-filled or polluted environments, or not getting at least five servings of fruits and vegetables as part of their daily diet.
The rest of my antioxidant recommendations are as follows:
Vitamin E: 400 IUs of mixed natural tocopherols (or at least 80 mg of mixed tocopherols and tocotrienols) a day. Since vitamin E is fat soluble, it must be taken with food to be absorbed. Also, choose natural forms of vitamin E (d-alpha tocopherol with mixed tocopherols, or better yet, mixed tocopherols and tocotrienols) instead of the synthetic form (dl-alpha-tocopherol). I take vitamin E at lunch or dinner. Selenium: 200 micrograms a day. Selenium is a trace mineral with antioxidant and anticancer properties. Selenium and vitamin E facilitate each other's absorption, so take them together. Vitamin C may interfere with the absorption of inorganic forms of selenium (sodium selenite), so take the yeast-bound form instead. Doses of selenium above 400 micrograms a day may not be healthy. Mixed carotenes: 15,000 IUs a day. I recommend a natural form, which is easily found in health food stores. Read the label to make sure it gives you lycopene, the red pigment in tomatoes that helps prevent prostate cancer, and lutein, which protects against cataracts and macular degeneration. I take mine at breakfast.
Q. I am concerned about your recommendations for supplemental vitamin A. Most conventional wisdom and research indicate that 20,000 I.U. of vitamin A can be toxic, even lethal. It scares me to follow this advice.
A. You are right to be concerned about vitamin A toxicity. But first, please note that vitamin A comes in many forms. It is the animal form that is toxic, not plant-derived beta-carotene, which is the form I recommend in the Vitamin Advisor.
The Upper Limit of vitamin A set by the Food and Nutrition Board of the National Academy of Sciences is 10,000 IU per day. Vitamin A can be found in such dietary supplements as palmitate, acetate or fish liver oil, all of which are derived from animal sources. Although vitamin A is an essential nutrient, an excessive chronic intake of these forms of vitamin A can be toxic, leading to hair loss, confusion, liver damage, and — more recently discovered — bone loss.
The form of vitamin A I recommend in our Vitamin Advisor is beta-carotene in addition to other mixed carotenoids. The body can make all the vitamin A it needs from beta-carotene, which is not toxic, unlike the animal forms of vitamin A. Carotenoids are plant pigments found in orange and yellow fruits and vegetables and dark leafy greens. Unlike vitamin a, beta-carotene is water-soluble and does not accumulate in the body (although very high intakes — 100,000 IU or more a day — can cause an orange tint to your skin). Aside from being unsightly, this side effect is innocuous.
Carotenoid-containing fruits and vegetables have great cancer-protective value. In addition to beta-carotene, the antioxidant formulation I recommend contains lycopene, alpha-carotene, astaxanthin, lutein, and zeaxanthin. Lycopene is the red pigment in tomatoes that helps prevent prostate cancer, and lutein has been found to protect against cataracts and macular degeneration.
Taking a mixed carotenoid supplement does not excuse you from eating tomatoes, carrots, fruits, and greens, but it is useful insurance against failing to supply your body with all the antioxidant protection it needs. Read labels carefully to make sure the product you’re using includes lycopene AND lutein and provides at least 20,000 IU of beta-carotene.
Dosage Update, October, 2004
In order to provide the most up-to-date health information, I may change my recommendations from time to time. Due to compelling new research on carotene, I now suggest that you take 15,000 IU of mixed carotenes. (My previous recommendation was 25,000 IU; please adjust your dosage accordingly.)
Q. What is sublingual B12? Is it more effective than B12 bought at a drug store? My niece found out she is anemic and is having trouble handling the iron. Is this a good thing for her to take?
A. Sublingual vitamin B12 is merely a form of the vitamin that is taken under the tongue. The advantage of sublingual vitamins is improved absorption. In the case of B12, this method of administration is often better for seniors who frequently have trouble absorbing the vitamin from the stomach.
Regardless of the form it comes in, vitamin B12 is used to treat pernicious anemia, a much different condition from the more common iron-deficiency anemia. If your niece has pernicious anemia, she needs B12 — not iron. If she has iron-deficiency anemia, she needs iron, not B12. Pernicious anemia is due to vitamin B12 deficiency and is rare in young people — except in strict vegetarians (vegans) who eat no animal products, our only dietary source of B12. The condition can also occur in older men and women who lack sufficient “intrinsic factor,” a protein produced in the stomach that is necessary for B12 absorption (which occurs in the small intestine). Failure to produce intrinsic factor can be genetic in origin or caused by atrophy of the stomach lining (common in older age), or by autoimmunity.
Mild to moderate cases of iron-deficiency anemia can be treated with an over-the-counter iron supplement. If your niece is having trouble taking an iron supplement, she can try the suggestions below for obtaining more iron from her diet:
Cook in cast-iron pots (the cooked food absorbs iron and delivers it to you). Increase your intake of red meat, chicken and fish, all of which provide some iron. Vegetarian sources include whole grains, dried beans, molasses, dried apricots and prunes, and leafy green vegetables such as kale, beet greens and chard, as well as exotic greens such as dandelions, lamb’s quarters, nettles and yellow dock. Eat more foods that enhance iron absorption. These include fruits and vegetables high in vitamin C, or yogurt or sauerkraut, both of which contain lactic acid, which promotes iron absorption. Fermented soy foods can help, too. Avoid caffeinated beverages, eggs, milk and bran, all of which can interfere with iron absorption.
If her physician has prescribed iron and your niece can’t handle the supplement, she should be sure to let the doctor know if she stops taking it and is trying to increase her iron stores via the steps outlined above. These may not be adequate if she is severely anemic.
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