To separate a pill’s merits from its marketing, it’s important to scrutinize the label carefully with your own nutritional needs in mind. First, though, have a solid understanding of what your needs are and where a multivitamin may fit in.
Vitamins in the right amount are needed for a variety of body processes, among them growth, digestion, mental alertness and resistance to infection. They also enable your body to use carbohydrates, fats and proteins. And they act as catalysts in your body, initiating or speeding up chemical reactions.
Surplus water-soluble vitamins are washed out in urine. Surplus fat-soluble vitamins can accumulate in the body and become toxic. You’re especially sensitive to excess vitamin A and vitamin D. In addition, because vitamin K affects blood clotting, talk with your doctor before taking a supplement that contains it if you’re taking a blood-thinning medication.
Your body also needs 16 minerals that help regulate cell function and provide structure for cells. Major minerals include calcium, phosphorus, magnesium, sodium, potassium, sulfur and chloride. Your body needs smaller amounts of chromium, copper, fluoride, iodine, iron, manganese, molybdenum, selenium and zinc.
However, many people don’t get all the nutrients they need from their diet because they don’t eat enough or don’t eat the right foods. For some people, multivitamins can provide vitamins and minerals that their diets often don’t.
The RDAs (Recommended Dietary Allowances), devised by scientists in the United States and revised and updated over the years, have been designed partly to prevent vitamin deficiency states (such as beriberi, caused by a lack of thiamin, for instance, or scurvy, by a lack of vitamin C) and partly to meet the needs, based on current scientific facts, of healthy people.
Here are some reasons to consider for taking a multi:
Many, if not most, people over 60 don’t get the nutrients they need for a variety of reasons. For instance, aging itself may make it more difficult to absorb and utilize certain nutrients. The major problem nutrients for older people are vitamins D, C, B-6, B-12, and folic acid, as well as minerals such as zinc.
All women who might become pregnant should take 400 IU of folic acid daily. This B vitamin helps prevent neural tube birth defects. The surest way to get that much folic acid is with a multi. The folic acid in supplements is better absorbed by the body than the vitamin found naturally in food.
Many premenopausal women do not consume enough iron. The amount found in most basic multivitamins can help prevent a decline in women’s iron stores.
Vegans, who consume no animal products, may not be consuming enough vitamin B-12, zinc, or calcium.
People on low-calorie diets, as well as heavy drinkers, are likely to have a shortfall of vitamins and minerals.
Pregnant women should probably be in a multi, but should discuss their nutritional needs with their doctors.
Anyone else not eating a balanced diet (at least five fruits and vegetables a day, as well as whole grains, low-fat dairy, and small servings of lean meat, poultry or fish) may not be getting enough folic acid, B-6 and B-12. In recent years, evidence has grown about the role these B vitamins play in lowering homocysteine levels in the blood and thus reducing the risk of heart disease. Folic acid may also help prevent cervical and colon cancer. Most multivitamin supplements have 100% of the daily recommended intake of these Bs.
• Take a basic multivitamin or senior formulation. Most products contain the RDA of all the essential vitamins, except biotin and vitamin K, which are easy to obtain from foods. They also contain a percentage of the RDAs of key minerals. Products formulated for seniors typically contain less iron and vitamin A and more calcium, vitamin B-12 and vitamin B-6. Most important: Look for 100% of the Daily Value of the following vitamins: A (some from beta carotene), B-1 (thiamin), B-2 (riboflavin), B-3 (niacin), B-6, B-12, folic acid and D.
• Look for up to 100 percent of the Daily Value of the following minerals: copper, zinc, magnesium, iron, iodine, selenium (not more than 200 mcg), and chromium (not more than 200 mcg). Most multis also contain tiny amounts of trace minerals such as boron, manganese, and molybdenum. Least important: Most contain some potassium, phosphorus, panthotenic acid, and biotin, but you can ignore these since they are easily found in food.
• Iron. Although supplemental iron is advised during pregnancy and for iron deficient anemia, some studies suggest that excess iron can increase the risk of heart disease and colon cancer for women (beyond menopause) and for men. For these people, it’s probably wise to use a pill with little – less than 9 mg – or no iron. Those who have the genetic disorder hemochromatosis (who absorb too much iron) should avoid supplemental iron.
• Most multis contain 100 percent, or even 200 percent, of the Daily Value of vitamins C and E, but there are those who feel that this is not enough to provide the full antioxidant effects and other potential benefits of these vitamins. The UC Berkeley School of Public Health for example, recommends that everyone consume 200 to 800 IU of E and 250 to 500 mg of C a day. You’ll definitely need a pill to get that much E. And unless you eat lots of broccoli, peppers, kiwifruit, and oranges, you’ll probably need a pill to get that much C. However, if you’re taking blood-thinning medication, are anemic, or have intestinal problems or liver disease, talk with your doctor before taking a supplement containing vitamin E.
• Vitamin D. This vitamin helps the body absorb calcium and is essential in maintaining proper bone strength and bone density. Because many older people have vitamin D deficiencies, taking a multivitamin with 400 IU will probably help improve bone health.
• Pyridoxine (vitamin B-6). Adequate levels of this vitamin may help lower blood homocysteine ( a risk factor for heart attack) and improve your immune system function. Older people have trouble absorbing it, so a multivitamin that contains at least 2 mg is often a good idea. Avoid excessive doses. Although vitamin B-6 is water soluble, nerve toxicity has been reported with excessive intake of this vitamin.
• Cobalamin (vitamin B-12). Adequate levels of this vitamin may reduce your risk for anemia, cardiovascular disease and stroke. Older people often don’t absorb this as well, either. A vitamin with at least 2 mcg may help.
• Taking large doses of most vitamins is not wise. Avoid megadoses. Excessive intake of vitamins and minerals can cause toxic reactions (such as heart problems from iron, and fatigue and nausea from vitamin A). Remember that more than 100 percent of Daily Value isn’t necessarily better. And large doses of vitamin A or D can be dangerous.