|04-18-2005, 02:03 PM||#1|
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Nutrition Basics: Dietary Nutrients: Dietary Supplements
Nutrition Basics: Dietary Nutrients: Dietary Supplements
Vitamin and Mineral Supplements
Healthful food choices can best provide the variety and balance of vitamins, minerals and other nutrients needed for good health. However, when circumstances make healthful eating a challenge, you may wonder whether taking a multivitamin and mineral supplement is for you.
You can get all the vitamins and minerals you need by eating a wide variety of foods. If you are getting the recommended number of servings from each of the five Food Guide Pyramid food groups every day, you probably don't need a supplement. Eating a wide variety of foods is important because food contains the ideal mix of nutrients, which work together.
For some people, a complete multivitamin/mineral supplement offers benefits that are both effective and safe. A supplement may help if:
You have a nutrient deficiency;
You consistently do not eat the recommended number of servings from the Food Guide Pyramid;
You follow a low calorie intake less than 1200 calories per day;
You are elderly and not eating as much as you used to or should;
You are a strict vegetarian;
You can't drink milk or eat cheese and yogurt;
You are a woman of child-bearing age who doesn't eat enough fruits, vegetables and beans;
You are taking medications that interfere with the body's use of specific nutrients;
You are taking medications that lower your appetite or change the way your body uses nutrients;
You have a disease, infection, or injury, or have undergone surgery that affects or changes the way your body uses nutrients.
This does not mean you should take vitamin or mineral supplements automatically or view them as a substitute for food. Before you take a vitamin or mineral supplements on your own, consult with your health care provider or a registered dietitian. A simple dietary change may be all that you need.
Vitamin or Mineral Deficiency Diseases
Vitamin or mineral deficiency diseases can be difficult to diagnose. Diseases have many possible causes. Anemia, for example, can result from a deficiency of vitamin C, folate, iron, copper, B6, B12, or protein. Anemia can also be totally unrelated to diet.
Symptoms by themselves can not accurately diagnose a disease. A symptom is a signal something is wrong - not what is wrong. Being tired could be a symptom of iron deficiency, folate deficiency, or totally unrelated to diet. Skin problems can result from a deficiency of vitamin A, niacin, or a reaction to a new soap. Be careful of claims for vitamins or minerals to cure or prevent a symptom or disease.
Increased vitamin or mineral intakes are needed to correct a nutritional deficiency. Taking large amounts of a vitamin or mineral approaches drug therapy and requires the help of a doctor. However, people often take large amounts of vitamins or minerals on their own in hopes of preventing or curing a disease. This practice is not only a waste of money it can be dangerous.
More Is Not Always Better
Before taking a supplement, be aware that health risks exist for some people. For instance, it is not recommended that pregnant women take more than 5000 IU daily of vitamin A from retinol (a form of vitamin A). Too much vitamin A can increase the risk of birth defects. In addition, too much iron can increase risk of chronic disease, so it is recommended that men and post-menopausal women not routinely take iron supplements at levels higher than 100 percent of the Daily Value. Check the label to be sure. Consult with your doctor before taking a single supplement. For those who choose to take a supplement, it is best to select a product that provides no more than 100 percent of the Daily Value for vitamins and minerals. Check the Nutrition Facts panel on the label.
Taking large doses, amounts far greater than the dietary reference intake (DRI) or tolerable upper limits (UL), is clearly not recommended without specific medical recommendations. One might think that more is better when taking vitamin or mineral supplements. However, a vitamin or mineral taken in large amounts can be dangerous. Overdoses happen easier with supplements than with food. Large amounts of vitamins or minerals can be toxic to the body. Our bodies store excess minerals and fat-soluble vitamins (vitamins A, D, E, and K). Excessive amounts of these nutrients can accumulate and be harmful. Dangerous levels can produce serious side-effects. Toxicity from water-soluble vitamins, such as vitamin C, is unlikely since excess amounts are flushed from the body in the urine. However, serious side effects can occur even with water-soluble vitamins. Because nutrients interact with each other, a balance of all nutrients is important. If the body has too much or too little of any nutrient it can affect how the body uses other nutrients.
A Balanced Diet, Not Supplements
Vitamin or mineral supplements can not make up for a poor diet. No supplement contains all the essential nutrients the body needs. Most healthy people can meet their nutritional needs through a balanced diet rather than supplements. The basis for good health depends on a well balanced diet from a variety of foods. The keys to good nutrition are variety and moderation. The greater the variety of foods, the less likely a deficiency or excess of any one vitamin or mineral will occur. Following the Food Guide Pyramid is the best guide for getting the right foods in the right amounts for good health.
Foods also provide protein, fat, carbohydrate, water and fiber in addition to vitamins and minerals. Different foods provide different vitamins and minerals. Some foods are better sources of certain vitamins and minerals than others are. As a result, you need foods from all five of the Food Guide Pyramid food groups. No single food group is more important than another is. The best way to get all the nutrients you need each day is to follow the Food Guide Pyramid.
The Food Guide Pyramid recommends you have six to eleven servings from the bread, cereal, rice, and pasta group each day. Each day you need three to five servings from the vegetable group, two to four servings from the fruit group, and two to three servings daily from the milk, yogurt, and cheese group. From the meat, poultry, fish, dry beans, eggs, and nuts group you need two to three servings daily. Use fats, oils, and sweets sparingly.
There are many false claims made about vitamins and minerals. For example, false claims are often made that vitamin E and zinc delay aging. There is no scientific evidence that extra amounts of these nutrients beyond recommended dietary allowances (RDA) will slow down aging.
Claims that vitamins or minerals help reduce stress or provide energy are false. Life stresses do not increase your need for vitamins or minerals beyond recommended dietary allowances. In addition, vitamins and minerals do not provide energy. Energy comes from carbohydrates, proteins, and fats in food. Vitamins and minerals do have a role in the release of energy from food. However, extra vitamins and minerals beyond recommended dietary allowances do not provide additional energy.
Expensive supplements are not necessarily better. You may hear that natural supplements are better than other forms. The body cannot tell the difference between natural and synthetic forms. There is no reason to pay extra for "natural" supplements.
Tips For Using Supplements
Do not take individual vitamins or minerals unless recommended by a doctor. One possible exception is calcium. Most combination vitamin and mineral supplements do not contain enough calcium to meet the recommended dietary allowance.
If you take a supplement, the best guide is to choose a combination vitamin and mineral supplement. Choose one that contains a variety of vitamins and minerals, in amounts no more than 100 percent of the Daily Value.
If your doctor or registered dietitian decides you need a supplement, only take a single dose. Do not take additional supplements to replace missed meals. Also, do not double up on doses if you are not feeling well.
Look for ingredients in products with the U.S.P. notation, which indicates the manufacturer, followed standards established by the U.S. Pharmacopoeia.
Dietary Supplement Labeling
The 1994 Dietary Supplement Health and Education Act (DSHEA) set up a new framework for FDA regulation of dietary supplements. The law gives dietary supplement manufacturers freedom to market more products as dietary supplements and provide information about their products' benefits in product labeling.
However, FDA's requirement for pre-market review of dietary supplements is less than that over other products it regulates, such as drugs and many additives used in conventional foods. This means that consumers have responsibility for checking the safety of dietary supplements and determining the truthfulness of label claims.
What is a dietary supplement?
Traditionally, dietary supplements referred to products made of one or more of the essential nutrients, such as vitamins, minerals, and protein. But DSHEA broadened the definition to include, with some exceptions, any product intended for ingestion as a supplement to the diet. This includes vitamins; minerals; herbs, botanicals, and other plant-derived substances; and amino acids and concentrates, metabolites, constituents and extracts of these substances.
One thing dietary supplements are not are drugs. A drug, which sometimes can be derived from plants used as traditional medicines, is an article that, among other things, is intended to diagnose, cure, mitigate, treat, or prevent diseases. Before marketing, drugs must undergo clinical studies to determine their effectiveness, safety, possible interactions with other substances, and appropriate dosages, and FDA must review these data and authorize the drugs' use before they are marketed. FDA does not authorize or test dietary supplements. A product sold as a dietary supplement and touted in its labeling, as a new treatment or cure for a specific disease or condition would be considered an unauthorized--and thus illegal--drug.
Another thing dietary supplements are not are replacements for conventional diets. Supplements do not provide all the known--and perhaps unknown--nutritional benefits of conventional food.
Information on dietary supplement labels includes:
Statement of identity (e.g., "ginseng")
Net quantity of contents (e.g., "60 capsules")
Structure-function claim and the statement "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."
Directions for use (e.g., "Take one capsule daily.")
Supplement Facts panel (lists serving size, amount, and active ingredient)
Other ingredients in descending order of predominance and by common name or proprietary blend.
Name and place of business of manufacturer, packer or distributor. This is the address to write for more product information.
Monitoring for Safety
Unlike food additives or drugs; however, supplements do not need FDA's approval before being marketed. Manufacturers alone determine if their product is safe and effective. If a problem occurs, FDA must prove the supplement poses a risk and should be removed from the market.
This was the case in 1997 when, FDA proposed, among other things, to limit the amount of ephedrine alkaloids in dietary supplements (marketed as ephedra, Ma huang, Chinese ephedra, and epitonin, for example) and provide warnings to consumers about hazards associated with use of dietary supplements containing the ingredients. The hazards ranged from nervousness, dizziness, and changes in blood pressure and heart rate to chest pain, heart attack, hepatitis, stroke, seizures, psychosis, and death.
Claims that tout a supplement's healthful benefits have always been a controversial feature of dietary supplements. Manufacturers often rely on them to sell their products. But consumers often wonder whether they can trust them.
Under DSHEA and previous food labeling laws, supplement manufacturers are allowed to use, when appropriate, three types of claims: nutrient-content claims, disease claims, and nutrition support claims, which include "structure-function claims."
Nutrient-content claims describe the level of a nutrient in a food or dietary supplement. For example, a supplement containing at least 200 milligrams of calcium per serving could carry the claim "high in calcium." A supplement with at least 12-mg per serving of vitamin C could state on its label, "Excellent source of vitamin C."
Disease claims show a link between a food or substance and a disease or health-related condition. FDA authorizes these claims based on a review of the scientific evidence. Certain dietary supplements may be eligible to carry disease claims, such as:
the vitamin folic acid and a decreased risk of neural tube defect-affected pregnancy, if the supplement contains sufficient amounts of folic acid
calcium and a lower risk of osteoporosis, if the supplement contains sufficient amounts of calcium
psyllium seed husk (as part of a diet low in cholesterol and saturated fat) and coronary heart disease, if the supplement contains sufficient amounts of psyllium seed husk.
Nutrition support claims can describe a link between a nutrient and the deficiency disease that can result if the nutrient is lacking in the diet. For example, the label of a vitamin C supplement could state that vitamin C prevents scurvy. When these types of claims are used, the label must mention the prevalence of the nutrient-deficiency disease in the United States.
These claims also can refer to the supplement's effect on the body's structure or function, including its overall effect on a person's well being. These are known as structure-function claims.
Examples of structure-function claims are:
Calcium builds strong bones.
Antioxidants maintain cell integrity.
Fiber maintains bowel regularity.
Manufacturers can use structure-function claims without FDA authorization. Structure-function claims must be accompanied with the disclaimer "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."
Consumers need to be on the lookout for fraudulent products. These are products that don't do what they say they can or don't contain what they say they contain. At the very least, they waste consumers' money, and they may cause physical harm. The types of claims made in their labeling, advertising and promotional literature often can identify fraudulent products. Some possible indicators of fraud are:
Claims that the product is a secret cure and use of such terms as "breakthrough," "magical," "miracle cure," and "new discovery." If the product were a cure for a serious disease, it would be widely reported in the media and used by health-care professionals.
"Pseudomedical" jargon, such as "detoxify," "purify" and "energize" to describe a product's effects. These claims are vague and hard to measure. So, they make it easier for success to be claimed even though nothing has actually been accomplished.
Claims that the product can cure a wide range of unrelated diseases. No product can do that.
Claims that a product is backed by scientific studies, but with no list of references or references that are inadequate. For instance, if a list of references is provided, the citations cannot be traced, or if they are traceable, the studies are out-of-date, irrelevant, or poorly designed.
Claims that the supplement has only benefits--and no side effects. A product potent enough to help people will be potent enough to cause side effects.
Accusations that the medical profession, drug companies and the government are suppressing information about a particular treatment. It would be illogical, for large numbers of people to withhold information about potential medical therapies when they or their families and friends might one-day benefit from them.
Claims that "natural" is better. Just because something is natural doesn't guarantee it is safe. Think of poisonous mushrooms. They're natural.
Today's Dietary Supplements
The majority of supplement manufacturers are responsible and careful. But, as with all products on the market, consumers need to be discriminating. FDA and industry have important roles to play, but consumers must take responsibility, too.
Paula Kurtzweil, An FDA Guide to Dietary Supplements, FDA Consumer, 1999. http://www.fda.gov
The Food Guide Pyramid, United States Department of Agriculture, Human Nutrition Information Service. Home and Garden Bulletin Number 252, U.S. Government Printing Office, Washington D.C., 1992.
Barrett, S. & Herbert,V. Fads, frauds, and quackery. In: Modern Nutrition In Health And Disease. pp 1526-1533, A Waverly Co., 1994
Committee on Diet and Health Food and Nutrition Board Commission on Life Sciences National Research Council. Dietary Supplements. In: Diet and Health: Implications for Reducing Chronic Disease Risk. National Academy Press, Washington D.C., 1989.
McDonald, JT Vitamin and mineral supplement use in the United States. Clinical Nutrition, pp 23-33, 1986.
Whitney, E.N. & Rolfes, S.R. Understanding Nutrition, 8th ed. West/Wadsworth Publishing Co., Belmont, CA, 1999.
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