There are several reasons. Many people are uncertain about the nutritional adequacy of their diets. Others think they can improve their health by doing so. Some do it because they have decided to treat themselves for an illness and think that vitamins are bound to help: On questioning, many will give as reasons for taking supplements: ‘to prevent colds and other illnesses:’ ‘to give me energy:’ and ‘to make up for what is not in food.’ Many people who use vitamin supplements tend to have a low opinion of the quality of today's foods.
 

Harm from vitamin and mineral over-dosage is very rare. Most vitamins can safely be taken in doses several times those of the RDA. In the case of vitamin C, ten times the RDA is commonly taken without harm. Some quite massive doses of this vitamin have been taken without problems. Vitamins A and D in excess, however, can certainly cause trouble. Very large doses of vitamin A cause chronic poisoning with. itchy, dry, peeling skin; irritability - an irresistible desire to sleep: headache: loss of appetite; enlargement of the liver and spleen: and painful and tender swellings over the bones. The vitamin accumulates in the body and the effects take weeks to wear off. Eskimos and their husky dogs never eat polar bear liver (which contains huge quantities of vitamin A) because they know of these effects. One gram of polar bear liver contains up to 12 mg of retinol — 12 times the minimum daily requirement Vitamin A is also dangerous to a foetus if taken by the mother in doses of 7to 12 mg a day during the first three months of pregnancy. This can cause congenital abnormalities. Too much vitamin D causes calcium to be deposited in the kidneys. arteries and other tissues — a serious matter that can lead to all sorts of problems, including kidney failure.
 

Usually because of an exaggerated belief in the power of vitamins to cure and a belief in the illogical proposition that if a little of something does you some good, a lot of it must do you a lot of good. Minerals taken in excess can be dangerous. Iron pills, for instance, are a quite common cause of poisoning especially in children. Fortunately. most adverse effects are minor and get better when the high dose of the nutrient is stopped. Most vitamin users take most nutrients in amounts that seldom exceeded one to two times the RDA. an amount most experts consider safe. Those taking larger amounts than this are likely to be taking vitamins C and E. which most experts agree are both quite safe for adults, even in large amounts. Same people. however take up to several hundred times the RDA of several of the B complex vitamins. Those amounts should be taken only with medical supervision.
 

Shopping for supplements can be difficult, no doubt about that Hundreds of different formulations exist for multivitamin and mineral supplements, and even single-nutrient supplements, such as vitamins C or E, come in a variety of dosages and types. And in health-food shops especially, vitamins and minerals may be mixed with herbs and other non-vitamin ingredients, which can make the selection even more bewildering. ideally, before you shop you should have a reasonably good idea of which nutrients you are looking for and in which amounts. You may want to make up a list of the vitamins and minerals you want based on the strengths and weaknesses of your diet and your needs and preferences. Take the list with you when you go shopping. Then read the ingredients on the labels of a number of different supplements and choose the supplement or supplements that most closely match what you believe are your needs.
 

These nutrients don’t have an RDA because we simply have no idea how much we need. We know that we need very little indeed, and most experts would agree that deficiencies are practically unknown. This group of nutrients includes biotin, pantothenic acid, copper, manganese, fluoride, chromium and molybdenum. A multivitamin and mineral supplement is less likely to contain these nutrients than those with an RDA. Some experts hold that of these nutrients, chromium, copper and manganese currently have the strongest research support for their use as supplements. Fluoride is not included in most multivitamin and mineral supplements. Adequate amounts are obtained from drinking water, and the element is seriously toxic in overdosage.
 

Again, check labels. Same multivitamin and mineral supplements do offer high amounts of these nutrients, but most do not If you are using C and E as antioxidants, it is far better to buy the vitamins separately, perhaps as I 000-mg coated C tablets, and 200- or 400-mg capsules of vitamin E. This will often work out cheaper. Several brands of multivitamin and mineral supplements are now indicating on their labels that they contain beta-carotene — but they do not state how much beta-carotene actually is in the supplement If you want to know how much you’re getting, find a brand that lists separate amounts of both vitamin A and beta-carotene. Most multiples offer very little beta-carotene — only 1000 to 2,500 U, which equivalent to 0.5 to 1.5 mg of beta-carotene. As a point of comparison, you should know that I inch (2.5 cm) of carrot contains about 1.5 mg of beta-carotene. The fact is that multiple-vitamin supplements will not give you nearly enough to produce a significant antioxidant effect
 

Yes. Most multivitamin and mineral supplements fall short on calcium, and also on magnesium. These bulky nutrients are required in quantities that just don’t fit into a one-a-day pill. The right way to get them is not from pills but from an adequate diet Most multivitamin and mineral supplements contain very little potassium, too, as do single-ingredient potassium supplements. This is probably just as well, since the requirement for potassium supplementation is really a medical matter and you shouldn’t be dosing yourself with this element without medical advice. So unless you are taking high-dose potassium supplements prescribed by a doctor, your best bet is to get this mineral from fruits and vegetables and their juices. Wash down your supplement with a cup of orange. grapefruit carrot or tomato juice for an additional 400 to 500 mg of potassium.
 

Most experts feel there is no need for these additional nutrients to be in a supplement. so don’t be fooled by a long list of ingredients, which may also include lecithin, glutamic acid, boron, silicon, nickel, vanadium and other nutrients which have not been proven to be necessary in the diets of humans. This kind of thing is just done to impress you
 

Probably not Much of this is just sales promotion. Read the product’s ingredients to see if it matches your needs. So-called ‘special formulations’ certainly do not take the place of a proper medical prescription. If you need vitamin and/or mineral supplement for a particular medical condition, your doctor should indicate what you need and how much. Problems such as premenstrual tension and osteoporosis require informed medical care, not vitamin manufacturers hype.
 

This could be sensible or silly, depending on how well-informed your friend is. A person who uses a large number of single-nutrient vitamin and mineral supplements could simply be wasting his or her money. But if the single nutrients are specific antioxidant agents such as vitamin C and E, this could be the best way. Doctors often recommend individual supplements of at least some nutrients, especially minerals, because they might be supplied in a form which people with absorption problems can more easily utilize, or because the individual nutrients are available in higher doses than can be found in most multivitamin compounds.
 

Usually but not always. We sell our own brands which are similar in formulation to expensive trade-name vitamins, but they cost much less. Vitamin C (ascorbic acid) is ascorbic acid — one substance only — whatever the price. Again, check labels to see exactly what you are getting for your money. If a manufacturer claims its product is more absorbable or better balanced. you may want to contact the manufacturer and ask for research that backs up such marketing claims. Same formulations of plain vitamin C are unpleasantly sour and you may have to pay a little more for a coated tablet you can more easily swallow.
 

No difference. Natural vitamins are derived from foods. Natural vitamin E, for instance, is isolated from soybean oil. Natural beta-carotene can be derived from carrots or algae. Natural vitamin C can be taken from citrus fruits. Synthetic vitamins, on the other hand, are constructed from organic molecules found in an array of substances, such as petroleum oil and corn oil. Unless you are being cheated by an unscrupulous purveyor who is not selling you what the label says, it makes no difference whatsoever whether the vitamin was made by nature or in a factory or laboratory. Synthetic does not mean ‘inferior’ or nearly the same as’; it simply means that the atoms have been linked together in a lab or manufacturing process to form a molecule that is identical in every respect to the natural product Synthetic vitamins have the advantage that they are much less expensive to make than natural vitamins.
 

The trouble here is that natural vitamin E is not just one substance but actually a mixture of eight very complicated but similar molecules known as tocopherols. Any of these could be synthesized, but the usual synthetic version of vitamin E is made up of just one of these The most active of the natural mix of tocopherols has slightly more biological activity in the body than the usual synthetic form. But this just means you have to take a fraction more of the synthetic vitamin E to achieve the same effect
 

No. Pure minerals are elements and come in one chemical form only. You can have isotopes with different atomic weights, but these are all chemically identical, and that is another story altogether. Minerals are derived from materials mined from the ground or otherwise found in nature, mostly from compounds of the elements. Calcium, for instance, is derived from limestone, oyster or eggshells, or from naturally occurring beds of calcium carbonate. All of these are calcium compounds in which the element calcium is combined with other elements to form molecules. Minerals are commonly taken in the form of compounds which are often more easily absorbed than in elemental form.