Multi Vitamin Supplements and Products |
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WHAT ARE VITAMIN MULTIPLE SUPPLEMENTS ?
 Multiple vitamin-mineral (MVM)
supplements, sometimes known as multivitamin-mineral supplements, contain a variable number of
essential and/or non-essential nutrients. Their primary purpose is to provide a convenient way
to take a variety of supplemental nutrients from a single product, in order to prevent vitamin
or mineral deficiencies, as well as to achieve higher intakes of nutrients believed to be of
benefit above typical dietary levels.
Many MVMs contain at least 100%
of the Daily Value (DV) or the U.S. Recommended Dietary Allowance (USRDA) of all vitamins that
have been assigned these recommended values. Mineral levels may be lower, or in the case of high
potency MVMs, most or all mineral levels may also be at 100% of DV or USRDA. Micronutrients that
should be included in a complete MVM are vitamin A (or beta-carotene), vitamin B-complex
(thiamine, riboflavin, niacin and/or niacinamide, vitamin B6, folic acid (folate), vitamin B12,
pantothenic acid, and biotin), vitamin C, vitamin D, and vitamin E, and the minerals calcium,
magnesium, zinc, iodine, selenium, copper, manganese, chromium, molybdenum, and possibly iron.
Some MVMs also contain vitamin K, but people taking the medication warfarin (Coumadin®) should
consult their doctor before taking vitamin K supplements. Phosphorus is another essential
dietary mineral, but is so abundant in the diet that it does not need to be included in an MVM
formula. The only exception is for elderly people, whose diets tend to be lower in phosphorus.
Calcium interferes with phosphorus absorption, so older people who are taking a calcium
supplement might benefit from taking additional phosphorus.
An MVM supplement should not
take the place of a healthful, well-balanced diet, but it will help prevent deficiencies that
often arise. People may consume diets that are deficient in one or more nutrients for a variety
of reasons. The typical Western diet often provides less than adequate amounts of several
essential vitamins and minerals. Weight-loss, pure vegetarian, macrobiotic, and several other
diets can also place some people at risk of deficiencies that vary with the type of diet. Aging,
some medications, and certain health conditions can effect appetite, which may reduce
nutrient intake.
Multiple vitamin / mineral supplements
What about "one-per-day" multiples ?
One-per-day multiples are primarily B-complex vitamins, with both vitamin A and vitamin D included either at high or low potency, depending on the supplement. The rest of the formula tends to be low potency. It does not take much of some of the minerals-for example, copper, zinc, and iron - to offer 100% or more of what people normally require, so these minerals may appear at reasonable levels in a one-per-day MVM.
One-per-day MVMs usually do not provide sufficient amounts of many nutrient supplements shown to benefit people eating a Western diet, such as vitamin E, calcium, magnesium, and vitamin C. One-per-day MVMs should therefore not be viewed as a way to "cover all bases" in the way that high-potency MVMs, requiring three or more pills per day, are viewed.
Which is better-capsule or tablet?
Multiples are available as a powder inside a hard-shell pull-apart capsule, as a liquid inside a soft-gelatin capsule, or as a tablet.
Most multiples have all the ingredients mixed together. Occasionally the B vitamins react with the rest of the ingredients in the capsule or tablet. This reaction, which is sped up in the presence of moisture or heat, can cause the B vitamins to "bleed" through the tablet or capsule, discoloring it and also making the multiple smell. While the multiple is still safe and effective, the smell is off-putting and usually not very well tolerated. Liquid multiples in a soft-gel capsule-or tablets or capsules that are kept dry and cool-do not have this problem.
Capsules are usually not as large as tablets, and thus some people find capsules easier to swallow.
Some people prefer vegetarian multiples. While some capsules are made from vegetarian sources, most come from animal gelatin. Vegetarians need to carefully read the label to ensure they are getting a vegetarian product.
One concern people have with tablets is whether they will break down sufficiently to allow the nutrients to be absorbed. Properly made tablets and capsules will dissolve readily in the stomach.
What about timed-release?
Some multiples are in timed-release form. The theory is that releasing vitamins and minerals slowly into the body over a period of time is better than releasing all of the nutrients at once. Except for work done on vitamin C-some of which showed timed-release C was better absorbed than non-timed-release-research on this question has been lacking. It is possible that some nutrients, especially minerals, will be poorly absorbed from timed-release multiples. Also, some doctors have concerns about the safety of ingesting the chemicals that are used in tablets or capsules to make them timed-release.
What about nutrient interactions?
Another area of controversy is whether all of the nutrients in a multiple would be better utilized if they were taken separately. While certain nutrients compete with each other for absorption, this is also the case when the nutrients are supplied in food. For example, magnesium, zinc, and calcium compete; copper and zinc also compete. However, the body is designed to cope with this competition, which should not be a problem if multiples are spread out over the day.
What about chewables?
Unfortunately, multiples do not taste very good. In order to make chewable multiples palatable, whether for children or adults, some compromises must be made. First, bad-tasting ingredients must be reduced or eliminated. Second, the rest of the ingredients must be masked with a sweetener.
Unless an artificial sweetener like aspartame (NutraSweet®) or saccharin is used, the only sweeteners available are sugars. Generally, consuming sugar is undesirable, and not having it in a chewable dietary supplement would be preferable. Xylitol, a natural sugar rarely used in chewables because it is relatively expensive, would be an ideal choice since it does not cause tooth decay or other known problems.
Some chewables, such as vitamin C, contain more sugar than any other ingredient. In such products, the sweetener should be listed as the first ingredient, but often is not. Care needs to be exercised when reading labels about chewable vitamins. If it tastes sweet, it contains sugar or a synthetic sweetener. In addition, chewable vitamin C products should contain buffered vitamin C, rather than the acidic form, ascorbic acid, in order to avoid damaging dental enamel.
When is the best time to take a multiple?
The best time to take vitamins or minerals is with meals. Multiples taken between meals sometimes cause stomach upset and are likely not to be as well absorbed.
Multi Vitamin Supplements and Products
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