Multiple Vitamin-Mineral Supplements
What do they do?
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
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.1
Potassium is an unusual case, as adequate
amounts of potassium cannot, by law, be sold in nonprescription products. Thus potassium, when
included in an MVM formula, represents only a trivial amount. MVMs may contain iron, but these should be taken only by people who
have been diagnosed as having, or being at high risk of, iron deficiency, or who have a history of frequent
Some nutrients may be beneficial at levels above what is possible to obtain from diet
alone, and an MVM formula can provide these levels as well. Nutrients that may be useful to
most people in larger amounts include vitamin
C, folic acid, and calcium.
Vitamin E has long been thought to protect against heart disease beginning at 100 IU per day, but more
recent research has cast doubt on the value of vitamin E for heart-disease
prevention.2 Large amounts of vitamin
B1, vitamin B2, vitamin B3, and pantothenic acid are often included in MVM formulas.
Some people claim to experience improvements in mood, energy, and/or overall well-being when
taking higher-than-RDA amounts of B vitamins.
While there is not a great deal of scientific research to support those observations, one
double-blind study of healthy volunteers found that an MVM supplement significantly reduced
anxiety and perceived stress levels, and possibly improved energy and the ability to
The importance of including the nonessential nutrient beta-carotene in MVMs remains speculative. The
synthetic beta-carotene found in most MVMs clearly does not prevent cancer and may increase the risk of lung cancer in smokers. Therefore, the inclusion of
synthetic beta-carotene in MVM formulas is of questionable value, and it should be avoided by
smokers. This concern was validated by the results of a large study in which male smokers who
supplemented with synthetic beta-carotene had an 18% increase in incidence of lung cancer,
compared with those given a placebo.4 On the other hand, because beta-carotene can
be converted to vitamin A without causing
vitamin A toxicity, some manufacturers use beta-carotene as a source of vitamin A. In contrast
to synthetic beta-carotene, however, natural beta-carotene and several other carotenoids may be helpful in preventing certain
diseases, including some cancers.5 6 7 Increasingly, natural
beta-carotene and several other carotenoids are found in higher quality MVMs.
Another class of non-essential nutrients is the flavonoids, which have antioxidant and other properties and have been
reported by some,8 though not all,9 researchers to be linked with a
reduced risk of heart disease. MVM supplements
also frequently include other nutrients of uncertain benefit in the small amounts supplied,
such as choline, inositol, and various amino acids.
Preliminary and double-blind trials have shown that women who use an MVM containing folic acid, beginning three months before
becoming pregnant and continuing through the first three months of pregnancy,10 11 have a
significantly lower risk of having babies with
neural tube defects (e.g., spina bifida) and other congenital defects.
In one double-blind trial, schoolchildren received, for three months, a daily low-potency
vitamin-mineral tablet containing 50% of the USRDA for most essential vitamins and the
minerals.12 The subjects were “working class,” primarily Hispanic,
children, aged 6 to 12 years. Dramatic gains in certain measures of IQ were observed in about
20% of the supplemented children. These gains may have been due to the correction of specific
nutrient deficiencies (for example, iron) found in these children. However, it was not
possible in this study to identify which nutrients caused the increases in IQ.
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 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.
How much is usually taken?
The following table shows the USRDA for nutrients as well as suggested optimum amounts of
each vitamin and mineral that should be present in a daily MVM supplement for healthy people. Some people may
want to take larger amounts because of specific health concerns. They should read the
individual nutrient sections to learn about safe upper ranges of supplementation.
Because one-per-day formulas typically do not contain even the minimum recommended amounts
of some of the nutrients listed here, multiples requiring several capsules or tablets per day
are preferable. With two- to six-per-day multiples, intake should be spread out at two or
three meals each day, instead of taking them all at one sitting. The amount of vitamins and
minerals can be easily increased or decreased by taking more or fewer of the multiple.
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
Capsules are usually not as large as tablets, and thus some people find capsules easier to
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
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
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.References:
1. Heaney RP, Nordin BEC. Calcium effects on phosphorus absorption:
implications for the prevention and co-therapy of osteoporosis. J Am Coll Nutr
2. Miller ER III, Pastor-Barriuso R, Dalal D, et al. Meta-analysis:
high-dosage vitamin E supplementation may increase all-cause mortality. Ann Intern
3. Carroll D, Ring C, Suter M, Willemsen G. The effects of an oral
multivitamin combination with calcium, magnesium, and zinc on psychological well-being in
healthy young male volunteers: a double-blind placebo-controlled trial.
4. The effect of vitamin E and beta carotene on the incidence of lung
cancer and other cancers in male smokers. The Alpha-Tocopherol, Beta Carotene Cancer
Prevention Study Group. N Engl J Med 1994;330:1029–35.
5. Shekelle RB, Lepper M, Liu S, et al. Dietary vitamin A and risk of
cancer in the Western Electric Study. Lancet 1981;2:1185–90.
6. Giovannucci E, Ascherio A, Rimm EB, et al. Intake of carotenoids and
retinol in relation to risk of prostate cancer. J Natl Cancer Inst
7. Seddon JM, Ajani UA, Sperduto RD, et al. Dietary carotenoids, vitamins
A, C, and E, and advanced age-related macular degeneration. JAMA
8. Hollman PC, Katan MB. Absorption, metabolism and health effects of
dietary flavonoids in man. Biomed Pharmacother 1997;51:305–10 [review].
9. Hertog MGL, Sweetnam PM, Fehily AM, et al. Antioxidant flavonols and
ischemic heart disease in a Welsh population of men: the Caerphilly Study. Am J Clin
10. Botto LD, Mulinare J, Erickson JD. Occurrence of congenital heart
defects in relation to maternal mulitivitamin use. Am J Epidemiol
11. Czeizel AE. Reduction of urinary tract and cardiovascular defects by
periconceptional multivitamin supplementation. Am J Med Genet
12. Schoenthaler SJ, Bier ID, Young K, et al. The effect of
vitamin-mineral supplementation on the intelligence of American schoolchildren: a randomized,
double-blind, placebo-controlled trial. J Altern Complement Med