Choosing a Multi-Vitamin Mineral Supplement
By James M. Gerber M.S., D.C., CCN
Dr. Gerber is on the NNFA NW Region healthcare advisory board
After twenty years of studying, teaching and practicing therapeutic
nutrition, I am convinced that the best initial recommendation for nutritional supplement
customers is to regularly take a good quality, complete, multivitamin-mineral (MVM)
supplement. This is not to take the place of a healthy, well-balanced diet, but such diets
are a real challenge for most people to comply with. An MVM supplement makes sense for
several reasons:
- It will guarantee that diets that are less than perfect will not put the person at risk
for micronutrient deficiencies.
- It will also provide a high level of certain nutrients that are beneficial at levels
above what is possible to obtain from diet alone.
- Since it is often difficult to motivate someone to take supplements for longer than a
few months, recommending a single MVM supplement provides a simpler behavior change for
people to incorporate into their lifestyle.
How does one choose the best MVM supplement? There are many good
candidates available to wholesalers and retail outlets. Rather than list the names of
those I have been impressed with, I would like to educate the reader on what to look for
in a quality MVM supplement.
The greatest challenge for a supplement manufacturer is to balance
cost, quality and convenience in a single product such as the multivitamin-mineral
supplement. Higher-cost ingredients are justified when they truly improve the quality of
the product in terms of effectiveness or safety. Using high cost ingredients merely to
"dress up" the label serves no one but the manufacturer.
Convenience is key to the ability of your customer to stay with a
regular supplement program. Unfortunately, the large amount of nutrients required to make
a complete MVM formula usually necessitate a dose of four to eight tablets or capsules per
day in order to achieve the desired level of intake. The time of the "One-A-Day"
multiple is past; those that are still marketed are woefully incomplete or low in potency.
In general, the comparisons on the label to the U.S. Recommended
Dietary Allowances (USRDA) for each nutrient are useful for deciding if one or more
nutrients are not supplied in adequate amounts. This is often the case for more expensive
ingredients, such as vitamin E and the ultratrace elements, as well as for bulky
ingredients, such as calcium, magnesium and potassium. Controversy exists over whether
some nutrients should be supplied at USRDA levels or much lower. Vitamin D, phosphorus and
iodine are considered by some to be overabundant in the US diet as it is, while extra iron
and possibly copper may be potentially dangerous for individuals who already consume
adequate amounts from the diet.
Vitamins and related factors
Vitamin A may be supplied by including retinol or beta-carotene
in the MVM formula. Beta-carotene has the advantage of very low toxicity potential as well
as being a superior antioxidant to retinol. Moreover, natural (but not synthetic)
beta-carotene appears to have a stronger association with cancer prevention than does
retinol. A daily dose of 5000-15000 IU (5-10 mg) of beta-carotene is adequate and
practical in an MVM supplement. Some individuals, however, such as those suffering from
diabetes or hypothyroidism, may not adequately convert beta-carotene to vitamin A.
Including some retinol (5000 IU/day for example) in an MVM supplement may be essential for
these patients.
As mentioned above, controversy exists over whether vitamin D is desirable in an MVM
supplement. While the USRDA is 400 IU/day, this represents the requirements during
skeletal growth; normal adults need only half this amount. For those patients who do not
get regular exposure to sunlight or vitamin D fortified foods, 200 IU/day may be an
optimal supplemental intake. However, individuals with increased risk for osteoporosis may
benefit from as much as 800 IU per day. Finally, vitamin D deficiency has been recently
linked to higher risks of colorectal and breast cancer, so it may now be more important to
guarantee adequate intake of this vitamin.
Vitamin E is an important antioxidant and should be supplied at
levels well above the USRDA of 30 IU/day. Many authorities recommend 100-400 IU/day for
the prevention of age-related degenerative diseases such as cancer and atherosclerosis.
Most natural health care providers prefer the natural d-alpha form of this vitamin,
though many successful clinical trials have used the synthetic d-alpha mixture,
which is also less expensive.
Vitamin K has only recently been added to some MVM formulas due
to recent evidence of an association with bone loss. Until more research is available, a
daily dose of 80-300 mcg conforms to current RDA standards and normal dietary intakes.
Supplementation with this vitamin is especially important to patients with a history of
chronic antibiotic therapy or intestinal malabsorption.
The vitamin B complex is a very misunderstood group of vitamins.
Each member is a separately functioning coenzyme in widely disparate parts of human
biochemistry. Their discovery in the early part of this century when chemical analysis was
primitive led to the mistaken belief that there was only one vitamin B. Later it was
discovered that many individual vitamins made up the original "vitamin B" and
that the different members were present in different foods in a wide variety of
concentrations. The idea that all B-vitamins must be consumed simultaneously in a precise
"balance" is a simplistic notion that has never been proven.
The common practice of including up to 5000% of the USRDA or more
for some B-vitamins is questionable and increases cost. Furthermore, many people report
nausea after taking supplements with very high levels of B-vitamins. Long-term side
effects are also possible. It should be sufficient to have each B vitamin represented in
amounts at, or moderately above, the human requirements for each member. I can see no
purpose in providing more than 5 or 10 times the USRDA for most patients. If a customer
has a specific condition for which a single B vitamin is known to be helpful, then a
separate supplement of this vitamin may be added to the MVM regimen, preferably after
consultation with a knowledgeable health provider.
Vitamin C is another important antioxidant and should be
supplied at levels above the minimum requirements. Nevertheless, 200 mg/day may be the
optimum dose, since this level has been shown to saturate body tissues. Higher daily
intake may only temporarily raise blood levels (as well as urinary and fecal content!),
though this could be beneficial. Many authorities do encourage higher intakes up to 1000
mg/day on the basis of therapeutic trials for specific human conditions and/or animal
studies. More research is needed to determine the most beneficial and cost-effective
amount for vitamin C in an MVM supplement.
The addition of bioflavonoids to an MVM formula is often done to provide so-called
cofactors for vitamin C. This is likely not the purpose of bioflavonoids in the human
body. Useful levels of bioflavonoids for therapeutic purposes begin at 500 mg/day for
certain health conditions; lesser amounts have no known benefit. The typical human diet is
estimated to contain as much as 1000 mg/day from foods and beverages alone. Therefore, a
truly valuable daily supplemental dose is probably in the range of several hundred
milligrams.
The presence of small quantities of other quasi-vitamins, such as
choline and inositol, in an MVM formula is probably not important for the same reasons as
discussed above for bioflavonoids. Too often, these trivial amounts are included in order
to increase the number of ingredients and claim greater "completeness."
Minerals
A common debate heard between various supplement manufacturers
concerns absorption and bioavailability of mineral compounds. Often these arguments
persist without the advantage of solid research to decide who, if anyone, is right. The
thinking person is left with only logic and basic biochemistry to use in evaluating these
claims.
Logic and basic physiology demands that minerals dissolve in the
gastrointestinal tract in time to be acted upon by the various absorptive mechanisms,
which are in place in the small intestine. Mineral compounds must usually also dissociate
(i.e. ionize or separate from their carriers), which does not necessarily happen
automatically with dissolving. However, these results will normally occur if the digestive
juices are sufficient to provide a good solution for the supplement to dissolve and the
compound is not too tightly bound.
Some supplements may not dissolve because of poor manufacturing
practices; others may be designed to rapidly break down even in the most unfriendly
environments. Most reputable manufacturers typically subject their products to artificial
"digesters" to establish the solubility of their products.
Dissociation is more likely when the chemical bond between mineral
and carrier is weakest. It is unclear whether very weakly bound compounds, such as amino
acid chelates, offer any advantage over simpler compounds such as sulfates, carbonates,
etc. It may be that the normal digestive environment is adequate to dissociate most, if
not all, of the compounds chosen by manufacturers for their mineral supplements,
especially if they are taken with meals when digestive secretions are maximal.
Calcium should be the mineral in greatest quantity in a mineral
supplement because its requirement is over two times larger than all of the other minerals
combined. Unfortunately, many manufacturers attempt to reduce daily tablet requirements by
lowering the calcium content in the daily total. As mentioned previously, at least six
tablets per day of a MVM supplement is usually necessary to provide all of the necessary
daily nutrients in adequate amounts.
Though many people assume calcium carbonate is an inferior form for
bioavailability, recent studies with improved technology for absorption measurement have
revealed only minor differences in absorption between calcium carbonate, lactate,
gluconate or citrate. Even when people have reduced stomach acid production, taking
calcium carbonate with meals results in adequate absorption. It appears that the
stimulatory effect of food in the stomach more than compensates for the weak alkalinizing
effect of carbonate. Newer forms of calcium, such as calcium citrate-malate and
microcrystalline hydroxyapatite, may actually offer improved absorption, but with a higher
price tag.
Phosphorus is often omitted from multiple mineral supplements
because of its widespread availability in the diet as well as a suggested negative effect
on calcium balance in animal studies. Phosphate may also interfere with iron absorption
from the same tablet. It is probably wise to choose a formula that provides a
calcium-phosphorus ratio of more than 2:1 or no phosphorus at all.
Magnesium is often discussed with calcium as the two share a
common absorption pathway. This means that large amounts of one may inhibit the uptake of
the other. However, this should not be a problem if the total of the two minerals is kept
below 500 mg per single dose. There is no unbiased evidence that one form of magnesium is
better absorbed than any other.
Potassium is often included in multiple mineral supplements at
doses around 100 mg per tablet. This compares to a recommended intake of 2000 mg or more!
Clearly this amount is insignificant, but it appears to be illegal by FDA ruling for
manufacturers to include more than this amount. Customers will have to depend on fruits,
vegetables, salt substitutes or liquid supplements to obtain their optimum potassium
intakes.
Many manufacturers offer MVM supplements with or without iron due to
concern over excessive iron accumulation in men and post-menopausal women. For those
customers who need iron, most forms are well absorbed but ferrous sulfate can be
irritating to the gastrointestinal tract and should be avoided, as should other mineral
sulfates.
Zinc and copper are thought to be interdependent in human
biology, so supplements should not contain large amounts of one at the expense of the
other. A 15:1 zinc-copper ratio is considered ideal with an acceptable range of 10 to 30.
Sulfated compounds may be irritating to some people.
Manganese has received a lot of attention for its role in bone
and joint health. Most MVM supplements provide only a few milligrams, but this satisfies
the minimum requirements. Iodine is not considered a nutrient at risk any longer due to
extensive sources available in water, salt and many foods. Still, manufacturers may supply
up to the RDA without risk of excessive intake.
Chromium is important in sugar and lipid metabolism and should
be present in any complete mineral formula. However, some manufacturers include far less
than the recommended 50-200 micrograms in their product’s daily dose. Organically
bound chromium (any available form except chloride) is known to be much better absorbed
than inorganic chromium chloride. While there has been recent debate over the relative
merits of chromium picolinate versus other forms of chromium for certain conditions, it
has never been shown to be better for general nutrition purposes.
Selenium has been identified as an important antioxidant
cofactor and may be important in cancer prevention. A new RDA has been established at 70
mcg/day but many formulas contain as much as 200 mcg per daily dose, which is in the upper
range of recommended intakes according to some authorities. Inorganic selenium appears to
be as available for absorption and metabolism as is organically combined selenium.
Some MVM supplements include such recently appreciated trace minerals as boron,
molybdenum and vanadium. It is unclear what intake levels are optimal for these elements.
MVM supplements will also at times include enzymes, botanical extracts, lactobacillus
cultures, etc. In my estimation, none of these substances are ever provided in large
enough amounts to contribute significantly to daily intake.
Reference: Gerber JM. Handbook of Preventive and Therapeutic
Nutrition. Gaithersburg: Aspen Publishers, 1993.
ABOUT THE AUTHOR: Dr. Gerber is Associate Professor of Clinical
Sciences at Western States Chiropractic College and a member of the NNFA Professional
Advisory Board. He holds two professional specialty certificates in nutrition and
orthopedics and is a Certified Clinical Nutritionist. His work has appeared in many
chiropractic and nutrition publications and he has presented seminars across the country.
He is the author of the Handbook of Preventive and Therapeutic Nutrition (Aspen, 1993) and
contributed to Conservative Management of Sports Injuries by Hyde and Gengenbach (Williams
& Wilkins, 1997). He may be reached via e-mail at jgerber2@qwest.net
