FEBRUARY 15, 2007


Teach patients how to take their
vitamins — safely

Vitamin buyer's guide

Before they choose a supplement, your patients should always:

Read labels carefully Product labels can tell you what the active ingredients are, which nutrients are included, the serving size — for example, capsule, packet or teaspoonful — and the amount of nutrients in each serving.

Avoid supplements that boast of "megadoses" In general, choose a multivitamin-mineral supplement that provides about 100% of the Daily Value (DV) of all the vitamins and minerals, rather than one which has, for example, 500% of the DV for one vitamin and only 20% of the DV for another. The exception to this is calcium — if they provided 100% of the DV, the tablets would be too large to swallow!

Look for "USP" on the label This ensures that the supplement meets the standards for strength, purity, disintegration and dissolution established by the testing organization US Pharmacopeia (USP).

Beware of gimmicks Synthetic vitamins are usually the same as so-called "natural" vitamins, but "natural" vitamins usually cost more. And don't give in to the temptation of added herbs, enzymes or amino acids — they add mostly cost.

Look for expiration dates Dietary supplements can lose potency over time, especially in hot and humid climates.

Source: Dietary supplements: Using vitamin and mineral supplements wisely, Mayo Clinic

Last week, the US watchdog ConsumerLab.com reported evidence of dangerous amounts of lead in several popular brands of multivitamins. They even found a kids multivitamin that contained a staggering 216% more vitamin A than stated on the label. Of the 21 products tested, only 10 met their claims and quality standards.

News like that is enough to cause your patients to run screaming from the supplement aisle. Yet it's clear most Canadians aren't getting anywhere near the recommended intake of vitamins and minerals from their increasingly fatty, vegetable-sparse diets. In fact, less than half your patients are getting all the nutrients they need out of the food they eat, according to Dr Sam Kacew, PhD, a professor of pharmacology at the University of Ottawa.

But your patients should proceed back to the supplement aisle with caution. As you well know, taking too much of the wrong type of vitamin can be dangerous. Here are some tips on how to help your patients get the extra nutrients their bodies need safely.

Lots of people probably think they can get away with unhealthy eating habits if they pop a multivitamin with their morning coffee. And they've no doubt heard the stories that taking megadoses of certain vitamins — quantities well above the minimum daily requirement — may prevent things like heart disease, cancer, osteoporosis and other chronic diseases. But Dr Kacew says the reality is that there's no good evidence that any of it's true — quite the contrary in fact. The important thing to remember, he says, is that not all vitamins are created equal.

Water-soluble vitamins include the B group of vitamins, vitamins C, H and folic acid. Explain to your patients that while the body absorbs these vitamins easily, any excess is excreted in urine, so loading up on them won't do them any good. There are exceptions, though. Too much vitamin B6 and vitamin C can have unpleasant side effects (see Vitamins 101). No matter what they may have heard, you should tell your patients that while vitamin C certainly plays a role in helping the body fight off infections, there's no evidence that loading up on it will prevent colds, heart disease, cancer, or eye diseases such as cataract and macular degeneration.

Another important exception, of course, is folic acid. Pregnant women need to get at least 400 micrograms a day to prevent severe birth defects like spina bifida. In fact, you should tell women who are considering having a baby to start taking the supplements immediately, because the potential defects occur very early on in development.

Fat-soluble vitamins A, D, E and K, on the other hand, are stored in body fat and people who don't get enough digestible dietary fats are susceptible to shortages. But you should impart to your patients that only you can diagnose a vitamin deficiency, and they should only take supplements of fat-soluble vitamins under your supervision. "Individuals deficient in fat soluble vitamins must take supplements, but this needs to be cautioned as excess results in toxicity," says Dr Kacew.

Symptoms of vitamin A deficiency include night blindness, dry eyes and inflammation; rough, dry skin; and vulnerability to respiratory and urinary tract infections. Patients with insufficient stores of vitamin D will experience bone pain or tenderness, skeletal and dental deformities and muscle cramps. Also, be sure to warn your patients on blood thinners that vitamin E and K can interfere with their medication — they shouldn't take them without your consent.

Generally speaking, most dietary supplements won't do any harm. Multivitamins, Dr Kacew points out, contain mostly water-soluble vitamins and a good portion of the preparation is excreted. "But they are absolutely not necessary for individuals ingesting an adequate diet," he emphasizes.

Unfortunately that's often not the case. The following patients in particular may be in need of a vitamin boost:

  • Those who consume less than 1,200 calories per day
  • Elderly patients who don't eat as much as they should; don't get enough sun; are lactose intolerant; or don't absorb and utilize Vitamin B12 because of changes in their gastric secretions
  • Strict vegetarians
  • Patients who are lactose intolerant
  • Chronically ill individuals who take medications regularly or are recovering from surgery or trauma
  • Alcoholics usually have trouble absorbing the B-complex vitamins
  • Smokers may need more vitamin C
  • Post-menopausal women generally need more calcium and vitamin D

Before they buy, though, be sure to remind your patients that like the vitamins they contain, not all supplements are created equal. Hand them a copy of our vitamin buyer's guide for some handy tips.



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