The A, B, Cs of Vitamins

Barbara Sax
Published Online: Friday, November 1, 2002

Americans. Last year, drugstore sales of supplements and V(itamins)vitamins totaled(and supplements)$1.3 billion, (are)according(very)to(popular)Information (with)Resources Inc (IRI). The category is not growing at the rate it was a few years ago: IRI data showed that dollar sales grew by less than 1% last year at drugstores. Many patients, however, who are determined to take a proactive role in their health care remain devoted to these products.

Pharmacists face a number of challenges in connection with the vitamin category. The first is the sheer number of products that enter the market each year. With so many conflicting studies on the benefits of so many different vitamins, supplements, and herbal remedies, it is nearly impossible for a pharmacist to keep up with the reams of information being generated.

At the same time that studies on the benefits of vitamins are being touted, other studies questioning the safety of vitamins and skepticism about manufacturers? claims also are circulating. In addition, because the FDA cannot by law review or evaluate the safety or the effectiveness of the supplement ingredients in vitamins, patients have only manufacturers? claims to assure them that the products are safe.

How can a pharmacist help patients make healthy choices concerning vitamin and mineral supplements? Pharmacy Times has put together some questions and answers designed to highlight some key category issues.

Can Everyone Benefit from Taking Vitamins and/or Supplements?
Not everyone favors the widespread use of multivitamins and single-component vitamins. Most health care practitioners agree that healthy adults who include a variety of foods from the 5 food groups in their diets are getting the vitamins and minerals they need. Experts say, that is the optimal approach: the vast majority of nutrient intake should be derived from diet. Many people, however, simply do not maintain a balanced diet.

Many Americans eat at fast-food restaurants, which have menus nearly devoid of vegetables and fruits. More and more Americans are eating on the run, and they often substitute junk food for a balanced meal. Young children also are likely to have marginal eating habits.

As a result, many patients are candidates for supplementation. Pharmacists should stress to patients, nevertheless, that taking vitamins should not be viewed as a painless way to avoid maintaining a balanced diet.

Who Can Benefit from Taking Vitamins?
Nutritionists may disagree about the benefits of vitamins for all patients, but there is a general consensus that vitamin supplementation for a few key patient groups is a good idea. For example:

? Pregnant and lactating women need more nutrients, particularly calcium, folic acid, and iron
? Vegans and other people with limited dietary selections may need additional dietary supplements, such as calcium, zinc, iron, and (vitamins B)12 (and D; B)12(, for example,) is found only in animal products, and deficiency in this key vitamin can lead to anemia and problems with nerves and muscles
? Patients on very low-calorie weight-loss diets (fewer than 1200 calories a day) may not consume enough food to meet daily requirements and may miss out on important nutrients; a multivitamin/multimineral supplement that provides no more than 100% of the daily value is a good way to ensure proper nutrition through the course of the diet
? People with limited dairy intake may need calcium supplements
? Menopausal women are often advised to supplement their calcium intake
? Smokers should increase their vitamin C intake by consuming more citrus fruits or fortified juices or by taking a supplement; smokers are advised to attain a daily intake level of 125 mg for men and 110 mg for women
? Patients with atrophic gastritis often suffer vitamin deficiencies and can benefit from supplementation from a daily vitamin pill
? Elderly patients may have trouble swallowing vegetables or may simply not eat enough to derive the needed benefit; they are frequently advised to take multivitamins or single-component vitamins

How Can I Assess Which Vitamins a Patient Needs?
In most cases, the pharmacist really should not be the health care practitioner making that call. ?We are teaching pharmacists much more about nutrition, and it?s important for pharmacists to be able to answer key questions, but nutritionists know more about nutrition than physicians or pharmacists,? said Timothy J. Maher, PhD, dean of research and graduate studies at the Massachusetts College of Pharmacy and Health Sciences in Boston.

A registered dietitian or nutritionist can help evaluate a patient?s eating patterns and determine whether supplements?including a multivitamincan be beneficial. Patients who fall into one of the above groups or those patients who are unwilling or unable to consume a balanced diet may be candidates for specific supplements or multivitamins.

It is never a good idea for patients to self-prescribe a specific supplement. ?Patients are getting a lot of information from the Internet, and not all of it is correct,? said Dr. Maher. Pharmacists can help dissuade patients from self-prescribing vitamins and minerals by pointing out the possible dangers associated with uninformed supplementation.

Are There Risks in Taking High Doses of a Single Supplement?
There have been no studies on the chronic use of large doses of many vitamins, so exceeding the daily requirement should be discouraged. Some fat-soluble vitamins, such as vitamins A and D, are stored in the tissue and build up in the body over time. If megadoses are taken, they can reach toxic levels. Excessive vitamin A intake can cause bone, liver, or nerve damage or birth defects.

Even some water-soluble vitamins taken excessively can cause problems. High-potency vitamin
(B)12, used to treat premenstrual syndrome, has been shown to cause irreversible nerve damage. At the least, overdoing water-soluble vitamins can be a waste of time and money. ?As far as many vitamins are concerned, patients in the United States have the richest urine in the world,? said Dr. Maher. ?With water-soluble vitamins, in many cases patients are just passing the vitamins through their urine.?

There is another reason to avoid excessive dosing of vitamins. ?Excess amounts of some vitamins and minerals can also mask deficiencies of others. For example, supplementing with (B)12 can hide a folic acid deficiency,? said Sandy Palmer, director of clinical nutrition at Mercy Medical Center in Baltimore, MD.

Are Adverse Interactions Possible with Vitamins?
Some vitamins and minerals decrease the absorption of prescription drugs. ?It?s well known that patients should not take calcium when they are taking tetracycline,? said Dr. Maher. ?Less well known is magnesium?s role in decreasing absorption. With magnesium becoming a more popular supplement, it?s important that pharmacists know that it can bind drugs just as well as calcium.? Dr. Maher suggests that, in consulting with patients, pharmacists always include questions about vitamins or other supplements when they ask which medications a patient is taking.

Just as important for pharmacists and physicians to watch is the vitamin and/or mineral depletion that is caused by the chronic use of many prescription drugs. Long-term use of diuretics, for example, can deplete calcium, magnesium, and B-complex vitamins. ?I often see patients on statin drugs show signs of muscle weakness since those drugs can deplete coenzyme Q10 levels,? said one nutritionist.

What?s the Difference Between Natural and Synthetic Vitamins?
Due to production processes, most vitamin supplements are synthetic to some degree. Even ?whole-food? vitamin supplements are a mix of dehydrated foods with added vitamins.
The body cannot distinguish between a vitamin molecule derived from a synthetic source and one derived from a natural source. Therefore, there is no difference in the absorption of natural and synthetic vitamins.

When Is the Optimal Time for a Patient to Take Vitamins?
Because supplements are really components of food, most supplements should be taken with food. There are some supplements, however, that should be taken between meals to increase absorption.

Oil or fat can help the absorption of fat-soluble nutrients, such as vitamins A, D, E, and K and carotenoids. Taking them with a teaspoon of peanut butter or some other fatty food will achieve the desired result.

Likewise, water-soluble nutrients, such as vitamins B and C and flavonoids, are easily absorbed without food, but all work better when taken at mealtime.

Some supplements should not be taken with food. Amino acid supplements, for example, should typically be taken 30 minutes before eating.

Glycinates are another example, and some manufacturers recommend that these products be taken before breakfast on an empty stomach.



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