- CONDITION CENTERS
With the ever-increasing awareness of the need for health promotion, more people are turning to OTC dietary and nutritional supplements to preserve and prolong their wellness. A seemingly endless supply of available products can puzzle both the health care professional and the patient. Knowledge on the part of the pharmacist of the wellness products available, their indications, and the patient population for which they are appropriate will help to minimize potential questions.
The antioxidant vitamins C, E, and beta-carotene have attracted media attention for their health-promoting activities. Antioxidants are thought to act as scavengers for free radicals, thus preventing cell damage. Vitamin E, a fat-soluble antioxidant, has been promoted to prevent coronary heart disease, cancer, and cataracts; however, its efficacy in disease prevention warrants further study. The Recommended Dietary Allowance of vitamin E is 22 international units (IU), and deficiencies are rare.1
Vitamins C and E have gained recent popularity for their role in the prevention of oxidative changes related to Alzheimer's disease.2 Research suggests that cognitive loss may be due to oxygen free radicals, and in animal studies antioxidant vitamin supplements seemed to increase neuron survival and synaptic response.3 Although further study is needed, it appears that using vitamins C and E in combination therapy may help reduce the prevalence and incidence of Alzheimer's disease.2 Other studies suggest vitamin C and E supplementation to protect against vascular dementia and to improve cognitive function.4
Similarly, ginkgo supplements may play a role in the treatment of memory problems and dementia. The active constituents are believed to act as free radical scavengers, thus mediating the oxidation and cell damage seen in Alzheimer's disease. Other proposed mechanisms of ginkgo include increased blood flow through small vessels, vasoregulatory effects, increased tolerance to hypoxia, neuroprotective properties, inhibition of phospholipase A, and decreased capillary fragility. Side effects of ginkgo are rare and include nausea, headache, stomach problems, diarrhea, allergy, anxiety, and sleep disturbances. Gingko has antiplatelet properties, and patients receiving anticoagulation therapy should be cautioned against its use.5
Supplements for Well-being
Ginseng has been advocated for its chronic strengthening effects; however, clinical data have yet to show a relationship. Its mechanism is complicated and is believed to result in corticosteroid-like actions, hypoglycemic activity, and neurotransmitter activity. Estrogenic adverse effects have been reported. Ginseng also exhibits antiplatelet activity, requiring caution in anticoagulated patients.5 Daily health maintenance doses range from 250 to 500 mg for up to 3 months. Side effects have not been clearly established but may include sleeplessness, increased blood pressure, headache, nausea, and vomiting.6
Prior to its 1998 introduction in the United States, S-adenosyl-methionine (SAM-e) was widely used in Europe for the treatment of arthritis and depression. SAM-e is naturally found throughout the body's tissues and fluids but appears to be more concentrated in the brain and liver. Some patients with depression, Alzheimer's disease, dementia, and Parkinson's disease have been found to have below-average levels of SAM-e in their cerebrol spinal fluid.7 SAM-e levels also may be low in patients with folate or vitamin B12 deficiencies.5 Patients with a history of bipolar disorder should not use SAM-e, because it may induce mania. A dosage of 400 mg per day is recommended in the treatment of depression, with up to 1600 mg per day in severely depressed patients. Arthritis patients typically require 400 mg twice a day for 2 weeks, followed by 400 mg daily.7 Side effects are minor and include insomnia, nervousness, appetite suppression, constipation, headaches, palpitations, nausea, dry mouth, sweating, and dizziness.5 Sexual dysfunction and weight gain have not been reported.7
Glucosamine and chondroitin sulfate have been marketed in conjunction for the treatment of osteoarthritis. Glucosamine is a cartilage component and may play a role in cartilage metabolic responses. In the collagen matrix, chondroitin sulfate appears to increase proteoglycan concentration and to decrease collagenolytic activity.8 A 3-year, randomized, placebo-controlled study of 212 patients found minimal joint space loss in the active treatment group taking 1500 mg of glucosamine daily. Advocates of nutraceuticals promote glucosamine as being safer than traditional nonsteroidal anti-inflammatory drugs for long-term treatment of osteoarthritis.9
Calcium affects many aspects of the body, including muscle and blood vessel contractility, hormone and enzyme secretion, and neurotransmission. Its impact on bone mineral density and its role in preventing osteoporosis are both well known and well promoted. For adults between the ages of 19 and 50, the National Institutes of Health recommends consuming 1000 mg of calcium a day; adults 51 years and above are recommended to take 1200 mg a day. The most popular formulations of calcium supplements are calcium carbonate and calcium citrate. The carbonate formulation owes its popularity to being inexpensive and easy to obtain; however, the citrate form is better absorbed by the gastrointestinal tract. Side effects of calcium include constipation, flatulence, and bloating and can be minimized by spreading the doses throughout the day.10
Vitamin D is partnered with calcium in the fight against osteoporosis. Its main role is to maintain serum calcium and phosphorus levels and to promote calcium absorption, which results in bone strengthening and maintenance. Vitamin D can be synthesized in the body after exposure to sunlight, as well as being found in foods and supplements. Adults aged 19 to 50 are recommended to consume 200 IU of vitamin D daily, those aged 51 to 70 require 400 IU daily, and those aged 71 and above require 600 IU daily.11
Whereas calcium supplementation has been shown to be significant in the prevention of osteoporosis, recent research suggests that potassium and magnesium supplementation may play a role in bone mineral density. Low potassium intake promotes urinary calcium excretion; conversely, increased dietary potassium results in calcium retention by the kidneys. Magnesium affects calcium balance in the bone and is necessary for calcium metabolism. Women with osteoporosis have demonstrated low magnesium content, which is reflected in brittler bone crystals than in women with adequate magnesium levels.12
The array of dietary supplements and their often-ambiguous indications present challenging situations for the health care provider. Preparation and education will guide both the patient and the provider in selecting an appropriate agent.
Dr. Holmberg is a pharmacist with Phoenix Indian Medical Center, Phoenix, Ariz. The opinions expressed are those of the author and not necessarily of any goverment agency.
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