Dietary supplements effect

This compilation of articles from the acclaimed EHN focuses on nutritional supplements. These include the traditional, well-known substances such as vitamins and major minerals, present in most diets consumed by humans. They also include other food constituents such as certain fatty acids and amino acids, fiber, carotenoids, and other compounds. Some of these may not have a defined nutritional role, but do affect health by their involvement in specific physiological functions. In addition, several chapters describe key biological mechanisms related to dietary supplement effects, such as cellular antioxidant activity. 

Brewers and bakers dried yeasts are used as dietary supplements. They contribute some protein and trace minerals, and some B vitamins, but no vitamin C, vitamin B 2 or fat-soluble vitamins. The glucose tolerance factor (GTE) of yeast, chromium nicotinate, mediates the effect of insulin. It seems to be important for older persons who caimot synthesize GTE from inorganic dietary chromium. The ceU wall fraction of bakers yeast reduces cholesterol levels in rats fed a hypercholesteremic diet. 

Zinc is also an essential food element in the human diet. Too Httle zinc in the diet can lead to poor health, reproductive problems and a lowered abHity to resist disease. Taking too much zinc into the body through food, water or dietary supplements can also affect health. The levels of zinc that produce adverse effects are higher than the Recommended DaHy AHowances, which are 15 mg/day for men, 12 mg/day for women, 10 mg/day for children and 5 mg/day for infants. 

HERMANSEN K, SONDERGAARD M, HOIE L, CARSTENSEN M and BROCK B (2001) Beneficial effects of a soy-based dietary supplement on lipid levels and cardiovascular risk markers in type 2 diabetic subjects. Diabetes Care. 24 (2) 228-33. 

For any intervention intended to impact favorably upon human health, it is important to evaluate its safety and efficacy in order to demonstrate that it does not cause harm and it does provide the expected benefit. The gold standard method for evaluating any intervention, whether it be a botanical product, dietary supplement, drug, medical device or medical procedure, is the randomized, clinical trial (RCT). A clinical trial is a type of experiment conducted in human subjects where the effects of at least two interventions are compared. Often, the clinical trial takes the form of an active treatment compared to an inactive control or placebo. 

SRB contains high-quality protein, oil, dietary fiber, polysaccharides, fat-soluble phytochemicals (plant derived bioactive compounds) and other bran nutrients. Rice bran and germ are the richest natural sources of B complex vitamins as well as E vitamins, polyphenols, several antioxidants and minerals. It is now available in the commercial food ingredient market as a safe and effective functional food and dietary supplement. 

The sterols and sterolins in rice bran are potent immunomodulators. The best response was obtained with a 100 1 sterol/sterolin mixture that demonstrated T-cell proliferation from 20% to 920% and active cell antigens after four weeks in human subjects (Bouic et al, 1996). Another in vitro experimental study with sterol/sterolins, demonstrated a significant increase in cytokinines, interleukin-2 and y-interferon between 17% and 41 % in addition to an increase in natural killer cell activity. These experiments (Bouic et al, 1996) prove that sterol/sterolins are potent immunomodulators with important implications for the treatment of immune dysfunction. Rice bran products are excellent dietary supplements for the improvement of immune function. It is probable that the effects of rice bran on diabetes, CVD and cancer all result from improved immune function. 

Kucuk, O. et al.. Effects of lycopene supplementation in patients with localized prostate cancer, Exp. Biol. Med. (Maywood), 227, 881, 2002. van Breemen, R.B. et al.. Liquid chromatography-mass spectrometry of cis- and all-trans-lycopene in human serum and prostate tissue after dietary supplementation with tomato sauce, J. Agric. Food Chem., 50, 2214, 2002. 

Youdim, K.A. et al.. Short-term dietary supplementation of blueberry polyphenohcs beneficial effects on aging brain performance and peripheral tissue function, Nutr. NeuroscL, 3, 383, 2000. 

Additional in vivo studies on the biological activity of proanthocyani-dins investigating a series of behavioral activities (motihty, body weight gain, body temperature, motoric coordination, anticonvulsant effects and central analgesic activities) showed no or only moderate pharmacological effects [53]. On the other hand, dietary supplementation with cocoa pro-cyanidin supplements can dose-dependently prevent the development of hyperglycemia in diabetic obese mice [54]. 

The effect of prolonged antioxidant therapy in relation to normal physiological processes (for example, redox cycling, cell-cell signalling, transcription factor activation) must be assessed. It is conceivable that the overload of one antioxidant by dietary supplementation (for example, a-tocopherol) may shift the levels of other antioxidants (for example, by decreasing ascorbate and /3-carotene concentrations), with unknown consequences. To assess the potential for lipid-soluble antioxidant treatment in inflammatory diseases such as RA, further investigations into these questions will be needed. 

Wu, D., Onwulata, C., Ren, Z., Pae, M., Pang, H., and Meydani, S. (2009). Effect of dietary supplementation with a formulated nutrient mixture together with whey-based protein on immune response of young and old mice. /. Fed. Am. Soc. Exp. Biol. 23, 909.7. 

Several different niacin formulations are available niacin immediate-release (IR), niacin sustained-release (SR), and niacin extended-release (ER).28,29 These formulations differ in terms of dissolution and absorption rates, metabolism, efficacy, and side effects. Limitations of niacin IR and SR are flushing and hepatotoxicity, respectively. These differences appear related to the dissolution and absorption rates of niacin formulations and its subsequent metabolism. Niacin IR is available by prescription (Niacor ) as well as a dietary supplement which is not regulated by the FDA.28 Currently, there are no FDA-approved niacin SR products, thus, all SR products are available only as dietary supplements. 

Obtain a thorough history of prescription, non-prescription, and dietary supplement use. Assess inhaler technique and adherence to the medication regimen. Ask the patient about effectiveness of medications at controlling symptoms and adverse effects. 

Obtain a thorough medication use history, including present and past drugs prescription and nonprescription drugs the patient s self-assessment of response and side-effect problems use of alcohol, tobacco, caffeine, and illicit substances and use of herbal products and dietary supplements, as well as any allergies and adherence difficulties. 

The risk of colon cancer appears to be inversely related to calcium and folate intake. Calciums protective effect may be related to a reduction in mucosal cell proliferation rates or through its binding to bile salts in the intestine, whereas dietary folate helps in maintaining normal bowel mucosa. Additional micronutrient deficiencies have been demonstrated through several studies to increase colorectal cancer risk and include selenium, vitamin C, vitamin D, vitamin E, and 3-carotene however, the benefit of dietary supplementation does not appear to be substantial.11... 

The above illustration should be a clear caution that components of food may interact with drugs, resulting in substantial positive or negative therapeutic effects. As will be noted later, this principle also applies to so-called dietary supplements, including bo-tanicals, used for the treatment of numerous medical conditions. 

In addition to food- or nutrient-based interactions in the metabolism of drugs, it has become quite clear in recent years that so-called dietary supplements including botanicals have the potential to participate in such interactions. The latter observation has special relevance because of the extensive use of such products worldwide ( 12 billion per year in the United States alone), their easy commercial availability (no prescription required), and their common use with prescribed drugs. Furthermore, many people consider such natural products to be safe and free of any bad effects (it should be pretty easy to recall many poisons... 

Some precautions are based on the dietary supplement s side effect profile. St. John s wort may induce photosensitivity therefore, fair-skinned persons should be cautioned about exposure to bright sunlight while taking the herb. 

A dietary supplement may be safe when taken in the recommended doses but may become dangerous in higher doses. However, patients may develop side effects even when ingesting recommended doses. Adverse reactions may be due to allergic reactions, dietary supplements containing toxic substances, mis-identification of plant, mislabeling of plant, natural toxic substances such as pyrrolizidine alkaloids in comfrey, unnatural toxic substances such as heavy metals, or pesticides. 

Although many patients believe that dietary supplements will not interact with medications, recent literature suggests otherwise. Recently, many St. John s wort-drug interactions have been reported in the literature. Cases of patients developing symptoms of serotonin syndrome have been reported with St. John s wort alone and in concomitant therapy with other antidepressants such as monoamine oxidase inhibitors, serotonin reuptake inhibitors, and venlafaxine. St. John s wort may exacerbate the sedative effects of benzodiazepines, alcohol, narcotics, and other sedatives. St. John s wort may decrease the levels of protease inhibitors, cyclosporine, digoxin, and theophylline. 

Many dietary supplements have antiplatelet activity, which may increase the risk of bleeding when used concurrently with anticoagulants. Feverfew inhibits cyclooxygenase and phospholipase A2 and may interact with anticoagulants and potentiate the antiplatelet effect of aspirin. Other supplements that possess antiplatelet activity include but are not limited to garlic, ginkgo, vitamin E, vitamin A, and selenium. 

If a pharmacist posted a sign in a pharmacy claiming a dietary supplement is effective in treating or preventing a certain disease, the pharmacist would be violating the FDCA. The product would be considered a drug but not properly labeled as a drug and therefore would be misbranded. 

Dietary supplements may be less expensive than prescription medications. However, dietary supplements are not guaranteed to be equivalent in safety and efficacy. Unfortunately, many consumers believe that dietary supplements are as safe and effective as prescription medications. As pharmacists, our role is to educate patients on the fallacies of dietary supplements. 

Patients should always start with the lowest recommended dose and increase slowly to avoid overdosing. Follow-up with the patient is necessary to evaluate whether the dietary supplement is safe and effective. Report any suspected adverse event to FDA s Medwatch, 1-800-FDA-1088. FDA has developed the Special Nutritionals Adverse Event Monitoring System (SN/AEMS), a database of adverse events associated with the use of special nutritional products dietary supplements, infant formulas, and medical foods. ... 

FIGURE 23.3 Effects of dietary supplementation with carotenoids on (a) serum carotenoid concentrations, (b) serum concentrations of ROMs, and (c) serum antioxidant capacity (OXY), in nestling European kestrels (Falco tinnunculus). Open circles are nonsupplemented controls, and closed circles are carotenoid-supplemented birds. Means SE are shown. Means that are significantly different are denoted by asterisks CP<0.05 "Pc0.01 mmP<0.001). 

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