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Chapter 107. Dietary Supplements. Dietary Supplements. FDA definition: “vitamins, minerals, herbs or other botanicals, amino acids, and substances such as enzymes, organ tissues, glandulars, and metabolites” intended to supplement the diet. Regulation of Dietary Supplements.
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Chapter 107 Dietary Supplements
Dietary Supplements • FDA definition: “vitamins, minerals, herbs or other botanicals, amino acids, and substances such as enzymes, organ tissues, glandulars, and metabolites” intended to supplement the diet
Regulation of Dietary Supplements • The Dietary Supplement Health and Education Act (DSHEA) of 1994 • Package labeling • Adverse effects • Impurities, adulterants, and variability • National Center for Complementary and Alternative Medicine • Promotional materials
Regulation of Dietary Supplements • Dietary Supplement and Nonprescription Drug Consumer Protection Act of 2006 • FDA Current Good Manufacturing Practices (CGMPs) ruling, 2007 • Quality certification programs • Standardization of dietary supplements
Common Herbal Remedies • Black cohosh • Coenzyme Q-10 • Cranberry juice • Echinacea • Feverfew • Flaxseed • Garlic • Ginger root • Ginkgo biloba
Common Herbal Remedies • Glucosamine • Green tea • Probiotics • Saw palmetto • Soy • St. John’s wort • Valerian
Harmful Supplements to Avoid Comfrey Kava Ma huang (ephedra)
Black Cohosh • Cimicifuga racemosa • Used to treat symptoms of menopause • MOA unknown • Effectiveness • Some studies have shown it to be as effective as estrogen • Has not been evaluated for long-term use
Black Cohosh • Drug interactions • May potentiate antihypertensives and the hypoglycemic effect of oral agents and insulin • Adverse effects • Safe for routine use • GI are most common side effects • Also rash, headache, dizziness, weight gain, and cramps
Coenzyme Q-10 • Potent antioxidant in the body; participates in production of ATP at the mitochondrial level • Therapeutic uses • Mitochondrial encephalomyopathies, CHF, and myopathies due to HMG-CoA reductase inhibitors (statins)
Coenzyme Q-10 • Adverse effects • Well tolerated, may have GI symptoms • Drug interactions • CoQ-10 is structurally similar to vitamin K2 and may antagonize the effects of warfarin
Cranberry Juice • Therapeutic use • Prevents UTI • The proanthocyanidins it contains interfere with bacterial adhesion to the urinary tract • Effectiveness • Daily intake helps prevent UTIs in women in their teens or 20s and elderly women – not older adults or young girls • Contradictory evidence that cranberry juice may increase INR of warfarin patients
Echinacea • Echinacea angustifolia, E. purpurea, E. pallida • Used orally and topically • Produces antiviral, anti-inflammatory, and immunostimulant effects • Widely taken, but effectiveness is highly questionable • Interactions • May interfere with immunosuppressant drugs
Feverfew • Used primarily for prophylaxis of migraine • MOA not well understood • Has shown to be effective • Adverse effects • Well tolerated, no serious effects • Mild GI reactions • Long-term safety studies are lacking
Flaxseed • Used to treat dyslipidemia and constipation • Soluble plant fiber • Seems to decrease total cholesterol and LDL, similar to other fiber products • Adverse effects are GI-related (bloating, cramping, etc.) • Should be taken 1 hour before or 2 hours after other medications
Garlic • Used primarily for cardiovascular system effects • To reduce levels of TG and LDL and raise HDL • Also used to reduce blood pressure, suppress platelet aggregation, increase arterial elasticity, and decrease formation of atherosclerotic plaque; antimicrobial and anticancer effects
Garlic • Can have favorable effects on blood pressure and plasma lipids • Must be raw, not cooked (allicin and allinase) • 1-2 cloves twice daily for effect • Only 5 of 18 common garlic products contain allicin in effective amounts • Generally well tolerated except for unpleasant taste and bad breath • Has significant antiplatelet effects
Ginger Root • Primary uses • To treat vertigo • To suppress nausea and vomiting caused by motion sickness or morning sickness; to suppress post-op nausea and vomiting • For cancer chemotherapy • Can suppress platelet aggregation
Additional Supplements • Ginkgo • Generally well tolerated • Glucosamine • Use with caution in patients with shellfish allergy • Increased risk for bleeding • Green tea • Overconsumption leads to caffeine overdose
Additional Supplements • Probiotics • Generally well tolerated – some GI effects • Saw palmetto • Conflicting results in treatment of BPH • May have antiplatelet effects • Soy • Should not be used with antiestrogenic medications (tamoxifen)
St. John’s Wort • Widely used to treat depression • Limited clinical studies show St. John’s wort is useful for mild to moderate depression – not severe depression • No prescription needed in United States • Interacts adversely with many drugs • Induction of cytochrome P450 enzymes • Induction of P-glycoprotein • Intensification of serotonin effects
Additional Supplements • Valerian • Generally well tolerated • Does not seem to potentiate CNS depressant effects of alcohol, but this may occur • Used as a tranquilizer in World War II
Harmful Supplements • Comfrey • Contains pyrrolizidine alkaloids that are associated with veno-occlusive disease • Kava • Can result in severe hepatic damage • Ma huang (ephedra) • Can elevate BP and stimulate the heart and CNS