Dietary Supplements & Herbal Medications

Dietary Supplements & Herbal Medications

The medical use of plants in their natural and unprocessed form undoubtedly began when the first intelligent animals noticed that certain food plants altered particular body functions. While there is a great deal of historical information about the use of plant-based supplements, there is also much unreliable information from poorly designed clinical studies that do not account for randomization errors, confounders, and—most importantly—a placebo effect that can contribute 30–50% of the observed response. Since the literature surrounding dietary supplements is evolving and much of it is not peer-reviewed, it is recommended that reputable evidence-based resources be used to help guide treatment decisions. An unbiased and regularly updated compendium of basic and clinical reports regarding botanicals is Pharmacists Letter/Prescribers Letter Natural MedicinesComprehensive Database (see references). Another evidence-basedresource is Natural Standard, which includes an international, multi-disciplinary collaborative website, http://www.naturalstandard.com. Unfortunately, the evidence available to these objective and unbiased evaluators is rarely adequate to permit clear conclusions. As a result, all statements regarding positive benefits should be regarded as preliminary and even conclusions regarding safety should be considered tentative at this time.

For legal purposes, “dietary supplements” are distinguished from “prescription drugs” derived from plants (morphine, digitalis, atropine, etc) by virtue of being available without a prescription and, unlike “over-the-counter medications,” are legally considered dietary supplements rather than drugs. This distinction eliminates the need for proof of efficacy and safety prior to marketing and also places the burden of proof on the Food and Drug Administration (FDA) to prove that a supplement is harmful before its use can be restricted or removed from the market. Although manufacturers are prohibited from marketing unsafe or ineffective products, the FDA has met significant challenges from the supplement industry largely due to the strong lobbying effort by supplement manufac-turers and the variability in interpretation of the Dietary Supplement Health and Education Act (DSHEA). DSHEA defines dietary supplements as vitamins, minerals, herbs or other botanicals, amino acids or dietary supplements used to supplement the diet by increasing dietary intake, or concentrates, metabolites, constituents, extracts, or any combination of these ingredients.

CASE STUDY

A 65-year-old man with a history of coronary artery disease, high cholesterol, type 2 diabetes, and hypertension presents with a question about a dietary supplement. He is in good health, exercises regularly, and eats a low-fat, low-salt diet. His most recent laboratory values show that his low-density lipoprotein (LDL) cholesterol is still slightly above goal at 120 mg/dL (goal < 100 mg/dL) and his hemoglobin A1C is well controlled at 6%. His blood pressureis also well controlled. His medications include simvastatin, metformin, benazepril, and aspirin. He also regularly takes a vitamin B complex supplement and coenzyme Q10. He asks you if taking a garlic supplement could help to bring his LDL cholesterol down to less than 100 mg/dL. What are two rationales for why he might be using a coenzyme Q10 supplement? Are there any supplements that could increase bleeding risk if taken with aspirin?