Transcript pptx
Supplements Bi 28: March 2015 Key Skills • Explain how dietary supplements are (and are not) regulated. • Discuss some of the uses and risks of supplements, and explain how people can make good choices about dietary supplementation. • Differentiate between vitamin, mineral, protein, herbal, and performance supplements, and give examples. Starter Question Before marketing a supplement, are makers legally required to show that it’s safe? Are they required to show that it’s effective in treating disease? Are they required to show that it’s labeled properly? Regulation of Supplements The Food and Drug Administration (FDA) regulates the safety of supplements. Unlike pharmaceutical drugs, supplements do not need to undergo clinical trials for effectiveness vs. placebo. And the FDA has the burden of showing that a supplement is unsafe. The Federal Trade Commission (FTC) oversees advertising and packaging claims. Legally, a supplement cannot claim to cure any disease. However, supplements are a multibillion-dollar industry (> $15 billion/yr in sales in U.S.). Hard to regulate effectively! Case Study: Oscillococcinum Oscillococcinum is a homeopathic medicine sold at a price of $20 for a 30-count package. It is marketed for the treatment of flu symptoms. It is not regulated as a pharmaceutical drug. No double-blind clinical trials are required. Its regulation is closer to that of supplements. The back of the package is designed to strongly resemble the package of a pharmaceutical over-thecounter drug! However, the active ingredient is written as a long Latin phrase: “Anas barbariae hepatis et cordis extractum” 200CK HPUS. Look up this ingredient online. What is it? Would you expect it to have any effect on cold/flu symptoms? Case Study: Oscillococcinum The ingredient in question is duck liver and heart that has been diluted in a 1 to 10400 ratio in water, i.e, 10000000000000000000000000000000000000 00000000000000000000000000000000000000 00000000000000000000000000000000000000 00000000000000000000000000000000000000 00000000000000000000000000000000000000 00000000000000000000000000000000000000 00000000000000000000000000000000000000 00000000000000000000000000000000000000 00000000000000000000000000000000000000 00000000000000000000000000000000000000 00000000000000000000 parts water to 1 part duck. In other words… “Of course it’s safe. There’s nothing in it.” - Representative of Boiron, as quoted in U. S. News and World Report Supplement Usage Some supplements, such as vitamin and mineral supplements, can be useful to people with special dietary and lifestyle needs. For example, many vegans and vegetarians supplement with Vitamin B12 (cobalamin) and vitamin D. Supplements are marketed heavily towards women, older people, and athletes. Iron and calcium supplements can reduce anemia and osteoporosis risk in some people. Pregnant women can supplement with folic acid, a B vitamin, to reduce the risk of spina bifida, a condition where a child’s spine does not close up properly. Should You Supplement? How can a person decide whether or not they ought to take supplements, and what sort of supplements might they take? What are some warning signs that can help us recognize false or exaggerated claims? Visit MedlinePlus and look up three different supplements from their list, and see whether or not they are listed as effective or ineffective (or “insufficient evidence”). Note any side effects. http://www.nlm.nih.gov/medlineplus/druginfo/herb_All.html General Rules Get a Balanced Diet: Many vitamins and minerals require cofactors found in food to be absorbed well. Supplements do not replace a healthy diet; they supplement it. Be skeptical! Get Medical Advice: Talk to a nutritionist or other medical professional who does not have a vested interest in selling a supplement to see what works best for you. Don’t Expect Extreme Results: At best, supplements support normal functioning. They cannot safely make you lose weight quickly or treat disease (unless you have a serious deficiency). Warning Signs The following are signs that a supplement product might be less effective than claimed, or even outright fraudulent: 1. Real science is exaggerated. You need carnitine to burn fat… but you don’t need to take it as a supplement. The body makes it! 2. Claims to treat everything. A vague statement about how a supplement is “beneficial” for 20 different diseases is suspect. 3. Personal testimonials/anecdotes. A clinical study requires a large sample size. People sometimes get spontaneously better, or feel a placebo effect, so testimonials from individuals aren’t trustworthy. 4. Suspicious language. “Secret ingredient,” “ancient remedy,” and “miraculous cure” are all suspect marketing claims. If the ingredient works, why would the maker need to keep it secret? Vitamin Supplements: Examples Vitamin C: Often marketed for immune relief; better to get it from fresh fruits in the diet, but not harmful in supplementation. Vitamin A: Although vitamin A is important for vision, overdose can be harmful! Get it from the diet as a provitamin instead. Vitamin B12: Important in nervous system function. Although vegans and vegetarians have a lower deficiency risk for most vitamins, B12 is the exception. Multivitamins/Multiminerals: Often marketed at older people. While a balanced diet is preferable, many people have lower caloric demands as they get older, so they eat less. Multivitamins are not strictly necessary, but can be worthwhile for some people. Pregnancy/postnatal vitamins: While many of the advertised benefits of prenatal and postnatal supplements are questionable, supplementation with folic acid can greatly reduce the risk of spinal defects in children. In addition, getting sufficient minerals such as calcium and iron can help during breastfeeding. Mineral Supplements: Examples Chromium: Marketed to athletes as a weight loss/performance supplement, but not particularly effective for most, and can cause rare problems in large doses. Iron: Needed to transport oxygen. Chewable iron tablets are not always well-absorbed when taken alone. Can be helpful to supplement during heavy menstrual flow. Calcium: Calcium supplements often combine calcium and vitamin D for better absorption. Can improve bone health in moderation, but overdoing it can sometimes lead to kidney damage. Take home point: Vitamin and mineral needs are best met through a balanced diet, but some people, such as women who are pregnant or have heavy menstrual flow, post-menopausal women at risk of bone damage, children, and the elderly can benefit from careful supplementation. Protein and Amino Acid Supplements Athletes do need more protein than the average person! However, this does not need to be in the form of a ton of meat products or protein supplements. Most Americans already get enough protein. Protein sources that provide all the essential amino acids, especially branched-chain amino acids, and some sugars can help muscle building… as can other, cheaper protein sources. However, evidence for the benefits of protein powders, individual amino acid supplements (arginine, glutamine/glutamate, etc) is limited and based on small studies. Some “protein supplements” also contain fat and corn syrup! (“Whey protein concentrate” is not the same thing as “whey protein isolate,” which is not the same thing as “whey.”) Performance-Enhancing and Weight-Loss Supplements Reliable data on performance-enhancing supplements are often limited. Many have side effects and are banned for use by professional athletes. Some supplements make promises of rapid weight loss. Such supplements are either ineffective in the long term or actively harmful! The most common “weight-loss/performance” supplement is caffeine. In small amounts, caffeine is relatively safe, but large doses can lead to high blood pressure and sleep loss, and regular users can become dependent and need more caffeine to have the same effect. Caffeine withdrawal can cause headaches and fatigue. Diet drugs that include large doses of caffeine are not recommended! Herbal Supplements People often believe that herbal supplements are healthy because they are natural in origin. However… • Herbal supplement makers often do not standardize doses well. Different batches of herbal supplements can have different potency. • Pharmaceutical drugs and effective herbal supplements work in the same ways. In fact, many pharmaceutical drugs, such as aspirin, were originally discovered from herbal supplements. • Any substance that can alter your body’s metabolism can also potentially do harm. But unlike pharmaceutical drugs, herbal supplements are not required to undergo double-blind trials. • Some herbal remedies can be quite effective in moderation.