Secrets of Supplements (II)

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Staying Alive, Secrets of Supplements

April 14, 2006 Matthew Edlund M.D., M.O.H. Longboat Key News & Manatee River News Contributing Columnist View Bio - EMail Dr. Edlund

What can you believe? In the last few weeks, calcium has been declared near useless in preventing bone loss. Glucosamine and chondroitin do not prevent joint pain or e osteoarthritis; saw palmetto and soy products do nothing to prevent enlarged prostates or prostate cancer. Have Americans been wasting tens of billions of dollars each year on junk that doesn’t work?        Probably. A major reason: the quality of our information. In most cases, we have no good idea whether supplements help or hurt.        Don’t expect the FDA to provide help. By law, the Food and Drug Administration can’t look into supplement use — until it injures your limbs and threatens your life. Bias and Human Studies       Studying human beings is tough. Getting answers you can believe is tougher.        Unlike scientifically studied peas or mice, people are usually not genetically identical. Even with identical twins, environments differ. The hormones and chemicals that change health, behavior and sexual orientation start in the womb. To figure out if something works you have to use the right statistics.        Unfortunately, research statistics functions on assumptions about which the public rarely hears.        One assumption is that study subjects are pretty much identical for what you are looking at. That’s a tough obstacle, but there are many others.       The problem in studying people, particularly on questions like food, is that there are too many variables. Biostatisticians then try to “control” these variables using techniques based on another bunch of statistical assumptions.       The problems you do not control for, or even imagine, may totally bias results.       A good example were the studies of the pill performed in the 1970’s and 80’s. Run out of the Harvard-led Nurse’s Health Study, ten of thousands of nurses were followed for decades. From this “gold standard study” the answers rang out loud and clear — the pill decreased heart attack deaths by 50%. To students like myself, attending the Harvard School of Public Health in the eighties, the result was incredible: the most common cause of death of American women could be cut in half! National policy was obvious — women needed to be on the pill.        How could they get it so wrong?        In turns out the nurses who took the pill were different. They exercised more, ate different foods, adopted new health practices faster than nurses who did not. These variables were not correctly controlled. Similar biases fouled up studies on the pill and breast cancer. National guidelines for treating women were literally dead wrong. How We Came to Use Supplements        Supplement use came about because different populations demonstrated a lot less disease. Why did Okinawans live to 107 times more often than Americans? Why did southern Italians have so much less prostate cancer?       The answer was lifestyle. Many studies tried to define why. Often the answer they came up with was diet. For most supplements, their “efficacy” is based on large populations diet studies. Rarely are the supplements themselves studied alone, or properly.        So don’t be surprised when large, carefully controlled studies show supplements don’t work. Their effectiveness has been based on a series of assumptions stacked on top of assumptions. One basic assumption is that somehow whole cultures and lifestyles can have their disease preventing character concentrated into a single pill. Follow The Money       There are many studies that supplements do work. Many have been sponsored by the industry making them.       The answers they come up with are expected. Epidemiologists design human studies. They have identified literally thousands of biases that change study results. David Sackett, one the main theorists, has shown over 1,500 biases just in selecting who enters a study.        Supplement and pharmaceutical companies know how to design studies that show their stuff works. That’s why we have an FDA. Except the FDA is pretty much toothless on supplements. Even when supplements makers are trying to be honest, their researchers often are not conscious of the hidden biases of human research. And there are billions of dollars on the line.   Secrets of Supplements, Part II   April 28, 2006         Most of the data supporting the use of supplements relies on observations of whole foods, not the supplements alone. Eating a nutritionally diverse diet of fruits, vegetables, cereals and fish will often provide what supplements cannot — unknown but critical ingredients that improve your health.        Because there are billions of dollars spent on supplements, some effective large-scale trials have been done. Since foods contain hundreds of nutrients and not just solitary supplements the results are not usually what companies or scientists expected: Vitamin B Complex        B Vitamins are critical in pregnancy, necessary for normal fetal development. How useful they are to adults is a more complex story.        Homocysteine is now defined as a marker and probable risk factor for heart disease. Since the main way to decrease homocysteine levels is to ingest lots of B Vitamins, large scale trials began.        One of the most useful was the Norwegian Vitamin Trial, or Norvit (no, this is not a product name). High dose vitamin B6 and folate were given to thousands of heart attack victims. Homocysteine levels dropped yet there were more deaths among those who took the vitamins, the opposite of what researchers hoped. Vitamins E and C        Vitamin E was thought to prevent heart attacks and Alzheimer’s disease until more recent clinical trials showed otherwise. In lung cancer victims adding the vitamins increased death rates, despite the vitamins’ “ a n t i o x i d a n t ” power. Small scale studies led some researchers to conclude vitamins E and C could prevent pre-eclampsia, a scourge of pregnant women leading to increased deaths of mother and fetus. A proper large-scale trial demonstrated instead high dose vitamin C and E brought on pre-eclampsia one week earlier while increasing low birth weight infants 15%. The British researchers were surprised to obtain such powerfully negative results. Fish and Fish Oil        Omega-3 fatty acids are now touted by multiple sources as a natural cure-all. They came in two major varieties, the short chain types, found in walnuts, leafy greens, flaxseed and other plant products, and the long chain forms found in fish.        Omega-3s demonstrate at least modest success in preventing relapses in people with bipolar disorder. They may also prevent depression in some people with serious illnesses.       Their effects elsewhere are more mixed, perhaps because the advantages lie in the whole foods. The human brain is 60% fat — don’t feel so bad when someone calls you a fathead, as they’re one, too. The composition of that brain fat can make a difference. A recent largescale study showed children of pregnant women who ate large amounts of fish had future IQs 6 points ahead of those who ate little.        Yet the U.S. government is telling pregnant women to stay away from fatty fish. Why? Mercury. Government recommendations are that pregnant women eat no canned tuna, the most affordable form of fatty fish.        Who’s right? Fish is probably very healthy for growing brains and the notsuch- fast-growing brains of adults. Up to a pound a week may improve mentation while avoiding the worst aspects of mercury damage. A few ounces a day may be just right for many of us. Vitamin D       The newest “anti-cancer” supplement is vitamin D, which researchers are claiming may prevent colon cancer, breast cancer, prostate cancer, and MS. However, the “cancer reducing” effects of vitamin D may be confounded by what normally produces vitamin D — sunlight.        Sunlight on our skin creates vitamin D, but sunlight also powerfully resets internal body clocks, changes mood and DNA repair mechanisms. It also causes skin cancer.       The idea that vitamin D supplements decrease some cancer rates is still a hypothesis. Sunlight exposure does seem to decrease prostate cancer, particularly when there is many years of light exposure. The mechanism of the effect is unknown. Only long, large scale clinical trials of Vitamin D will tell that story. Unfortunately when supplements have been studied on their own their health benefits have often proven illusory. Which means you can save money. Certainly you can take a single multivitamin and probably vitamin D. Eating fish regularly, in small amounts, looks like a good choice at present, perhaps because you ply safer ground eating whole foods.        Nutritional diversity is a mark of most long-lived populations. Do what the Japanese do — put a lot of different colors on your plate. Different colors mean different vitamins and minerals.       As we grow old, many worry about fractures. Doctors often tell you to take in more calcium, yet Americans take in more calcium than any population on earth.       The real way to prevent fractures is to move. The human body is designed for walking. A way to lower weight and stress is to walk with a friend after each meal.        You’ll change your insulin metabolism, making it easier to lose weight. You’ll help your bones rebuild. You’re regenerate new tissue. You’ll get mood enhancing, and perhaps cancer-reducing sunlight.