More than half of all Americans now use supplements. The industry's sales have grown from $8.8 billion in 1994 to $26.7 billion in 2009. But now the trend is slowing, as more and more studies question the value of our supplement additction.
Let's take a look at some recent evidence. Two of the most popular, highly touted nutrient supplements warrant special attention:
Omega-3 fatty acids, abundant in some fish, help prevent blood platelets from forming clots. Data from the 1998 "Physicians' Health Study" showed that people who ate fish once a week were half as likely to die from sudden heart attack than those who ate fish less than once a month. A year later, The Lancet reported a study in which men who had suffered heart attacks received a 1) a fish oil supplement, 2) 300mg of vitamin E, 3) both, or 4) neither. Subjects who received fish oil experienced significantly lower rates of heart attack, stroke, and death. Sudden death rates dropped by 45%.
Subsequent studies have confirmed fish oil benefits. The American Heart Association recommends eating fish -- especially oily fish like salmon, sardines, or herring -- at least once or twice a week. If you don't like fish, there's no risk in taking a daily fish oil supplement. People with heart disease or high triglyceride levels should consult their doctors about the potential benefit of taking even more than 200-400mg typically found in over-the-counter supplements.
We use "antioxidants" to describe compounds that can counteract unstable molecules (like free radicals) that damage DNA and cells. Our bodies produce lots of antioxidants. The food we eat -- and perhaps the supplements we take -- are another source.
Articles and ads tout antioxidants for their ability to slow aging, fend off heart disease, improve fading vision, and curb cancer. Reports hype these benefits from eating foods rich in antioxidants... AND from taking supplements. But most of the evidence comes from "observational trials," in which subjects first answer questions about their diets and supplement use, and then their health is tracked. But those studies don't prove cause and effect. The more dependable "randomized controlled trials," in which subjects receive either the supplement in question OR a placebo, have not supported the broad claims of antioxidant benefits.
A study that pooled results from 68 randomized trials with over 230,000 participants concluded that antioxidants did not extend life, and may even have casued harm. After reviewing antioxidant studies, the authors of the Harvard Medical School's special report, Vitamins and Minerals, concluded:
These findings suggest little overall benefit of the antioxidants in pill form. On the other hand, many studies show that the people who consume higher levels of these antioxidants in food face a lower risk of many diseases, so eating a healthy diet... is the best way to get your antioxidants.Other Popular Supplements (And Ones I Have A Personal Interest In)
Glucosamine and Chondroitin: Our bodies produce G&C,which are involved in the production and maintenance of the cartilage that cushions joints. This best-selling supplement is widely used to treat osteoarthritis. I have a personal interest in learning about this supplement, since my persistent back pain is caused by recently-diagnosed osteoarthritis. Here's what my research uncovered:
Americans spend billions of dollars every year on unproven arthritis remedies. There is no cure, but almost anything seems to work for some people, at least for a while. One study found that placebos relieved symptoms for a whopping 60% of subjects -- about the same success rate as the supplements.
Even reputable sites give conflicting advice about G&C. The Mayo Clinic's main discussion of glucosamine indicates "there is good evidence to support the use of glucosamine sulfate in the treatment of mild-to-moderate knee osteoarthritis." But in a different Mayo link, a Mayo staffer -- in response to an inquiry about glucosamine -- says, "research has never demonstrated this effect." Go figure.
Kaiser Permanente rheumatologist Eduardo Baetti says he finds that "about 40% of my patients benefit from taking 1,500mg of glucosamine and 1,200mg chondroitin sulphate a day for four to eight weeks." But he acknowledges that most of them are also taking Tylenol.
With all this conflict and confusion, what's a guy to do? I'm inclined to follow this advice from the UC-Berkeley's Dietary Supplements:
We suggest you forget about glucosamine and chondroitin -- unless you are willing to pay $20 or more a month for what is probably a placebo.Memory Supplements and Ginkgo Biloba: Given my fading memory and fears of dementia, I'm always tempted by the dozens of dietary supplements touted to improve memory. But I still have enough good sense to check these out to see if there is reliable evidence to support the hype. Until recently, the "brain booster" that seemed to hold the most promise was ginkgo, from the maidenhair tree (ginkgo biloba). I tried it, and abandoned it.
Ginkgo biloba is widely prescribed in Europe for "cerebral insufficiency." Most aging people like me surely suspect their brains aren't what they were, so it's no wonder ginkgo is so incredibly popular.
Some researchers have hypothesized that ginkgo biloba has antioxidant and anti-inflammatory effects that might prevent dementia. A dozen years ago, a study suggested that the supplement might help preserve memory function in people age 85 and older. But a later large, well-designed study found that it wasn't effective in slowing the development of dementia or Alzheimer's disease.
A caution: taking ginkgo biloba with aspirin -- or other meds or supplements that have blood-thinning effects -- can increase the risk of bleeding.
Coenzyme Q10: Another supplement I've tried, CoQ10 is a natural substance essential to the functioning of the body's cells. Its levels decrease with age and are low in patients with chronic diseases like Parkinson's, muscular dystrophy, cancer, diabetes and HIV/AIDS. Given that list, it's no surprise that CoQ10 is a best-selling supplement.
A few years ago, preliminary studies with a small group of Parkinson's patients suggested that high doses of CoQ10 (1200mg a day) might slow the deterioration of brain cells associated with Parkinson's. The authors cautioned that a larger, more definitive study was needed before they could recommend using CoQ10. Many people with Parkinson's (including me) decided not to wait for those definitive results.
Then last May, NIH stopped studying CoQ10 for people with PD at the mid-point review because the data showed CoQ10 did not offer benefits greater than the placebo. Yet another disappointment in my quest for a magic supplement cure!
The claims for CoQ10 are overblown and there's no reason to take the supplement especially if you are healthy. No one knows how much to take (studies have used varying amounts) or which of the many formulations is best. Of more concern, its long-term safety is still unknown.
If you have heart disease, high blood pressure, or Parkinson's disease [this was written before NIH scratched the hopes for PD] and are considering CoQ10, discuss it with your doctor first. If you have heart failure, there are effective drugs available; at best CoQ10 would be an adjunct therapy. It is expensive - usually $15 to $45 a month and $100 or more for the higher doses sometimes recommended.There are many other supplements out there, and the evidence for using them is mostly anecdotal... and not substantiated by well-designed studies. This brings us back to the recent unsubstantiated but hopeful news about coconut oil and dementia, which is where we started this five-part series on supplements. There's so much more to say. But let's stop here for now.
I'll return to the subject later with a report on my ongoing experimentation with 5-HTP, and a final wrap-up on supplements.