Glad you posted this -- this is a letter I got from Dr. McManus this morning that you will appreciate I am sure.
In the past few days, many of you have probably seen the headlines regarding multivitamins and their inability to prevent chronic disease – the result of three studies published in the Annals of Internal Medicine.Starting from a 30,000-foot view, the premise of these studies is the first problem: looking at the use of a multivitamin alone as a way to prevent disease. The purpose of a multivitamin is to fill in nutritional gaps and provide optimal levels of vitamins and minerals. It is well established that the vast majority of North Americans fail to obtain even adequate levels of these nutrients.
Prevention of any disease is a multi-factorial process that has to include diet, weight management, and lifestyle. To expect to see disease prevention accomplished by virtue of taking a daily multivitamin is a flawed premise. So, why are these large-scale (and very expensive) studies undertaken? It is simply the model of research that scientists and physicians understand: studying a single drug to determine what effect it may have on a single disease. Studying nutrition is far more complex.
While drugs have a primary effect (usually something positive), they also have a myriad of side effects (which are usually negative and even life threatening). Every year, pharmaceuticals are removed from the market because of these serious side effects. A study published in JAMA in 1998 showed that as many as 125,000 Americans die each year as the result of properly prescribed pharmaceuticals. Wow! When was the last time a vitamin was removed from the market?
Vitamins and minerals all have multiple positive functional roles to play in our bodies, which is why so many North Americans pop a multi each day. People simply feel better when they take a multi because they are filling in those all-too-common nutritional gaps.
All three of these studies showed that multivitamins have an excellent safety profile. Well, of course they do – they are essential for life! The only “potential harm” that continues to be mentioned every time we have a study such as this published is the slight increased risk of lung cancer in smokers who took beta carotene. My response to that is – smokers: stop smoking!
Let me quickly summarize these studies. The largest one is another report from the Physicians' Health Study; previous publications of data from this large U.S. government-funded study did show an association of reduced cancer associated with multivitamin usage. It reported that multis had no beneficial effect in preventing cardiovascular disease or cancer – claims that no supplement companies should be making in the first place.
The next study looked at cognitive decline in physicians, who are at the upper end of the intelligence scale and pretty well-nourished. The study showed no difference between groups taking either a multivitamin or a placebo for 12 years. Showing a significant change in cognitive decline in this population is going to take some intervention beyond a multi, as this population is most likely doing lots of the right things to protect their brain function.
The third study tried to show that higher doses of specific vitamins decrease the likelihood of a second heart attack in folks who have already had a heart attack, but it was unable to come to any firm conclusions about the vitamins’ effectiveness. Hmmm. Maybe we should look at weight reduction, cholesterol and blood pressure lowering, and blood sugar management as opposed to putting the burden of prevention of a second heart attack in someone with heart disease on vitamins!
I have been recommending a multivitamin (and beyond) to my patients, and consumers in general, for my entire 30 years as a physician – and nothing in these studies changes my mind. The statistics on inadequacies in our North American diet are clear: most everyone is deficient in multiple nutrients. We have a Landmark Study, published in the journal Nutrition in 2007, which showed a nice correlation of better health with multiple supplement usage, starting with a multivitamin. We have more than 100 published studies that validate the positive connection between nutrition and health. I urge you to continue taking your supplements – but also to remember the importance of eating healthfully, avoiding fast foods, and getting to a healthy weight on your journey to better health.
Be well!
Jamie McManus, MD, FAAFP