Those of us who have diabetes have enough to be concerned about for me to be writing here about all those things that don't help us. You won't find me writing about any of those many supplements and miracle cures that won't do anything for you except separate yourself from your money. You don't need me to tell you that if it sounds too good to be true, it probably is.
Have you noticed that whenever you encounter a problem, the act of dealing with that problem can create more problems, unless you are especially careful? Those of us who have diabetes need to be especially careful of the drugs that our doctors prescribe, because any drug carries with it unwanted side effects.
Even the type of drug that more Americans and people around the world take has a long list of side effects. Statins, a class of drugs that lower low-density lipoprotein cholesterol (LDL), are commonly prescribed to people with diabetes and pre-diabetes when our lifestyle changes don't achieve the LDL targets that our doctors like.
About 32 million Americans take a statin. One-fourth of us 45 and over do. One of the statins, Lipitor, is the all-time biggest selling prescription medicine in the history of the world with sales of more than $130 billion.
Our obsession with LDL is based on myths that Drs. Jonny Bowden and Stephen Sinatra explode in their recent book, which I reviewed here last year at "Cholesterol Myths." This book also addresses some of the many side effects that taking a statin drug have.
But now researchers at the University of Missouri have discovered a new side effect that is particularly serious for those of us who have either diabetes or pre-diabetes. They found that simvastatin, a generic type of statin that was previously sold under the brand name "Zocor," prevents those of us who are overweight from getting the benefits from exercise that we need. Now that simvastatin is available as a low-cost generic, many people expect that it will replace Lipitor as the most prescribed drug in the world.
The abstract of the study, "Simvastatin impairs exercise training adaptations," is online at the website of the Journal of the American College of Cardiology where it is in press. The university's news bureau kindly sent me the full-text pre-print on my request.
"Fitness has proven to be the most significant predictor of longevity and health because it protects people from a variety of chronic diseases," said John Thyfault, Ph.D. He is associate professor of nutrition and exercise physiology at the University of Missouri. "Daily physical activity is needed to maintain or improve fitness, and thus improve health outcomes. However, if patients start exercising and taking statins at the same time, it seems that statins block the ability of exercise to improve their fitness levels."
Dr. Thyfault says many cardiologists want to prescribe statins to all patients over a certain age regardless of whether they have metabolic syndrome and that drugs also are recommended for people with type 2 diabetes. But his recommendation is that cardiologists more closely weigh the benefits and risks of statins now that we know about what effect they have on exercise training.
"Statins have only been used for about 15 to 20 years," Dr. Thyfault says, "so we don't know what the long-term effects of statins will be on aerobic fitness and overall health. If the drugs cause complications with improving or maintaining fitness, not everyone should be prescribed statins."
Dr. Thyfault and his colleagues measured cardio-respiratory fitness in 37 obese people who had been sedentary and had a low fitness levels. All of the people in the study followed the same exercise regimen for 12 weeks. But about half of them -- 18 of the 37 people -- also took 40 mg daily simvastin.
This statin significantly affected the exercise outcomes of the study participants. Those in the exercise-only group increased their cardiorespiratory fitness by an average of 10 percent while those who also took statins had only a 1.5 percent increase.
The researchers found another problem. It's something called "skeletal muscle mitochondrial content." The site where muscle cells turn oxygen into energy decreased by 4.5 percent in the group taking statins. But those people in the study who didn't take statins had a 13 percent increase, which Dr. Thyfault says is a normal response following exercise training.
While this new research focuses on simvastatin, it doesn't let other statins off the hook. They haven't been studied for their effects on exercise yet. Our ability to benefit from exercise is just as important as our diet in managing our diabetes. Statins are one of those things that can hurt as much if not more than they might help.