Lifestyle Changes -- Do They Work? - Man to Man - Harvard Commentaries

Americans' health is not what it should be. Diabetes and obesity are increasing at an alarming rate. The prevalence of heart disease, cancer, stroke and other devastating illnesses remains stubbornly — and unacceptably — high. Our lifestyle habits — the way we eat, exercise, smoke and drink — reflect the truth: We are simply not taking care of ourselves.

You've heard the advice to lose weight, exercise, eat more fruits and vegetables and quit smoking often enough. The ideas are so simple that they may seem trivial in a medical system dominated by high-tech procedures, gee-whiz surgery and genetically engineered drugs.

But will improving your lifestyle actually make you healthier and help prevent diseases?

The short answer, of course, is yes. Two studies published in 2008 demonstrate the enormous power of even a few lifestyle changes:

A Harvard study of 2,357 men compared those who lived to age 90 and beyond with their less fortunate peers. Researchers identified five simple risk factors associated with a shorter lifespan. Three of these factors (smoking, lack of exercise, and obesity) can be corrected or modified by lifestyle changes. Two others (high blood pressure and diabetes) can be prevented or modified by lifestyle changes, medical treatment or both. Men who were free of all five risk factors at age 70 were 54% more likely to live to age 90 or beyond. Having just one risk factor reduced the chance of making it to age 90. Smoking was the most dangerous. Men with all five risk factors had a slim chance — 4% — of living to 90. Living to 90 is a powerful reward. And the men with healthy behaviors were in remarkable physical and mental shape.

A team of British scientists looked at the relationship between certain health habits and death rates in 20,244 people who were 45 to 79 years old when the study began. The subjects were also free of heart disease and cancer. The four health habits were: not smoking, being physically active, eating at least five servings of fruits and vegetables a day and consuming one to 14 alcoholic drinks a week. Over 11 years, people who did not practice any of the four good habits were four times more likely to die than people who practiced all four healthy behaviors. So a 74-year-old man who practiced all four healthy habits had the same death rate as a 60-year-old who did not. In effect, the absence of these four protective behaviors was equivalent to shaving 14 years off the calendar.

Many medical studies show that excess body fat takes a toll on health. But a 2008 study should encourage people who are overweight, even if they don't lose weight. Researchers from Denmark and the U.S. followed 54,783 people who were free of coronary artery disease and cancer when they volunteered for the study. Each extra point on the body-mass index scale boosted a man's risk of suffering an acute coronary event by 7%. But even among men who were overweight and obese, healthy choices about smoking, diet, and exercise lowered the risk of heart disease.

Genes alone do not determine your health. How you live matters. In fact, new studies suggest that your lifestyle choices may actually improve your genes!

We are born with about 25,000 genes. Our parents pass them on to us. These genes determine many physical and some personality traits. Some genes also increase or decrease the risk of disease.

But genes aren't static. As cells grow and divided, errors (mutations) crop up in our DNA. Fortunately, our cells have ways to detect and correct most genetic errors. But errors can slip through and may start a cell down the path to disease, including cancer.

Many mutations develop on their own. Others are triggered by the environment. That's how smoking and radiation increase the risk of cancer.

While most research has looked at how bad things happen to good genes, a few scientists are starting to ask if good lifestyle choices can actually make good things happen to genes.

For example, researchers asked 22 men who were scheduled for prostate biopsies to eat four servings of either broccoli or peas per week. At the end of the 12 months, the men who ate broccoli showed genetic changes that might reduce the risk of prostate cancer.

In another study, scientists from California followed 30 men who were getting prostate biopsies periodically to check for early prostate cancer. The men made extensive changes to their diets and exercise habits. They also took steps to reduce stress. Their weight, abdominal obesity, blood pressure and blood lipids all improved. In just three months, tissue changed, too: 48 of the genes were ramped up and 453 were turned down.

In a third experiment, researchers studied how exercise affects telomeres. These are special bits of DNA located on the ends of chromosomes. Telomeres protect chromosomes. But as cells divide, their telomeres get shorter and shorter. Getting older, oxidative stress and obesity all make telomeres shorter. In turn, short telomeres have been linked to an increased risk of coronary artery disease, heart failure, diabetes and osteoporosis. In a study of 2,401 twins, regular exercise was linked to longer telomeres. The DNA of the most active subjects scored about 10 years "younger" than those from the least active subjects. Telomeres may help explain how regular exercise seems to slow the aging process.

Our unique genetic profiles play an important role in determining health and longevity. Heredity may deals us a hand of cards, but lifestyle determines how we play those cards. Now we're beginning to see that our lifestyle choices can actually reshuffle the deck, for worse or for better.

Healthy habits pay big dividends. Lifestyle changes can be difficult to achieve. Given the enormous health benefits they have, the change is worth your effort. Your health is too important to be left to your doctors.

Harvey B. Simon, M.D. is an Associate Professor of Medicine at Harvard Medical School and a member of the Health Sciences Technology Faculty at Massachusetts Institute of Technology. He is the founding editor of the Harvard Men's Health Watch newsletter and author of six consumer health books, including The Harvard Medical School Guide to Men's Health (Simon and Schuster, 2002) and The No Sweat Exercise Plan, Lose Weight, Get Healthy and Live Longer (McGraw-Hill, 2006). Dr. Simon practices at the Massachusetts General Hospital; he received the London Prize for Excellence in Teaching from Harvard and MIT.