A lot of news about cancer shines the spotlight on new and exciting drugs or treatments. Lost in the shuffle is something scientists have long known: lifestyle plays a big role in the prevention of many types of cancer.
Such a strong role, in fact, that a recent study in the journal JAMA Oncology suggests four key lifestyle habits — not smoking, exercising regularly, keeping weight at a healthy level, and drinking in moderation — could potentially cut cancer deaths in half. That’s right: 50% of all cancer deaths might be prevented with some simple changes in the way you eat, drink and live.
The study in a nutshell: Researchers at the Harvard T.H. Chan School of Public Health and Massachusetts General Hospital in Boston pooled data from long-term studies done on two large groups of health professionals (more than 136,000 men and women aged 40 to 75).
They placed participants into “low-risk” and “high-risk” groups based on four key lifestyle habits strongly connected with cancer risk. What they discovered is that about half of cancer deaths might be prevented with the right lifestyle habits.
Here’s a detailed look at these “low-risk” behaviors:
1. Smoker or former smoker? Cancer risk varies depending on two key factors.
Obviously, the best cancer prevention strategy regarding smoking is to never smoke. But for former smokers, “the amount of risk reduction depends on the number of years you smoked and the amount of cigarettes you smoked before quitting,” says lead study researcher Dr. Mingyang Song of the T.H. Chan Harvard T.H. Chan School of Public Health.
For the study, he considered former smokers at low risk for cancer if they smoked for less than five years (no more than one pack a day). But Song says if you do smoke, whenever you quit, you’ll reap health benefits.
It’s something his friends and family still question. And he frequently hears this same reasoning: “I know someone who didn’t smoke and exercised but he still ended up with lung cancer. So why should I stop smoking?”
Song suspects stories about people who adopt healthy lifestyle habits, like not smoking, and are able to prevent cancer don’t tend to make headlines. Nor do they hold the kind of strong emotional impact as someone who seemingly did everything right and still developed cancer.
However, the scientific reality is that the less you smoke, the better your chances of preventing certain types of cancer, particularly lung cancer. Song says approximately 80 to 90% of lung cancer deaths could be avoided if everyone adopted the lifestyle habits of the low-risk group, particularly quitting smoking.
2. Moderate and high-intensity exercise are both good.
Plenty of strong and convincing evidence shows that people who are physically active have a lower risk of developing a whole host of chronic diseases, including cancer. (Evidence confirms that the cancer-fighting benefits are particularly strong for cancers of the colorectum, breast and endometrium.)
There’s also plenty of agreement about just how much exercise is preventive. Researchers in the Boston study defined activity levels as “low-risk” if study participants met the basic government Physical Activity Guidelines: 150 minutes of moderate intensity activity each week or half as much time spent on high-intensity pursuits. Song says it doesn’t matter how those numbers are achieved — in 10-minute increments or all at once.
Not sure what’s meant by moderate-intensity pursuits? That includes things like brisk walking (3 miles per hour or more), water aerobics, ballroom dancing, doubles tennis or any pursuit where you’re easily able to talk while exercising but don’t have enough lung power to sing a few bars of a favorite song.
Vigorous-intensity activity is defined as the kind of exertion you experience when hiking up a steep hill, swimming laps, jogging, playing singles tennis or aerobic dance pursuits like Zumba. You know the feeling: while exercising, it’s hard to say more than a few words to someone without pausing to catch your breath.
3. Just the right amount of alcohol.
Researchers defined “low-risk” as not drinking at all or drinking only moderate amounts of alcohol — one drink or less a day for women or two drinks a day for men. That amount appears protective not just against cancer but for cardiovascular disease as well.
Keep in mind, however, this scientific “evidence is based on moderate amounts,” stresses Dr. Walter C. Willett, one of the top nutrition experts in the country and professor of epidemiology and nutrition at Harvard T.H. Chan School of Public Health.
And in our supersize-it culture, it’s unbelievably easy to lose sight of what a moderate serving of alcohol looks like. Opening a bottle of wine? Count on getting five (5-ounce) servings. Sipping on an after-dinner brandy? One serving is a tiny 1.5 ounces or one shot glass full.
One last caveat: If you’re a woman and worried about alcohol and breast cancer, talk to your doctor about individual risk. “Alcohol is complicated, especially for women,” admits Willett. “With one drink, there is a lower risk for cardiovascular disease, but there’s a very clear elevation in breast cancer risk. So there’s a trade-off there.”
4. The challenges of determining what is a healthy weight.
Although researchers in this study compared weight in relation to height — a measure called Body-mass index (BMI) — to arrive at “low-risk” and “high-risk” body fat categories, chances are you already know if you’re overweight, says Willett. It could be a growing waist size or maybe the numbers on the scale are creeping up.
Either way, these are all unhealthy signs, particularly when it comes to cancer risk. “The evidence for excess weight, whether it’s measured as BMI or waist circumference or relative weight, is extremely strong,” Willett says. “And it’s extremely important. It cuts across many types of cancer.”
The good news: It’s never too late to take that excess weight off. “Even a 5% weight loss, if it is maintained, can have strong protective benefits,” says Willett. And the way to get there, he says, is by eating healthier and being more physically active. As for the eating, that really boils down to a traditional Mediterranean diet, a way of eating that focuses on fruit, vegetables and whole grains.
These Boston researchers are digging deeper to determine more diet and lifestyle strategies that could help lower cancer risk, but they say a good first step for any 50-something is to master these four habits.
Wondering how risk stacks up if you’ve nailed down only one or two of them? “It is really difficult to differentiate the impact of each lifestyle factor,” says Song. “They are all correlated.” Still, “overall, it’s never too late to change your lifestyle, including smoking.”
Willett agrees and points out that making these changes doesn’t mean you’ll have to wait 10 to 20 years to reap benefits. “Eating like this and keeping physically active can have immediate benefits. People can feel the benefits within a few weeks or months in terms of energy and feeling better,” he notes.