WEDNESDAY, June 6 (HealthDay News) -- Five new studies offer more evidence that healthy habits and preventive care can protect against disease.

The studies looked at how eating fish reduces the risk of colon and rectal cancer; how regular teeth cleaning improves cardiovascular health; how primary-care doctors can help patients lose weight; how low-dose aspirin can reduce cancer risk; and how hypnosis and acupuncture can help people quit smoking.

In one study, Chinese researchers reviewed 41 studies published between 1990 and 2011 and concluded that regularly eating fresh fish reduces the risk of colon cancer by 4 percent and rectal cancer by 21 percent.

Colon cancer is the third leading cause of cancer death in the Western world. Previous research has found that people who live in countries with high levels of fish consumption are less likely to develop colon or rectal cancer.

In another study, Canadian researchers found that smokers were 4.6 times more likely to quit smoking if they underwent hypnosis therapy and 3.5 times more likely to kick the habit if they had acupuncture, compared to smokers who didn't have the treatments.

Researchers in Taiwan found that regular tooth scaling (deep cleaning) is associated with a decreased risk for heart attack, stroke and other cardiovascular events. They compared nearly 11,000 people who had undergone tooth scaling with nearly 11,000 people who did not receive tooth scaling.

Over an average follow-up of seven years, the tooth-scaling group had a lower incidence of cardiovascular events than the non-scaling group. The more often people underwent tooth scaling, the lower their risk.

In another study, American researchers found that moderately obese patients who followed a weight-loss program supervised by a primary-care doctor lost as much weight as those who went to a weight-loss center, and lost more body fat.

Regardless of whether they used a primary-care clinic or a weight-loss clinic, patients lost an average of 11 percent of their body weight after 12 weeks of treatment. All the patients received behavioral modification sessions and a diet plan partially or fully supplemented by meal replacements.

In the fifth study, Canadian researchers analyzed 23 studies and said there is conclusive evidence that low-dose aspirin has cancer-preventive effects. Low-dose aspirin is commonly used to prevent cardiovascular disease.

The studies were published in the June issue of the American Journal of Medicine.

More information

The American Academy of Family Physicians outlines what you can do to maintain your health.