•  Guidelines on Nutrition and Physical Activity for Cancer Prevention

Good nutrition and physical activity is thought to have a protective effect against cancer in general, but there's more evidence about the role of nutrition and exercise in some cancers than others. The American Cancer Society (ACS) offers this information roundup:

Smoking tobacco and exposure to particular industrial chemicals have been shown to be the main risk factors for bladder cancer. Studies also indicate that increased fluid intake and consuming more vegetables may reduce your risk.

No known dietary factors have been linked to brain cancer.

Your risk of developing breast cancer is increased by a number of factors. Some of these are difficult or impossible to change:

•First menstrual period before the age of 12

•Not giving birth to a child, or giving birth for the first time after age 30

•Menopause at a later-than-average age

•Family history of breast cancer

Risk factors for breast cancer include hormone replacement therapy (HRT), excess alcohol consumption, weight gain, and a sedentary lifestyle. These risks can be reduced or eliminated by a variety of measures:

•Limiting the use of hormones (HRT)

•Restricting your alcohol consumption to no more than one drink per day

•Breastfeeding babies

•Avoiding obesity and weight gain throughout your life by exercising and limiting calories

•Keeping physically active, with vigorous activity at least four hours a week

It's possible that eating a diet with a large amount of fruits and vegetables may lower the risk for breast cancer, although the link is not so clear as with other types of cancer, according to the ACS. Exercising for longer periods and more vigorously may also be associated with decreasing breast cancer risk.

Higher risk of colorectal cancer is associated with:

•A family history of colorectal cancer

•Tobacco use

Diets high in vegetables and fruit may lower the risk of colon cancer, and diets high in red meat may increase it. Folic acid supplements may also reduce the risk of colon cancer.

There is some evidence that moderate, regular physical activity may lower the risk of colorectal cancer, and that vigorous activity may offer even stronger preventive advantages. (The link between physical inactivity and cancer is more evident with colon cancer than with rectal cancer.)

Recommendations for lowering your risk of colon cancer:

•Get more physical activity

•Increase your intake of fruit and vegetables

•Eat less red meat and processed meats

•Prevent obesity

•Limit your alcohol intake

•Get recommended levels of calcium

The American Cancer Society has established guidelines for regular colorectal screening. It is essential to follow their advice, because discovering polyps in the colon and removing them at an early stage can prevent colon cancer.

Studies cited by the ACS show that certain factors raise the risk of endometrial cancer (cancer of the lining of the uterus, or womb):

•Obesity

•Excess exposure to estrogen through hormone replacement therapy after menopause, certain types of birth control pills, and polycystic ovarian syndrome.

Currently, scientists believe that the link between weight and endometrial cancer has to do with higher estrogen levels in postmenopausal women who are overweight.

You can lower your risk of developing endometrial cancer by maintaining a healthy weight through good nutrition (including eating less red meat and limiting your consumption of alcohol) and getting regular physical activity.

While the reasons for it have yet to be established, studies have shown that people who smoke or are overweight are at increased risk for kidney cancer.

No links have been established between nutrition and development of leukemias or lymphomas.

More than 85 percent of lung cancers result from smoking tobacco. Another 10 to 14 percent may be linked to exposure to radon. Multiple studies have confirmed that the risk of lung cancer is lower among both smokers and nonsmokers who consume at least five servings of vegetables and fruits a day. Although eating a healthy diet may lower a person's risk of developing lung cancer, the risks from smoking, chewing tobacco, and snuff are pivotal.

Notably, studies have shown that among smokers, the use of high doses of vitamin A and beta-carotene supplements heightens, rather than lowers, the risk of developing lung cancer. To reduce your risk of lung cancer, avoid using tobacco or being exposed to secondhand smoke or radon, and consume at least five servings of fruits and vegetables daily.

Studies have shown that, used alone or especially in combination, tobacco and alcohol put you at higher risk for cancer of the mouth and esophagus. Consuming very hot beverages and foods may increase the risk of oral cancers due to the thermal damage they can cause. Obesity further increases the risk. Currently, it's thought that eating five or more servings of fruits and vegetables daily probably reduces the risk of oral and esophageal cancers as well.

Recommendations for lowering the risk of cancer of the mouth and esophagus include avoiding the use of any form of tobacco (cigarettes, chewing tobacco, and snuff), restricting your alcohol intake, maintaining a healthy weight, and eating the recommended servings of fruits and vegetables daily.

There are no dietary factors linked to the risk of ovarian cancer. It is possible that risk may be lowered, however, by eating a diet rich in fruits and vegetables and limiting alcohol consumption.

Increased risks for pancreatic cancer include:

•Smoking tobacco

•Type 2 diabetes

•Impaired glucose tolerance

Obesity and physical inactivity (both factors strongly linked to abnormal glucose metabolism) and a diet high in processed and red meats have also been associated with higher risk of pancreatic cancer; a fruit and vegetable-rich diet is associated with decreased risk.

Recommendations for lowering pancreatic cancer risk include avoiding tobacco use, keeping a healthy weight, being physically active, and eating the recommended daily minimum of five servings of vegetables and fruit.

Studies have observed a clear association between prostate cancer and male sex hormones, but the exact mechanism that links them has not been established. Consuming large quantities of dairy products and red meat has been shown to raise the risk of developing prostate cancer. High calcium intake through supplements has been linked to an increased risk for more aggressive types of prostate cancer. Eating significant amounts of certain vegetables (for example, tomatoes, beans, and other legumes) may lower risk. However, evidence for these dietary links is not yet firmly established.

To reduce your risk of developing prostate cancer, the ACS recommends limiting your consumption of animal products, especially red meats and high-fat dairy foods. In addition, eat at least five servings of vegetables and fruit daily and maintain a healthy weight.

There's good news about stomach cancer: Its incidence around the world is decreasing. The explanation? In past eras, eating fresh foods was a seasonal activity. Today, refrigeration and food preservation techniques make it possible to have fresh foods all year long. An improved diet seems to be one of the factors in reduced stomach-cancer rates. It's not all good news, however. Cancers in the first part of the stomach has risen in the United States in recent years, possibly due in part to the increase of gastric reflux, a condition linked to obesity.

Chronic stomach infection by the bacterium Helicobacter pylori -- which can cause ulcers -- also raises the risk of stomach cancer.

To lower risk of developing stomach cancer, eat at least five vegetables or fruit servings daily, reduce your intake of salt-preserved foods, and stay at a healthy weight.

-- Diana Reiss-Koncar is a freelance writer based in Oakland, California.

References

First published June 23, 2004
Last updated January 29, 2008
Copyright © 2004 Consumer Health Interactive

Find more on:

Back to top of page