Diet and Activity Factors That Affect Risks for Certain Cancers

Breast cancer

The risk of breast cancer in women is increased by several factors that cannot be easily changed:

• Having your first period before age 12
• Not having children or having your first child after age 30
• Late age at menopause
• Family history of breast cancer

Other well-known risk factors include the use of menopausal hormone therapy and exposure of the breasts to radiation, especially at a young age.

Both increased body weight and weight gain as an adult are linked with a higher risk of breast cancer after menopause. Alcohol also increases risk of breast cancer. Even low levels of alcohol intake have been linked with an increase in risk.

Many studies have shown that moderate to vigorous physical activity is linked with lower breast cancer risk. A diet that is rich in vegetables, fruit, poultry, fish, and low-fat dairy products has also been linked with a lower risk of breast cancer in some studies. But it is not clear if specific vegetables, fruits, or other foods can lower risk.

Most studies have not found that lowering fat intake has much of an effect on breast cancer risk.

At this time, the best advice about diet and activity to possibly reduce the risk of breast cancer is to:

• Get regular, intentional physical activity.
• Reduce lifetime weight gain by limiting your calories and getting regular physical activity.
• Avoid or limit your alcohol intake.

Colorectal cancer

The risk of colorectal cancer is higher for those with relatives who have had colorectal cancer or polyps. Risk may also be increased by long-term tobacco use and excessive alcohol use. Several studies have found a higher risk of colorectal cancer with increased alcohol intake, especially among men.

Most studies have found that being overweight or obese increases the risk of colorectal cancer in both men and women, but the link seems to be stronger in men. Having more belly fat (that is, a larger waistline) has also been linked to colorectal cancer.

Overall, diets that are high in vegetables, fruits, and whole grains (and low in red and processed meats) have been linked with lower colorectal cancer risk, although it's not exactly clear which factors are important. Many studies have found a link between red meat or processed meat intake and colorectal cancer risk.

Studies show a lower risk of colorectal cancer and polyps with increasing levels of activity.Moderate activity on a regular basis lowers the risk, but vigorous activity may have an even greater benefit.

In recent years, some large studies have suggested that fiber intake, especially from whole grains, may lower colorectal cancer risk. Research in this area is still under way.

Several studies have found that calcium, vitamin D, or a combination of the two may help protect against colorectal cancer. But because of the possible increased risk of prostate cancer in men with high calcium intake, the ACS does not recommend increasing calcium intake specifically to try to lower cancer risk.

At this time, the best advice about diet and activity to possibly reduce the risk of colorectal cancer is to:

• Increase the intensity and amount of physical activity.
• Limit intake of red and processed meats.
• Get the recommended levels of calcium and vitamin D.
• Eat more vegetables and fruits.
• Avoid obesity and weight gain around the midsection.
• Avoid excess alcohol.

It is also very important to follow the ACS guidelines for regular colorectal screening because finding and removing polyps in the colon can help prevent colorectal cancer.

Endometrial (uterine) cancer

There is strong evidence of a link between being overweight or obese and having a higher risk of endometrial cancer (cancer of the lining of the uterus). Some research has also found a link between having more belly fat (that is, a larger waistline) and endometrial cancer. The link to weight is thought to result from the increase in estrogen levels that happens when women are overweight.

Studies have also found a lower endometrial cancer risk with high physical activity levels, although in some studies this has been limited to women who are overweight or who have not yet gone through menopause. Spending more time sitting (regardless of overall activity level) has also been linked with a higher risk.

Vegetable and fiber intake may lower risk, although some studies have not found this. The evidence for red meat, saturated fat, animal fat, and alcohol raising risk is also conflicting among different studies.

At this time, the best advice about diet and activity to possibly lower the risk of endometrial cancer is to get to and stay at a healthy weight and to get regular physical activity.

Kidney cancer

The causes of kidney cancer are not clear, but the best-known risk factors that can be changed are obesity and tobacco smoking. Studies looking for links between specific parts of the diet and kidney cancer have not shown clear results. A small number of studies have found a possible link between physical activity and lowered risk of kidney cancer.

The best advice to possibly lower risk for kidney cancer is to stay at a healthy weight and avoid tobacco use.

Lung cancer

About 80% of lung cancers result from cigarette smoking, but other factors, such as radon exposure, are also linked to lung cancer.

Many studies have shown that the risk of lung cancer is lower among both smokers and non-smokers who eat at least 5 servings of vegetables and fruits a day. Although healthful eating may reduce the risk of lung cancer, the risks from tobacco remain high. Using high-dose beta-carotene and/or vitamin A supplements has been shown to increase (not decrease) lung cancer risk among smokers.

The best advice to reduce the risk of lung cancer is to avoid tobacco use and secondhand smoke and to avoid radon exposure.

Mouth, throat, and esophagus cancers

Tobacco (including cigarettes, chewing tobacco, and snuff), alcohol, and especially the combination of the two, increase the risk for cancers of the mouth, larynx (voice box), pharynx (throat), and esophagus.

Obesity raises the risk for cancer in the lower esophagus and at the junction of the esophagus and stomach (likely due to increased acid reflux). Very hot beverages and foods may also increase the risk of mouth and esophagus cancers, likely as a result of the damage heat can cause.

A diet high in vegetables and fruits may reduce the risk of mouth and esophagus cancers.

The best advice to possibly reduce the risk of these cancers is to:

• Avoid all forms of tobacco.
• Restrict alcohol intake.
• Avoid obesity.
• Eat at least 2½ cups of vegetables and fruits each day.

Ovarian cancer

The causes of ovarian cancer are not well understood. Family history is a risk factor, but only about 10% of ovarian cancers are inherited.

There are no clearly proven nutritional risk factors for ovarian cancer. Some studies have found that obesity may increase the risk for ovarian cancer, as may a diet high in fat (especially saturated fat). The role of physical activity in ovarian cancer risk is unclear. Studies of vegetables, fruits, meat, dairy products, and alcohol have not found clear links.

Some studies have found possible role for eating soy foods and drinking tea (especially green tea) in lowering ovarian cancer risk, but not all studies have found this.

At this time, it is not clear how nutrition and physical activity might be related to ovarian cancer risk, so no strong recommendations can be made.

Pancreatic cancer

Tobacco smoking, type 2 diabetes, and impaired glucose tolerance (sometimes called "pre-diabetes," or "borderline diabetes") all increase the risk for pancreatic cancer.

Several studies have found a link between being overweight or obese and having a higher risk of pancreatic cancer. Some research has also found a link between having more belly fat (that is, a larger waistline) and pancreatic cancer, especially in women.

Some studies have suggested that pancreatic cancer risk may be reduced with higher levels of physical activity, especially if it is part of a person's job. On the other hand, diets high in red and processed meats and low in fruits and vegetables have been linked with increased risk in some studies. More research is needed to confirm these findings.

Few studies have looked at possible links between specific foods or alcohol intake and risk of pancreatic cancer.

The best advice to possibly lower the risk of pancreatic cancer is to avoid tobacco use and stay at a healthy weight. Being physically active and following the other ACS recommendations related to a healthy diet may also be helpful.

Prostate cancer

Prostate cancer is related to age, family history, and male sex hormones, but just how diet and activity factors might affect risk is not clear.

In recent years, researchers have learned it may be important to distinguish between prostate cancers that are aggressive (likely to grow and spread quickly) and those that are less likely to cause problems.

For example, some studies have found that men who are overweight may have a lower risk of prostate cancer overall, but a higher risk of prostate cancers that are likely to be fatal. Being overweight is also linked with a worse outlook in men who have been diagnosed and treated for prostate cancer.

Studies have found that men who get regular physical activity have a slightly lower risk of prostate cancer. Vigorous activity may have a greater effect, especially on the risk of advanced prostate cancer.

Several studies suggest that diets high in certain vegetables (including tomatoes, cruciferous vegetables, soy, beans, and other legumes) or fish may be linked with a lower risk of prostate cancer, especially more advanced cancers. Examples of cruciferous vegetables include broccoli, cauliflower, and cabbage.

Studies so far have not found a benefit from taking supplements containing antioxidant nutrients, such as vitamin E or selenium. In fact, a recent large study found that vitamin E supplements might actually raise prostate cancer risk slightly.

Several studies have found that diets high in calcium may raise prostate cancer risk. Dairy foods may also increase risk.

For now, the best advice about diet and activity to possibly reduce the risk of prostate cancer is to:

• Eat at least 2½ cups of a wide variety of vegetables and fruits each day.
• Be physically active.
• Stay at a healthy weight.

It may also be sensible to limit calcium supplements and to not get too much calcium in the diet. But because calcium and dairy intake may lower the risk of colorectal cancer, the ACS does not have specific recommendations on calcium and dairy food intake to try to lower cancer risk.

Stomach cancer

The number of stomach cancer cases in most parts of the world is falling. While stomach cancer is fairly rare in the United States, the rate of cancers in the first part of the stomach (the cardia) has risen in recent years. This may be due at least in part to increases in gastric reflux, which has been linked to obesity.

Many studies have found that a high intake of fresh fruits and vegetables is linked with a lower risk of stomach cancer, while a high intake of salt, salt-preserved foods, and possibly processed meat, is linked with a higher risk.

Not many studies have looked at the possible effects of body size or obesity on stomach cancer, but most have found an increased risk with higher body weight. There are also few studies that have looked at the effects of physical activity on stomach cancer, but it seems to be linked with a lower risk.

At this time, the best advice to possibly reduce the risk of stomach cancer is to:

• Eat at least 2½ cups of vegetables and fruits daily.
• Reduce intake of processed meat, salt, and foods preserved with salt.
• Be physically active.
• Stay at a healthy weight.

Click here for more information from the American Cancer Society