Bladder cancer
The major risk factors for bladder cancer are tobacco smoking and being exposed to certain industrial chemicals. Some research suggests that drinking more fluids and eating more vegetables may lower the risk of bladder cancer.
Brain tumors
There are no known nutritional risk factors for brain tumors.
Breast cancer
The risk of breast cancer is increased by several factors that cannot be easily changed:
- Having your first period before age 12
- Not having children or having your first birth after age 30
- Late age at menopause
- Family history of breast cancer
But other factors may raise breast cancer risk as well. Both increased body weight and weight gain during adulthood are linked with a higher risk of breast cancer after menopause. Alcohol also increases risk to some extent, especially in women whose intake of folate is low.
Moderate to vigorous physical activity may lower breast cancer risk. Greatly lowering fat intake may also lower breast cancer risk, although a recent major study found that this effect may be very small.
The best advice to reduce the risk of breast cancer is to:
- Engage in moderate to vigorous physical activity 45 to 60 minutes on 5 or more days a week.
- Reduce lifetime weight gain by limiting your calories and getting regular physical activity.
- Avoid or limit your intake of alcoholic beverages.
Colorectal cancer
The risk of colorectal cancer is higher for those with relatives who have had colorectal cancer. Risk is also increased by long-term tobacco use and possibly excessive alcohol use.
Risk may be decreased by use of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDS, such as aspirin, ibuprofen, naproxen, and drugs like them) and hormone replacement therapy after menopause (postmenopausal.) But neither aspirin-like drugs nor hormones after menopause are currently recommended to prevent colorectal cancer because of their potential side effects.
Some studies show a lower risk of colon cancer among those who are moderately active on a regular basis, and more vigorous activity may even further reduce the risk of colon cancer. Obesity raises the risk of colon cancer in both men and women, but the link seems to be stronger in men. Diets high in vegetables and fruits have been linked with lower risk, and diets high in processed meats and/or red meats have been linked with a higher risk of colon cancer.
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 with high calcium intake, it may be wise for men to limit their daily calcium intake to less than 1,500 mg per day until further studies are done.
The best advice to reduce the risk of colon cancer is to:
- Increase the intensity and duration of physical activity.
- Limit intake of processed and red meats.
- Get the recommended levels of calcium.
- Eat more vegetables and fruits.
- Avoid obesity.
- Avoid excess alcohol.
In addition, it is very important to follow the American Cancer Society guidelines for regular colorectal screening because finding and removing polyps in the colon can prevent colorectal cancer.
Endometrial cancer
The major risk factors for the most common type of endometrial cancer (cancer of the lining of the uterus) involve excess exposure of the endometrium to estrogen, for instance:
- Estrogen therapy after menopause
- Certain types of birth control pills
- Polycystic ovarian syndrome
- Obesity
There is strong evidence of a link between obesity and endometrial cancer. Studies have also suggested lower endometrial cancer risk with high physical activity levels. Vegetable and fiber intake may lower risk, whereas red meat, saturated fat, and animal fat may increase risk. The link to weight is thought to result from the increase in estrogen levels that happens when women are overweight after menopause.
At this time, the best advice to reduce the risk of endometrial cancer is to maintain a healthy weight through diet and regular physical activity, and to eat a plant-based diet rich in vegetables, whole grains, and beans.
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.
The best advice to lower risk for kidney cancer is to maintain a healthy weight and avoid tobacco use.
Leukemias and lymphomas
There are no known nutritional risk factors for leukemias or lymphomas.
Lung cancer
More than 85% of lung cancers result from tobacco smoking, and another 10% to 14% may be linked to radon exposure. 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 increased (not decreased) lung cancer risk among smokers (see “Beta-carotene” under the section, "Common questions about diet and cancer").
The best advice to reduce the risk of lung cancer is to avoid tobacco use and secondhand smoke. Avoid radon exposure. Eat at least 5 servings of vegetables and fruits every day.
Mouth, throat, and esophagus cancers
Tobacco (including cigarettes, chewing tobacco, and snuff) and 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). There is some evidence that very hot beverages and foods may increase the risk of oral and esophageal cancers, likely as a result of the damage heat can cause. Eating the recommended amounts of vegetables and fruits probably reduces the risk of oral and esophageal cancers.
The best advice to reduce the risk of these cancers is to:
- Avoid all forms of tobacco.
- Restrict alcohol intake.
- Avoid obesity.
- Eat at least 5 servings of vegetables and fruits each day.
Ovarian cancer
The causes of ovarian cancer are not well understood. Family history is a risk factor, but fewer than 10% of ovarian cancers are inherited. There are no clearly proven nutritional risk factors for ovarian cancer -- studies of vegetables, fruits, and dairy products have not found clear links. Moderate alcohol intake may lower risk. The roles of obesity and physical activity in ovarian cancer risk are unclear.
Pancreatic cancer
Tobacco smoking, adult-onset diabetes, and impaired glucose tolerance (sometimes called "pre-diabetes," or "borderline diabetes") all increase the risk for pancreatic cancer. Some studies have linked obesity, physical inactivity (both factors strongly linked to diabetes and pre-diabetes), and diets high in processed and red meats with increased pancreatic cancer risk. Some studies have also found high fruit and vegetable intake to be linked with a reduced risk. But none of these links has been clearly proven.
The best advice to reduce the risk of pancreatic cancer is to:
- Avoid tobacco use.
- Maintain a healthful weight.
- Remain physically active.
- Eat 5 or more servings of vegetables and fruits each day.
Prostate cancer
Prostate cancer is related to male sex hormones, but just how nutritional factors might increase risk remains unclear. Several studies suggest that diets high in certain vegetables (including tomatoes, cruciferous vegetables, soy, beans, and other legumes) or fish may be linked with decreased risk. There is some evidence that foods or supplements containing antioxidant nutrients, such as vitamin E, selenium, beta-carotene, and lycopene, may lower prostate cancer risk. However, a recent large study found no benefit from vitamin E or selenium supplements.
Several studies have found that eating large amounts of red meats or dairy products may be linked with increased risk of prostate cancer. A high calcium intake, mainly from supplements, has also been linked to an increased risk for more aggressive types of prostate cancer.
Although the link between obesity and prostate cancer risk is not clear, recent studies suggest that being overweight is linked to a worse outcome in men already diagnosed with prostate cancer. Exercise, especially vigorous exercise, may offer some benefit for prostate cancer.
For now, the best advice to reduce the risk of prostate cancer is to:
- Eat 5 or more servings of a wide variety of vegetables and fruits each day.
- Limit intake of red meats and dairy products.
- Maintain an active lifestyle and healthy weight.
Stomach cancer
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-preserved foods is linked with a higher risk. There is also convincing evidence that chronic stomach infection by the bacterium Helicobacter pylori raises the risk of stomach cancer. Rates of stomach cancer have also likely been reduced by refrigeration and better food preservation, which allow fresh foods to be eaten all year long.
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 incidence of cancers in the first part of the stomach (the top, or 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.
At this time, the best advice to reduce the risk of stomach cancer is to:
- Eat at least 5 servings of vegetables and fruits daily.
- Reduce intake of foods that are preserved with salt.
- Maintain a healthy weight.
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