Fewer Omega-6's May Reduce Cancer Risk

Researchers at UCLA show that reducing intake of corn oils helps to prevent prostate cancer in mice (Cancer Research, April 15, 2008). Corn oil and other vegetable oils are extremely rich sources of omega-6 fatty acids.

Fats are classified by their chemical structure into omega-3s, omega-6s, and omega-9s. Omega-6s cause your body to produce prostaglandins that turn on your immunity to cause inflammation, while omega-3s turn down your immunity to reduce inflammation.

Your immunity is supposed to be good for you. When a germ enters your body, your immunity produces white blood cells and proteins called antibodies that attack and kill the germ. After that germ is gone, your immunity is supposed to stop making so many immune cells and proteins. If it remains active, your immunity attacks your own body to damage tissue and increase risk for heart attacks, certain cancers, and diabetes; it can also worsen existing diseases such as some types of dementia, asthma or psoriasis.

For more than 2 million years, humans have eaten diets that have a ratio of omega-6s to omega-3s of about two to one. However, over the last 100 years, humans have added extracted vegetable oils to other foods that they eat and increased the ratio to 12 to one and perhaps as high as 20 to one. This increase in the ratio of omega-6s to omega-3s is a cause of inflammation. The increase in omega-6's has come primarily from vegetable oils that are added to baked, fried and other prepared foods. Omega-3s oils are relatively unstable so they are not found in most prepared foods.

Good food sources of omega-3's include seafood and beans, whole grains, nuts and other seeds. We do not know if changing the ratio of omega-6s to omega-3s will help to prevent cancers in humans, but several studies show that they appear to both prevent and slow cancers in animals.
More on omega-3s and omega-6s

Breast Cancer Risk Lower with Exercise

A recent study from Washington University School of Medicine in St. Louis shows that exercise starting during adolescence can protect girls from breast cancer (Journal of the National Cancer Institute, May 2008). Researchers tracked 65,000 nurses who answered questionnaires about exercise. Within six years, 550 were diagnosed with breast cancer before menopause. Those who exercised regularly as teens were 23 percent less likely to develop premenopausal breast cancer than their sedentary peers. Ages 12 to 22 appear to be the most important time to use exercise to help prevent breast cancer.

Higher estrogen levels increase risk of breast cancer. Exercise lowers estrogen by reducing body fat. Fat cells make estrogen, and after the menopause fat cells are the principal source of estrogen. Other factors that increase breast cancer risk are also related to higher estrogen levels: starting to menstruate at an early age, late onset of menopause, taking estrogen after menopause, and being overweight.