A 2002 report issued by the World Health Organization’s International Agency for Research on Cancer estimates that one-fifth to one-third of all breast, colon, endometrial, kidney and esophageal cancers can be related to overweight and obesity.
In a recent population study published in the New England Journal of Medicine (April 24, 2003), researchers conclude that overweight and obesity account for up to 14 percent of all cancer deaths in American men over 50 and 20 percent of all cancer deaths in American women over 50. The researchers estimated that more than 90,000 deaths from cancer per year could be avoided if all adults maintained a normal body weight throughout life.
What’s the link ?
Fat cells are known to secrete hormones and hormone-like substances into the blood stream to help cells grow properly. Many scientists believe that in people with excess body fat, greater amounts of hormones are produced causing cells to grow and divide rapidly. Under these conditions, the chances increase that cell division will go wrong, leading to cancer. Also, the more the women weigh, the higher their levels of a formof estrogen called estradiol.
For instance, excess body fat has been linked to postmenopausal breast cancer because of its effect on estrogen levels. Although the ovaries stop producing estrogen after menopause, fat cells continue to pump the hormone into the blood stream. Scientists believe that this extended lifetime exposure to estrogen increases breast cancer risk after menopause.
Carrying excess weight may also encourage backflow of stomach acid into the esophagus, which has been linked to cancer of the esophagus. In addition, obesity makes cancer harder to diagnose and treat. Excess weight may interfere with proper examination or testing or even influence the effectiveness of cancer treatment.
Researchers connect excessive fat to the development of all “hormonal” cancers—breast, prostate, ovary, endometrial and testes. The international study comparing obese women to women of normal weight confirms what doctors have long suspected — that fat cells release the hormone into the blood, allowing it to help turn normal cells cancerous.
According to the AICR, obesity increases the likelihood of developing the following cancers by 25 to 33 percent:
Steps you can take
The recommendations of the AICR report can be summarized in six practical guidelines. These simple action steps represent the best advice science currently offers for lowering your cancer risk.
1- Choose a diet rich in a variety of plant-based foods
Vegetables, fruits, whole grains and beans contain natural substances that help our bodies destroy carcinogens before they cause cancer. In study after study, scientists have documented various vitamins, minerals and other helpful compounds within these foods that fight – and sometimes even reverse – the cancer process. Focusing on plant foods doesn’t have to mean banishing meat altogether. Add more rice and beans, more salad, more steamed vegetables to your dinner plate, and you’ll likely find meat and other animal-based foods being nudged to the side.
2- Eat plenty of vegetables and fruits
In addition to vitamins and minerals, vegetables and fruits contain thousands of natural substances called phytochemicals. Researchers are hard at work trying to discover the role of phytochemicals in cancer prevention. It now appears these substances work together in complex ways.
For this reason, most researchers believe that foods are more effective at preventing cancer than dietary supplements. Study after study indicates the best way to ensure you’re getting a safe and effective mix of phytochemicals is to stick with a mostly plant-based diet high in vegetables and fruits.
3- Maintain a healthy weight and be physically active
Physical activity plays a vital role in helping us reach and stay at a healthy weight. Regular exercise burns calories, builds muscle and helps the body run more efficiently. In addition, there is now scientific evidence that exercise itself possesses anti-cancer benefits. Regular physical activity has been shown to protect against colon cancer, and it probably lowers the risk for lung and breast cancers as well. Go about household chores or outdoor jobs with a bit more spring in your step. Everything from vacuuming and mopping to washing the car and pushing a lawn mower around can give you a workout, if you do it energetically. At home or out, use the stairs as often as you can. Walk to the corner market for bread instead of taking the car. For people with sedentary jobs and lives, the AICR report recommends an hour a day of moderate physical activity and an hour a week of vigorous activity. If you are not currently active, start slowly and gradually add more activity to your day. You also don’t have to set aside an entire hour for exercise. Break up your workouts however you like throughout the day. Remember that all activity is good for you, and some is better then none.
4- Drink alcohol only in moderation, if at all
Alcohol probably increases the risk for cancers of the colon, rectum and breast, even at very low levels of consumption. And cancer isn’t the whole story. High alcohol consumption is also linked to high blood pressure, stroke, heart disease, birth defects, osteoporosis, accidents, violence and suicide. If you do drink alcohol, use moderation. ‘Moderation’ means women should have no more than one drink a day, and men should have no more than two drinks a day.
5- Select foods low in fat and salt
According to research, fat and salt are two additional substances that could increase our risk for cancer and other health problems. High fat diets possibly increase the risk for cancers of the lung, colon, rectum, breast, endometrium (uterine lining) and prostate. In addition, eating too many fatty foods can lead to obesity and the rise in cancer risk that comes with it. AICR recommends minimizing the saturated and trans-fats in your diet. Instead, choose moderate amounts of monounsaturated fats such as olive and canola oils.
Diets high in salt and salted foods probably increase the risk for stomach cancer. Processed foods can be high in sodium. When you can’t cook from scratch, compare labels and select lower sodium varieties of frozen dinners, canned soups and vegetables. For rice mixes, use only part of the seasoning packet. Rinse canned beans to wash away some of the salt.
6- Prepare and store food safely
Cooking meat, poultry and fish at high temperatures, especially over an open flame, causes cancer-promoting substances called HCAs (heterocyclic amines) to form on the surface of the meats. In addition, when fat drips into the fire, the smoke and flames that rise up onto the food leave behind carcinogenic substances called PAHs (polycyclic aromatic hydrocarbons). A diet high in meat cooked by grilling, barbecuing, broiling or pan frying possibly increases the risk of stomach, colon and rectal cancers.
When cooking meats, it’s best to use lower-heat options like baking, poaching, stewing, roasting and microwaving.
7- Do not use tobacco in any form
Tobacco is the chief cause of lung cancer in the world, and it also causes cancers of the mouth and throat. In addition, tobacco contributes to cancers of the pancreas, cervix and bladder. Regardless of how it’s used – as cigars, cigarettes, pipes or chew – the link between tobacco and cancer is clear.
There are many successful methods for quitting tobacco use. Adapt these guidelines in your daily life to achieve a healthy weight and prevent cancer.
The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.