Can the food we eat ward off disease?


There's no doubt about it -- especially if you combine that with some daily exercise. As many as one-third of all cancer cases are related to a poor diet and a sedentary lifestyle, according to the American Institute for Cancer Research. In fact, four out of the six leading causes of death in the United States -- cancer, stroke, heart disease and diabetes -- are linked to diet. And in some cases prevention is simple: Getting enough folic acid alone, for example, can reduce the risk of heart disease, birth defects, and possibly colon cancer.


 


Of course, some people take things too far, shopping for groceries as if they were chemists on the track of the ultimate disease-fighting drug. They believe that if they could only find the right mix of ingredients in the right doses, they'd never get sick -- or so they think. Unfortunately, many diseases have little to do with how well you eat. But experts do know that a varied, satisfying food life gives you the best chance to stay healthy.


 


What's the best diet for good health?


The fundamentals of a healthy diet are the same for three-year-olds, senior citizens, athletes, and couch jockeys. And not coincidentally, the dietary guidelines that are designed to prevent cancer and heart disease will also help you avoid obesity and Type 2 diabetes. The United States Department of Agriculture, the American Heart Association, the American Diabetes Association, and the American Cancer Society all agree on these same strategies for healthy eating:


 



  • Get less than 30 percent of your calories from fat, and less than 10 percent from saturated fat. For a person who eats 2,000 calories each day, that means drawing the line at 67 grams of fat and 22 grams of saturated fat. If you eat the typical American high-fat diet, cutting back on fat will help clear cholesterol from your arteries, improve your body's ability to control blood sugar, and decrease your chances of getting cancer of the colon and (for men) the prostate.



  • For a typical 2,000 calorie diet, eat two cups of fruit and two and a half cups of vegetables every day. This may sound like produce overkill, but the benefits are dramatic: lower blood pressure, improved cholesterol levels, reduced risk of dangerous blood clots, a stronger immune system, and lower incidence of a wide range of cancers.



  • Have at least six portions of beans, cereal, grains, pasta, rice (preferably brown), or whole-grain bread per day. The fiber in these foods (and in fruits and vegetables) can cut your cholesterol levels and protect you against cancer of the mouth, throat, larynx, esophagus, stomach, and lungs. Two recent studies by Harvard University found that a high-fiber diet can also reduce the risk of Type 2 diabetes by about 30 percent. By upping your intake of whole grains -- and eating your fruits and vegetables -- you'll have no trouble getting the 14 grams per 1,000 calories of daily fiber recommended by the USDA and other groups. You'll also get an abundance of vitamins, minerals, and nonfattening, energy-packed complex carbohydrates.



  • Consume three cups of fat-free or low-fat milk or similar dairy products per day.



  • Go easy on the salt shaker. You should get no more than 2,300 mg -- or about a teaspoon -- of salt per day.



  • Watch your calories. Staying trim is an important part of staying healthy, so try not to take in more calories than you burn. Extra weight increases blood pressure and cholesterol, encourages the onset of Type 2 diabetes, and heightens the risk of several types of cancer.



  • Eat a variety of foods. There's no single food that provides all the nutrients your body needs. Eating a variety of foods from all of the food groups helps you make sure you're getting all the nutritional elements you need to stay healthy.


Why do nutritionists say we should eat a multi-colored diet?


Phytochemicals -- the substances which give fruits and vegetables their bright and varied colors -- turn out to be essential in making our bodies strong and keeping them disease-free. In their book The Color Code, Tufts scientists James Joseph, Ph.D. and Daniel Nadeu, M.D. recommend that your daily diet includes fruits and vegetables from all four color groups: red, orange-yellow, green, and blue-purple. That way, you'll make sure to get enough of all of the different nutrients and phytochemicals needed to help you live a long and healthy life. Here is a thumbnail sketch of the benefits:


 



  • Red : Plants like strawberries, raspberries, tomatoes, and red bell peppers possess some of the strongest antioxidants known to science. Antioxidants trap and absorb free radicals, those unstable oxygen molecules in the body that can damage cells and lead to cancer. Free radicals are also linked to heart disease.



  • Orange-Yellow : Mangoes, carrots, and sweet potatoes are loaded with the antioxidant beta-carotene. They're also packed with vitamin A, which boosts your immune system and is crucial to healthy eyes and strong bones. Oranges -- besides being a powerhouse of vitamin C -- also contain the disease-fighting chemicals known as liminoids and flavonoids. (One flavonoid found in oranges, hesperetin, is thought to protect against cancer, heart disease, and infections.) Bananas are full of potassium, which can prevent or reduce high blood pressure (and may help keep plaques from forming in arteries as well).



  • Green : Chlorophyll, the phytochemical that makes plants green, is not a huge disease-fighter. Nevertheless, the green vegetables are stuffed with other nutrients and substances essential to good health. Broccoli is the king of cancer-fighters with its rich supply of vitamins C and K (used in photosynthesis), as well as specific cancer-preventing compounds like indoles (thought to be especially effective in fighting breast cancer). Spinach is a rich source of vitamin K, folic acid, and lutein, which helps prevents age-related macular degeneration (and may reduce cataracts as well).



  • Blue-Purple : Blueberries are extremely rich in antioxidants and contain nearly 100 phytochemicals, which help protect against cancer, bacteria, and ulcers, among other things. They may also help protect the brain against aging, according to Joseph and Nadeu. On the vegetable side, the antioxidants in eggplant have been shown in preliminary studies to reduce the wrinkling and aging of skin.


Will dietary supplements help me stay healthy?


For the most part, a well-balanced diet will give you all the nutrients you need for good health. However, in certain cases supplements make good sense. Women should take extra folic acid before and during pregnancy to prevent neural-tube birth defects. And later in life, many women and men may need calcium supplements to ward off osteoporosis and broken bones. Older adults, people with dark skin, and people who don't get enough sunlight should consume extra vitamin D either through vitamin D-fortified foods or supplements. Many people over age 50 have trouble getting enough vitamin B12, so new USDA guidelines recommend eating vitamin B12-fortified cereals or taking B12 crystalline supplements. Talk to your doctor to see if these or other supplements may be right for you.


 


Chris Woolston, M.S., is a health and medical writer with a master's degree in biology. He is a contributing editor at Consumer Health Interactive, and was the staff writer at Hippocrates, a magazine for physicians. He has also covered science issues for Time Inc. Health, WebMD, and the Chronicle of Higher Education. His reporting on occupational health earned him an award from the northern California Society of Professional Journalists.


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