DR. WALLACE: My grandfather works for the American Cancer Society, which is very interested in getting teens to start early on living a healthy life and reducing the risk of cancer. It has come up with five protective factors to add to your life and five risk factors to subtract from your life. You would really do your teen readers a big favor by printing these factors.

PROTECTIVE FACTORS

1. EAT MORE VEGETABLES IN THE CABBAGE FAMILY. Important studies show these vegetables (also known as cruciferous vegetables) appear to protect against colorectal, stomach and respiratory cancers. They include broccoli, cauliflower, Brussels sprouts, cabbages and kale.

2. ADD MORE HIGH-FIBER FOODS. A high-fiber diet may protect you against colon cancer. Fiber occurs in whole grains, fruits and vegetables, including peaches, strawberries, potatoes, spinach, tomatoes, wheat and bran cereals, rice, popcorn and whole-wheat bread.

3. CHOOSE FOODS WITH VITAMIN A. This vitamin may help protect against cancers of the esophagus, larynx and lungs. Fresh foods with beta carotene, such as carrots, peaches, apricots, squash and broccoli, are the best source of vitamin A — not vitamin pills.

4. DO THE SAME FOR VITAMIN C. This vitamin may help protect against cancers of the esophagus and stomach. You'll find it naturally in lots of fresh fruits and vegetables, like grapefruit, cantaloupe, oranges, strawberries, red and green peppers, broccoli and tomatoes.

5. ADD WEIGHT CONTROL. Obesity is linked to cancers of the uterus, gallbladder, breast and colon. Exercise and lower calorie intake help you avoid gaining too much weight. Walking is ideal exercise for most people, and it strengthens you for other sports. Check with your physician before undertaking strenuous activity or a special diet.

RISK FACTORS

1. TRIM FAT FROM YOUR DIET. A high-fat diet increases your risk of breast, colon and prostate cancer. Fat-loaded calories mean weight gain, especially if you don't exercise. Cut overall fat intake by eating lean meat, fish, skinned poultry and low-fat dairy products. Avoid pastries and candies.

2. SUBTRACT SALT-CURED, SMOKED OR NITRATE-CURED FOODS. Cancers of the esophagus and stomach are common in countries where these foods are eaten in large quantities. Indulge in bacon, ham, hot dogs or salt-cured fish only occasionally, if at all.

3. BAN TOBACCO PRODUCTS. Smoking is the biggest cancer risk factor of all. It is the main cause of lung cancer and 30 percent of all other cancers. Smoking at home potentially means more respiratory and allergic ailments for family members. Pregnant women who smoke can harm their babies. Chewing tobacco is a harmful risk for mouth and throat cancer.

4. GO EASY ON ALCOHOL. If you drink a lot of alcohol, your risk of liver cancer increases. Smoking and drinking alcohol also greatly increase the risk of cancers of the mouth, throat, larynx and esophagus. If you do drink alcohol, be moderate in your intake. But better yet, don't drink at all.

5. RESPECT THE SUN'S RAYS. Too much sun can cause skin cancer and other damage to your skin. Protect yourself with sunscreen — at least 15 SPF — and wear long sleeves and a hat during the day, especially between 11 a.m. and 3 p.m. Don't use indoor sunlamps, tanning parlors or tanning pills. If you see changes in a mole or a sore that does not heal, see your physician. — Angie, Atlanta, Ga.

ANGIE: Thanks so much for the important information. It will help educate both teens and adults.

Dr. Robert Wallace welcomes questions from readers. Although he is unable to reply to all of them individually, he will answer as many as possible in this column. E-mail him at rwallace@thegreatestgift.com. To find out more about Dr. Robert Wallace and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.