But beyond that generality, few people seem to know how to fine-tune their meals for the most anti-cancer bang per bite.

Over the course of the lifetime of planet Earth, the plant world has devised and concocted a wealth of nutrients that can help your body fight off cancer.

It's time to put them to work for you.

Would you be interested in a tasty, quick way to cut your chances of certain types of cancer in half? The means to this desirable end are about as close as your refrigerator and your dining room table: All you have to do is cut open and eat a single orange every day.

According to cancer research in Australia, adding that extra serving of citrus fruit to your diet every day, only once a day, boosts immunity enough to significantly lower your risk of some common cancers.

" Citrus fruits [protect] the body through their antioxidant properties and strengthen the immune system, inhibiting tumor growth and normalizing tumor cells," says Katrine Baghurst, PhD, of the Commonwealth Scientific and Industrial Research Organization (CSIRO). According to Dr. Baghurst and her fellow researchers, oranges possess the most antioxidants of any fruit: more than 170 different phytochemicals.

The protection you can get from oranges is due to their influence on immunity. Your immune system has the assigned task of protecting you against cells that can turn cancerous. Sixty of the chemicals in oranges are substances called flavonoids that can help the immune system fend off inflammation and tumors.

Better Vegetables
When Americans eat fruits and vegetables, they don't eat the ones with the most anti-cancer (or other) health benefits. Instead, we dine on the same so-so produce too frequently. If we want more health benefits from our veggies, we'd better look to expand our culinary horizons.

" While people understand they should eat a variety of fruits and vegetables each day, they are not translating 'variety' in a way to capture health benefits, such as reducing their risk of developing chronic diseases," says Susie Nanney, PhD, acting director of the Obesity Prevention Center at Saint Louis University.

" People aren't eating the fruits and vegetables that contain the most nutrients," warns Dr. Nanney. "People are quite frankly confused about nutrition. I feel their pain."

Unfortunately, Americans rely too often on iceberg lettuce, corn, apples, potatoes and bananas; a steady diet of that produce doesn't produce the same benefits as indulging in a wider variety of vegetarian foods.

Dr. Nanney points out that the vegetables and fruits most effective at helping the body fight cancer are dark green leafy veggies, citrus (oranges, grapefruits), cruciferous vegetables (broccoli and cauliflower) and produce that has yellow or orange color.

Making Dinner Plans
Dr. Nanney's spectrum of desirable foods includes:
• White: Don't eat the usual potatoes; add cauliflower to your meals.
• Green: Eat dark lettuces, like romaine and red leaf; eat a lot more spinach, broccoli and Brussels sprouts.
• Yellow/orange: Instead of eating corn and bananas frequently, eat more carrots, winter squashes, sweet potatoes, cantaloupe, oranges and grapefruit.
• Red: Apples are helpful in some ways, but indulge more often in tomatoes (colored by lycopene, a strong antioxidant); include red peppers and strawberries in your diet; these are rich in vitamin C.

Desirable Diet
" When we look at how to get the most bang for your buck, the most power, it's by eating these other fruits and vegetables instead of the traditional choices," Nanney insists.

Studies show that tomatoes, colored by a pigment called lycopene, may be particularly helpful in lowering men's chances of prostate cancer. For instance, research on about three dozen men with prostate cancer found that those taking supplements of lycopene and other tomato phytochemicals had smaller tumors and less spread of their cancers (Exper Bio and Med, 2002; 227: 881).

The researchers conclude that "lycopene may have an antitumor effect and may be useful as an adjunct to standard treatment of prostate cancer, such as surgery, radiation therapy, hormones and chemotherapy. In addition, lycopene supplementation appears to have reduced the [spread of cancer within the prostate], suggesting that lycopene may have a role in the prevention of prostate cancer."

In a study on African-American men, who suffer a higher rate of prostate cancer than other Americans, researchers also found that lycopene can limit the DNA damage that may presage cancer (Amer Chem Soc Meeting #222, 2001).

" This study does not say that tomato sauce reduces cancer," cautions Phyllis E. Bowen, PhD, a nutritionist at the University of Chicago and lead investigator in the study. " It says that it reduces DNA damage that we think is associated with cancer."

Tomato Consumption
Other studies have confirmed the finding that men who eat tomatoes suffer less prostate cancer. And if you want the most anti-cancer benefit from tomatoes, better cook them.

According to Rui Hai Liu, MD, Cornell assistant professor of food science, "[Our] research demonstrates that heat processing actually enhanced the nutritional value of tomatoes by increasing the lycopene content-[the] phytochemical that makes tomatoes red-that can be absorbed by the body, as well as the total antioxidant activity. The research dispels the popular notion that processed fruits and vegetables have lower nutritional value than fresh produce."

Less Meat
While you're making an effort to eat more of the colorful vegetables, you should also eat less fatty red meat and cut back on high-fat dairy foods, according to research from Harvard.

In this study, which covered eight years and looked at the diets of more than 90,000 women, scientists found that those premenopausal women who ate the most fatty red meat and regular milk had the highest chance of developing invasive breast cancer.

The scientists taking part in this study believe that eating more saturated fat from meat may increase hormone levels that boost the chances of breast cancer (Jrnl Natl Cancer Inst 2003;95:1079).

In this research, the total amount of fat didn't affect cancer risk, but the amount of animal fat did. Women who ate the most red meat had a 54% higher chance of breast cancer. Aside from avoiding red meat, women who wish to lower their risk of breast cancer should also limit their consumption of alcoholic beverages.

A study of two thousand post- menopausal women found that those who averaged about two drinks a day raised their risk of breast cancer by about 80% (Cancer Epidem, Biomarkers and Prevention, 10/03).

Here, too, researchers believe that alcohol affects the level of hormones that influence cancer.

The moral of the research into how food can slow cancer risk: Eat a wide variety of vegetables and fruits early and often. Limit meat and alcohol.

Change the color of the fruits and vegetables on your plate for a better chance of a brighter future.