Tecnología de la Información y Comunicación

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following 384 men with prostate cancer over a five-year period. It turned out that those who consumed the most saturated fat—the kind particularly prevalent in meats and dairy products—had three times the risk of dying from the disease compared to those with the lowest saturated fat intake.

Increased risk was also found with higher intakes of total and monounsat-urated fat, but these increases were not significant.²

The following year, researchers in Toronto and Vancouver reported the results of a study of 263 men with prostate cancer. The study found that the men who consumed the most monounsaturated fat (the type that is abundant in olive and canola oils) lived the longest. Their risk of dying was 70 percent lower compared to those with the lowest intake of monounsat-urates. The study also found increased risk from animal fat and saturated fat intake, although these latter findings were not strong enough to reach statistical significance.³

Using a Vegan Diet

Dean Ornish, founder and director of the Preventive Medicine Research Institute and clinical professor of medicine at the University of California, San Francisco, who had already demonstrated the benefits of a low-fat, vegetarian diet for heart patients (finding that it reversed heart disease in 82 percent of research participants), decided to put a similar program to the test for prostate cancer.⁴The ninety-three volunteers were men with early-stage cancer who were able to defer treatment, at least for the moment, because they were keeping a careful watch on their prostate-specific antigen (PSA, an index of cancer spread) levels, a strategy known as “watchful waiting.” Typically, PSA levels slowly rise, and eventually treatment (such as surgery) may be required. Ornish randomly assigned half of the men to fol-low their usual habits (the control group), and the remaining half were to follow a low-fat vegan diet along with moderate aerobic exercise and stress management. In the experimental vegan group, PSA levels decreased by 4 percent after one year, while PSA levels rose by 6 percent in the control group.

Six of the men in the control group needed treatment during the one-year study period because their prostate cancer was progressing, whereas no one in the experimental group needed treatment during the study period.

Using Diet to Fight Recurrent Cancer

Ornish’s approach is extremely promising for men with early prostate dis-ease. But what about advanced cancer? Evidence suggests that dietary changes can still play a vital role. Two studies have used special diets in men who had previously been operated on for prostate cancer but who had experienced recurrences of their disease. Using a macrobiotic diet empha-sizing whole grains, vegetables, and legumes, while avoiding dairy products

and most meats, nine men with prostate cancer had an average survival of 228 months compared to 72 months for a matched group of men receiving no special diet.⁵

A study at the University of Massachusetts tested the benefits of a dietary change in ten men with prostate cancer that had recurred after surgery. The diet was based on whole grains, legumes, green and yellow vegetables, seeds, soy products, and fruit, and the men were also instructed in stress-reduction techniques. To measure the program’s effect, researchers tracked how long it took for the patients’ PSA levels to double—the longer the PSA doubling time, the slower the cancer is spreading. Before the study began, the average PSA doubling time was 6.5 months. But after four months in the program, it had slowed to 17.7 months, an encouraging finding. In three of the men, PSA levels actually fell.⁶

Cancer-Fighting Power You Can See

In 2002, researchers at the University of California at Los Angeles reported a series of unusual experiments that demonstrated the power of diet and exercise. They drew blood samples from a group of eight men who had been following a low-fat diet and exercising regularly for several years.

They also drew blood samples from overweight men who were not follow-ing the diet and exercise program. They added portions of each man’s blood serum to test tubes containing standardized prostate cancer cells.

Serum from men on the low-fat diet and exercise program slowed cancer cell growth by 49 percent compared to serum from the other men. How could this be? Differences in testosterone, estrogen, and insulin account for part of the effect, but other changes in the blood exert additional effects the researchers have not yet teased out.⁷ The research team also found that a man’s serum shows demonstrable cancer-inhibiting power within as little as eleven days after beginning a low-fat diet and exercise regimen.⁸

Lycopene and Prostate Cancer

Part of the value of plant-based diets comes from the protective compounds they contain. As we saw in chapter 5, carotenoids are a specific class of antioxidants that includes lycopene, lutein, α-carotene and β-carotene. This class of antioxidants is primarily found in vegetables and fruits. Lycopene is considered one of the most potent antioxidants in the carotenoid family and has been linked with reduced prostate cancer risk.^9,10The highest con-centrations of lycopene are in cooked tomato products, such as pasta sauce.

Smaller but significant amounts are also found in raw tomatoes, grapefruit, watermelon, and guava. A 2004 meta-analysis evaluating lycopene and prostate cancer risk concluded that high tomato and lycopene intake may reduce prostate cancer risk by 10–20 percent.¹¹Diet intervention studies in

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newly diagnosed patients with localized prostate adenocarcinoma have found that consuming as little as 30 milligrams a day of lycopene in whole food or supplement form may reduce serum PSA levels.¹²

The Bottom Line

While more research will be of great value, evidence already suggests that men with prostate cancer—and their families—should be encouraged to adopt a low-fat vegan diet. By boosting vegetables, fruits, beans, and whole grains, and avoiding dairy products, meats, eggs, and fried foods, men are able to take advantage of protective nutrients and avoid cancer-promoting factors.

Recommended Recipes Braised Kale (page 173)

Mushroom Gravy (page 156) No-Meat Loaf (page 195)

Tomato, Cucumber, and Basil Salad (page 150)

ou now have the basic knowledge and cooking skills you need to begin to make some major changes in your eating habits. There is much more to learn, of course, but now’s the time to put what you know to work. In this chapter, you’ll have a chance to experience what it is like to be on as perfect a diet as possible. We will use a unique method to learn new tastes and break away from bad habits. Along the way, we will also look at what to do when you do not have complete control over the menu, for example at restaurants or fast-food outlets.

The Three-Week Break

The best and easiest way to try a new way of eating is to take what you might call a “three-week break.” That is, select a three-week period and during this time build your meals only from the best possible foods while setting aside unhealthful foods completely. Your taste buds have a memory of about three weeks, which means that, in that short time, you’ll be adjusted to new tastes. So whether you are looking to cut the fat from your diet, reduce salt, break a sugar habit, or get to know truly health-promoting foods, using a three-week break—and really doing it all the way—will give you the momentum you need.

At the end of three weeks, see how you feel. If you like how things are going—if you’ve lost a few pounds and are feeling healthier and more energetic—you can stick with it. If, however, this just doesn’t feel right to you, you are free to go back to your old way of eating. Your diet experiment lasts only three weeks, and remembering that will help you to give it your all.

Do not do it halfway. Now is the time to really see what healthful eat-ing feels like. If you were just to have an occasional nutritious vegetarian meal while continuing to eat meaty, cheesy dishes at other times, you would keep reminding your taste buds of the very foods that cause health problems and would never lose your taste for these foods. Have a complete

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The best and easiest way to try a new way of eating is to take what you might call a

“three-week break.”

C H A P T E R

Y

Planning

Health-Promoting