Diet and Survival After Prostate Cancer Diagnosis

Authors: Berkow, Susan E.; Barnard, Neal D.; Saxe, Gordon A.; Ankerberg-Nobis, Trulie

Source: Nutrition Reviews, Volume 65, Number 9, September 2007 , pp. 391-403(13)

The news story, “Tomatoes No Help Against Prostate Cancer?” was recently posted regarding a new study on tomato consumption and prostate cancer. While it may seem that this is another example of nutrition advice getting thrown out the window with a new contradicting study, it actually is further confirmation on the importance of the whole foods for health. Looking to one specific nutrient as a key to health and ignoring all others does not play out to be effective. It is as much the other nutrients that come packaged within a certain food and the avoidance of other nutrients packaged in other foods that make the difference.

This new study is important to understanding nutrition for cancer as it looked at 28,000 men and their eating habits. This study found no association with lycopene consumption and reduced risk of prostate cancer. However, other equally compelling studies found this association. Why would this be? Is one study right and the other wrong?

While the experts continue to look at this study and fit it into the puzzle, it seems that lycopene may be interacting with other equally important phytochemicals in other plant foods or its effects could be countered by other variables like too much saturated fat in other foods like the cheese on that tomato sauce. This study may have isolated the effect of only the one phytochemical. So many other variables may contribute to the reduced risk of prostate cancer: reduced consumption of dairy products, reduced saturated fat intake, lower body weight with a lower fat diet, increased consumption of a variety of fruits, vegetables, legumes, and whole grains, etc. Presumably, other studies attempted to control the effects of these other variables, but this is where research gets tricky. It is very hard to find causation or lack of causation in diet studies since people don’t live in laboratories.

While we wait for new reports and recommendations, my recommendations to you would be to throw away any isolated phytochemicial pills/supplements and continue to load up on yummy tomato-based dishes and other lycopene rich foods. There are many other nutrients to receive in these nutritious foods.

Here’s the article:

Diet-cancer experts at the American Institute for Cancer Research (AICR) weighed in on a new study which suggests that tomatoes and other foods containing a well-known phytochemical called lycopene offered no protection against prostate cancer in a group of 28,000 men.

The new study, published in the journal Cancer Epidemiology Biomarkers and Prevention, is the latest in a long line of research into the effects of lycopene-containing foods. The majority of previous studies have suggested that tomatoes and tomato-based products offer some measure of protection against prostate cancer.

“This new study is a major contribution to the research, and it will be considered alongside all of the work that has come before,” said AICR Nutrition Advisor Karen Collins, RD.

“It’s long been clear that loading up on any one food, or food supplement, is not supported by the research,” Collins said. “The strongest evidence shows that diets high in a variety of different fruits, vegetables, whole grains and beans are associated with lower risk of developing cancer, including prostate cancer.”

New Findings Compared to Previous Evidence

In the coming weeks and months, researchers will continue to examine the new study and place it in context with compelling evidence from previous scientific investigations.

In the laboratory, tomato components have stopped the proliferation of several cancer cells types, including breast, lung, and endometrium. Tomatoes have attracted particular attention from prostate cancer researchers because lycopene and its related compounds tend to concentrate in tissues of the prostate. In animal models, consumption of tomato compounds has been linked to large decreases in prostate cancer risk.

In fact, studies that compare the diets and disease rates of different populations have repeatedly associated diets high in tomatoes with lower prostate cancer risk, as well as lower risk of stomach and pancreatic cancers.

One notable study that tracked the diets of more than 47,000 men for six years found that those who ate the most tomato products (cooked tomatoes, tomato sauce, pizza and tomato juice) had a 35% lower risk of early prostate cancer and a 53% lower risk of advanced prostate cancer than men who ate the least of these foods.

“This new study doesn’t close the book on tomatoes and lycopene, it just starts a new chapter,” Collins said.

No Magic Bullets

AICR experts repeatedly caution that no single food or food substance should be seen as a magic bullet of protection. All fruits, vegetables, whole grains and beans contain natural phytochemicals, and many of these compounds have shown the potential to protect against cancer development in a variety of ways.

Because many of these substances seem to work in combination, the key is to eat a diet that’s high in a variety of the foods that contain them. Loading up on any one food, or a supplement that contains high doses of isolated food components, is not recommended.

Expert Report Will Help Dispel Confusion

On November 1st of this year, AICR and its international affiliate organizations will publish the most comprehensive assessment of the scientific literature on diet, physical activity and cancer risk ever undertaken.

That report, Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective, will synthesize data from thousands of studies and provide guidelines for the public, and for the scientific/medical community. It will provide answers to questions about nutrition and cancer – including the role of lycopene – that are based on a thorough review of the available science.

Find out more about the WCRF/AICR Expert Report here.