Joanna Cosgrove07.01.07
It's been estimated that one in eight women are diagnosed with breast cancer each year but only a slim minority of breast cancer survivors follow a healthy lifestyle that includes the recommended intakes of vegetables and fruits, as well as moderate levels of physical activity. According to a new study published in the Journal of Clinical Oncology, a diet high in vegetables and fruits, in combination with moderate exercise, can favorably impact breast cancer survival, even if the patient is overweight or obese (Vol. 25, No. 17 [June 10], 2007: pp. 2345-2351).
Researchers from The Moores UCSD Cancer Center at the University of California, San Diego, followed 1490 women diagnosed and treated for early-stage breast cancer between 1991 and 2000. The women consumed five or more servings of plant food per day and exercised moderately-about 30 minutes a day, 6 days a week. Of those enrolled in the study seven were lost to follow-up through December 2005.
The most important factor to realize in this study, pointed out Gordon Saxe, M.D., Ph.D., assistant professor in the department of family and preventative medicine, The Moores UCSD Cancer Center at the University of California, San Diego, was that the study determined that the benefit relied upon the combination of plant food and regular exercise. "When they looked at women just in terms of good diet and no exercise, or bad diet with exercise, while they saw a little effect, it was not nearly as pronounced when both were combined. Also, they were only looking at women who consumed five or more servings a day of plant foods," he said. "There will be some more data coming out later regarding women who had higher than five servings a day of plant foods. It's possible that when women have an even higher level of intake the effect is stronger. That's still pending, though."
Dr. Saxe classified "plant food" as not just fruits and vegetables, but also whole grains. "From what we know, it appears that the beneficial effects of plant foods on cancer in general are most strongly found in vegetables and whole grains," he said, adding that vitamins and nutritional supplement consumption were not specifically addressed by this study.
"In the nutraceutical segment there could be the question of 'Could we supplement with certain things that could be beneficial,' but I think to get the optimal effect it's important to go in the direction of the whole diet, not taking out, in isolation, one part," he said. "Even here the source goes beyond the diet, as a combination of diet and exercise. To combat a disease as difficult as cancer effectively you have to work on multiple things."
Numerous studies have observed that among breast cancer patients, women who are overweight have an increased of risk cancer recurrence and death. What made this study especially interesting is that it clarified that obesity doesn't necessarily increase a woman's risk of death if she's making an effort to eat plant foods and exercise. "In this study, even if women who were overweight or obese still made changes in their diet and exercise, it might not have changed their weight, but it still had a (positive) effect," said Dr. Saxe. "To put it more clearly, this study found that the combination of diet and exercise wiped out the effect of body weight. While numerous studies have attributed worse survival to being obese, it may be that it's because they didn't measure the diet and exercise habits of those women and had they done so it's possible those studies might have shown that diet and exercise not body weight were the variables here. This has ramifications beyond the goodness of simple diet and exercise."
The UCSD study is the latest one in a collection of recent studies linking diet and cancer incidence. A 2005 National Cancer Institute study found that breast cancer patients who reduced their fat consumption lowered their risk of tumor recurrence by as much as 42%. High-fat foods, including beef, vegetable oils and chicken, can boost the hormones that promote cancer cell growth. But most plant-based foods are naturally low fat and offer people a healthy way to stay slim.
All plant foods (whole grains, legumes, vegetables, and fruit) are loaded with fiber which is helpful in normalizing estrogen levels and reducing breast cancer risk and recurrence," said Jennifer Reilly, RD, senior nutritionist with The Cancer Project, a Washington, D.C.-based collaborative group of physicians, researchers and nutritionists that educates the public on the benefits of a healthy diet for cancer prevention and survival. "Plant foods are also naturally low in fat. Fat drives estrogen production and therefore increases breast cancer risk. In addition, the cruciferous family of vegetables (broccoli, kale, Brussel sprouts, cabbage, etc.) are especially effective at helping the body rid itself of excess hormones and have been shown to have a crucial role in breast cancer prevention."
Beyond a multivitamin, The Cancer Project recommends getting all nutrients from foods. "A varied plant-based diet will provide a wealth of cancer-fighting antioxidants and phytochemicals as well as healthy fiber," Ms. Reilly said. "Plus, some research-namely with beta-carotene-indicates that taking supplements of antioxidants may increase cancer risk. The nutrients found in foods are in the right proportion and likely come along with other cancer-fighting nutrients which have not even been discovered yet."
Another recent study from the National Cancer Institute suggests that eating soy foods as a child and teenager-specifically, before a girl enters puberty-may be a way to prevent breast cancer. "In this study, Asian women in California who consumed higher amounts of soy between the ages of five and 11 were 58% less likely to develop breast cancer, as compared to women who consumed less soy during this period of their lives," explained Mark Messina, Ph.D., adjunct professor in nutrition at Loma Linda University, former National Cancer Institute researcher and expert on the role of soy in diets. "These exciting results are similar to those from a Chinese study, which found that girls who had high soy intake between the ages of 13 and 15 were half as likely to develop breast cancer later in life The amount of soy consumed as adults was not protective against breast cancer, although soy foods' overall benefits in reducing cholesterol and providing high quality protein are well proven."
Dr. Saxe added that The Moores UCSD Cancer Center is also embarking on two new cancer studies within the same purview of interest. The first has a similar focus as the Center's aforementioned breast cancer study, whereby 800-1000 men with prostate cancer who've undergone surgical removal of the prostate will be studied for recurrence and its possible relation to diet, body weight and activity levels. "In addition," he added, "we'll be looking at over 1100 gene expressions that are thought to relate to the progression of prostate cancer. The question we'll be looking to answer with this study is 'Does diet change the expression of those genes, and if so, what dietary components thereby possibly influence the risk of relapse and long-term clinical outcome.'" This study will be conducted in the same division at UCSD but not by the same team who conducted the breast cancer study. The study is currently underway.
"We're also planning an evaluation project, not a study per se, to evaluate the scientific literature of a large number of nutraceutical agents for their possible use in the treatment of advanced prostate cancer," explained Dr. Saxe. "This project is tentatively scheduled to begin in mid-to late summer and is expected to run for the two to three years. We'll be looking at a range of things, including vitamin D, which seems to look very promising right now."
Researchers from The Moores UCSD Cancer Center at the University of California, San Diego, followed 1490 women diagnosed and treated for early-stage breast cancer between 1991 and 2000. The women consumed five or more servings of plant food per day and exercised moderately-about 30 minutes a day, 6 days a week. Of those enrolled in the study seven were lost to follow-up through December 2005.
The most important factor to realize in this study, pointed out Gordon Saxe, M.D., Ph.D., assistant professor in the department of family and preventative medicine, The Moores UCSD Cancer Center at the University of California, San Diego, was that the study determined that the benefit relied upon the combination of plant food and regular exercise. "When they looked at women just in terms of good diet and no exercise, or bad diet with exercise, while they saw a little effect, it was not nearly as pronounced when both were combined. Also, they were only looking at women who consumed five or more servings a day of plant foods," he said. "There will be some more data coming out later regarding women who had higher than five servings a day of plant foods. It's possible that when women have an even higher level of intake the effect is stronger. That's still pending, though."
Dr. Saxe classified "plant food" as not just fruits and vegetables, but also whole grains. "From what we know, it appears that the beneficial effects of plant foods on cancer in general are most strongly found in vegetables and whole grains," he said, adding that vitamins and nutritional supplement consumption were not specifically addressed by this study.
"In the nutraceutical segment there could be the question of 'Could we supplement with certain things that could be beneficial,' but I think to get the optimal effect it's important to go in the direction of the whole diet, not taking out, in isolation, one part," he said. "Even here the source goes beyond the diet, as a combination of diet and exercise. To combat a disease as difficult as cancer effectively you have to work on multiple things."
Numerous studies have observed that among breast cancer patients, women who are overweight have an increased of risk cancer recurrence and death. What made this study especially interesting is that it clarified that obesity doesn't necessarily increase a woman's risk of death if she's making an effort to eat plant foods and exercise. "In this study, even if women who were overweight or obese still made changes in their diet and exercise, it might not have changed their weight, but it still had a (positive) effect," said Dr. Saxe. "To put it more clearly, this study found that the combination of diet and exercise wiped out the effect of body weight. While numerous studies have attributed worse survival to being obese, it may be that it's because they didn't measure the diet and exercise habits of those women and had they done so it's possible those studies might have shown that diet and exercise not body weight were the variables here. This has ramifications beyond the goodness of simple diet and exercise."
Unraveling the Diet/Cancer Connection
The UCSD study is the latest one in a collection of recent studies linking diet and cancer incidence. A 2005 National Cancer Institute study found that breast cancer patients who reduced their fat consumption lowered their risk of tumor recurrence by as much as 42%. High-fat foods, including beef, vegetable oils and chicken, can boost the hormones that promote cancer cell growth. But most plant-based foods are naturally low fat and offer people a healthy way to stay slim.
All plant foods (whole grains, legumes, vegetables, and fruit) are loaded with fiber which is helpful in normalizing estrogen levels and reducing breast cancer risk and recurrence," said Jennifer Reilly, RD, senior nutritionist with The Cancer Project, a Washington, D.C.-based collaborative group of physicians, researchers and nutritionists that educates the public on the benefits of a healthy diet for cancer prevention and survival. "Plant foods are also naturally low in fat. Fat drives estrogen production and therefore increases breast cancer risk. In addition, the cruciferous family of vegetables (broccoli, kale, Brussel sprouts, cabbage, etc.) are especially effective at helping the body rid itself of excess hormones and have been shown to have a crucial role in breast cancer prevention."
Beyond a multivitamin, The Cancer Project recommends getting all nutrients from foods. "A varied plant-based diet will provide a wealth of cancer-fighting antioxidants and phytochemicals as well as healthy fiber," Ms. Reilly said. "Plus, some research-namely with beta-carotene-indicates that taking supplements of antioxidants may increase cancer risk. The nutrients found in foods are in the right proportion and likely come along with other cancer-fighting nutrients which have not even been discovered yet."
Another recent study from the National Cancer Institute suggests that eating soy foods as a child and teenager-specifically, before a girl enters puberty-may be a way to prevent breast cancer. "In this study, Asian women in California who consumed higher amounts of soy between the ages of five and 11 were 58% less likely to develop breast cancer, as compared to women who consumed less soy during this period of their lives," explained Mark Messina, Ph.D., adjunct professor in nutrition at Loma Linda University, former National Cancer Institute researcher and expert on the role of soy in diets. "These exciting results are similar to those from a Chinese study, which found that girls who had high soy intake between the ages of 13 and 15 were half as likely to develop breast cancer later in life The amount of soy consumed as adults was not protective against breast cancer, although soy foods' overall benefits in reducing cholesterol and providing high quality protein are well proven."
Dr. Saxe added that The Moores UCSD Cancer Center is also embarking on two new cancer studies within the same purview of interest. The first has a similar focus as the Center's aforementioned breast cancer study, whereby 800-1000 men with prostate cancer who've undergone surgical removal of the prostate will be studied for recurrence and its possible relation to diet, body weight and activity levels. "In addition," he added, "we'll be looking at over 1100 gene expressions that are thought to relate to the progression of prostate cancer. The question we'll be looking to answer with this study is 'Does diet change the expression of those genes, and if so, what dietary components thereby possibly influence the risk of relapse and long-term clinical outcome.'" This study will be conducted in the same division at UCSD but not by the same team who conducted the breast cancer study. The study is currently underway.
"We're also planning an evaluation project, not a study per se, to evaluate the scientific literature of a large number of nutraceutical agents for their possible use in the treatment of advanced prostate cancer," explained Dr. Saxe. "This project is tentatively scheduled to begin in mid-to late summer and is expected to run for the two to three years. We'll be looking at a range of things, including vitamin D, which seems to look very promising right now."