Soy appears to protect against development of breast cancer (Medical Research News - 10/04/2008)


Evidence is growing from animal and human studies that genistein, a potent chemical found in soy, protects against development of breast cancer - but only if consumed during puberty, says a Georgetown University Medical Center researcher in the British Journal of Cancer published online. The challenge now, she says, is for scientists to understand precisely why soy appears to provide a shield against the most common cancer in women. "Timing seems to be vitally important in use of this bioactive food, and if we can figure out why that is so, then we may be able to help prevent breast cancer in the widest sense 
possible," says the researcher, Leena Hilakivi-Clarke, Ph.D., a professor of oncology at the Lombardi Comprehensive Cancer Center at Georgetown. Although there are a number of tantalizing theories to explain the connection, "at the present time no convincing explanation can be offered as to why the breast cancer-risk reducing effect of genistein might be strongest during childhood and early adolescence," she says. Hilakivi-Clarke is a senior author of a review article published in the journal that sums up the state of knowledge concerning the role of early life genistein exposures in modifying breast cancer risk. She has long studied the link between soy use and breast cancer, as have her three co-authors, all Finnish researchers.

There have only been three human studies that tracked soy use during puberty and later breast cancer development, and two of them focused on Asian females, who eat soy in their traditional diet. But these studies suggest soy offers a very strong protective effect - a 50 percent or more reduction in the risk of breast cancer - when soy is eaten during childhood and adolescence. The strongest evidence for genistein's protective effect comes from studies in mice and rats, Hilakivi-Clarke says. For example, numerous studies in rats show that the data regarding prepubertal exposure to genistein are very consistent in showing a reduction in mammary cancer risk, she says. Exposure to soy in fetal development or in adult life does not have the same protective effect. Further examination of experimental versus control rats demonstrated that use of genistein in puberty cut the number of so-called "terminal end buds" in the breast. These are the structures that lead to growth of the mammary epithelium, which are the cells lining milk ducts, etc., and it is in these epithelial cells that breast cancer originates. But Hilakivi-Clarke says it is not clear if a mere reduction in the number of these structures could reduce cancer 
risk, or why.

Other studies suggest that genistein controls expression of genes in terminal end buds that regulate cell growth, repair and death. For example, the chemical could be controlling the ability of stem cells, found on these buds, to reproduce themselves or to differentiate into more specialized cells. "There is evidence that suggests that the more stem cells there are on these structures, the greater the risk of breast cancer development," she says. This evidence 
supports the theory that breast cancer arises from stem cells that have lost growth control. Other associated research has found that the genes that genistein appears to activate in developing mammary glands are well known --- BRCA1, p53, and PTEN tumor suppressors, Hilakivi-Clarke says. These genes repair genetic damage and control cell survival and death, and they may also help control stem cell reproduction, she says, and genistein apparently 
"up-regulates" these genes, boosting production of their beneficial proteins.
What is perhaps most intriguing, she says, is that the same process that protects the breast from excess growth during pregnancy seems to be at work during puberty. "In pregnancy, BRCA1 is also up-regulated, perhaps in order to control the fate of stem cells, allowing them to make more cells for milk production, for example, but not more of themselves."

So Hilakivi-Clarke favors the notion that genistein is acting as a breast cancer protective just as an early first pregnancy in women is known to protect against later development of the cancer:
"If malignancies occur in breast stem cells, then it is better that many of these cells are differentiated earlier rather than later. Pregnancy hormones do that, so the shorter time there is between puberty and pregnancy, the greater that protection may be," she says. "Genistein may also help control the fate of stem cells in the same way." "We think this is the mechanism by which genistein works, but we really don't know and we need to find out," Hilakivi-Clarke says. "The findings will matter."

[Back]

Studies show how fruits and veggies reduce cancer- (Reuters- 7/12/2007) 

Just three servings a month of raw broccoli or cabbage can reduce the risk of bladder cancer by as much as 40 percent, researchers reported this week.  Other studies show that dark-colored berries can reduce the risk of cancer too -- adding more evidence to a growing body of research that shows fruits and vegetables, especially richly colored varieties, can reduce the risk of cancer. Researchers at the Roswell Park Cancer Institute in Buffalo, New York, surveyed 275 people who had bladder cancer and 825 people without cancer. They asked especially about cruciferous vegetables such as broccoli and cabbage. These foods are rich in compounds called isothiocyanates, which are known to lower cancer risk.

The effects were most striking in nonsmokers, the researchers told a meeting being held this week of the American Association of Cancer Research in Philadelphia. Compared to smokers who ate fewer than three servings of raw cruciferous vegetables, nonsmokers who ate at least three servings a month were almost 73 percent less likely to be in the bladder cancer group, they found.

Among both smokers and nonsmokers, those who ate this minimal amount of raw veggies had a 40 percent lower risk. But the team did not find the same effect for cooked vegetables. "Cooking can reduce 60 to 90 percent of ITCs, (isothiocyanates)," Dr. Li Tang, who led the study, said in a statement. A second team of researchers from Roswell Park tested broccoli sprouts in rats. They used rats engineered to develop bladder cancer and fed some of them a freeze-dried extract of broccoli sprouts. The more they ate, the less likely they were to develop bladder cancer, said Dr. Yuesheng Zhang, who led the research. They found the compounds were processed and excreted within 12 hours of feeding. That suggests the idea that compounds are protecting the bladder from the inside, said Zhang.

"The bladder is like a storage bag, and cancers in the bladder occur almost entirely along the inner surface, the epithelium, that faces the urine, presumably because this tissue is assaulted all the time by noxious materials in the urine," Zhang said. In a third study, a team at The Ohio State University fed black raspberries to patients with Barrett's esophagus, a condition that can lead to esophageal cancer. Black raspberries, sometimes called blackberries or blackcaps, are also rich in cancer-fighting compounds.

Ohio State's Laura Kresty and colleagues fed 1.1 ounces (32 grams) of freeze-dried black raspberries to women with Barrett's esophagus and 1.6 ounces (45 grams) to men every day for six months. They measured urine levels of levels of two compounds -- 8-isoprostane and GSTpi -- that indicate whether cancer-causing processes are going on in the body. Kresty said 58 percent of patients had marked declines of 8-isoprostane levels, suggesting less damage, and 37 percent had higher levels of GSTpi, which can help interfere with cancer causing damage and which is usually low in patients with Barrett's.

[Back]

Bad diet ups cancer risk for poor, black women (Reuters- 28/11/2007) 

Poor black women in U.S. cities face a greater risk of getting cancer because of unhealthy diets, according to a report released on Wednesday that says the finding applies to other ethnic groups. The study of more than 150 women living in public housing in Washington, D.C., found that 61 percent of them met none or just one of five goals for maintaining a healthy diet. The goals included adequate consumption of fruit and vegetables, a low percentage of fat intake, consuming no alcohol, eating moderate calories and adhering to a U.S. government Healthy Eating Index, which measures overall quality of diet.

"African-American women ... face a worse cancer incidence and mortality rate than most other ethnic groups and poor African-American women are at an even greater disadvantage," said Ann Klassen, an associate professor at Johns Hopkins University's Bloomberg School of Public Health. "Improving diet is one effective way to help these women lower their risk for developing cancer," Klassen said, adding that the women in the study went on to participate in a program aimed at improving nutrition.

Cancer risk can be assessed using measures that include diet, age, ethnicity and genetic factors. The study was relevant not just to black women in cities elsewhere but to poor women from other ethnic groups, researchers said. The findings were presented at a conference in Atlanta of the American Association for Cancer Research. Less than 1 percent of the women met all the ideal standards in each category, although 64 percent of the 156 women in the study reported drinking no alcohol on the days in which they were questioned.

Younger women were more likely to eat convenience foods and drink soda than older women even when eating meals with family, the report said, adding that young women appeared to lack the skills to build a well-balanced diet. "We believe that there are structural factors in society that make it more difficult for low-income people to modify their lifestyle in a way that they might know are healthy," said Klassen. The study also found a link between depression, smoking and poor diet, and determined that women born in the U.S. capital were more likely to have an unhealthy diet than women who had moved to the city from elsewhere.

[Back]

The best tool in cancer prevention-(McClatchy News Service- 20/11/2007)


Stick to common sense.I was reminded of this last week when the American Institute for Cancer Research and the World Cancer Research Fund released their new report about diet and cancer. The findings are a mouthful: If you want to reduce your cancer risk, stay as lean as possible within your healthy weight range; eat no more than 18 ounces of beef, pork and lamb a week; abstain from processed meats such as bacon, ham, cured sausage and lunchmeat; cut salt; drink no more than two alcoholic beverages daily if you're a man (or one if you're a woman); stay away from sugary, fatty processed foods; and eat mostly fruits, vegetables and grains.

"If these recommendations were adopted around the world, scientists estimate it could prevent about one-third of global cancer cases," says W. Phillip T. James, one of 21 international experts who analyzed more than 7,000 large-scale scientific studies for the report. You can imagine the controversy over this one. The American Meat Institute accused the World Cancer Research Fund of an "anti-meat bias." And I'm skeptical about diet and exercise preventing one-third of cancer cases, especially in light of factors such as genetics, tobacco use and environment.

Called "Food, Nutrition, Physical Activity and the Prevention of Cancer: a Global Perspective," the report took five years to finish. According to the American Institute for Cancer Research, nine teams of scientists, hundreds of peer reviewers and those 21 experts worked on the report. Check it out at www.dietandcancerreport.org -- and remember your common sense. For example, don't beat yourself up if you're not at the lowest point of the body mass index's healthy range. (The body mass index is a measure of body fat.) So what if you can't get close to an 18.5, as the report recommends?

Just exercise daily for at least 30 minutes, and preferably more. And don't worry that every extra pound raises the risk of post-menopausal breast cancer; adenocarcinoma of the esophagus and endometrium; and cancers of the colon, kidney and pancreas. Likewise, instead of measuring all the ounces of red meat you eat, just follow this easy guideline from the "The New American Plate Cookbook: Recipes for a Healthy Weight and a Healthy Life" (University of California Press, $24.95): Make sure your plate has two-thirds fruit, vegetables, legumes and whole grains and one-third meat. Be sure to eat many different types of plant foods and animal foods.

This 2005 cookbook from the American Institute for Cancer Research does a better job of encouraging healthy habits than the report released last week. And its advice is common sense.If a single week's meals are chicken, fish, shrimp, black beans and lamb with lots of different fruits and veggies, you're getting a wide range of nutrients. Better yet, you're not leaving enough room for the fatty and sugary processed foods the report advises you to avoid.

It all makes sense to me, except for the recommendation to avoid all processed meats. The report says meats preserved with nitrites, salt or smoke are linked to colon and stomach cancer. I asked Karen Collins, the institute's nutrition adviser, about cancer rates before refrigeration made fresh meat common. Could traditional methods of preserving meat really be that bad? Stomach cancer rates used to be higher, Collins says. And "the reason people didn't get colon cancer was because they didn't live long enough." Her response is precisely why I'll still enjoy ham at Christmas and the occasional hot link. After all, we don't know what will kill us in the end. And we can't live just to avoid cancer. We also have to enjoy life.

[Back]

Diet, growth found to cause cancer- (Reuters- 31/10/2007) 

What people eat and how fast they grow are both significant causes of cancer, but many Americans still incorrectly believe that factors such as pesticides on food are bigger causes, experts reported on Wednesday. Breastfeeding reduces the risk of cancer for mother and child, and tall people have a higher risk of cancer than shorter people, the report found. "We need to think about cancer as the product of many long-term influences, not as something that 'just happens,"' Dr. Walter Willett, a nutrition expert at the Harvard School of Public Health in Massachusetts, told a news conference.

The report, released jointly by the World Cancer Research Fund and the American Institute for Cancer Research, is the result of five years of study by nine teams of scientists. They reviewed 7,000 studies on diet, exercise, weight and cancer. Most of what they recommended is in line with what health experts, including governments and the World Health Organization, have long been advising -- that diets based on fruits, vegetables and whole grains and that go easy on red meats, dairy products and fats protect against heart disease, diabetes and cancer.

They found evidence that factors such as hormones that cause the body to grow quickly may be involved in some cancers. "We found that tallness is also probably linked to increased risk for ovarian, pancreatic and pre-menopausal cancer as well," said Willett. He stressed that tall people are not destined to get cancer but should take care to maintain healthy habits.

The groups make keeping a healthy weight their No. 1 recommendation to reduce the risk of cancer. "Be as lean as possible within the normal range of body weight," the 400-page report reads. That means keeping a body mass index, they said, of between 21 and 23. BMI is a calculation of height to weight, and the normal range is usually considered to be 18 to 25, with anything over 25 being overweight.

Exercise is also key. "Be physically active as part of everyday life," is the second of 10 recommendations made by the expert panel. The recommendations also include eating mostly plant foods, such as fruits, vegetables and grains, avoiding calorie-dense foods such as sugary drinks, and limiting red meat, alcohol and salt. The American Institute for Cancer Research also released a survey of 1,000 U.S. adults that show most do not understand these risks. Only 38 percent knew of the link between cured and processed meats and cancer, 49 percent knew that diets low in fruits and vegetables raised the risk of cancer and 46 percent knew that obesity was a well-documented risk.

But 71 percent thought that pesticide residue on produce was a cause -- something that has never been shown; 56 percent thought stress causes cancer, again not proven; and 49 percent believed hormones in beef cause cancer. "Americans are increasingly likely to attribute cancer to factors over which they have no control, and for which no proven links to the disease exist," the report reads. "This reflects an 'everything causes cancer' mindset," it adds.
The meat industry quickly denounced the report. "WCRF's conclusions are extreme, unfounded and out of step with dietary guidelines," said American Meat Institute Foundation Vice President of Scientific Affairs Randy Huffman.

[Back]

Can Foods Prevent Cancer? (Yahoo News- 19/09/2007)


According to cancer researchers, one in two men and one in three women will face cancer in their lifetimes. Most of us know someone who has it. But did you know foods from your refrigerator could help prevent it? NewsCenter 5's Heather Unruh reported Wednesday on the foods experts say may help. Dr. Paulette Chandler has a passion for cooking with foods that may fight cancer.

Nutrition is a key component to preventing disease,? said Chandler, an associate physician at Brigham and Women?s Hospital in Boston. Chandler works for The Cancer Project, a non-profit organization with its own guide on cancer survival. It promotes a diet, one that is low in fat and loaded with fruits and vegetables.Those people who are vegetarians have lower incidences of cancers,? said Chandler.

At a Prostate Cancer Symposium at UMass Medical School in Worcester on Wednesday, Chandler served up dishes packed with so-called super foods. Soy also seems to protect. It seems to halt the growth of prostate cancers, Chandler said. Chandler also said artichokes are high in fiber, but any fiber is a cancer fighter. It helps take out the trash that builds up in our system. Prostate cancer survivor Ken Hokanson plans to read up on the information he learned at the symposium, hoping it will keep him cancer free. I kind of want to try a little more of it, and be a little more diligent in eating correctly,? Hokanson said. According to Dr. Lucia Languino, an associate professor of cancer biology and cell biology at UMass Medical School, foods can improve our lifestyle. There is no doubt that diet is very important. Anti-oxidants have been proven to prevent cancer,? Languino said. Despite all the research, there is no proof dietary changes will make a difference, but they are unlikely to be harmful. Genetics loads the trigger, but lifestyle pulls the gun,? Chandler said.

[Back]