At Cornell University’s department of food science and Institute for Comparative and Environmental Toxicology, researchers randomly divided rats treated with a known mammary carcinogen into different groups, feeding them either low, middle or high doses of Red Delicious apple extracts (the equivalent of one, three and six apples a day in humans, respectively) or a control extract. Rats fed the strongest apple extract experienced the lowest cancer rate (40% developed cancer)… followed by the group fed middle-strength extract (43%)… and the lowest strength extract (59%). In comparison, 71% of those fed the apple-free control extract developed mammary cancer over the 24-week study period. The study appeared in the December 10, 2008, online edition of Journal of Agricultural and Food Chemistry.

WHAT’S THE SECRET?

According to researcher Rui Hai Liu, MD, PhD, associate professor of food science at Cornell University, the study demonstrated not only that apple extracts effectively inhibited the growth of mammary tumors in the rats but that the more administered, the greater the anticancer effect. “Not only did animals treated with apple extract have fewer tumors overall, the tumors were smaller, less likely to be malignant and grew more slowly when compared with tumors in the untreated animals,” he said.

Why are apples so powerful against breast cancer, I wondered? Dr. Liu explained to me that apples are one of the best sources of phenolics and flavonoids, which are phytochemicals (bioactive compounds) that have powerful antioxidant and anti-proliferative (antigrowth) effects in the body. In two previous studies, Dr. Liu and his colleagues discovered that phytochemicals from apples effectively inhibited the growth of human breast cancer cells. In another study, Dr. Liu found that phytochemicals from apple peels inhibited an important inflammation pathway, NFkB, in human breast cancer cells, thereby reducing the proliferation of the cancer.

Dr. Liu told me that although other fruits and vegetables also contain phenolics and flavonoids, apples are one of the best dietary sources of fruit phenolics. In fact, of the top 25 fruits consumed in the US, apples provide 33% of the phenolics that Americans consume annually. “Americans love to eat apples, so it makes sense to encourage them as part of a balanced diet for optimal health,” he said, adding that this doesn’t mean anyone should forsake other fruits and vegetables. “It’s clear that regular consumption of fruits, vegetables and whole grains can help to prevent chronic diseases, such as heart disease and cancer,” Dr. Liu said.

Source(s):

Rui Hai Liu, MD, PhD, is an associate professor in the department of food science at Cornell University in Ithaca, New York.

This is because the polyphenols found in the tea target molecular pathways that shut down the production and spread of tumor cells. Further, they inhibit the growth of tumor-nurturing blood vessels.

The study, which involved using a mouse model for human prostate cancer, indicated the consumption of green tea polyphenols (GTP) adjusted and reduced levels of the insulin-like growth factor-1 (IGF-1)-driven molecular pathways in prostate tumor cells.

The findings supported other studies, which found that increased levels of IGF-1 were associated with the increased risk of various cancers, including:

~  Prostate

~  Breast

~  Lung

~  Colon
Researchers also discovered that these GTP reduced the expression of proteins typically linked to the metastatic (additional location) spread of cancer cells. This is because the polyphenols inhibited the levels of urokinase plasminogen activator as well as cellular molecules linked to the metastasis.

The results were published online July 28, 2009 in the British Journal of Sports Medicine.

Physical inactivity over a person’s lifespan might be a “key factor in the initiation of cancer development,” the authors note.

This study adds ammunition to the public-health message promoting at least 30 minutes a day of exercise, lead author Sudhir Kurl MD, from the School of Public Health at the University of Kuopio in Finland, told Medscape Oncology.

All doctors should be giving their patients this message.

“All doctors should be giving their patients this message,” he said, although he acknowledged that many do not have the time, and many are not aware of all of the research showing benefits.

“We found a 50% reduction in the risk of dying prematurely from cancer,” Dr. Kurl pointed out. Exercise also improves well being and confidence, and leads to better sleep and weight control, he added.

The study was carried out in men, but Dr. Kurl said he expects to see similar results in women.

Intensity of Physical Activity Was Important

The study involved 2560 men, aged 42 to 60 years, living in the town of Kuopio and the surrounding rural communities. They self-reported their leisure-time physical activities on questionnaires over a period of 1 year, and were then followed for an average of 16.7 years, during which time there were 181 cancer-related deaths.

In their analysis, the researchers adjusted for age, cigarette smoking, alcohol consumption, body mass index, and total intake of calories, fat, and fiber.

The reduction in the risk for premature death from cancer was seen in men who exercised for more than 30 minutes every day, and with an intensity that was moderate to high, Dr. Kurl noted. The activities they performed included jogging, swimming, cycling to work, and gardening or yard work, he said

Exercise intensity was measured in metabolic equivalents of oxygen consumption (METs). The average intensity of jogging was 10.1 MET, of skiing was 9.6 MET, of ball games was 6.7 MET, of swimming was 5.4 MET, of rowing was 5.4 MET, of cycling was 5.1 MET, of gardening/farming/yard work was 4.3 MET, and of walking was 4.2 MET.

“Anything above an average of 4 MET can be considered [to be] moderate-intensity exercise,” Dr. Kurl told Medscape Oncology.

Other activities reported by the men included crafts, repair or building, which had an average intensity of 2.7 MET, hunting, picking berries or gathering mushrooms (3.6 MET), and fishing (2.4 MET).

“The intensity of leisure-time physical activity should be at least moderate so that the beneficial effect of physical activity for reducing overall cancer mortality can be achieved,” the authors write.

The results show that at least moderate-intensity physical activity is more beneficial than low-intensity physical activity in the prevention of cancer, the authors note. This finding is consistent with American consensus statements suggesting that at least moderate-intensity physical activity is needed to prevent chronic diseases caused mainly by cardiovascular disease, they add.

Several Mechanisms Involved

They speculate that the mechanisms by which physical activity could protect against cancer include beneficial effects on energy balance and body mass, intestinal transit time, hormonal concentrations (e.g., reduced testosterone), prostaglandin levels, and antioxidant enzymes activities.

For example, exercise increases the F-series of prostaglandinsbut decreases the E2 series, and these physiologic events have been shown to increase gut motility and to decrease colonic cell division, the researchers point out.

Many of the cancer-related deaths that were reported during the follow-up period affected the gastrointestinal tract (57 of 181 cases). The remaining cancers affected the lung (n = 48), prostate or urinary tract (n = 25), brain (n = 9), or lymphoma (n = 6).

“Our results indicate that those with an active lifestyle have a decreased risk of gastrointestinal cancers,” the researchers note. This finding may be due to changes in energy balance, which includes body mass, which is particularly important for colon cancer, they note. In addition, the increased gut motility with exercise training decreases gastrointestinal transit time, thereby reducing the contact time between fecal carcinogens and the colonic mucosa, as well as allowing less opportunity for the initiation of carcinogenesis and colonic cell division and proliferation. There may also be an affect on insulin and fat metabolism, they add.

Asked by Medscape Oncology if he practices what he preaches, Dr. Kurl replied: “Of course!” He reported jogging 3 times a week and working out in the gym twice a week .

The researchers have disclosed no relevant financial relationships.

Br J Sports Med. Published online before print July 28, 2009.