Green Tea Found to Reduce Rate of Some Digestive System Cancers

Women who drink green tea may lower their risk of developing some digestive system cancers, especially cancers of the stomach/esophagus and colorectum, according to a study led by researchers from Vanderbilt-Ingram Cancer Center.

The study by lead author Sarah Nechuta, Ph.D., MPH, assistant professor of Medicine, was published online in the American Journal of Clinical Nutrition. Wei Zheng, M.D., Ph.D., MPH, professor of Medicine, chief of the Division of Epidemiology and director of the Vanderbilt Epidemiology Center, was the principal investigator for the study.

To determine green tea’s impact on cancer risk, the investigators surveyed women enrolled in the Shanghai Women’s Health Study, a population-based study of approximately 75,000 middle-aged and older Chinese women. During the initial interview participants were asked if they drank tea, the type of tea consumed and how much they consumed. Most of the Chinese women reported drinking primarily green tea.

The researchers found that regular tea consumption, defined as tea consumption at least three times a week for more than six months, was associated with a 17 percent reduced risk of all digestive cancers combined. A further reduction in risk was found to be associated with an increased level of tea drinking. Specifically, those who consumed about two to three cups per day (at least 150 grams of tea per month) had a 21 percent reduced risk of digestive system cancers.

The trend toward fewer digestive cancers was strongest for stomach/esophageal and colorectal cancers.

“For all digestive system cancers combined, the risk was reduced by 27 percent among women who had been drinking tea regularly for at least 20 years,” said Nechuta. “For colorectal cancer, risk was reduced by 29 percent among the long-term tea drinkers. These results suggest long-term cumulative exposure may be particularly important.”

Tea contains polyphenols or natural chemicals that include catechins like EGCG and ECG. Catechins have antioxidant properties and may inhibit cancer by reducing DNA damage and blocking tumor cell growth and invasion.

The researchers also asked about other lifestyle factors including the kinds of food eaten regularly, exercise habits, education level and occupation. Women who had ever smoked or who drank alcohol were excluded from the study.

Regular tea drinkers in the study were younger, had higher education, exercised more and consumed more fruits and vegetables. While the researchers adjusted for these factors, they could not rule out an effect from these and other unmeasured lifestyle habits.

The study was conducted in nonsmoking and nondrinking Chinese women to minimize the potential influence of these two risk factors on the results for tea consumption and digestive system cancer risk.

Source: Vanderbilt University Medical Center

Dietary Fiber Alters Gut Bacteria, Supports Gastrointestinal Health

A University of Illinois study shows that dietary fiber promotes a shift in the gut toward different types of beneficial bacteria. And the microbes that live in the gut, scientists now believe, can support a healthy gastrointestinal tract as well as affect our susceptibility to conditions as varied as type 2 diabetes, obesity, inflammatory bowel disease, colon cancer, and autoimmune disorders such as rheumatoid arthritis.

As these microbes ferment fiber in the intestine, short-chain fatty acids and other metabolites are produced, resulting in many health benefits for the host, said Kelly Swanson, a U of I professor of animal sciences.

“When we understand what kinds of fiber best nurture these health-promoting bacteria, we should be able to modify imbalances to support and improve gastrointestinal health,” he said.

This research suggests that fiber is good for more than laxation, which means helping food move through the intestines, he added.

“Unfortunately, people eat only about half of the 30 to 35 grams of daily fiber that is recommended. To achieve these health benefits, consumers should read nutrition labels and choose foods that have high fiber content,” said Swanson.

In the placebo-controlled, double-blind intervention study, 20 healthy men with an average fiber intake of 14 grams a day were given snack bars to supplement their diet. The control group received bars that contained no fiber; a second group ate bars that contained 21 grams of polydextrose, which is a common fiber food additive; and a third group received bars with 21 grams of soluble corn fiber.

On days 16-21, fecal samples were collected from the participants, and researchers used the microbial DNA they obtained to identify which bacteria were present. DNA was then subjected to 454 pyrosequencing, a “fingerprinting” technique that provides a snapshot of all the bacterial types present.

Both types of fiber affected the abundance of bacteria at the phyla, genus, and species level. When soluble corn fiber was consumed, Lactobacillus, often used as a probiotic for its beneficial effects on the gut, increased. Faecalibacterium populations rose in the groups consuming both types of fiber.

According to Swanson, the shifts in bacteria seen in this study—which occurred when more and differing types of fiber were consumed—were the opposite of what you would find in a person who has poor gastrointestinal health. That leads him to believe that there are new possibilities for using pre- and probiotics to promote intestinal health.

“For example, one type of bacteria that thrived as a result of the types of fiber fed in this study is inherently anti-inflammatory, and their growth could be stimulated by using prebiotics, foods that promote the bacteria’s growth, or probiotics, foods that contain the live microorganism,” he said.

The study will appear in the July 2012 issue of the Journal of Nutrition.

Source: EurekAlert!

Study Shows How High-fat Diets Increase Colon Cancer Risk

Epidemiologists have long warned that, in addition to causing obesity, eating too much fat and sugar puts a person at greater risk for colon cancer. Now, researchers at Temple University have established a link that may explain why.

The findings were published in the March issue of the Cancer Prevention Research.

“There have always been questions about why things like diet and obesity are independent risk factors for colon cancer,” said the study’s lead author. “This study suggests how and why high fat diets are linked to colon cancer.”

The researchers compared colon tissue in non-colon cancer patients with normal colon tissue in patients with the disease. In the normal tissue from patients with colon cancer, they found that epigenetic marks on genes involved in breaking down carbohydrates, lipids and amino acids — abundant in the fatty Western diet — appeared to have been retrained. Epigenetic marks are chemical modifications that serve as on/off switches for many genes.

“These foods are changing the methylation patterns on a person’s insulin genes so that they express differently, pumping out more insulin than the body requires,” said the researcher. “In people that have colon cancer, their glucose metabolic pathways and insulin signaling pathways are running at completely different levels than people who don’t have colon cancer.”

Cancer cells love insulin and studies have shown that tumors feed off of insulin. “Insulin is only supposed to be expressed in your pancreas, so having this extra insulin is bad,” he said.

People don’t usually get colon cancer until the age of 50 or older, so it is unclear when the epigenetic modification of the genes begins.

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Diets High in Fibre Won’t Protect Against Diverticulosis

For more than 40 years, scientists and physicians have thought eating a high-fibre diet lowered a person’s risk of diverticulosis, a disease of the large intestine in which pouches develop in the colon wall. A new study of more than 2,000 people reveals the opposite may be true.

The study, conducted by researchers at the University of North Carolina School of Medicine, found that consuming a diet high in fibre raised, rather than lowered, the risk of developing diverticulosis. The findings also counter the commonly-held belief that constipation increases a person’s risk of the disease.

Diverticulosis affects about one-third of adults over age 60 in the United States. Although most cases are asymptomatic, when complications develop they can be severe, resulting in infections, bleeding, intestinal perforations and even death. Health care associated with such complications costs an estimated $2.5 billion per year.

Since the late 1960s, doctors have recommended a high-fibre diet to regulate bowel movements and reduce the risk of diverticulosis. This recommendation is based on the idea that a low fibre diet will cause constipation and in turn generate diverticula as a result of increased pressure in the colon. However, few studies have been conducted to back up that assumption.

The study also found constipation was not a risk factor and that having more frequent bowel movements actually increased a person’s risk. Compared to those with fewer than seven bowel movements per week, individuals with more than 15 bowel movements per week were 70 percent more likely to develop diverticulosis.

The study found no association between diverticulosis and physical inactivity, intake of fat, or intake of red meat. The disease’s causes remain unknown, but the researchers believe gut flora may play a role.

The study appears in the February 2012 issue of the journal Gastroenterology.

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What is Diverticulitis? ….

Fiber-rich Vegetarian Diet Improves Gut Microflora Profile

Consuming a vegan or vegetarian diet results in different profiles of gut microflora, with lower levels of potentially pathogenic bacteria such as E. coli, says a new study.

By studying fecal samples from 144 vegetarians and 105 vegans, researchers from the University Hospital in Tubingen, Germany report that the fiber and carbohydrate content of the diets led to a lower pH in stools, and such acidic conditions do not support the growth of bacteria like E. coli and Enterobacteriacea.

“The degradation of dietary fibers by exoenzymes mainly leads to greater amount of short-chain fatty acids such as acetate, propionate and butyrate that create a slightly acidic milieu with values between pH 5.5 and 6.5,” explained researchers.

“This effect may have been amplified by germs that grow because of the large amount of fibers. These pH ranges do not support bacteria such as E. coli and Enterobacteriacea in their growth as they prefer pH ranges greater than 6.5.”

The researchers note that the pH of stools in omnivorous women is higher than in men, despite both genders consuming similar amounts of fiber. However, when men and women adhere to a strict vegan diet rich in fibers for a long time both then differences in stool pH are no longer observed. This indicates that females profit more from maintaining a strict vegan diet than do men.

The study was published in the European Journal of Clinical Nutrition.

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Past Trauma May Contribute to Bowel Disorder

Major psychological and emotional events experienced over a lifetime may contribute to the development of irritable bowel syndrome (IBS), according to a new study.

Researchers looked at 2,623 people and found that psychological and emotional traumas — such as divorce, death of a loved one, house fire, car accident, and mental or physical abuse — were more common among adults with IBS than those without the condition.

Dr. Yuri Saito-Loftus, of the Mayo Clinic in Rochester, Minn., was scheduled to present the findings Monday at the annual scientific meeting of the American College of Gastroenterology in Washington, D.C.

“While stress has been linked to IBS, and childhood abuse has been reported to be present in up to 50 percent of patients with IBS, at a prevalence twice that of patients without IBS, most studies of abuse have focused on sexual abuse with sparse detail and also have not looked at other forms of psychological trauma,” said Saito-Loftus in an ACG news release.

“This is the first study that looks at multiple forms of trauma, the timing of those traumas, and traumas in a family setting,” he added.

It’s believed that IBS — which is characterized by abdominal discomfort, bloating, constipation and diarrhea — is caused by changes in the nerves and muscles that control sensation and motility of the bowel. The condition affects an estimated 10 to 15 percent of adults in the United States — more often women than men — but only about half have been diagnosed with IBS, the researchers said.

Psychological and emotional trauma may sensitize the brain and gut, and it’s important for doctors and patients to understand the potential link between prior stressful experiences and IBS, Saito-Loftus said in the release.

It’s also important not to underplay the role of stress in IBS symptoms, Saito-Loftus said.

“Someone who thinks they have coped with their traumatic experiences adequately on their own and continues to have IBS symptoms should be encouraged to explore professional evaluation and treatment for traumatic life experiences,” Saito-Loftus said.

Source: healthfinder.gov

Calcium May Enhance Benefits of Probiotics in Intestinal and Cholesterol Metabolism

Calcium in the form of pentacalcium hydroxy-triphosphate, combined with Lactobacillus paracasei (LPC37) was associated with significant reductions in total and LD cholesterol following four weeks of supplementation, and the results were greater than those observed for L.paracasei alone, according to findings published in Clinical Nutrition.

“To the best of our knowledge, there are no published studies examining the influence of a combinatory supplement consisting of probiotics and calcium phosphate on the faecal microbiota and on cholesterol metabolism in humans,” wrote researchers from Friedrich Schiller University Jena in Germany.

“The results of the present human study imply that calcium phosphate positively affects the colonization of LPC37 in the human gut under conditions of combinatory supplementation of calcium phosphate and LPC37.

“This combined supplementation is also capable of beneficially modulating blood lipids in healthy, hypercholesterolemic men and women.”

The study adds to the ever growing body of science supporting the potential benefits of probiotics.

Source: Abstract of original article

Gut Microbes May Differ Based on Diet

You are what you eat — especially when it comes to the microbes that live in your gut.

New research shows that people who eat a diet that’s high in fats and animal proteins have a certain group of bacteria that flourish in their digestive tract, while the guts of people who eat a more plant-based, higher carbohydrate fare favor other microbes.

What that means for human health is still unknown. But there’s increasing evidence that the “microbiota” that live in the human gut may play an important role in health, including possibly contributing to obesity and other ailments, researchers said.

The findings are published in the Science.

Read more ….

Vegetarian Diet Lowers Risk of Common Bowel Disorder

Vegetarians are a third less likely to get a common bowel disorder (diverticular disease) than their meat eating counterparts, finds a new study published on bmj.com.

Diverticular disease has been termed a “disease of western civilisation” because of the higher numbers of cases in countries like the UK and the US compared with parts of Africa. The condition affects the large bowel or colon and is thought to be caused by not consuming enough fibre. Typical symptoms include painful abdominal cramps, bloating, wind, constipation and diarrhoea.

Their findings are based on 47,033 generally health conscious British adults who were taking part in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Oxford study. Of those recruited, 15,459 reported consuming a vegetarian diet.

After an average follow-up time of 11.6 years, there were 812 cases of diverticular disease (806 admissions to hospital and six deaths). After adjusting the factors such as smoking, alcohol and body mass index (BMI), vegetarians had a lower risk of diverticular disease compared with meat eaters.

Furthermore, participants with a relatively high intake of dietary fibre (around 25g a day) had a lower risk of being admitted to hospital with or dying from diverticular disease compared with those who consumed less than 14g of fibre a day.

These findings lend support to the public health recommendations that encourage the consumption of foods high in fibre such as wholemeal breads, wholegrain cereals, fruits and vegetables, they conclude.

Source: bmj.com

High Folate Intake May Reduce Risk of Colorectal Cancer

Intake of high levels of folate may reduce colorectal cancer risk, according to a new study in Gastroenterology, the official journal of the American Gastroenterological Association (AGA) Institute. Folate is a water-soluble B vitamin that occurs naturally in food.

“We found that all forms and sources of folate were associated with lower risk of colorectal cancer,” said Victoria Stevens, PhD, of the American Cancer Society and lead author of this study. “The strongest association was with total folate, which suggests that total folate intake is the best measure to define exposure to this nutrient because it encompasses all forms and sources.” Total folate includes naturally occurring food folate and folic acid from fortified foods and dietary supplements.

A research team investigated the association between folate intake and colorectal cancer among 99,523 participants in the Cancer Prevention Study II Nutrition Cohort; a total of 1,023 participants were diagnosed with colorectal cancer between 1999 and 2007, a period entirely after folate fortification began. Neither higher nor lower risk was observed during the first two years of follow-up (1999 to 2001), while associations were statistically significantly inverse for the subsequent years (2002 to 2007).

The findings of this study add to the epidemiologic evidence that high folate intake reduces colorectal cancer incidence. Further, one important difference between the current study and previous studies was the separate assessment of natural folates and folic acid. Previous studies that discriminated between folates considered only the source (i.e., diet versus supplement) and not the chemical form.

The study also addressed concerns that the intake of high levels of folate frequently consumed in the U.S. — as a result of the recent increase in the use of folate-containing supplements and mandatory folate fortification of food — may actually increase risk of cancer. No increased risk of colorectal cancer was found for the highest intake levels, suggesting that the high levels of this vitamin consumed by significant numbers of Americans should not lead to increased incidence rates of this cancer in the population.

Folates are essential nutrients needed to make components used for functions required for normal cell growth, including DNA synthesis and repair. Because these processes are critical for cell growth and differentiation, the relationship between folate intake and cancer development has been investigated in several cancers, and most extensively in colorectal cancer.

Source: American Gastroenterological Association

Read about foods rich in folate ….