Health for life

Drinking three to four cups of coffee per day may help to prevent type 2 diabetes according to research highlighted in a session report published by the Institute for Scientific Information on Coffee (ISIC), a not-for-profit organisation devoted to the study and disclosure of science related to coffee and health.

Recent scientific evidence has consistently linked regular, moderate coffee consumption with a possible reduced risk of developing type 2 diabetes. An update of this research and key findings presented during a session at the 2012 World Congress on Prevention of Diabetes and Its Complications (WCPD) is summarized in the report.

The report outlines the epidemiological evidence linking coffee consumption to diabetes prevention, highlighting research that shows three to four cups of coffee per day is associated with an approximate 25 per cent lower risk of developing type 2 diabetes, compared to consuming none or less than two cups per day1. Another study also found an inverse dose dependent response effect with each additional cup of coffee reducing the relative risk by 7-8 per cent2.

Whilst these epidemiological studies suggest an association between moderate coffee consumption and reduced risk of developing diabetes, they are unable to infer a causal effect. As such, clinical intervention trails are required to study the effect in a controlled setting. One prospective randomized controlled trial3, tested glucose and insulin after an oral glucose tolerance test with 12g decaffeinated coffee, 1g chlorogenic acid, 500 mg trigonelline, or placebo. This study demonstrated that chlorogenic acid, and trigonelline reduced early glucose and insulin responses, and contribute to the putative beneficial effect of coffee.

The report notes that the association between coffee consumption a reduced risk of type 2 diabetes could be seen as counter intuitive, as drinking coffee is often linked to unhealthier habits, such as smoking and low levels of physical activity. Furthermore, studies have illustrated that moderate coffee consumption is not associated with an increased risk of hypertension, stroke or coronary heart disease4 ,5, 6. Research with patients with CVD has also shown that moderate coffee consumption is inversely associated with risk of heart failure, with a J-shaped relationship7.

Finally, the report puts forward some of the key mechanistic theories that underlie the possible relationship between coffee consumption and the reduced risk of diabetes. These included the Energy Expenditure Hypothesis, which suggests that the caffeine in coffee stimulates metabolism and increases energy expenditure and the Carbohydrate Metabolic Hypothesis, whereby it is thought that coffee components play a key role by influencing the glucose balance within the body. There is also a subset of theories that suggest coffee contains components that may improve insulin sensitivity though mechanisms such as modulating inflammatory pathways, mediating the oxidative stress of cells, hormonal effects or by reducing iron stores.

Critical research released in the industry publication journal Neurology from the American Academy of Neurology provides evidence that regular consumption of olive oil can help lower the risk of stroke. The study examined individuals over the age of 65 that are most vulnerable to the devastating effects of a stroke.

A new study finds that getting screening colonoscopies may reduce the risk of developing advanced colon cancer.

In average-risk people, screening colonoscopies were associated with a 70 percent reduction in risk for new, late-stage colon cancer, including hard-to-detect cancers on the right side of the colon. Advanced colon cancer is the least curable form.

Although colonoscopy is widely used as a screening test for colon cancer, there is little research that proves it is effective in reducing colon cancer deaths, according to the study authors. The researchers wanted to answer a simple question: If you ended up with late-stage cancer, were you more or less likely to have had a screening colonoscopy as many as 10 years before the disease was discovered?

The study authors also wanted to show whether a colonoscopy is able to evaluate the entire colon, including the right side, which is harder to adequately cleanse before the test, more difficult to reach, and often has pre-cancerous areas that are tougher to spot and identify.

"Colonoscopy has the ability to identify both left- and right-sided colon cancers before they have progressed to an advanced stage," said lead study author Dr. Chyke Doubeni, associate professor in the department of family medicine at the University of Pennsylvania.

The researchers also discovered that screening sigmoidoscopy, a less costly procedure that enables a physician to look at the part of the large intestine closest to the rectum, was linked to a significant reduction in late-stage disease in most of the large intestine, but not in the right colon.

However, the study does not show that colonoscopy or sigmoidoscopy is better than the much easier, far less expensive "fecal occult blood test" (FOBT), which is done at home by swiping a tiny amount of stool onto a card for three days, said Doubeni. "There is strong evidence showing the effectiveness of the [fecal occult blood test] when done annually. There is no reason, based on the knowledge we currently have, that you should switch to a colonoscopy if youre getting a FOBT every year," said Doubeni.

If simpler tests are effective, why are patients encouraged to undergo a colonoscopy? "Let me just say there are other factors beyond the evidence that are driving the use of colonoscopy in the U.S.," said Doubeni. "No other country uses colonoscopy for screening purposes as much as the United States, although Germany comes close," he noted.

The U.S. Preventive Services Task Force recommends that people 50 to 75 years old be screened for colon cancer in one of three ways: a home fecal occult blood test every year; a sigmoidoscopy every five years combined with a home fecal occult blood test every three years; or a colonoscopy every 10 years.

A colonoscopy examines the inside of the large intestine with a camera-tipped tube. The test enables the physician to remove any precancerous growths -- adenomatous polyps -- which sometimes develop into cancer. Colorectal tumors are a major cause of death from cancer in the United States, with about 137,000 new cases and 52,000 deaths every year, according to the U.S. Centers for Disease Control and Prevention.

For the study, published in the March 5 issue of the Annals of Internal Medicine, the authors reviewed health records of more than 1,000 average-risk adults between the ages of 55 and 85 who were members in four health management organizations (HMOs).

The researchers identified 474 people with late-stage colon cancer and then looked back 10 years to see if they had been screened for the disease with colonoscopy or sigmoidoscopy. They compared them to 538 "control" patients and used additional information from state or local tumor registries to see whether there was an association between having had a colonoscopy or sigmoidoscopy and developing cancer.

Dr. David Bernstein, a gastroenterologist at North Shore University Hospital in Manhasset, N.Y., said the study had a critical design flaw. "Making assumptions that any cancers that were found would have been seen 10 years prior doesnt make sense," he said. "It doesnt prove that these cancers didnt occur two years ago."

A key part of effective colon screening is getting the tests at the recommended interval, experts say. To better understand what might be effective in prodding people to get screening, another study published this month in the same journal found that people who were mailed a letter, a pamphlet and a fecal occult blood test kit completed recommended screening twice as often and for less cost than those who were not reminded or got automated and other reminders by nurse coaches.

Doubeni recommends something far more simple: doing the fecal occult blood test every year right around the time of your birthday.