Gut Bugs: They Are What You Eat

http://healthland.time.com/2011/09/06/gut-bugs-they-are-what-you-eat/
By ALICE PARK Tuesday, September 6, 2011

A new study shows that what we eat can affect our gut, both inside and out. The community of bacteria that colonize our intestines may shift depending on the makeup of our overall diet.

Why is that important? Increasingly, research in the field of gut flora shows that these bugs have a big impact on some crucial bodily functions: they aid digestion and metabolism, affect immunity and determine how many calories we extract from food, possibly contributing to obesity and diabetes, among other health effects.

Now researchers in the U.S. and Brazil report online in the journal Science that the dominant species of bacteria in the gut microbiome, as it's known, may change in accordance with your diet — at least if you stick with a particular diet for a long enough period of time.

Gary Wu, a professor medicine in the division of gastroenterology at the University of Pennsylvania, and his colleagues studied the eating habits and gut flora (the latter is most easily examined by looking at stool samples) of 98 participants over two time periods. In the long-term comparison, the researchers looked at how frequently people ate certain kinds of foods over the course of a year; in the short-term analysis, they looked at what people ate over three consecutive 24-hour periods.

Analyzing the longer term data, the researchers found that two types of diets were linked with certain dominant species of guts bugs. The gut microbiomes of people who ate higher-fat and low-fiber diets rich in animal proteins predominately contained bugs of the Bacteroides genus, while those who ate more fiber and less animal fat and protein showed higher concentrations of Prevotella microbes.

In the shorter-term analyses, the researchers did not find the same patterns emerging between diet and gut flora, suggesting that gut bugs are relatively consistent in terms of their composition over the long term, says Wu.

The research team also looked at whether they could alter the makeup of the microbiome by changing people's diets — whether, for example, a low-fat diet could lead to a drop in Bacteroides microbes and boost the population of Prevotella. The scientists sequestered 10 people in a hospital setting and controlled every bit of food they ate for 10 days to see what would happen.

"Almost all of the participants started out in the Bacteroides group — high animal protein, high fat — which is not surprising since the study took place in the U.S. where the western diet is more prevalent," says Wu. "None of them switched permanently into the other when they changed their diet."

Wu notes that the participants were sequestered for only 10 days, which is a relatively short time period of time. And while there wasn't a switch from one dominant microbe to the other, the scientists did see an overall change in the composition of the gut flora within 24 hours of the participants' change in diet. It wasn't enough to boost populations of the fiber-loving Prevotella, but the shift does hint that diet may, over the long term, help change the gut environment to one that may be linked to healthier eating.

It's not clear yet whether the relationship also works the other way around — whether different types of gut flora influence your eating habits. For example, could having more Prevotella make it easier or even more appealing to eat high-fiber, low-fat foods? It's also not clear whether one gut bug profile is better for your health than another — that's the subject of ongoing research. But the current study certainly gives new meaning to the idea that you are what you eat.

Post title5 Ways to Avoid Diabetes — Without Medications

http://healthland.time.com/2011/09/07/5-ways-to-avoid-diabetes-without-medications/
By ALICE PARK Wednesday, September 7, 2011

New research suggests that when it comes to lowering your risk of diabetes, the more changes you make to your diet and lifestyle, the better.

Led by Jared Reis at the National Heart, Lung and Blood Institute, scientists report in the Annals of Internal Medicine that people can lower their risk of developing diabetes by as much as 80% if they adhere to a combination of lifestyle changes: exercising more, not drinking as much alcohol, quitting smoking, avoiding obesity and eating high-fiber, low-fat foods.

Although the advice sounds familiar, the new study is the first to demonstrate the effect of combining all the recommendations together. Previous studies have shown that losing weight or eating healthier can independently help reduce the risk of diabetes, but this study is the first to show the potential cumulative benefits of making multiple lifestyle changes.

The study involved more than 207,000 men and women aged 50 to 71 who were enrolled in the National Institutes of Health (NIH)–AARP Diet and Health Study. The participants were all healthy and free of heart disease, cancer and diabetes at the start of the study in 1995-96. When they joined, the volunteers filled out questionnaires about their lifestyle and diet, including what they ate, how much they weighed, how physically active they were, and whether they smoked or drank alcohol. The researchers tracked them for nearly a decade to see who developed diabetes.

Reis and his team then divided the volunteers into low- and high-risk groups, depending on their responses to the lifestyle questions. People included in the low-risk diet group, for example, were those who ate foods with a low glycemic index (that is, foods that don't cause a sharp a spike in blood glucose levels, which can impair the body's ability to break down the sugar with insulin), more unsaturated as opposed to saturated fats, higher fiber and lower trans fats.

Women in the low-risk alcohol group drank no more than one alcoholic beverage a day; men drank no more than two. The low-risk physical activity group got at least 20 minutes of exercise three or more times a week. People whose BMI fell into normal ranges were considered low risk in terms of weight.

Each low-risk lifestyle habit was associated with a reduction in diabetes risk. Among men, those who were normal weight had a 70% lower risk of developing diabetes over 10, compared to those were overweight or obese. For women, the reduction in risk was 78%.

For men, the next most influential factors were not smoking and exercising regularly: non-smokers had a 24% lower risk of diabetes than current smokers or those who quit less than 10 years ago, and men who reported being physically active enjoyed a similar reduction in diabetes risk, compared with more sedentary men.

For women, avoiding overindulgence in alcohol was an important factor in reducing diabetes risk: those who drank just one glass or less a day had a 37% lower risk, compared with women who drank more. And being physically active also helped women avoid diabetes; those who exercise regularly were 23% less likely to develop the disease than those who didn't.

What was more intriguing was how much the participants were able to lower their diabetes risk when they combined many of these healthy lifestyle habits. A man who ate a high-fiber, low-saturated fat diet and exercised regularly, for example, had a 28% lower risk of diabetes than his counterpart who ate less healthily and spent more time on the couch. If that man was also a non-smoker, his risk of diabetes dropped by 32%; if he also cut back on his alcohol, his risk fell by 39%. If he maintained a normal weight on top of everything, his overall risk of developing diabetes was 72% lower than his peers who adhered to none of the healthy lifestyle behaviors.

The numbers were even more impressive for women, who, by combining all five lifestyle factors, were able to lower their risk of developing diabetes by 84%.

While there are effective medications to treat diabetes, it's encouraging news that standard lifestyle modifications such as losing weight, eating right, exercising, quitting smoking and drinking in moderation can significantly lower the risk of the disease. Not everything, it seems, needs to be treated with a pill.

Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny. You can also continue the discussion on TIME's Facebook page and on Twitter at @TIME.

Rethinking the Framingham Score: Is There a Better Way to Predict Heart Disease?

http://healthland.time.com/2011/09/14/rethinking-the-framingham-score-is-there-a-better-way-to-predict-heart-disease/
By ALICE PARK Wednesday, September 14, 2011

Doctors are constantly telling us that prevention is the best medicine, especially when it comes to chronic problems like heart disease. The key to a good prevention strategy is, of course, controlling the risk factors that contribute to disease. But now a new study shows that a commonly used measure to predict — and therefore help prevent — heart disease may not be as accurate as previously thought.

Researchers in Spain report this week in the Annals of Family Medicine that the Framingham risk score, a standard score that doctors use to gauge a patient's risk of heart disease, overestimated that risk in a population of healthy Spanish men and women.

A version of the Framingham model specially calibrated to the Spanish population also failed to accurately predict risk. That could mean that doctors using such scores may be basing treatment decisions on inaccurate numbers.

The Framingham model is designed to predict heart risk based on five factors — age, gender, cholesterol levels, blood pressure and smoking status. In the Spanish study, which tracked 447 healthy men and women aged 35 years to 74 years for 10 years, the Framingham score predicted that 15% of the study population would have a heart event. In fact, 10% of participants did. Meanwhile, the customized model estimated that only about 6% would develop heart trouble.

Overall, that means the original Framingham risk assessment overestimated heart disease risk by 73%, while the Spanish version underestimated risk by 64%.

As discouraging as that sounds, the findings don't necessarily mean the Framingham score isn't worth a beat. The model is based on a study that was begun in the 1960s (and still continues today, with surviving members of the original cohort and their children), at a time when the risk factors for heart disease — high-fat diets, high blood pressure and smoking, for example — weren't as well known as they are today.

Given that patients today are constantly told to eat better and quit cigarettes, the authors say it's not surprising that the original model would overestimate risk in people who were more likely to get many of these risk factors under control between the start and end of the study.

Plus, says Dr. Robert Eckel, a professor medicine at the University of Colorado and past president of the American Heart Association, the number of participants in the current study was small, which means the number of actual heart events was small as well. So it's hard to say how valid the conclusions are.

The findings do hint, however, that perhaps it's time for an update to the decades-old model. Taking into account a person's history of heart disease, weight (via body mass index), and use of drugs to control hypertension, for example, could refine the Framingham model and make it more accurate.

That's exactly what heart experts in the U.S. are doing now. There is some discussion about how globally useful the Framingham risk score remains, since its original cohort was not as ethnically diverse as is our current population. Plus, heart experts have been concerned about the fact that the model does not include a consideration of family history of heart disease, which recent studies show can play a role in an individual's risk.

"My opinion is that ultimately we need to expand on the current way of assessing global risk," says Eckel. "This study is just an appetizer for the full meal to follow."

Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny . You can also continue the discussion on TIME's Facebook page and on Twitter at @TIME.