Poor diet and lack of exercise accelerate the onset of age-related conditions in mice

Could an unhealthy diet and lack of exercise be making you age faster? Researchers at Mayo Clinic believe there is a link between these modifiable lifestyle factors and the biological processes of aging. In a recent study, researchers demonstrated that a poor diet and lack of exercise accelerated the onset of cellular senescence and, in turn, age-related conditions in mice. Results appear today inDiabetes.

Senescent cells are cells that contribute to diseases and conditions associated with age. Researchers from the Mayo Clinic Robert and Arlene Kogod Center on Aging found that exercise prevents premature senescent cell accumulation and protects against the damaging effects of an unhealthy diet, including deficiencies in physical, heart, and metabolic function, equivalent to diabetes.

"We think at both a biological level and a clinical level, poor nutrition choices and inactive lifestyles do accelerate aging," says Nathan LeBrasseur, Ph.D., director of the Center on Aging's Healthy and Independent Living Program and senior author of the study. "So now we've shown this in very fine detail at a cellular level, and we can see it clinically. And people need to remember that even though you don't have the diagnosis of diabetes or the diagnosis of cardiovascular disease or the diagnosis of Alzheimer's disease today when you're in midlife, the biology underlying those processes is hard at work."

In the study, researchers introduced mice to either a normal, healthy diet or a diet that they termed a "fast food diet" -- one that was high in saturated fat and cholesterol, along with a sugar-sweetened beverage. Mice on the fast food diet showed harmful changes in health parameters, including body weight and composition, increasing their fat mass by nearly 300 percent over the course of about four months. The fat mass accumulated largely in the midsection surrounding internal organs, an area that is often linked to a number of diseases related to obesity.

While the harmful effects of the fast food diet were clear, researchers found significant health improvements after introducing exercise. Half the mice, including mice on both the healthy and unhealthy diets, were given exercise wheels. Mice that had been exposed to the fast food diet but exercised showed suppression in body weight gain and fat mass accumulation, and were protected against the accumulation of senescent cells. Mice on a normal diet benefited from exercise as well.

"Some of us believe that aging is just something that happens to all of us and it's just a predestined fate, and by the time I turn 65 or 70 or 80, I will have Alzheimer's disease and cardiovascular disease and osteoporosis," says Dr. LeBrasseur. "And this clearly shows the importance of modifiable factors so healthy diet, and even more so, just the importance of regular physical activity. So that doesn't mean that we need to be marathon runners, but we need to find ways to increase our habitual activity levels to stay healthy and prevent processes that drive aging and aging-related diseases."

Communicating genetic disease risk has little or no impact on health related behavior

Communicating genetic disease risk has little or no impact on health related behavior

Communicating the results of DNA tests has little or no impact on behaviour change, such as stopping smoking or increasing physical activity, finds a study published by The BMJ.

These results are timely, given high levels of interest in personalised medicine and increasing use of direct-to-consumer testing for a range of common complex disorders, say the research team, led by Professor Theresa Marteau at the University of Cambridge.

They reviewed the results of 18 studies on the effects of communicating genetic risk estimates of heart disease, cancers, and Alzheimer's disease, for which behaviour change could reduce that risk.

Behaviours included smoking, alcohol consumption, diet, and physical activity. Other outcomes analysed were motivation to change behaviour and levels of depression and anxiety.

The results show no significant effects of communicating DNA based risk estimates on smoking cessation, diet, or physical activity.

There were also no effects on any other behaviours (alcohol use, medication use, sun protection behaviours, and attendance at screening or behavioural support programmes).

There were also no effects on motivation to change behaviour, and no adverse effects, such as depression and anxiety.

Further analyses provided no clear evidence that communication of a risk-conferring genotype affected behaviour more than communication of the absence of such a genotype.

The researchers point out that studies were predominantly at high or unclear risk of bias, and evidence was typically of low quality.

Nevertheless, they say their results suggest that communicating DNA based disease risk estimates has little or no effect on risk-reducing health behaviour.

"Existing evidence does not support expectations that such interventions could play a major role in motivating behaviour change to improve population health," they conclude.

US adults get failing grade in healthy lifestyle behavior

US adults get failing grade in healthy lifestyle behavior 

Only 2.7 percent of the U.S. adult population achieves all four of some basic behavioral characteristics that researchers say would constitute a "healthy lifestyle" and help protect against cardiovascular disease, a recent study concluded.

In this study, researchers from Oregon State University and the University of Mississippi examined how many adults succeed in four general barometers that could help define healthy behavior: a good diet, moderate exercise, a recommended body fat percentage and being a non-smoker. It's the basic health advice, in other words, that doctors often give to millions of patients all over the world.

Such characteristics are associated with a lower risk of cardiovascular disease as well as many other health problems, such as cancer and type 2 diabetes.

"The behavior standards we were measuring for were pretty reasonable, not super high," said Ellen Smit, senior author on the study and an associate professor in the OSU College of Public Health and Human Sciences. "We weren't looking for marathon runners."

From the perspective of public health, the findings of the research were not encouraging, Smit said.

"This is pretty low, to have so few people maintaining what we would consider a healthy lifestyle," she said. "This is sort of mind boggling. There's clearly a lot of room for improvement."

Part of the value of this study, the researchers said, is that the results are based on a large study group, 4,745 people from the National Health and Nutrition Examination Survey. It also included several measured behaviors, rather than just relying on self-reported information.

Measurements of activity were done with an accelerometer, a device people wore to determine their actual level of movement, with a goal of 150 minutes of moderate-to-vigorous activity a week. Blood samples were done to verify a person was a non-smoker. Body fat was measured with sophisticated X-ray absorptiometry, not just a crude measurement based on weight and height. A healthy diet was defined in this study as being in about the top 40 percent of people who ate foods recommended by the USDA.

The lifestyle characteristics were then compared to "biomarkers" of cardiovascular health. Some are familiar, such as blood pressure, cholesterol and glucose levels. Others are more sophisticated, such as C-reactive protein, fasting triglycerides, homocysteine and other data that can provide evidence of cardiovascular risk.

Many people, of course, accomplished one or more of the four basic lifestyle goals, such as not smoking or being adequately active. The most striking finding was how few people accomplished all the goals.

"I would expect that the more healthy lifestyles you have, the better your cardiovascular biomarkers will look," Smit said.

Indeed, the researchers found that having three or four healthy lifestyles, compared to none, generally was associated with better cardiovascular risk biomarkers, such as lower serum cholesterol and homocysteine levels. Having at least one or two healthy lifestyle characteristics, compared to none, was also associated with better levels of some cardiovascular risk biomarkers.