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How Obesity Raises Breast Cancer Risk

We know that obesity raises the risk of breast cancer in women – it also worsens the outlook when the disease occurs – and recent research from Cornell University might help explain the association. The proposed mechanism is a change in the consistency of breast tissue in ways that can promote malignancy. The study found that obesity seems to prompt a remodeling of fat in the breast, including a thickening of the matrix found between breast cells, and that these changes create conditions that foster tumor growth. The researchers explained that fat tissue in obese women has more wound healing cells than fat tissue in normal weight women.  When these cells, called myofibroblasts, create an extracellular matrix, they pull together as they would to close a wound, with the effect of stiffening the tissue. This process of remodeling appears to open the door for tumors to develop, increasing the risk of cancer. Because these changes don’t show up on mammograms, lead researcher Claudia Fischbach suggested that higher resolution imaging techniques might be needed to detect them. Another practical consideration: use of fat cells from obese patients in plastic or reconstructive surgery following mastectomy in breast cancer patients may create conditions that could lead to another malignancy.

Weight Benefits of Standing

If you can spend at least a quarter of the day standing (and moving) you’re less likely to be obese than if those hours are spent sitting. A new study from the American Cancer Society shows that men who spent a quarter of their waking time on their feet were 32 percent less likely to be obese and those who spent half their daytime standing were 59 percent less likely to be obese than people who don’t stand as much. Women who spent a quarter of their time standing were 35 percent less likely to be have large waist circumferences (abdominal obesity) while the risk was 47 percent lower for those who spent half their time on their feet and 57 percent lower for those who spent three-quarters of the day standing. Researchers came to these conclusions after examining more than 7,000 adults attending the Cooper Clinic in Dallas from 2010 to 2015. They checked each individual’s body mass index, body fat percentage and waist circumference. The study participants also reported on the amount of time they spent on their feet. Those who said they met guidelines to perform 150 minutes of moderate activity or 75 minutes of vigorous activity daily had even lower risks of obesity. The researchers said that it is unclear whether their study participants were standing still or moving but noted that standing motionless essentially burns no more calories than sitting. 

Too Many Pounds = Heart Trouble

If you're seriously overweight or obese, you are at increased risk of heart failure, period. This remains true whether or not you have any other risk factors such as diabetes, high blood pressure, or high cholesterol. This news comes from a 12-year long study showing that levels of a predictive heart enzyme signal silent damage to the heart among overweight and obese individuals. Researchers from Johns Hopkins tested more than 9,500 men and women ages 53 to 75 who were free of heart disease for the enzyme, troponin T. This blood marker is considered the gold standard for diagnosing ongoing or recent heart attacks in patients who come to emergency rooms with chest pain. After testing, the investigators followed the study participants for more than 12 years. During that time, 869 of the participants developed heart failure. When the investigators looked at the participants' troponin T test results, they saw that levels of this enzyme were much lower than they are in heart attack patients. However, troponin T levels rose as body mass index (BMI) increased, the researchers reported. They found that severely obese individuals with elevated troponin levels were nine times more likely to develop heart failure than study participants of normal weight with undetectable troponin levels, and that this additional risk persisted even after accounting for other possible causes of heart damage. 

My take? This interesting study shows that you don't get a free pass for being overweight or obese, even if you're otherwise relatively risk free for heart disease. The findings suggest that obesity alone increases your risk, and the authors made the point that their results are an "alarm bell" for physicians to monitor their obese patients rigorously for emerging signs of heart disease. Bear in mind that heart disease isn't the only threat obesity poses to health - it also increases the risk of stroke, kidney and gallbladder disease, some types of cancer as well as osteoarthritis and sleep apnea.

Coffee Compound Offsets Obesity Effects

The compound under investigation is chlorogenic acid (CGA, for short) and in studies with mice researchers at the University of Georgia found that it can reduce insulin resistance and the accumulation of fat in the liver, two harmful side effects of obesity. Untreated, these side effects can lead to type 2 diabetes and compromised liver function. The researchers noted that earlier studies indicate that regular consumption of coffee may help lower the risks of type 2 diabetes and cardiovascular disease in some individuals. For their study, the investigators fed mice a high-fat diet for 15 weeks and injected them twice a week with a solution of CGA. They report that the mice didn't gain the weight normally expected as a result of their high fat diet and that the animals maintained normal blood sugar levels and healthy liver composition. In addition to coffee, CGA is found in apples, pears, tomatoes and blueberries." But don't reach for that second cup just yet - the dose of chlorogenic acid given the mice was much higher than amounts humans would get from drinking coffee and eating the fruits and vegetables that provide the compound, and the researchers don't suggest boosting your coffee intake to get more CGA. Instead, they're hoping to create a CGA based treatment that would provide benefits for humans similar to those observed in mice.

Abdominal Obesity: Is this You?

Although average Body Mass Index (BMI) numbers have been holding somewhat steady in recent years, American waistlines continue to expand, which is bad news for our country's health. The latest look at these measurements focuses on the changes over time in abdominal obesity. This "belly fat" is closely associated with metabolic syndrome, and can indicate increased risks of diabetes and heart disease. The investigation reveals that since 1999, waistlines and belly fat have increased among men, women, whites, blacks and Mexican Americans. The researchers, from the U.S. Centers for Disease Control and Prevention (CDC), reported that in 2012 abdominal obesity was present in 54.2 percent of us, up from 46.4 percent in 1999. (In men, a waist measurement greater than 40.2 inches signals abdominal obesity. For women, abdominal obesity is present at a waist measurement greater than 34.6 inches). The CDC team analyzed data from nearly 33,000 men and nonpregnant women age 20 and up to reach their conclusions. The biggest increases from 1999 to 2012 were among non-Hispanic white men in their 40s and among African Americans in their 30s. You might not notice an increase in your waist size if your scale says you haven't gained weight, and you're better off using a tape measure to keep track of where the fat resides.

Can Pollution Make You Fat?

Maybe so, and worse, it could lead to heart disease. A new study of seniors living in Massachusetts suggests that black carbon, a component of traffic-generated air pollution, influences levels of leptin. High levels of this hormone are associated with obesity, diabetes and heart disease.

A team of researchers from Brown University measured blood levels of leptin in 765 seniors living in Boston and found that levels of the hormone were 27 percent higher among those with the most exposure to black carbon. These individuals also had lower incomes and higher rates of high blood pressure and diabetes than others in the study. The research team didn't establish where the pollution was generated, reporting that the proximity of the nearest major highway was not apparently related to leptin levels. Rather, they suggested that black carbon exposure probably reflects overall pollution from traffic on a wider range of roads in the immediate vicinity of the participants' homes. The study doesn't prove that black carbon exposure increases leptin levels, but the researchers suggested that their findings may help explain increases in cardiovascular disease associated with air pollution.

Brain Chemistry and Obesity

Differences in brain chemistry between people who are obese and those who are not may help explain what triggers overeating in response to food cues such as the aroma of popcorn at the movies. To arrive at this conclusion, researchers at the National Institutes of Health (NIH) looked at 43 men and women with varying amounts of body fat. The investigators found that, compared to the study’s lean participants, those who were obese tended to have more dopamine activity in the brain’s habit-forming region and less activity in the brain area controlling rewards. (Dopamine is a chemical messenger in the brain that influences reward motivation and habit formation.) The finding suggested that the brain differences observed might result in obese people being more susceptible to environmental food cues than those who are lean. At the same time, the action of dopamine in other areas of the brain may make food less rewarding to the obese. During the study, all participants were on the same eating, sleeping and activity schedule. The researchers determined the tendency to overeat from the participants’ responses to detailed questions and to PET (positron emission tomography) scans that looked at sites in the brain where dopamine action can occur. The study didn’t prove cause and effect but did reveal a link between dopamine activity and the urge to overeat.

Source:
Kevin D. Hall et al  “Striatal dopamine D2-like receptor correlation patterns with human obesity and opportunistic eating behavior.” Molecular Psychiatry, 2014; DOI: 10.1038/mp.2014.102

Warning Labels for Sweet Drinks?

Would you support mandatory warning labels on sodas and other sugar-sweetened drinks similar to the warnings on cigarette packs? In California, legislation proposed on February 13 would require placing warning labels on all bottles and cans of sweet drinks providing 75 or more calories in every 12 ounces. The labels would read as follows: "STATE OF CALIFORNIA SAFETY WARNING: Drinking beverages with added sugar(s) contributes to obesity, diabetes, and tooth decay." This isn’t the first effort of this type: the Associated Press reported a similar bill was introduced in Vermont in 2013 but has been held in committee. At California fast-food restaurants with self-serve soda dispensers, the label would be on the dispenser, according to the Los Angeles Times, while in movie theaters or businesses where the drink dispenser is behind the counter and drinks are served by employees, the warning labels would be placed on the counters. In restaurants, the warning may be required on menus, the Times reported.

My take? The California effort seems to echo the failed proposal by former New York City Mayor Michael Bloomberg to ban the sale of large-size sugary drinks sold in delis, fast-food outlets, carts on the city's sidewalks and in its parks, movie theaters and sports arenas. I’ll be interested to see what happens to the California legislation. I'm in favor of experimenting with ways of encouraging people to make better food choices and discouraging them from making worse ones, and sugary drinks are certainly not good choices. Although these drinks are not the only contributor to the obesity epidemic in the United States, they are a major source of the average intake of 355 calories of sugar per person per day. That amounts to 22 teaspoons of sugar daily. A single 12-ounce soda contains about 130 calories and the equivalent of eight teaspoons of sugar. Moreover, the high glycemic load of sugary drinks provokes insulin resistance in many people, which underlies much of the obesity in our society and raises risks of type 2 diabetes.

Sources:
Patrick McGreevy, “California lawmaker proposes adding health warning labels to sodas,” Los Angeles Times, February 13, 2014, accessed February 14, 2014, http://www.latimes.com/local/la-me-soda-warning-20140214,0,7510007.story#ixzz2tQMX1qvj

The Obesity Paradox – Health Effects of Excess Weight (Video)

Dr. Weil discusses the health effects of excess weight and how new research is showing that carrying extra weight may not be as bad as once believed. The Obesity Paradox is a term used to describe that being fat and fit may be healthier than skinny and unfit due to the fact that extra fat may protect the body.

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Overcoming the Risks of Too Much Sitting

Sitting all day at a desk job has been linked to high blood pressure, obesity and heart disease, risks that exercising before or after work don’t seem to change. Researchers in Australia tested three strategies to get desk-bound workers up and moving: the use of treadmill or cycling desk for 10 to 30 minutes several times a day; light to moderate exercise on breaks and before and after work; and the use of ergonomic workstations, breaking up computer tasks, moving around more often and periodically perching on the edge of the chair. A total of 133 people enrolled in the study but only 62 stayed with it until it ended. The upshot of all this physical activity was an average reduction of eight minutes per day in time spent sitting, a drop of only one to two percent in sedentary time, the researchers found, and potentially enough to have a positive impact on health. They suggest taking a break from sitting once every 30 minutes and simple strategies to do more office work while you’re mobile including standing while you’re on the phone, having walking meetings and using a bathroom that’s farther from your desk than the one you usually use.

Source:
Leon Straker et al, “Participatory Workplace Interventions Can Reduce Sedentary Time for Office Workers—A Randomised Controlled Trial,” PLOS One, November 12, 2013