Biopeer

Obesity can spread through social networks

A study published in the New England Journal of Medicine found that obesity can spread through social connections. The researchers call it ‘social contagion,’ where people who become obese tend to influence their friends and family and convey the subliminal message that being overweight is acceptable. Researchers used data from a long-term heart disease study based in Massachusetts, which involved 12,000 people. The study evaluated the addresses of the participants, heights, and weights as well as names of their close friends. The researchers tracked social connections over a 32-year period and then examined individuals’ BMI, weight and height for signs of obesity. The results showed that an individual's chances of becoming obese increased by 57% if a friend grew obese and increased by 171 % if a very close friend grew obese, often within a span of three to four years. “We were stunned to find that friends who are hundreds of miles away have just as much impact on a person's weight as those who are geographically close,” said James Fowler, study author. This fact led researchers to think that the 'social contagion' wasn't just about eating together, but about sharing ideas of acceptable appearance. The study doesn't challenge or replace the effects of genetics, a sedentary lifestyle or overeating as contributors to obesity.

Researchers at the New Zealand's National Research Center for Growth and Development and The University of Southampton found that a poor diet during pregnancy might lead the child to become obese as an adult. A preliminary study conducted two years ago, involved dosing newborn rats that had been undernourished in the womb, and were thus at risk of growing into obese adults, with the hormone leptin. Leptin is a hormone associated with metabolism and the body's signal to the brain that it is full. The second study evaluated the long-term effects of prenatal malnutrition and leptin treatment on key genes that control metabolism of adult rats. They found that rats with well-fed mothers reacted to leptin in the opposite way as rats with malnourished mothers. The study has raised questions about the nutritional signals received by individuals in their fetal stage and the possibility that humans might be programmed to be fat or thin depending on nutritional signals they received in the womb.

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Molecular link to obesity found

Scientists from the European Molecular Biology Laboratory (EMBL), the German Institute for Nutrition (DIFE), Potsdam, and the University of Cincinnati discovered the missing link between spontaneous physical activity and food intake. According to the report, published in the current issue of Cell Metabolism, mice with low levels of the molecule Bsx show less spontaneous physical activity and have lower concentration of feeding hormones in their brains than normal mice. The scientists suggested that a lack of Bsx also reduced hunger in the mice. Bsx is preserved across species and can play a similar role in controlling body weight in humans. “Differences in Bsx activity between individuals could help explaining why some people are intrinsically more active than others and less susceptible to diet-induced obesity. Bsx might be the key to why the same diet makes one person fat, while leaving another unaffected,” said Maria Sakkou, researcher at the EMBL.

Experts from the Food and Drug Administration (FDA) are of the opinion that Sanofi-Aventis’ widely used obesity treatment, Zimulti, might trigger suicide and other psychiatric adverse events. “I don't think the FDA has really put forward a view in the committee meeting papers,” said Ben Yeoh, analyst with Dresdner Kleinwort. “I still think it's still very much up for the committee whether they think it's safe.” Yeoh acknowledged the drug’s high risk of neurological side effects, but felt the need to compare the risk with its benefits of weight loss and improvements in cardiovascular factors like hypertension and cholesterol. The FDA experts maintained a log of Zimulti, in which there were as many as 15 reports of suicidal ideation. However, it should be noted that Zimulti also reduced HbA1c levels in overweight patients with type 2 diabetes, and it yielded small improvements in systolic and diastolic blood pressure.

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Baby food to combat obesity

In the journal Chemistry and Industry the researchers from the University of Buckingham have presented their research on a baby formula that would control children’s metabolic system in their infancy in order to control obesity in their adulthood. The formula is enriched with appetite-controlling hormone leptin and is already tried on mice. Although the results on mice showed reduction in weight, there are apprehensions regarding the introduction of the appetite-controlling hormone in baby foods. Therefore, the trials should be carried out on obese people before ensuring the parents of the infants regarding the safety and efficacy of leptin.

Research published in the Public Library of Science Medicine report claims that children who were born to mothers having an early puberty history are likely to be overweight in their childhood and obese in their adulthood. The study involving 6000 children showed that children of mothers who had entered into early puberty were fatter by the age of nine. Although the researchers suspect a genetic link behind early puberty and weight gain, the overall findings are hinged on feeding patterns taken up by a child in the early years of his life.

The inefficacy of losing weight through dieting is reportedly confirmed by the researchers at the University of California, Los Angeles (UCLA). The study involving 31 diet studies with a follow-up of two to five years of weight loss, showed a contrary weight gain in almost two-thirds of dieters. The study suggested that eating the right kind of foods alongside exercising is the best way to weight-loss. “It’s just plain difficult to modify your diet and turn away from the pleasures of eating. We’re driven to eat.” said Michael Goran, an obesity researcher at the University of Southern California.

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Obesity linked to growth of cancer

Researchers from the University of Glasgow have discovered that fat negates the anti-cancer properties of vitamin C. Through laboratory experiments, they detected that vitamin C or ascorbic acid cleared the stomach of the cancer-causing compound, which was a result of saliva and food combining with the acid in the stomach. However, the ascorbic acid could no longer fight the cancer-causing compound when fat was added to the combination. The researchers feel that their findings emphasize the value of a balanced diet with a low intake of fat.

Another group of researchers has suggested that a fat hormone encourages the development of colon cancer. Scientists from the University of California, San Diego, studied the results of leptin, the fat hormone, on three cell lines. They discovered that an increase in leptin led to an increased growth of colon cancer cells in all the cell lines. Their conclusion was that people with a greater amount of leptin were at an added risk of suffering from colon cancer. Since obese people have a higher amount of fat cells, they also have a higher amount of leptin. These findings will help formulate better therapies against colon cancer.

Additionally, researchers from RAND Corporation, a non-profit research organization, have received shocking results for their recent study. They found that the number of severely obese people has made a significant increase in America between 2000 and 2005. People with a Body Mass Index (BMI) of over 30 are considered obese. The study showed that people with a BMI of over 40 made a 50 percent increase and those with a BMI of over 50 made a 75 percent increase. These results have important health implications and contradict the belief that the proportion of obese people remains the same.

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Mothers spawn obesity

Researchers at Harvard Medical School, Boston have linked weight gain during pregnancy to the child’s weight. The scientists analyzed 1,044 pairs of mother and child. The subjects were classified into three groups according to the amount of weight gained during pregnancy. According to the Institute of Medicine standards, 51 per cent of the subjects gained too much weight, while 35 per cent gained the right amount. The children of these subjects were four times more likely to become overweight at the age of three, as compared to 14 per cent of the subjects, who gained too little weight. A mother’s weight gain during pregnancy has been a significant factor for determining the child’s health. The findings are important in the light of the growing number of obese children and may help in the fight against obesity. The researchers have recommended that the Institute of Medicine revise its guidelines for weight gain during pregnancy.

Additionally, American researchers have suggested a link between obesity and asthma. The scientists re-examined the history of more than 330,000 patients. They found that the overweight patients were twice as likely to suffer from asthma as the normal weight patients. However, the researchers were unable to identify the reason for the increased risk. They also feel that the symptoms that they identified as asthma, might actually be pointing towards something else. The study still holds significance. Obesity has in the past been linked to diabetes, stroke, heart disease and so on, and now, these findings add asthma to the list.

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Studies on obesity expose significant secrets

Researchers in Denmark have found a link between obesity and fertility. The scientists acquired data from the Danish National Birth Cohort and studied the history of 47,835 Danish couples from 1996 to 2002. They conducted extensive interviews over a period of 2 years and collected information about the couples. In 1.4 per cent of the couples, both the man and the woman were overweight. After closely studying the couples, they found that the sub-fertility period of these couples was likely to be nearly 3 times more than normal weight couples. The delay was likely to be higher in the case of an obese woman and an underweight man. They found that every 1 kg gained, added an extra 2.84 days to the waiting period and a loss of every 1 kg cut down the wait by an average on 5.5 days. More studies need to be conducted to figure out if there is a common cause for the obesity and sub-fertility.

Meanwhile, researchers at the Joslin Diabetes Center in USA have determined how a specific type of fat prevents diabetes and obesity. The researchers examined two genetic strains of mice – the B6 mouse and the 129 mouse, taking into account their basal energy expenditure, metabolic syndrome and their likelihood of developing obesity. The 129 mouse has a tendency to gain 40-50 per cent less weight as compared to the B6 mouse. The mice were also found to have higher basal energy expenditure due to clusters of brown fat cells in certain muscles. The 129 mouse had over 100 times more brown fat than the B6 mouse. Studies need to be conducted to see if brown fat cells in humans can provide the same type of protection and accordingly new drugs can be manufactured to motivate activity of these fat cells.

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Obesity comes under the scanner

People suffering from obesity now have a fresh ray of hope. Researchers have developed a pill to combat obesity. The pill Excalia was tested on 27 obese men and women for 24 weeks. While they lost five per cent to 10 per cent of their weight during this period, most had lost 12 per cent by the end of 48 weeks. Excalia’s success is due to its ability to overcome the weight-loss plateau by compelling the hypothalamus to ensure that the body’s metabolic rate continues to remain high. The firm Orexigen is manufacturing the drug. Though the trial threw up positive results, larger trials will be held to test the efficacy of the drug.

Meanwhile, researchers from the Washington University in St Louis School of Medicine, USA, have established that the relative amounts of gut bacteria is linked to obesity. In a study conducted on 12 obese humans, the researchers found that they had a lesser amount of Bacteroidetes and a larger amount of Firmicutes. As they lost weight, there was a reduction in the amount of Firmicutes while the amount of Bacteroidetes increased. The study affirmed that differences in gut microbial ecology can decide how many calories are deposited in the fat cells. This, in turn, leads to a person being lean or obese.

In another study, researchers from the Kaiser Permanente of Northern California, USA, have determined that obesity in the abdominal area raises the chances of heart disease. The researchers followed 101,765 people for 12 years and found that a large sagittal abdominal diameter (SAD) increased the chances of heart disease by 42 per cent for men and 44 per cent for women. The researchers hope their findings will help people to be more aware and prevent the occurrence of heart disease.

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Drugs step in to fight obesity

Cashing in on the growing awareness about obesity, three companies are testing drugs that will combat obesity.

Amylin Pharmaceuticals Inc declared the results of its Phase 2 extension study of its drug pramlintide. According to the company, a 52-week study of pramlintide showed that the drug decreased body weight by 7 to 8 per cent in patients when compared to the 1 per cent reduction in patients on a placebo. Amylin is now planning five clinical studies in order to test the efficacy of pramlintide when taken in combination with other compounds.

Meanwhile, another pharmaceutical company Vivus Inc presented encouraging results for an investigational oral treatment for obesity at the North American Association for the Study of Obesity (NAASO) 2006 Annual Scientific Meeting at Boston, USA. A double-blind, randomized, placebo-controlled trial of Qnexa involving 200 participants was conducted to test the efficacy. The results showed that patients on the drug who completed twenty-four weeks of the trial achieved an average weight loss of 26 pounds while the placebo group achieved an average of 7 pounds. The former group also lost an average 11.1 per cent of baseline body weight while the latter averaged 2.8 per cent.

Orexigen Therapeutics Inc too presented data at the NAASO meeting that established that Excalia aids significant weight loss. In a six-month, double-blind, phase 2a clinical study, it was found that participants on Excalia who completed the blinded 24-week phase lost on average 9.2 per cent of their weight from baseline while those on placebo averaged an 0.4 per cent weight loss from baseline. Also, weight loss continued through an additional 24-week open-label period.

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Obesity causes global concern

Obesity is emerging as the big killer in Asian countries as well after overpowering the developed world. Obesity has reached epidemic proportions globally, with at least 300 million of them clinically obese. And what is alarming is that per latest research the desire to overeat in overweight people is controlled by the same part of the brain that controls cravings for drugs in addicts. Apparently, compulsive eating is regulated by emotional centres in the brain, which leads people to resort to overeating as a means of comfort.

Per the research exercise, a group of seven volunteers were implanted with gastric stimulators for close to two years. Each volunteer was placed in a positron emission tomography (PET) scanner and brain activity measured when the gastric stimulator was on and then off. Each volunteer was also asked to answer questions that measured three different aspects of eating behaviour—personal restraint, uncontrolled eating and emotional eating. The information was then used to correlate which type of eating behaviour was linked to which part of the brain.

Meanwhile, in encouraging news, scientists have identified a molecule responsible for making mammals feel full. This will surely give an impetus to new ways to treat obesity in humans. Rats were injected with the molecule (nesfatin-1) and subsequently they ate less and lost weight. Moreover, after anti-nesfatin-1 antibody was injected in the rats they showed increased appetite as well as an increase in body weight. With a billion overweight adults globally, this research may just pave the way for treating obesity.

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NZ positions itself for stronger research profile with new fund

New Zealand's new International Investment Opportunities Fund has awarded two Univertsity of Auckland medical researchers $1.5 million in funding to study obesity and diabetes in conjunction with overseas researchers, it was reported in Scoop.

Researchers will research the causes of obesty and Type II diabetes, in particular the role of leptin in regulating body weight and metabolism.