outlook: OBESITY epidemic

MARCH 01, 2007
Susan Farley

Moms' Weight Loss Following Gastric Bypass Impacts Future Children's Weight

Recent research shows that women who are morbidly obese can help prevent their children from becoming obese by losing a large amount of weight after gastric bypass surgery and before they become pregnant.

The study looked at obesity rates in 172 children between the ages of 2 and 18, who were born to 113 mothers who were previously obese and lost weight following surgery. These rates were compared with those of 45 siblings born to the mothers prior to their weight loss through gastric bypass.

For children born after mom's surgery, obesity rates dropped by 52%, and severe obesity rates dropped by 45%. Among children between 6 and 18 years old, rates of overweight were similar to those in the general population.

Researchers noted no increase in underweight children in this study group, as a concern exists that weight loss surgeries may cause harmful undernutrition. They also note that gastric bypass may prevent the harmful effects of excess pregnancy weight, which may cause "overnutrition" of the fetus.

Lead author John G. Kral, MD, PhD, remarked, "It is nothing short of remarkable that both genes and family environment are nullified by preventing overnutrition in the womb."

Healthy Lifestyle Without Dieting Is OK

British researchers tested a program of lifestyle changes on 62 obese women and found that health benefits can be achieved without dieting. By implementing exercise programs such as tai chi, water aerobics, and circuit training and adding behavior modification, the obese women were able to improve their health risks in the absence of significant weight loss.

Women following this lifestyle-modification program for a year lost a small amount of weight—5.3 lb, but they showed significant improvements in self-image, they were more fit, and they were experiencing less stress. They also showed improvements in blood pressure, cholesterol levels, and heart rates.

Researchers encouraged the women, aged 24 to 55, not to diet, but they were taught healthy eating choices, how to understand food labels, and how to prepare nutritious meals. The program also included 4 hours of exercise per week and social support.

Erika Borkoles, MSc, of Leeds Metropolitan University in England noted, "Psychological and physical health improved independent of substantial weight loss." She went on to say that weight is a proper predictor of health.

Lack of Exercise Affects Bone Health

Weight loss through calorie restriction can result in bone loss at the hip and spine, resulting in fractures and osteoporosis, according to a study published in the December 2006 issue of Archives of Internal Medicine.

Researchers at the Washington University School of Medicine in St. Louis, Mo, studied the effects of weight loss on bone health in 48 men and women whose average age was 57 and who were overweight and not obese.

For one year, 19 participants adhered to a restricted-calorie diet, 19 consumed their usual calories but added regular exercise, and 10 in a control group received only healthy lifestyle tips. Only 2 participants dropped out of the study. After a year, the calorie-restricting group lost an average of 18.1 lb, the exercising group lost an average of 14.8 lb, and the control group had no significant weight loss. The dieters also lost an average of 2.2% of bone density in the lower spine and hip, whereas participants in the other 2 groups had no significant changes in bone mineral density.

The effect of muscles pulling on bones during exercise is believed to impose a healthy strain on bones, including stimulating the production of new bone.

Lead author Dennis T. Villareal, MD, asserts, "It's important that calorie restriction not be seen as a bad thing because it offers enormous benefits... however, to maintain healthy bones, exercise should be an important component of a weight-loss program to offset adverse effects of calorie restriction on bone."

Obesity Adversely Affects Type 1 Diabetics

According to a new study, the risk of kidney disease is increased for individuals with type 1 diabetes who also suffer from obesity. Normally, obesity is associated with adult-onset type 2 diabetes, which makes up 95% of all reported diabetes cases.

This study, however, focused on the data of 1300 individuals with type 1 diabetes who were participating in a large study of intensive insulin therapy and its effects on reducing the risk of kidney disease and other disease-related complications. Researchers specifically zeroed in on obesity's effect—namely, central obesity—on the risk of developing kidney disease.

During the average follow-up of 6 years, 8.4% of the patients developed microalbuminuria, the first sign of a diabetic kidney. The risk of microalbuminuria was 4.5% among those who received intensive insulin therapy and 12.8% among those who received standard insulin treatment.

The data review revealed that the larger a person's waist measurement, the greater his or her risk was for developing kidney disease. For every 4- inch increase in waist measurement, risk for microalbuminuria increased by 34%, which remained true even when adjusted for other factors.

Results of the data review appeared in the January issue of the Journal of the American Society of Nephrology.

Bacteria May Cause Obesity

New research on obese humans and mice has pinpointed a "microbial component" to the presence of obesity. The study from Washington University's Center for Genome Studies posits that obese humans and mice have a lower percentage of the bacteria Bacteriodetes and more of the bacteria Firmicutes. Whether obesity causes the production of more Firmicutes, or the bacteria cause obesity, is not yet understood. Scientists do, however, believe that the bacteria can fight both obesity and malnutrition.

Professor of Infection and Obesity Nikhil Dhurander, MD, of Louisiana State University's Pennington Biomedical Research Center remarked, "We are getting more and more evidence to show obesity isn't what we thought it used to be. It isn't just [that] you're eating too much and you're lazy."

He goes on to say that "infectobesity" addresses various causes of obesity and that the current solution of diet and exercise "is like treating all fevers with one aspirin."

The study included 12 obese people whose gut bacteria, before starting a diet, was 3% Bacteriodetes. After dieting, the people—now considered normal size—had close to 15% Bacteriodetes.

Whereas doctors previously approached bacteria in an adversarial manner, recent research demonstrates how beneficial these microbes can be. Findings appear in the December 21, 2006, issue of Nature.

Ms. Farley is a freelance medical writer based in Wakefield, RI.