Diet, exercise aid weight loss after childbirth
PREGNANCY naturally leads to weight gain, and most women gradually lose weight once their baby is born. But there are many different opinions on the best way to return to pre-pregnancy weight. In the latest issue of the CochraneDatabaseofSystematic Reviews , a new study has found that combining diet and exercise is the best way to lose weight after pregnancy, and is more effective than dieting alone. By combining the results of six different trials involving a total of 245 women, researchers found that women who only exercised did not lose significantly more weight than women who maintained a standard post-pregnancy lifestyle. However, women who combined aerobic exercise and dieting lost an average of 2.89kg more over the trial period (ranging from 11 days to one year) than those who did neither. Gradually returning to pre-pregnancy weight after giving birth may also be important for long-term health, as women who regain their prepregnancy weight within six months are thought to have a lower risk of being overweight 10 years later. Cochrane Database Syst Rev 2007; doi:10.1002/ 14651858.CD005627.pub2 (Amorim AR, et al) SMOKING and depression have a common genetic link, according to a new study in the journal TwinResearchandHumanGenetics . The study found that nicotine dependence and major depression are both associated with extreme rebellious behaviour during childhood and adolescence — a condition known as ‘‘ conduct disorder’’. In 1992, the research team conducted telephone interviews with 3360 pairs of male twins aged 35 to 53, who served in the military during the Vietnam War. Fifty-six per cent of the pairs were genetically identical twins, and 44 per cent were fraternal twins who shared half their genes. Answers from each twin were compared to estimate the genetic and environmental influences on nicotine addiction and major depression. Genes that increased a person’s risk of developing nicotine addiction and major depression were also found in those with conduct disorder. The findings may also help to explain why smoking seems to run in some families, say the authors. TwinResHumGenet 2007;10:470-478 (Fu Q, et al) CROHN’S disease — an inflammatory disorder of the gastrointestinal tract — affects an estimated 28,000 Australians and has no known medical cure. But a study in theNew EnglandJournalofMedicine this week has found that a new drug called certolizumab pegol is an effective treatment for adults with the disease. The drug acts by blocking a protein called tumour necrosis factor (TNF), which is a major cause of gut inflammation. The study involved 662 patients with moderate to severe Crohn’s disease, who were randomly assigned to receive certolizumab pegol or a placebo. After six weeks, 35 per cent of patients who received the drug showed improvement in their symptoms, while improvement was seen in 27 per cent of patients who received the placebo. The only side effect of certolizumab pegol was a small increase in the risk for serious infection, including one case of pulmonary tuberculosis. NEnglJMed 2007;357:228-238 (Sandborn WJ, et al) OLDER women with memory loss are more likely to have restless nights than those with normal brain function, say the authors of a new study in Neurology . Over 15 years, 2474 women with an average starting age of 69 and no sign of memory problems were given a range of cognitive tests to assess their brain function. At the end of the study, electronic activity monitors were used to measure their sleeping patterns during three separate 24-hour periods. Overall, 18 per cent of women experienced a decline in brain function. These women were 71 per cent more likely to have difficulty staying asleep, 57 per cent more likely to have problems falling asleep and 43 per cent more likely to be awake for more than 90 minutes during their sleep cycle compared to women whose brain function remained normal. Neurology 2007;69:237-242 (Yaffe K, et al) FOODS that release energy slowly are better for weight loss than those that provide a sugar rush, conclude the authors of a new study in the CochraneDatabaseofSystematic Reviews . Different foods break down at different rates after they are consumed. Foods that break down slowly and generate a long, gentle release of sugars have a low glycaemic index (GI), while foods like white bread send a sudden rush of sugar into the blood stream and are said to have a high GI. The Australian research team, led by Diana Thomas from the Children’s Hospital at Westmead, found six separate studies that compared the effects of low and higher GI diets, involving a total of 202 participants. The trials lasted for between five weeks and six months. People eating lowGI diets lost an average of 1kg more than those on higher-GI diets with similar energy values. Low-GI diets were particularly effective for people who were obese. Cochrane Database Syst Rev 2007; doi:10.1002/ 14651858.CD005105.pub2 (Thomas DE, et al) REDUCING the effects of insulin in the brain can prolong lifespan in mice, which may explain why low-calorie diets have been linked to longer life expectancy in people. In Science this week, the study suggests that achieving the right balance in insulin signalling between the brain and the rest of the body may lead to a longer life. Insulin is a hormone that tells cells to absorb and use sugar from the blood. More insulin is thought to be a good thing, but this study shows that excess insulin can have harmful effects on the brain. Scientists generated mice that were genetically unable to transmit insulin signals inside cells. One group of mice had the defect in every cell in the body, and the other group only had the defect in brain cells. Both groups of mice lived longer compared to normal mice. But those with reduced insulin signalling only in the brain lived almost half a year longer than normal mice— an 18 per cent increase in lifespan. Science 2007;317:369-372 (Taguchi A, et al) Want to know more? Items are referenced where possible. A reference such as ‘‘ 2007;35:18-25’’ means the source article was published on pages 18-25 in volume number 35 of the publication, in 2007. A doi number or website address is used for research published on a journal’s website.
After baby: Slim down for better health