Saturday, December 19, 2009

Overeating prevention hormone 'may protect against Alzheimer's'

Journal article here. A study of 89 Alzheimer's sufferers. There may be something in this but the sample is of unknown representativeness, the effects are weak and extreme-group analyses are not very persuasive. And confounding factors do not appear to have been explored

A hormone that helps to prevent overeating may also protect against Alzheimer's disease, researchers have discovered. Scientists discovered that higher levels of leptin are associated with a reduced risk of Alzheimer's.

Leptin is produced by fat cells and sends a "feeling full" signal to the brain that reduces appetite. But there is growing evidence that the hormone also benefits brain development and function, and memory. Earlier research has shown that it reduces levels of beta-amyloid protein in the brain, a major component of the sticky deposits that are a key hallmark of Alzheimer's.

In the latest study, scientists carried out regular brain scans on 198 older volunteers after measuring their leptin levels. Over a 12-year follow-up period, a quarter of those with the lowest levels of leptin developed Alzheimer's compared with six per cent of those with the highest levels. Higher leptin concentrations were also associated with greater total brain volume. The findings are published in the Journal of the American Medical Association.

Study leader Dr Sudha Seshadri, from Boston University Medical Center in the US, said: "If our findings are confirmed by others, leptin levels in older adults may serve as one of several possible biomarkers for healthy brain ageing and, more importantly, may open new pathways for possible preventive and therapeutic intervention."


Drinking three cups of tea or coffee a day cuts risk of age-related diabetes by 23%

Good to see a metanalysis of this crowded field but the overall effect they come up with is too slight to be taken very seriously. Lots of diabetics DO drink tea and coffee, so where does that lead us?

Drinking more than three cups of tea a day cuts the risk of diabetes, say researchers. Studies show that regular tea drinkers have a 25 per cent lower chance of developing Type 2 diabetes compared to those drinking tea occasionally or not at all. Almost 80 per cent of Britons are tea drinkers, getting through 165million cups a day. Diabetes affects 2.3million. Researchers are suggesting doctors tell patients most likely to develop the condition to step up their tea consumption.

The seven studies involved almost 300,000 tea drinkers, while further studies included information on those who drank regular coffee and decaffeinated coffee. They showed coffee drinking was also linked with a reduced risk of developing diabetes, says a report in the Archives of Internal Medicine journal.

The researchers from the University of Sydney collated studies involving 286,701 people which looked at the association between tea consumption and diabetes risk published between 1966 and 2009. In addition, 18 studies on coffee and diabetes found that drinking four cups cut the risk of getting diabetes by 25 per cent compared to those drinking no coffee.

Dr Rachel Huxley, who led the research team, said the protection appeared to be due to 'direct biological effects' A link was also found with decaffeinated coffee, so caffeine was unlikely to be solely responsible for the effect. She said: 'The identification of the active components of these beverages would open up new therapeutic pathways for the primary prevention of diabetes.'

Dr Carrie Ruxton, scientific adviser to the industry-backed Tea Advisory Panel, said: 'The authors found that individuals who drank three to four cups per day had a 25 per cent lower risk than those who drank between zero and two cups per day. 'This protective effect may be due to the variety of compounds present in tea, including antioxidants.'


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