Testosterone dive baffling The overall testosterone level of American men has fallen steadily during the past two decades - and researchers don't know why. Neither ageing nor health factors such as smoking or obesity fully explains the decline, discovered by New England Research Institute's analysis of blood from about 1,500 men over 45 years old during three periods since 1987. Testosterone is the primary male sex hormone and helps maintain bone and muscle mass, healthday.com reports. Low levels have been linked to problems such as low libido and diabetes. Curry guards against dementia Eating curry may help stave off dementias such as Alzheimer's, according to two studies focusing on curcumin, which is found in the spice turmeric and has potent anti-inflammatory and antioxidant properties. Preliminary findings by University of California, Los Angeles, researchers suggest that curcumin helps immune-system cells purge amyloid beta - a protein that forms damaging plaque in the brains of Alzheimer's sufferers. And a National University of Singapore study of more than 1,000 people aged between 60 and 93 found that those who ate curry even only twice a year scored significantly better in cognitive tests than those who rarely or never did so, Reuters reports. The researchers say the results provide 'the first epidemiologic evidence supporting a link between curry consumption and cognitive performance'. Spice blocks arthritis in rats Meanwhile, researchers at the University of Arizona say extracts of turmeric containing curcumin are remarkably effective at blocking the onset of rheumatoid arthritis in rats. They may also help treat other inflammatory disorders such as asthma, multiple sclerosis, inflammatory bowel disease and possibly osteoporosis, BBCi reports. However, the researchers say that 'simply eating more spices is not likely to be effective clinically'. Alternative relief for labour pains Acupuncture and hypnosis may be effective in relieving pain during labour, according to Australian analysis of data from 14 studies involving almost 1,500 women. Those using acupuncture had a 30 per cent less need for pain-relieving drugs, as well as less call for epidurals and drugs to stimulate labour, Reuters reports. Those who used self-hypnosis were also much less likely to need drugs, according to the University of Adelaide researchers. Watch the birdies for sociability The reason some people are shy and others gregarious may have a lot to do with how their brains are wired, according to University of California, San Diego, studies of birds. Team leader James Goodson says the findings may help researchers treat various social problems, healthday.com reports. The brains of birds from more social species are better at handling chemical signals that seem to promote bonding - in other words, they're programmed to be friendly. Pain tolerance in the genes Being brave is all very well, but how people handle pain may be more to do with their genes, according to research by the Harvard Medical School in Boston. The discovery of a gene, GCH1, that appears to affect how people feel discomfort could lead to the development of new painkillers, Reuters reports. 'Individuals who say they feel less pain are not just stoics but have inherited a molecular machinery that reduces their perception of pain,' says team leader Clifford Woolf. 'This difference results not from personality or culture, but real differences in the biology of the sensory nervous system.' Tennis elbow served a treatment A simple technique that uses the concentrated natural healing ability of the blood may provide a cure for chronic cases of so-called tennis elbow, according to preliminary trials at Stanford University Medical Centre. Blood is drawn from the patient's arm and spun in a centrifuge to create a sample with a high concentration of cells called platelets. This is then injected directly into the elbow tendon, Reuters reports. The 15 patients studied had 60 per cent pain relief within eight weeks. After two years, nearly all were 'essentially pain free'. Jason Sankey is a tennis professional
