Ray of hope for depression sufferers Dutch researchers have identified a link between elderly depression and low levels of vitamin D, based on a study of more than 1,000 people aged 65 to 95. Vitamin D levels were about 14 per cent lower in those suffering depression, say the researchers from Vrije Universiteit in Amsterdam. Some forms of depression, AFP reports, have been linked to a lack of exposure to sunlight, which is the main source of vitamin D. Low levels of the vitamin lead to an increase in hormones secreted by the parathyroid gland, which can cause depression. Drawing the short straw Having short arms and legs may significantly increase the risk of developing Alzheimer's and other memory problems later in life, say researchers from Tufts University in Boston, based on a five-year study of almost 2,800 elderly people. In men, only a shorter arm span was linked with a higher risk. Short limbs may be a sign of nutritional deficits early in life that play a role in brain development, Reuters reports. Snorers more likely to wet bed Children who wet their beds typically have high levels of a hormone that regulates fluid around the heart, and habitual snorers are about three times more likely to wet their beds than those who don't, say researchers from the University of Louisville in Kentucky, who analysed data on 18,000 children. About 9 per cent of seven-year-old boys and 6 per cent of girls suffer from enuresis, whereby their brains don't react to the normal cues to wake up, although it's unclear why, healthday.com reports. The researchers say the link with snoring is significant because blocked airways put pressure on the lungs and heart, raising levels of the hormone. Breastfed children have the edge Children who were breastfed - and breastfed for longer - score significantly higher in IQ tests, say Canadian and Belarusian researchers, based on a study of 14,000 children over six years. But the difference may be due to the mothers rather than the milk. 'Mothers who breastfeed or who breastfeed longer are different,' says researcher Michael Kramer of McGill University in Montreal. 'They tend to be smarter ... more invested in their babies [and] tend to interact with them more closely.' Previous studies have suggested a link between breastfeeding and brain development and intelligence, Reuters reports. Grapefruit can help prevent hepatitis A compound in grapefruit can significantly block the secretion of the hepatitis C virus by infected cells, suggesting new treatments for the disease, which infects about 3 per cent of the world's population and can lead to cirrhosis and liver cancer. Standard treatments are effective in only about one in two cases and can have serious side effects. Harvard Medical School researchers say that a grapefruit flavonoid called naringenin cuts virus secretions by 80 per cent, healthday.com reports. However, because naringenin is not effectively absorbed by the stomach, the researchers say that it might have to be injected, or given as part of a compound, healthday.com reports.