Today at @ontariosdoctors we consider whether a simple switch in the brain can control hunger. Also we look at why it is important to eat five servings of fruits and vegetables each day.
Scientists have recently discovered that a very small network of cells in the brain known as amygdala, may have the ability to turn appetite on and off. This area of the brain had been previously studied in mice and is linked to triggering emotions such as fear. Scientists accidently discovered a link to hunger when the mice had an unexpected reaction to light signals while eating. Researchers expected the mice to become anxious and fearful when the amygdala was triggered, however, they stopped eating instead. The Hamilton Spectator brings us this story:
Because the researchers had expected the signal to cause fearful or anxious behaviour, “this was really a surprising result,” said Dr. Anderson, a professor of biology and Institute investigator.
The researchers used different wavelengths of light to genetically manipulate the mice’s appetite. It was concluded that the amygdala might act as an appetite control hub. When researchers activated this part of the brain with light signals, appetite turned off. Appetite turned back on again when the neurons stopped sending signals. Neurons in the amygdala could also be activated by bad tastes and the feeling of nausea.
Richard D. Palmiter, a University of Washington neuroscientist said, “I think it’s likely that these neurons in the amygdala help an animal avoid toxic or unpleasant foods. But there are many other ways the brain regulates appetite and feeding”
Researchers suspect humans have similar appetite control networks as mice. Since this area of the brain which is also strongly associated with emotion has been targeted to treat other mental health disorders such as depression, it is possible that treatment for those with a life-threatening eating disorder may become possible.
Researchers have uncovered additional evidence linking good health to a diet rich in fruits and vegetables. During a study, it was noted that the more fruits and vegetables people ate, the less likely they were to develop heart problems. The study compiled 16 existing studies which involved more than 800,000 people. Some results were measured after four years while others lasted up to 26 years. During this time period, about 56,000 people died. The Globe and Mail brings us this story:
“Compared with people who ate no fruits or vegetables, those who ate one serving a day were roughly 5 per cent less likely to die of any cause over the course of the studies. And with every additional serving, the risk of death decreased by another 5 per cent.”
Scientists recommend people consume five servings of fruits and vegetables per day. However, eating more than five servings daily did not appear to hold any additional benefit. The vitamins, minerals, and phytochemicals found in fruits and vegetables have also hold additional health benefits including reduced inflammation and insulin resistance and improvement of blood lipids, blood pressure.
“Since the average consumption of fruits/veggies in the general population is far below five servings per day, there is still a long way to go before meeting the recommended intakes,” Said lead researcher Dr. Frank Hu