By Kim O’Hare
Some people are concerned about health risks associated with grapefruit as the result of an e-mail chain circulating around the world.
The message refers to a 2007 study in The British Journal of Cancer that found an increased risk of breast cancer among postmenopausal women who ate large amounts of grapefruit. But that study is being disputed.
In the group of women, more than 46,000 overall, those who ate about a half a grapefruit every other day had a 30 per cent higher risk of breast cancer than those who ate none, even after other risk factors were taken into account. Scientists said they suspected that an enzyme in grapefruit known as CYP3A4 had the ability to increase oestrogen.
But a more recent report, published 2008 in the same journal, reached a far different conclusion. That analysis used data from the Nurses’ Health Study, which followed more than 77,000 women 30 to 55 over many years. The scientists looked at intake of both grapefruit and grapefruit juice and found no rise in breast cancer risk, either among women over all, or among postmenopausal women.
You’re smarter than you think
The human brain seems to be able to detect the calorie content of food, even when it’s not tasting it.
Researchers at Duke University Centre genetically altered the brains of mice, making them unable to perceive sweet tastes. The sweet-blind mice were given a choice of a sugar solution and one sweetened with a fake non-caloric sweetener. They found the mice showed a decided preference for the higher-calorie solution with real sugar, indicating that the calorie content, not the taste, likely governed their decision.
The study shows that even in the absence of taste, changes in the body let the brain know a high-calorie food has been ingested. “Our findings suggest that calorie-rich nutrients can directly influence brain reward circuits that control food intake independently of taste,” the authors write.
This means that if a person is dieting and consuming lower-calorie foods, the body will still sense that it isn’t getting enough calories. This finding could change how obesity is tackled, viewing the consumption of foods as a process that is driven not only by taste but also by caloric training of the brain. The study is published in the March 27 2008 issue of the journal Neuron.
Smells dangerous to me
Some people just seem to be able to smell danger, and they may be right. Researchers at Northwestern University in Chicago, found that a single bad experience connected to a smell quickly teaches the nose to identify and distinguish the scent.
Researchers presented eight females and four males with a pair of nearly identical grassy smells in a set of three vials. The participants couldn’t distinguish between the scents. Then, they electrically shocked the participants in conjunction with one of the smells. After a series of shocks, the study said the participants were better able to distinguish between the similar scents.
The finding, says the report, “illustrates the tremendous power of the human sense of smell to learn from emotional experience”.
“Odours that once were impossible to tell apart became easy to identify when followed by an aversive event.”
The study was published in the March 28 2008 edition of the journal Science.
Easing damage to hearts
Researchers from Johns Hopkins University say studies in rats show that high doses of folate, already used to prevent anemia in pregnant women and to prevent birth defects, can blunt the effects of heart attacks.
Giving the supplement for days before a heart attack or infusing it into the bloodstream during an attack reduced damage to the heart by 90 per cent, they found in a study that will be published next month in the journal Circulation.
The researchers cautioned that people should not self-medicate until a clinical trial can be performed, but they held out hope that the supplement could be used prophylactically in people at high risk for heart attacks and to treat victims.
Long considered the epitome of bad manners, there may be some merit in spitting.
Researchers have identified all 1,116 unique proteins found in human saliva glands, a discovery that they say could usher in a wave of convenient spit-based diagnostic tests to replace the drawing of blood. As many as 20 per cent of the proteins that are found in saliva are also found in blood, they said.
The researchers hope saliva-based tests can be used to diagnose cancer, heart disease, diabetes and a number of other conditions, they report in the Journal of Proteome Research. Like a genome, which lists all of the genes in an organism, a proteome is a complete map of proteins. While genes provide the instruction manual, proteins carry out the instructions by regulating cellular processes.