The scientists from University of Wisconsin-Madison found in a study with mice that a diet supplemented with the compound resveratrol starting at their equivalent of middle age slowed the ageing process down.
Grapes and red wine have an abundance of resveratrol and some research has shown that in high doses, resveratrol extends the life span of fruit flies and worms and prevents early death in mice fed a high-fat diet.
For this study the mice were given relatively low doses of resveratrol but still experienced important ageing-related benefits say the researchers.
The mice began the resveratrol diet when they were 14 months old (middle age for mice) and were then followed until they were about 30 months old (old age).
Tests then conducted to assess cardiac function and gene activity related to ageing, revealed that low doses of resveratrol can retard some aspects of the ageing process, including heart ageing.
The effect of resveratrol was seen to be stronger in the heart than in the brain and muscles, but did prevent some ageing-related changes in the other tissues.
The researchers suspect resveratrol works by mimicking some of the effects of caloric restriction, which is known to retard ageing in several tissues and extend life span.
Other research has shown that animals on a diet where the caloric intake is greatly reduced have also lived longer than animals with normal diets.
But as the the researchers say perpetual hunger is a heavy price to pay for greater longevity.
Most striking say the researchers, was how the resveratrol, like calorie restriction, blocked the decline in heart function typically associated with ageing.
According to Tomas Prolla, a professor of genetics who helped lead the study, it is highly likely that the findings are applicable to humans and more research can be expected in future on the effects of resveratrol supplementation in people.
The study is published in the scientific journal PLoS ONE.
"This research suggests that childhood type 1 diabetes may be preventable with a modest intake of vitamin D3 (1000 IU/day) for children, ideally with 5 to 10 minutes of sunlight around noontime, when good weather allows," said Garland. "Infants less than a year old should not be given more than 400 IU per day without consulting a doctor. Hats and dark glasses are a good idea to wear when in the sun at any age, and can be used if the child will tolerate them."
The association of UVB irradiance to incidence of type 1 diabetes remained strong even after the researchers accounted for per capita healthcare expenditure. This was an important consideration because regions located near the equator tend to have lower per capita healthcare expenditures, which could result in under-reporting of type 1 diabetes.
The researchers created a graph with a vertical axis for diabetes incidence rates, and a horizontal axis for latitude. The latitudes range from -60 for the southern hemisphere, to zero for the equator, to +70 for the northern hemisphere. They then plotted incidence rates for 51 regions according to latitude. The resulting chart was a parabolic curve that looks like a smile.
In the paper the researchers call for public health action to address widespread vitamin D inadequacy in U.S. children.
"This study presents strong epidemiological evidence to suggest that we may be able to prevent new cases of type 1 diabetes," said Garland. "By preventing this disease, we would prevent its many devastating consequences."
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