You can teach old dogs new tricks

By STEVE CONNOR in Seattle

Diet and exercising the brain with mental puzzles can reverse the effects of ageing, according to a series of studies that are finally beginning to explain the causes of Alzheimer's disease.

Separate teams of scientists have found that vitamin supplements, a low-fat diet and mental games can play a critical role in delaying the onset of senile dementia and that dietary fats in particular are intricately involved in triggering Alzheimer's.

One of the studies identified a link between the damaged brain cells of Alzheimer's patients and higher levels of cholesterol and another fatty compound called ceramide in the brain. Both fats can be reduced with the aid of dietary supplements, said Mark Mattson of the US National Institute on Ageing.

"We found that we could block the increase in ceramide by increasing levels of antioxidants. Finally we found that increases in ceramide levels in the nerve cells may play a role in dysfunction and degeneration," said Dr Mattson.

"The implications for delaying or preventing the triggering of Alzheimer's disease are that ceramide levels can be influenced by diet, in particular by intake of saturated fats."

Another study of more than 70 dogs of varying ages found that feeding them vitamins and antioxidants enables older dogs to learn tricks that they could only do when they were much younger and more alert.

Carl Cotman, a neurochemist at the University of California at Irvine, used the dogs to test the theory that a diet rich in vitamins and antioxidant supplements could slow or reverse mental decline in old age.

The dogs were either fed a basic diet or given extra supplements of vitamin E and other antioxidants. Over several years he tested their performance in distinguishing between unfamiliar objects - a recognised test of mental ability in animals.

"What we found is that we can basically improve learning and memory in these ageing animals so that they can do much more complicated tasks and make many fewer mistakes," Dr Cotman said.

"But the really remarkable finding is that ... they learned to do tasks that they could only do when they were younger and they'd lost as a function of age.

"Actually the data show that those animals that have lost it can be rejuvenated by this long-term diet."

The findings support the view that brain cells are constantly trying to repair themselves and need antioxidants to help them mop up destructive chemicals such as cholesterol and ceramide.

"Healthy nerve cells cannot be replaced. They are in the brain for 60 or 70 years and they are being pounded all the time by various insults," Dr Cotman said.

"If one or two things go wrong they fall into greater risk until the last one comes along and away they go. But if you can stop one of them, often they can reset themselves."

- INDEPENDENT