Eighty Candles Strong

by the Canadian Institutes of Health Research

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Research Profile - June 2007

There's no doubt about it: when it comes to ageing with strong muscles, calorie-restricted diets produce impressive results.

Calorie restricted diets, the focus of recent media attention, involve reducing food energy intake by about 40 per cent. The trick is how to get the necessary vitamins and nutrients in as little food as possible.

"For the vast majority of people it's not a very practical approach. It requires the attention to eating of an Olympic athlete," says Dr. Russel Hepple, a researcher with the Canadian Institutes of Health Research's Institute for Aging.

The scientific challenge, he says, is to help us get the muscle benefits of a calorie-restricted diet without the severe food restrictions. To achieve this he's taking a cellular approach, gradually teasing apart the chemical soup involved in muscle cell function, decline and regeneration as we age.

Starting in our early 40s, we start to lose muscle cells - cells that like brain cells, generally can't be replaced.

"It's a gradual process that most people don't even notice until it's happened," says Dr. Hepple.

Yet the rats on calorie restricted diets in Dr. Hepple's University of Calgary lab lose only a fraction of their muscle mass by the time they're the equivalent of 80-years old.

"And what's most dramatic of all is that there's an almost complete preservation of muscle function in these calorie-restricted rats - their muscles work like they're in their prime of life," says Dr. Hepple.

Part of the key, he says, is the realization that when starved, a muscle cell becomes more efficient in converting energy into movement. It's as if a car motor became more efficient as the gas gauge hits "empty".

The result says Dr. Hepple is the production of fewer free chemical radicals - a key cause of cellular breakdown.

"We're years from being able to give specific advice," says Dr. Hepple, himself 41 and on the edge of muscular decline. "We're building a cell-level instruction book on what it takes to keep muscle healthy. This could lead to new pharmaceuticals or eating and exercise guidelines."

All while still being able to eat desert.