The Collison Newsletter August 2005

        LONGEVITY: RECENT RESEARCH **

 

In “How To Live to 100+ Years Free from Symptoms & Disease”, on page 22, the fact that “the only way it is possible to increase the life span in healthy animals is by diet restriction”is set out. Rat studies have been repeated in several research centres with the same results, namely that restricted calorie/kilojoule intake - short of starvation and with balanced nutrition (essential amino acids, essential fatty acids, vitamins and minerals etc) - results in a significant extentsion in the lifespan of rats. The same studies (CRAN - Calorie / Kilojoule Restrication with Adequate Nutrition) in multiple other species including yeast, worms, insects, birds and dogs, resulted in similar extensions of life span, up to 100 %, ie a doubling of life expectancy.

Thus it has been shown repeatedly that, in many animals, the restriction of food has resulted in prolongation of their life span. This ‘dietary restriction’has been referred to as ‘calorie (kilojoule) restriction’. It has been suggested and inferred that reduction in calories, rather than reduction of particular nutrients in the diet, mediates the extension of life span.

It has been suggested that this is a ‘species survival mechanism’at work. This is based on the concept that, during times of famine, resources are diverted towards maintenance of the body, which will increase the chances of the organism surviving through times of food scarcity, thereby increasing chances for future reproduction and species survival. However, in many of the studies, reproduction was normal when there was dietary (calorie/kilojoule) restriction short of starvation (ie with adequate (basic) nutrition).

A recent publication by William Mair & co-workers, in the July 2005 issue of Plos Biology*, unravels this story a little further and casts important light on a possible mechanism/explanation for the extension of life span.

Fruit flies were used in these experiments. They were divided into 4 groups and put on different diets.

The basic diet was the standard fruit fly laboratory meal of yeast (which contains protein and fat) and sugar. 1200 kilocalories per litre.

Group 1, the control group received this standard meal. (1200 kilocalories per litre)

Group 2, the calorie restricted experimental group was fed a calorie-restricted diet, with equal amounts of yeast and sugar. (520 kilocalories per litre.)

Groups 3 and 4 each had 860 kilocalories per litre, ie less than the control group 1 but significantly more that the calorie-restricted group 2.

Group 3, the higher fat and protein experimental group was fed more yeast than sugar. (860 kilocalories per litre)

Group 4, the lower fat and protein experimental group was fed more sugar than yeast. (860 kilocalories per litre).

 

Results:

 

Group 2 flies, on the calorie-restricted diet, lived the longest, 82% longer compared to controls.

Group 3 flies, on a high fat/protein diet with some restriction of calories, had only a small increase in longevity of 9%.

Group 4 flies, on a low fat / protein diet with some restriction of calories, compared favourably to group 2, with an increase in thier lifespan of nearly 65%

This study challenges the long held belief that the key ‘ingredient’for longevity is simply calorie/kilojoule reduction –from any source. It would appear that long life (and associated health) comes significantly from the restriction of specific nutrients, namely fat and protein, rather than just ‘starving’. With significant dietary restriction there is, of course, reduced intake of both fat and protein. In the above studies, there was some calorie/kilojoule restrictions, but the significant difference between groups 3 and 4 is the amount of fat and protein –in an isocaloric diet.

In “How to Live to 100+ Years”the dietary guidelines clearly restrict calories /kilojoules, fat and protein. The emphasis on a dominantly alkalinising diet (75%-80%), with a limited intake of acid forming foods (20%-25%) [refer pages 34-36] means switching from animal products (red meats, white meats, fish and dairy products) and processed foods to mainly fruits, vegetables, grains, beans and nuts. Refer to notes on protein foods on page 54, and to notes on fats on pages 55 & 56. These dietary guidelines limit calorie/kilojoule intake, the aim being to achieve the correct Body Mass Index (page 41). The guidelines also significantly restrict both fat and protein intake.

This is the way to a healthy life and the way to eventually ‘Die Healthy’.

 

* MAIR W, PIPER MD, PARTRIDGE L. “Calories do not explain extension of life span by dietary restriction in Drosophilia”Plos Biol. 2005 Jul:3(7).

** Copyright 2005: The Huntly Centre.

 

Back to the list  Print friendly version