CR vs drugs?

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CR or drugs may be comparable for longevity, suggests the

paper below, which is available in pdf format.

Caloric restriction versus drug therapy to delay the

onset of aging diseases and extend life (Review)

Age 27 (1) Mar 2005, 39-48

Arthur V. Everitt, S. Roth, G. Le Couteur

and N. Hilmer

Abstract

There are two firmly established methods of prolonging

life. Calorie restriction (CR) using nutrient-rich

diets to prolong life in lower animals, and life

saving medications in humans to delay the development

of the major diseases of middle and old age. These two

approaches have different mechanisms of action. In

rats, CR at 40% below ad libitum intake begun soon

after weaning and continued until death, reduces body

weight by about 40% and increases lifespan. There have

been no lifelong CR studies performed on humans.

However, in healthy adult human subjects about 20% CR

over a period of 2-15 years, lowers body weight by

about 20% and decreases body mass index (BMI) to about

19. This CR treatment in humans reduces blood pressure

and blood cholesterol to a similar extent as the

specific drugs used to delay the onset of vascular

disease and so extend human life. These same drugs may

act by mechanisms that overlap with some of the

mechanisms of CR in retarding these pathologies and

thus may have similar antiaging and life prolonging

actions. Such drugs may be regarded as CR mimetics

which inhibit the development of certain life

shortening diseases, without the need to lower calorie

intake. In developed countries, better medical care,

drug therapy, vaccinations, and other public health

measures have extended human life by about 30 years

during the 20th century without recourse to CR, which

is so effective in the rat. The percentage gain in

human life expectancy during the 20th century is twice

that achieved by CR in rat survival. However, rat

longevity studies now use specific pathogen-free

animals and start CR after weaning or later, thereby

excluding deaths from infectious diseases and those

associated with birth and early life. There is a need

to develop CR mimetics which can delay the development

of life-threatening diseases in humans. In the 21st

century due to the human epidemic of overeating with a

sedentary lifestyle, it may necessary to utilize CR to

counter the aging effects of overweight. Since the

greatest life-extending effects of CR in the rodent

occur when started early in life, long-term antiaging

therapy in humans should be initiated soon after

maturity, when physiological systems have developed

optimally.

Table 2. Gains in life expectancy at birth of human

populations in 10 developed countries during the 20th

century due to improvements in public health and

medical care compared with the increased survival of

male laboratory rats in 10 long-term 40% calorie

restriction studies.

====================================

>>>>>>>>>>>>Human life expectancy in years---Mean or

median rat survival in days

Country 1900 2002 %Gain---Rat strain (ref.) Control CR

%Gain

====================================

>>>Japan 44.5 81.9 84.0---F344 (Yu et al. 1982) 701

986 40.7

>>>Switzerland 50.7 80.6 59.0---BN (Sprott 1997) 903

1,078 19.4

>>>Sweden 55.8 80.4 44.0---BN (Turturro et al. 1999)

935 1,115 19.3

>>>Australia 56.5 80.4 42.3---F344xBN (Turturro et al.

1999) 890 1,180 32.6

>>>France 47.0 79.7 69.6---F344 NIH (Turturro et al.

1999) 760 855 12.5

>>>Italy 44.5 79.7 79.1---F344 PUR (Turturro et al.

1999) 740 910 23.0

>>>New Zealand 59.4 78.9 32.8---F344 (Thurman et al.

1994) 707 875 23.8

>>>Germany 46.6 78.7 68.9---Sprague-Dawley (Keenan et

al. 1994) 595 728 22.4

>>>United Kingdom 50.5 78.2 54.9---Sprague-Dawley

(Barrows and Kokkonen 1982) 706 924 30.9

>>>USA 49.3 77.3 56.8 ---Long- (Holloszy 1997)

858 1,051 22.5

>>>Mean 50.5 79.6 59.1---Mean 779.5 970.2 24.7

>>>Standard dev 4.94 1.27 15.7---Standard dev 105.2

130.4 7.59

====================================

>>>Data for Human Life Expectancy in 1900 are taken

from the United Nations Statistical Yearbook 1955

(United Nations 1957).

>>>Data for Human Life Expectancy in 2002 are taken

from the World Health Report 2003 (World Health

Organization 2003).

>>>Survival in rodents varies with the strain (Masoro

2002b).

>>>The difference in % gain in survival of humans and

rats was significant (t-test, P <0.001).

-- Al Pater, alpater@...