Caloric restriction
"To lengthen thy life, lessen thy meals." - Benjamin Franklin, "Poor Richard's Almanack", June 1733
A widely discussed experimental trial in 1986 demonstrated that restricting the calorie intake of laboratory mice proportionally increased their lifespan compared to a group of non diet restricted mice.
The findings have since been accepted, and generalised to a range of other animals. Researchers are investigating the possibility of parallel physiological links in humans (see Roth et al below).
Recent research has demonstrated (see Bluher et al) that it is not reduced intake which influences longevity. This was done by studying animals which have their metabolism changed to reduce insulin uptake, consequently retaining the leanness of animals in the earlier studies. It was observed that these animals can have a normal dietary intake, but have a similarly increased lifespan.
This suggests that lifespan is increased for an organism if it can remain lean and if it can avoid any accumulation of fatty tissue: if this can be done while not diminishing dietary intake (as in some minority eating patterns, see e.g. Living foods diet or Joel Fuhrman) then the 'starvation diet' anticipated as an impossible requirement by earlier researchers is no longer a precondition of increased longevity.
The extension of these findings to human nutrition and longevity is as noted above still in progress.
See:
- The retardation of aging in mice by dietary restriction: longevity, cancer, immunity and lifetime energy intake. (Journal of Nutrition, 116(4), pages 641-54.Weindruch R, et al.,April, 1986.
- Caloric Restriction and Aging Richard Weindruch in Scientific American, Vol. 274, No. 1, pages 46–52; January 1996.
- 2-Deoxy-D-Glucose Feeding in Rats Mimics Physiological Effects of Caloric Restriction. Mark A. Lane, George S. Roth and Donald K. Ingram in Journal of Anti-Aging Medicine, Vol. 1, No. 4, pages 327–337; Winter 1998.
- Biomarkers of caloric restriction may predict longevity in humans. Roth GS, Lane MA, Ingram DK, Mattison JA, Elahi D, Tobin JD, Muller D, Metter EJ.: 297: 811, Science 2002.
- Eat more, weigh less, live longer, New Scientist, January 2003.
- Extended longevity in mice lacking the insulin receptor in adipose tissue. Bluher, Khan BP, Kahn CR, Science 299(5606): 572-4, Jan 24, 2003.
- Interview,I want to live forever, Cynthia Kenyon Professor of Biochemistry and Biophysics at the University of California, San Francisco, by James Kingsland. New Scientist online, 20th October 2003.
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