obsessive/extreme CRON: another issue

[Guest guest]

This is my first post (though I am guilty of lurking here for a

while). I have had a strong interest in CRON since reading

Walford's first book and have practiced moderate CR

intermittently over the years. Although I've never been

overweight, I prefer to be like I have been during my CRON

periods, and hope to become more faithful to the process. I find

CRON difficult within a family that includes my sons, two young

men (13 and 20 yrs old) with voracious appetites. I also find that

travel (particularly international travel) too easily upsets the

greatest of CRON intentions. A recent week in Italy easily

derailed my latest CRON effort, and it's taken another week to

get back on the program.

I am interested in the issue of a minimum body fat percentage

threshold below which the health benefits of CRON in the face of

infection are compromised. I searched Medline on the PubMed

website and it appears that there are only a few studies relating

CR and infection outcome, but none seem to address body fat

percentage as a variable within the CR context. Perhaps my

search was too limited. Does anyone know of anything

published on this issue? I did come up with the following

abstract, which is interesting but doesn't answer the question.

Search term: " Calorie restriction " AND infection

JPEN J Parenter Enteral Nutr 1992 Nov-Dec;16(6):561-5

The role of protein and calorie restriction in outcome from

Salmonella infection in mice.

Peck MD, Babcock GF, JW.

Department of Surgery, University of Miami School of Medicine,

Florida 33101-6310.

We studied the separate effects of protein and calorie restriction

in mice challenged with Salmonella typhimurium, an

intracellular pathogen eliminated by cell-mediated immunity.

Female A/J mice (n = 73) were placed on one of eight solid diets

for 3 weeks. Animals were weighed at the beginning and the

end of the feeding period. Diets were adjusted by two factors.

The total amount of protein in the diet was 1%, 5%, 20%, or 40%

by weight. The diets were fed to half the mice in quantities of 3 g

and to the other half at 1.5 g per mouse per day. At the end of 3

weeks, mice were injected intraperitoneally with bacteria and

mortality was observed for 2 weeks. Mortality was related to

protein intake and was significantly higher in the 1% and 5%

groups (chi 2: p = .0021). However, mortality was lower in the

calorie-restricted groups (chi 2: p = .0242). Although caloric

intake did not affect cell-mediated immunity, the response to 2,4-

dinitrofluorobenzene was greater in the low protein groups.

Lymphoproliferative responses in the mixed lymphocyte

response were not affected by either caloric or protein intake.

Lymphoproliferative responses to both lipopolysaccharide and

phytohemagglutinin were affected by dietary protein but not by

caloric intake; proliferative responses were higher in the low-

protein groups. We conclude that protein restriction can increase

mortality in this model. On the other hand, short-term calorie

restriction can improve survival.

PMID: 1494214 [PubMed - indexed for MEDLINE]