Undernutrition without malnutrition as a protective factor to prevent DNA damage in the elderly

Abstract 

Caloric restriction (CR), undernutrition without malnutrition, is a successful method of extending the life span and reducing the incidence of several diseases. In animals, CR can reach 40% with beneficial effects, whereas in human beings, CR must be moderate (only 10%-20%) to avoid health risks. We have examined whether undernutrition without malnutrition is a protective factor for DNA damage in the elderly. The sample included a total of 260 older subjects: 96 well-nourished subjects, 52 subjects with undernutrition without malnutrition (CR 10%-20%), and 112 overweight subjects, all diagnosed as clinically healthy. DNA damage in peripheral blood lymphocytes was assessed through an alkaline unicellular electrophoresis procedure (comet assay). Fifty-six percent of the well-nourished subjects, 38% of the CR, and 44% of the overweight had DNA damage. Odds ratio (OR) of logistic regression analysis for DNA damage were: gender (men; OR 2.1, 95% CI [confidence interval] 1.19-3.71, P < .01), age (≥70 years; OR 1.7, 95% CI 1.05-3.02, P = .03), overweight (body mass index ≥27; OR 0.67, 95% CI 0.38-1.19, P = .18) and CR subjects (OR 0.40, 95% CI 0.19-0.82, P < .01). The groups of CR women and 60- to 69-year olds had a lower percentage of DNA damage than CR men and 70-year olds, respectively (P < .01 and P < .001). Present results suggest that a 10% to 20% CR is a protective factor for DNA damage in elderly people and that CR has better effects on women and on subjects aged 60 and 69 years.

Keywords: Caloric restriction, DNA damage, Elderly, Comet assay