Protein intake protects against weight loss in healthy community-dwelling older adults

Weight loss is prevalent in the elderly population, with deleterious health consequences, notably loss of lean body mass and subsequent functional decline. Protein intake below the current RDA [0.8 g/(kg · d)] is also common in older adults; however, the link between the 2 has received little attention. Our objective was to assess the relation between protein intake and incident 1-y weight loss ≥5% in community-dwelling older adults. We conducted a nested, prospective, case-control study in 1793 community-living elderly participants of the Quebec Longitudinal Study of Nutrition as a Determinant of Successful Aging (NuAge). We studied 211 incident cases of 1-y weight loss (≥5%) and 211 weight-stable controls (±2%) matched by sex and age category (70 ± 2, 75 ± 2, and 80 ± 2 y). Diet was measured by 3 nonconsecutive 24-h recalls. ORs (95% CIs) for the association between protein intake and weight loss were computed by using conditional logistic regression. After adjustment for body mass index, energy intake, appetite, smoking status, physical activity level, physical function, chronic diseases and medications, depressive symptoms, and serum albumin and ultrasensitive C-reactive protein, the ORs of weight loss in participants with low protein intakes [<0.8 g/(kg · d)] were 2.56 (95% CI: 1.01, 6.50) compared with participants with very high protein intakes [≥1.2 g/(kg · d)]. Corresponding numbers were 2.15 (95% CI: 1.02, 4.56) in participants with moderate protein intakes [0.8-<1.0 g/(kg · d)] and 1.33 (95% CI: 0.77, 2.28) in participants with high protein intakes [1.0-1.2 g/(kg · d)]. Our results suggest that protein intakes >1.0 g/(kg · d) are protective against weight loss in healthy older adults. These findings add epidemiologic evidence in support of higher optimal protein intakes than the current guidelines for healthy older adults.