Nordic nutrition recommendations (2012) suggest protein intake ≥ 1.1 g/kg body weight (BW) to preserve physical function in Nordic older adults. However, no published study has used this cut-off to evaluate the association between protein intake and frailty. This study examined associations between protein intake, and sources of protein intake, with frailty status at the 3-year follow-up.

Participants were 440 women aged 65─72 years enrolled in the Osteoporosis Risk Factor and Prevention-Fracture Prevention Study. Protein intake g/kg BW and g/d was calculated using a 3-day food record at baseline 2003─4. At the 3-year follow-up (2006─7), frailty phenotype was defined as the presence of three or more, and prefrailty as the presence of one or two, of the Fried criteria: low grip strength adjusted for body mass index, low walking speed, low physical activity, exhaustion was defined using a low life-satisfaction score, and weight loss > 5% of BW. The association between protein intake, animal protein and plant protein, and frailty status was examined by multinomial regression analysis adjusting for demographics, chronic conditions, and total energy intake.

At the 3-year follow-up, 36 women were frail and 206 women were prefrail. Higher protein intake ≥ 1.1 g/kg BW was associated with a lower likelihood of prefrailty (OR = 0.45 and 95% confidence interval (CI) = 0.01-0.73) and frailty (OR = 0.09 and CI = 0.01-0.75) when compared to protein intake < 1.1 g/kg BW at the 3-year follow-up. Women in the higher tertile of animal protein intake, but not plant protein, had a lower prevalence of frailty (P for trend = 0.04).