New project on sex differences in protein needs in old age

A new project on protein needs in older men and women has started. Dr. Hanneke Wijnhoven and dr. Laura Schaap from the Department of Health Sciences received a ZonMw grant for the project entitled: ‘Do protein needs differ between older men and women? An epidemiological study on differences between older men and women in the association of protein intake with loss of muscle mass and physical function’. The project is part of the Gender and Health program, for which both researchers are already leading another project on the female disadvantage in healthy ageing. In this new project, ir. Liset Elstgeest will investigate differences in the associations between protein intake and decline in physical functioning using data of the Health Aging, and Body Composition study and the Longitudinal Aging Study Amsterdam. Other project members from the VU and VUmc are dr. Martijn Heymans (Department of Epidemiology and Biostatistics) and prof.dr. Marjolein Visser (Department of Health Sciences), and also involved are dr. Denise Houston (Wake Forest University, N.C., United States), dr. Elke Naumann (HAN University of Applied Science, European Federation of the Association of Dietitians) and drs. Carlijn van Aalst (senior organization KBO-PCOB). The findings are expected at the end of this year.

Project summary

Ageing is associated with a gradual loss of muscle mass and muscle function with a subsequent decline in physical performance. A low dietary protein intake is one of the (modifiable) factors that likely influences this decline. Previous studies showed that low dietary protein intake is associated with decline in muscle mass and physical functioning in old age. Moreover, protein needs are higher in older compared to younger adults.

Current guidelines for dietary protein intake advise ≥0.8 grams of protein per kilogram body weight per day, irrespective of age and sex. Recently, based on accumulating scientific evidence, international expert panels of geriatricians and nutritional experts propose at least 1.0 g protein/kg body weight/d for older adults. Current recommendations are similar for men and women, while sex differences in body composition or hormones may influence protein needs in old age. Women have relatively more fat mass and less muscle mass compared to men of similar height. Protein needs expressed per unit of body weight may therefore be lower in women than men. This project will examine if protein needs differ between older men and women by studying differences in the (shape of the) association of dietary protein intake with muscle mass loss and physical functioning decline in a US and Dutch cohort of older adults using sophisticated statistical techniques.

After analyzing and defining optimal cut-offs for protein needs, the results will be disseminated to relevant stakeholders: the general public including older adults, health professionals (dietitians, geriatricians), scientists, and the food industry. An older adults representative and health professional (dietitian) representative are involved to ensure the project results will be translated to a clear message for different relevant stakeholders. Findings of the proposed project will also be disseminated within the PROMISS project (, an European project on the role of protein to prevention of malnutrition in older adults.