Background a number of nutrients have been found to be associated with better muscle strength and mass; however, the role of the whole diet on muscle strength and mass remains still unknown.

Objective to examine whether the healthy Nordic diet predicts muscle strength, and mass 10 years later among men and women.

Methods about 1,072 participants belong to the Helsinki Birth Cohort Study, born 1934–44. Diet was assessed with a validated food-frequency questionnaire during 2001–04. The Nordic diet score (NDS) was calculated. The score included Nordic fruits, vegetables, cereals, ratio of polyunsaturated to saturated fatty acids, low-fat milk, fish, red meat, total fat and alcohol. Higher scores indicated better adherence to the healthy Nordic diet. Hand grip strength, leg strength (knee extension) and muscle mass were measured during the follow-up, between 2011 and 2013.

Results in women, each 1-unit increase in the NDS was related to 1.83 N greater leg strength (95% confidence interval [CI] 0.14–3.51; P = 0.034), and 1.44 N greater hand grip strength (95% CI: 0.04–2.84; P = 0.044). Women in the highest quartile of the NDS had on average 20.0 N greater knee extension results, and 14.2 N greater hand grip results than those in the lowest quartile. No such associations were observed among men. The NDS was not significantly related to muscle mass either in men or women.

Conclusions adherence to the healthy Nordic diet seems to protect from weaker muscle strength in old women. Therefore, the healthy Nordic diet may help to prevent disability.