Association of Protein Intake with Handgrip Strength and Its Relation to Strength Exercise in Korean Adults Aged over 60 Years in the KNHANES (2014-18)

Weak handgrip strength (HGS) is associated with many negative health outcomes in older adults. There is evidence that with strength exercise, high protein intake leads to increased HGS. The goal of this study was to examine the relationship between weak HGS in older adults and dietary protein and it’s relation to resistance exercise. Data on 8497 Korean adults aged over 60 years from the Korea National Health and Nutrition Examination Survey (2014-18) were analyzed. Dietary protein intake measured by 24-h recall were categorized as three levels: low (<0.8 g/kg body weight (BW)), adequate (≥0.8 g/kg BW and <1.2 g/kg BW), and high (≥1.2 g/kg BW). Complex sample multiple logistic regression analyses were carried out. The prevalence of weak HGS was 18.3 (0.7)% in men and 28.8 (0.9)% in women. In a multiple logistic regression analysis, low protein intake was significantly associated with higher risk of weak HGS in men, as compared with adequate protein intake, but this relationship was not statistically significant in women. The risk of weak HGS was significantly reduced for both men and women who engaged in strength exercise and increased their dietary protein intake. In this study, based on a representative sample of Koreans aged over 60, men with low protein intake had a higher risk of weak HGS than did men with adequate protein intake. Men and women with a higher protein intake who also engaged in strength exercises had a lower risk of weak HGS. Increasing protein intake and engaging in strength exercises may be an effective way to preserve muscle strength in older men and women.