The effects of supplementation with whey proteins high in leucine content were tested in older nursing home residents.

Resident of a municipal nursing home (n=106) were recruited to this 6-month randomized controlled trial. Both the test (n=49) and control group (n=57) received 1.5 deciliters of juice three times a day. The test juice was fortified with whey protein fractions (20g/d: 75% β-lactoglobulin, 25% ⍺-lactalbumin). The responses of muscle mass (bioimpedance spectroscopy), strength (hand grip, knee extension) and physical performance (walking, toileting) were measured. In addition to blood samples, data from comprehensive geriatric assessment were collected.

Whey supplementation resulted in 2.1% increase in body weight, in contrast to 1.9% weight loss in the control group (P=0.001). The skeletal muscle index decreased in the control group (P=0.028), resulting in mean difference of 10.3% between groups (P=0.039) during the first 3months, but this difference leveled off at 6months. The responses in muscle strength were similar, but patients on whey protein needed less physical assistance after 6months. Insulin like growth factor 1 (IGF-1) and insulin increased in the test group, in which patients experienced less often infections, skin ulcers, and worsening of discomfort behavior.

Supplementation with whey protein fractions increases body weight and activates the IGF-1 axis in typical nursing home residents in Finland. Supplementation seems to also associate with maintenance of skeletal muscle mass, reduction in required physical assistance and general well being. However, larger well-designed trials are needed to confirm these associations.