Serum zinc concentrations correlate with mental and physical status of nursing home residents

Zinc (Zn) is one of the most important trace elements in the body. Zn deficiency seems to play a role in the development of age-related diseases and impairment of quality of life. Zn status has been especially studied in free-living or hospitalised people, but data from older residents of nursing homes are scarce. This study aimed to determine the Zn status among the older individuals in correlation to their mental and physical performance.

A total of 100 participants aged between 60-102 years were recruited between October 2010 and May 2012 at the nursing home in Bialystok (Poland). Zn status was evaluated by determining the concentration in serum by flame atomic absorption spectrometry. Anthropometric variables and fitness score (FS) were measured. Abbreviated Mental Test Score (AMTS), Geriatric Depression Scale (GDS), Self-Rated Health (SRH), independence in Activities of Daily Living (ADL) were recorded.

The mean serum Zn concentration was 0.83 ± 0.20 mg/L, 28% of residents had Zn deficiency. Cognitive functions were impaired (AMTS ≤ 8) in 45% of the studied persons and 48% showed depressive symptoms (GDS ≥ 1). The ability to independently perform activities of daily living (ADL = 6) was found in 61% of participants, but most of them (90%) had weak body type (FS < 70), correlating with GDS, SRH and body mass index (BMI). Serum Zn concentration correlated with mental efficiency and was statistically significantly higher in older people with normal cognitive function and without depression than in patients with memory impairment and showing depressive symptoms.

Nursing home residents seem at risk of marginal Zn status, which correlates with their mental status as measured by the AMTS and GDS. Their low FS is associated with mental health deterioration and obesity.