Zinc status, psychological and nutritional assessment in old people recruited in five European countries: Zincage study

Abstract

The paper shows the results on the relationship between zinc status, psychological dimensions (cognitive functions, mood, perceived stress) and nutritional aspects in European healthy old subjects recruited for ZINCAGE Project (supported by the European Commission in the Sixth Framework Programme). The old healthy subjects were recruited in Italy, Greece, Germany, France, Poland taking into account the different dietary habits between Northern and Southern European Countries and the pivotal role played by zinc for psychological functions. Measures of the cognitive status, mood and perceived stress level were obtained at baseline, using the “Mini Mental State Examination (MMSE)”; the “Geriatric Depression Scale (GDS – 15 items)” and the “Perceived Stress Scale (PSS)”, respectively. Nutritional status was assessed using “Frequency Food Questionnaire”. The sample included 853 old subjects, classified in 4 groups of age: 60–69-years-old (n = 359); 70–74-years-old (n = 225); 75–79-years-old (n = 153); 80–84-years-old (n = 116). Subjects were studied on the basis of plasma zinc, in which zinc ≤11 μM means marginal zinc deficiency. The total samples showed that the 82% had no cognitive decline, whereas 76% presented a low GDS value indicating no depression. However, all psychological variables were related to plasma zinc values and nutritional assessment. In particular, a relationship between marginal zinc deficiency and impaired psychological dimensions occurred in Greece than in other European countries due to low intake and less variety of foods rich of zinc. This phenomenon was independent by the age, suggesting that a correct zinc intake from a wide range of foods may be useful to maintain a satisfactory plasma zinc levels as well as psychological status in elderly with subsequent achievement of healthy ageing.