Relação de biomarcadores de cálcio, magnésio, zinco e selênio em idosos longevos saudáveis com quantidade e qualidade da massa muscular

Abstract

Introduction: Life expectancy has increased, but the elderly has individual and varied experiences at each stage of aging. Healthy lifestyle habits can contribute to longevity and nutrition plays a role in modulating successful aging. Calcium, magnesium, zinc and selenium are associated with muscle mass and senescence, but this relationship in healthy elders needs further clarification. Objective: To study the relationship of Ca, Mg, Zn and Se biomarkers with muscle quantity and quality in healthy longevous elderly. Methods: Cross-sectional, analytical study with elderly people aged 80 and over not considered fragile, seen at a reference clinic. Socioeconomic, health and anthropometric data were collected. Body composition was assessed by dual energy X-ray absorptiometry (DEXA) and food consumption by three non-consecutive food records. Muscle quality was assessed by handgrip strength, Short Physical Performance Battery (SPPB) and gait speed tests. Plasma, erythrocyte and urinary biomarkers were evaluated in a 24-hour blood and urine sample. Results: 25 elderly people were included, with an average age of 86.5 (6.6) years, 60% of whom were female and 65% with appendicular skeletal muscle mass corrected by height² appropriate. 76% of the elderly had adequate strength, 82% had good physical performance and 85% adequate gait speed, with no difference by sex. Mineral intake was low and not correlated with the respective biomarkers. All the elderly had plasma and urinary Ca and erythrocyte and urinary Se within the reference values, however the plasma Se was below the reference values in 100% of the elderly. Regarding Mg, 48%, 32% and 83% of the elderly showed adequacy for plasma, erythrocyte and urinary biomarkers, respectively. For Zn, the adequacy was found in 80%, 4% and 91% of the sample, for the respective compartments. Elderly people with adequate strength had lower plasma Mg values (p=0.026) with higher urinary excretion (p=0.030), compared to those with low strength. The elderly with adequate SPPB had lower plasma Zn values (p=0.035), while those who presented adequate gait speed had lower plasma Ca concentration (p=0.027). The quantity of muscle mass was not associated with biomarkers. Conclusion: In longevous and healthy elderly people, the biomarkers studied were not associated with muscle quantity, and those that were associated with quality had lower plasma concentrations, probably due to the higher demand for minerals in certain compartments, increasing the use, as muscle, bone, enzyme and immune systems, in order to maintain the homeostasis of oxidative and inflammatory processes essential for successful aging.