Additionally, serum zinc concentrations were noted to increase as serum albumin levels increased, suggesting a positive relationship between the compounds and further opportunities for deficiency detection.
“To the best of our knowledge, this is the first study to demonstrate the associations among serum zinc level, dietary zinc intake and multimorbidity among older adults in Thailand.”, the researchers from Mahidol University highlight in the report published in ‘Nutrients’.
With a growing ageing population, it is inevitable that the number of those suffering from chronic and geriatric-associated conditions will also grow. It is established that many of the most common conditions, including dyslipidaemia, as well as diabetes mellitus and hypertension, have been associated with serum zinc status. These associations may result from observations noting its anti-inflammatory and antioxidant potentials, alleviating oxidative stress by reducing free radicals.
Despite the vital nature of zinc as an essential micronutrient, with key roles in metabolic function and cell structure, the importance of its intake is not widely understood, say the authors of the recent study.
“Worldwide, the prevalence of zinc deficiency ranges from 20% to 40% of the total population, whereas one third of older adults are at greater risk of zinc deficiency”, they say.
“Zinc deficiency has adverse effects on health outcomes through impairment of the immune response, psycho-cognitive problems and delayed wound healing. However, there have been few studies of the relationships among dietary zinc intake, serum zinc concentration and multimorbidity in the Thai older population.”, they stress, emphasising the need for research into this area.
The study included volunteer participants from the Electric Generating Authority of Thailand, including 300 employees aged 60 years and above.
Utilising multivariate, multinominal logistic regression analysis, factors associated with low serum zinc levels were established following the completion of self-reported questionnaires collating demographic characteristics and dietary intakes. In addition, laboratory assessments obtaining twelve-hour-fasting serum samples were conducted as well as clinical measurements. Depression, activities of daily living (ADL), and cognitive function was assessed using structured interview-administered questionnaires.
It was found that the population mean of serum zinc level was 80.5 µg/d, highlighting the prevalence of those at risk of a deficiency (< 84 µg/dL). Yet, there were no significant associations found between chronic diseases established to be associated with low levels of serum zinc.
However, it was reported that a TGDS score of less than five, suggesting the presence of depression, was found to be significantly associated with a low serum Zinc level. Therefore, these findings imply that depression may be a risk factor for low zinc levels, in addition to the observed factors of being female and in education for 12 or more years.
It was observed that there were positive associations with albumin, calcium, homocysteine, and haemoglobin, highlighting the importance of the role zinc plays in further processes within the body.
“The link between zinc status and depression can be explained through effects on serotoninergic pathways, given that zinc plays a major role in the regulation of serotonin receptors,” the scientists explain with regards to the established association.
“Additionally, ROS are involved in the pathophysiology of depression. Zinc can prevent ROS production and accumulation through numerous mechanisms, including the inhibition of nuclear factor kappa B and the activation of superoxide dismutase.”
The results highlight the importance of maintaining zinc serum concentrations and provide insight into a potential dietary intervention strategy to contribute to the prevention of depression. Further long-term RCTs are required to acknowledge the potential biases, such as from the inclusion of self-reported data, to establish cause and effect.
“Associations among Dietary Zinc Intake, Serum Zinc Level and Multiple Comorbidities in Older Adults”
by Sirasa Ruangritchanku, Chutima Sumananusorn, Jintana Sirivarasai, Wutarak Monsuwan and Piyamitr Sritara