Men over the age of 70 are more likely to be zinc deficient and have inadequate dietary intakes of Zinc. According to the Australian Bureau of Statistics, 66% of males over the age of 70 do not meet the Estimated Average Requirement (EAR) for dietary zinc intake. In addition, an Australian study also found that 30% of men over the age of 70 had clinical zinc deficiency as measured by blood test. Zinc plays an essential role in immune function as well as many other important biochemical functions in the body.
The general causes of zinc deficiency include inadequate intake in the diet (e.g. plant-based diets), increased requirements (e.g. during active infection), conditions that impair gut absorption (e.g. coeliac disease), increased losses (e.g. from diarrhoea) and impaired utilisation of zinc in the body (as occurs during active infection).
It is important to note that inadequate dietary intake of absorbable zinc is the primary cause of zinc deficiency in most situations.
Various dietary factors can influence zinc absorption. Phytic acid (inositol hexa- and penta-phosphate) is the principal dietary factor known to limit zinc bio-availability by strongly binding zinc in the gastrointestinal tract. Phytic acid is the major phosphorus storage compound in plant seeds especially cereals and legumes. While some dietary compounds can decrease absorption, others can help improve zinc absorption.
Ingestion of protein for example can have a positive influence on zinc absorption. Consumption of animal proteins (e.g., beef, eggs and cheese) improve the bioavailability of zinc from plant food sources possibly because amino acids released from the animal protein improve the absorption characteristics of zinc; or the protein binds phytate, preventing it from interfering with zinc absorption.
1. Australian Health Survey: Usual Nutrient Intakes, 2011-12 financial year [Internet]. Australian Bureau of Statistics. 2021 [cited 17 May 2021]. Available from: https://www.abs.gov.au/statistics/
2. Beckett J, Ball M. Zinc status of northern Tasmanian adults. Journal of Nutritional Science [Internet]. 2015;4. Available from: https://www.ncbi.nlm.nih.gov/
3. Roohani N. 2013. Zinc and its importance for human health - an integrative review. Journal of Research in Medical Sciences. Available from: https://www.ncbi.nlm.nih.gov/