Zinc

• Zinc is a mineral that promotes immunity, resistance to infection, and proper growth and development of the nervous system3, and is integral to healthy pregnancy outcomes.
• It is also essential for the function and activity of over 200 body metalloenzymes.
• Zinc has important effects on metabolism, and on the thermoregulation (regulation of the body temerature) of obese individuals.
• 17.3% of the global population is at risk for zinc deficiency due to dietary inadequacy, though up to 30% of people are at risk in some regions of the world.
• Zinc supplementation reduces the incidence of premature birth, decreases childhood diarrhea and respiratory infections, lowers all-cause mortality, and increases growth and weight gain among infants and young children.

A relationship between zinc and obesity was first found in obese patients and obese mice (genetically and dietary obese) to that the obese had lower blood zinc levels than their lean controls, and the zinc level was inversely related to the degree of obesity.

The association of zinc with obesity and body composition is not consistent.

In obese Chilean children, for example, no association was found between zinc status and body composition. In adults living in urban India, low concentrations of zinc were associated with higher abdominal fat.

A negative association was found between zinc and leptin concentrations in women with obesity, with a body fat content of 36-40% and high waist circumference. This association could be explained by the effect of zinc-alpha2-glycoprotein (ZAG) on leptin concentrations. ZAG is an adipokine involved in the metabolism of lipids in the adipocyte that is down-regulated in obesity, probably due to the inflammation process associated with obesity.

In obese individuals, low ZAG gene expression is associated with low serum adiponectin and high plasma leptin levels, and may play an important role in the development of obesity.

The influence zinc has on the adipocyte through the expression of leptin, by promoting free fatty acid release and glucose uptake, may also be controlled through the expression of a number of zinc-transporters in the adipocyte, that may be altered in obesity.