The human body needs zinc to function properly but its required levels of the mineral are quite low and chronic (“clinical”). Zinc deficiency is rare in both humans and animals. Due to this a pair of researchers at the Technical University of Munich were unsatisfied with the current state of zinc deficiency research. Observing that most studies only compared clinical zinc deficiency with normal intake in animals, they sought to see if any impact could be seen from less severe (“subclinical”) reductions. What they found is that even if normal symptoms of zinc deficiency aren’t present, lesser reductions of the mineral can cause a slowing effect on the pancreas and digestion.
Observing that most studies only compared clinical zinc deficiency with normal intake in animals, they sought to see if any impact could be seen from less severe (“subclinical”) reductions.
What they found is that even if normal symptoms of zinc deficiency aren’t present, lesser reductions of the mineral can cause a slowing effect on the pancreas and digestion.
Munich Zinc Study: Summary
- The study subjects were 48 piglets that had recently been weaned and were all given and adequate zinc supply for two weeks prior to the start of the study
- The animals were divided into eight groups of six piglets each, with each group getting the same type of feed except for the zinc levels
- Over the eight day study period (enough to produce clinical deficiency symptoms), pancreas activity, blood zinc levels, liver activity, and food digestibility were monitored
- It was observed that even without showing symptoms of clinical deficiency, the piglets getting reduced zinc levels were experiencing impacts on their metabolism
- Specifically, the efficiency of zinc absorption was increasing but the pancreas was also releasing less zinc during digestion, and this was correlated with lower digestive enzymes being released
- Reduced digestibility was also observed, also before clinical deficiency symptoms appeared
What This Means
At the risk of oversimplification, these findings make sense. The body only needs a small amount of zinc, so even low levels of deficiency could produce noticeable effects. As zinc supplies dwindle, the body tries to absorb more and also tries to hold on to its current stores. The pancreas, which normally releases zinc during digestion, therefore doesn’t excrete as much zinc as normal and the release of other digestive enzymes is lowered as a result. This causes slower digestion and therefore less digestibility of feed.
It is worth keeping in mind that this is an animal study and one that was conducted by researchers in animal nutrition, so the findings (and significance of affecting digestibility in general) are more relevant to livestock than humans. Although pigs are similar to humans, they are still a different species so it is unclear whether subclinical zinc deficiencies would have the same type of effect on humans. Of specific note is that only pancreatic activity and digestibility were monitored during the study—any potential impact on nutrition, weight, bowel health, or any other health effects are outside the constraints of the study.
- Lesser forms of zinc deficiency may slow digestion and pancreatic excretions in pigs, but other than a possible avenue of research there is no translatable meaning in these findings for humans
- The above point is not a criticism of the study, simply an observation
Brugger, D., et. al., “Subclinical zinc deficiency impairs pancreatic digestive enzyme activitiy and digestive capacity of weaned piglets,” British Journal of Nutrition, 2016; http://orcid.org/0000-0001-7267-0335
“A diet lacking in zinc is detrimental to human and animal health,” Technical University of Munich web site, June 6, 2016; https://www.tum.de/en/about-tum/news/press-releases/short/article/33155/, last accessed June 10, 2016.