As can be seen on the bottom map in the link below, the risk of zinc deficiency is low in North America, but there are other places in the world where it is much more common.

Figure 12.821 Worldwide prevalence of zinc deficiency¹

At particular risk are children, pregnant women, elderly and the poor1. Symptoms of zinc deficiency include^2,3:

Growth inhibition
Delayed sexual maturation
Dermatitis
Hair loss
Impaired immune function
Skeletal abnormalities

In the link below you can see a picture of an infant with dermatitis caused by zinc deficiency.

Another cause of zinc deficiency is mutation of ZIP4 that results in the condition acrodermatitis enteropathica. Without ZIP4, zinc cannot be taken up efficiently into the enterocyte. This condition is managed by administering very high levels of zinc, some of which is absorbed through other mechanisms³.

Zinc toxicity is not common, but an acute toxicity results in²:

Nausea

Vomiting
Intestinal cramps

Diarrhea

Chronic toxicity can result in copper deficiency, as will be discussed in the copper section³.

References & Links

1. Wessells KR, Brown KH. (2012) Estimating the Global Prevalence of Zinc Deficiency: Results Based on Zinc Availability in National Food Supplies and the Prevalence of Stunting. PLoS ONE 7(11): e50568

2. Byrd-Bredbenner C, Moe G, Beshgetoor D, Berning J. (2009) Wardlaw’s perspectives in nutrition. New York, NY: McGraw-Hill.

3. Gropper SS, Smith JL, Groff JL. (2008) Advanced nutrition and human metabolism. Belmont, CA: Wadsworth Publishing.

Links

Zinc Deficiency – http://www.izincg.org/publications/deficiency

Zinc Deficiency Dermatitis – http://img.tfd.com/mosbycam/thumbs/50029X-fx3.jpg