Zinc is one of the most common nutrient deficiencies, but also one of the least talked about. Most of us roll our eyes at the thought of someone being deficient of a nutrient, especially in developed countries. However, in the US nutrient experts estimate that about 12 percent of the population is at risk for deficiency, and up to 40 percent of the elderly (1).
The primary reasons are due to eating less foods that contain zinc and inadequate absorption of zinc. Our bodies also lack a specialized zinc storage system that is needed to maintain a steady state (2). Part of the issue also lies in the challenge of testing for zinc status (3), although serum zinc appears to be the gold standard test. Individual needs also highly vary depending on health status and disease states. Infections, intense physical activity, stress, malabsorption due diarrhea or IBS/IBD, genetic defects in zinc transporters, too little animal protein intake, too high of fiber and phytate intake (mostly grains) and even type 2 diabetes and insulin resistance can all influence the our body's demand of zinc (4-6). Getting sufficient amounts of zinc largely depends on the consumption of meats such as beef, poultry, and in even higher levels oysters. In fact strictly following a vegan and vegetarian diet can put someone at high risk for zinc deficiency (7).
Zinc does so many things in the body on a macro and micro level. Zinc literally helps hold DNA together (zinc fingers) and even a minor deficiency can lead to damage. Zinc supports cell function, and is a cofactor for 300 enzymes that are essential for (8):
helping cells divide and grow
maintaining the sense of smell and taste
promoting wound healing
testosterone production and hormone balance
appetite, hunger and glucose regulation
Zinc Deficiency Symptoms
Frequent symptoms of the common cold
Delayed wound healing
A weak immune system
Predisposition to infections
A skin rash, especially around the mouth
Vision problems due to an increased risk of age-related macular degeneration
Abnormal taste and/or smell sensation
A predisposition to frequent asthma exacerbations
Zinc in Infection and Inflammation
Zinc primarily plays a crucial role in the normal development of immune cells and their functions (9):
natural killer cells
Without adequate zinc we lose both some first line immune defense mechanisms as well as our ability to make antibodies and mount specific targeted attacks against infectious invaders that we encounter again.
Zinc is also required by bacteria that invade our bodies and during an infection our body actually begins to sequester zinc away from microbes (10). Zinc deficiency weakens innate and adaptive responses. And adding chronic diseases and chronic inflammation to the equation literally allows pathogens to launch a potent attack with little defense (9).
Zinc supplementation has been shown to have a positive benefit on many infectious diseases. Some of the best outcomes have shown an 18% reduction in diarrhea and duration of diarrhea (15%), 41% reduction in pneumonia as well as a decrease in individuals catching malaria. It was also found that mothers who supplemented with zinc reduced infections in their babies, and some studies even have shown a reduction in child mortality by 50%. Other studies have investigated the common cold, HIV and tuberculosis as well but more research is needed to come to a solid recommendation with zinc (11).
To ensure adequate levels are reached on a regular basis most should at least take a multivitamin to reach minimum RDA levels with levels for woman at 8 mg and levels for men at 11 mg. These levels ensure deficiency is avoided, but may be insufficient depending on disease processes, genetics, quality of diet, stress, activity levels, medications, and overall health status.