We’ve covered a variety of vitamins and minerals in our “Nutrient in the Spotlight” series, including vitamin C, thiamin, iron, vitamin E, and choline. Next up is zinc, a mineral needed by more than 200 different enzymes in the body.
Why do we need zinc?
Zinc is essential in the production of DNA and the reproduction of cells; our bodies wouldn’t get far without it. The wound healing process and the immune system also need zinc to function.
How much do we need?
Adult males need around 11 milligrams per day, while females need 8 daily. Needs for women do increase during pregnancy and breastfeeding.
Are deficiencies common?
Zinc deficiency is not common in the United States, but wherever malnutrition is common it can occur. Certain groups are more vulnerable to zinc deficiency, including those who have had bariatric surgery, women who breastfeed past six months, and those who follow a vegan diet.
Inadequate zinc during childhood can severely stunt growth, and a zinc deficiency during pregnancy is likely to cause birth defects. Other symptoms of this condition include hair loss, losing senses of smell and taste, diarrhea, and reduced immunity.
It is possible to consume an excessive amount of zinc, which leads to diarrhea, nausea, headaches, and eventually heart problems. Eating a very large amount of beef on a daily basis (about 12-16 ounces) or eating oysters regularly can put you over the recommended upper limit of 40 milligrams per day. Although this is excessive for most, the rise of “carnivore” diets has raised the likelihood of zinc toxicity in certain individuals.
Which foods contain zinc?
Most foods contain at least trace amounts of zinc, but here are the best sources:
Ground beef (3 ounces): 5.6 mg
Crab (3 ounces): 3.2 mg
Wheat bran (1/2 cup): 2.1 mg
Pork loin (3 ounces): 1.8 mg
Sunflower seeds (1 ounce): 1.5 mg
Milk (1 cup): 1.0 mg
Almonds (1 ounce): 0.9 mg
Kidney beans (1/2 cup): 0.8 mg
Peanut butter (2 Tablespoons): 0.8 mg
As mentioned earlier, oysters contain an exceptionally high amount of zinc. Six oysters provide approximately 75 milligrams of zinc, almost double the recommended daily upper limit. Eating oysters on occasion is unlikely to be a problem, but daily consumption could lead to the health complications listed above.