By David Grotto, RDN, LDN
Sniff…just sent my kids off to school. Two of my girls are in high school and the other is heading back to college. All three have enjoyed reasonably good health this summer, but I know sniffles (and not the kind brought on from emotions) won’t be too far off as they will be in close quarters with germ-spreading classmates. But, hey, what are a few germs amongst friends?
To lessen the impact of the germ-sharing, I try to make sure that my daughters get at least 8 hours of sleep, are engaged in regular physical activity, and eat foods that support their immune system. One of the key immune-boosting nutrients, that kids often have a hard time getting adequate levels of, is zinc.
The importance of zinc for human health was first written about back in 1963 where it was found that zinc promotes wound healing and bolsters the immune system - vital in warding off invading bacteria and viruses. So how much zinc does one need and where can you find zinc in the diet? The daily RDA for zinc is 11 mg for men and 8 mg for women. Most multivitamins contain zinc and you can also find zinc in lozenge or syrup form, which may reduce the duration and severity of the common cold, if taken within 24 hours of onset of symptoms. The upper limit for zinc is 40 mg and exceeding that amount may cause nausea/vomiting, low appetite, diarrhea, and headache.
Zinc can be found in a balanced diet; however, plant based diets make it difficult to achieve adequate levels as the best sources tend to be found in animal protein. Whole grains are terrific for your health, but the phytate content of whole grains can reduce the bioavailability of zinc, which may be more of a concern for vegetarians. Zinc can also be found more abundantly in fortified cereals, baked beans, ricotta cheese and wheat germ. Some of the best dietary sources of zinc:
Oysters: A 3-ounce portion provides 33 mg of zinc along with a hefty dose of iron, B-12 and phosphorus.
Beef: A 3-ounce portion provides 9mg of zinc. Choosing lean sources that contain less than 5 grams of fat per 3 oz serving,
Alaskan King Crab: In 3 ounces, crab supplies 6.75mg of zinc plus lean protein along with vitamin B12, copper, and selenium. Don’t be fooled by imitation crab though, which has less of these nutrients and is made up mostly of artificially flavored Pollock fish!
Lamb: A 3-ounce portion supplies 6.2 mg of zinc. The average American eats less than a pound of lamb a year – usually just for holiday dinners! Lamb is a good source of zinc while providing iron, vitamin B12, and selenium. Like other animal protein, it’s best to choose leaner varieties.
Turkey (dark meat): A 3-ounce portion supplies 5 mg of zinc. Turkey is a good source of iron, riboflavin, thiamine, vitamin B6, and B12 but the dark meat has a slightly higher concentration of these micronutrients and a bit more fat. Studies have suggested that eating zinc-rich foods like turkey may lower the risk of childhood asthma in pregnant women.
Pork: A 3-ounce portion supplies nearly 4mg of zinc. Lean pork is also an excellent source of protein, selenium, niacin and vitamin B-12 and a good source of vitamin B-6. A Danish study found that young women who consumed a diet that included lean pork had higher blood zinc levels than women who ate a vegetarian diet.
Lobster: A 3-ounce serving provides 3.44 mg of zinc. Lobster is also an excellent source of the minerals copper and vanadium as well as protein.