17 whole foods packed with zinc to help boost your immune system naturally

• Zinc is a mineral that's important for many functions including maintaining a strong immune system.
• There are plenty of ways to get enough zinc in your diet, even if you're vegan or vegetarian.
• Oysters, king crab, pumpkin seeds, and cashews are some of the richest sources of zinc.

Zinc is one of the most abundant trace elements in the human body, playing an important role in immune function, wound healing, your sense of taste and smell, and the production of key proteins and DNA.

Because the body can't store it in significant amounts, it's important to get enough zinc in your diet. ​​And that's sometimes harder said than done as an estimated 17% of the global population - and 40% of the elderly - is at risk for a zinc deficiency.

Important: The daily recommended dietary allowance (RDA) for zinc is 11 milligrams for adult men, and 8 milligrams for adult women. This requirement increases to 11 milligrams in pregnant women, and 12 milligrams in lactating women.

It's best to get this mineral through your diet rather than a supplement, says Jonathan Clinthorne, PhD, a nutritional scientist and Director of Nutrition at Atkins.

With supplements, it's easier to consume too much zinc, which can cause problems like a copper deficiency, high cholesterol, and impaired immune function. With that in mind, below are some of the richest food sources of zinc.

1. Eggs

One large hard-boiled egg contains 0.53 milligrams of zinc (4.8% RDA for men, 6.6% RDA for women).

Eggs are a complete protein, meaning they provide all nine essential amino acids - none of which your body can produce on its own, so you have to get them through food.

Eggs get a bad rap for being high in cholesterol, but the vast majority of cholesterol is produced in the body, and research has shown that limiting dietary cholesterol doesn't necessarily lower levels of the "bad" artery-clogging LDL cholesterol in the blood.

So, as long as you aren't serving them up with bacon and butter-loaded toast, eggs are a healthy food packed with high-quality protein and important minerals. That said, experts recommend limiting egg consumption to seven per week.

2. Regular and sweet potatoes

One medium-sized russet potato contains 0.61 milligrams of zinc (5.5% RDA for men, 7.6% RDA for women). Sweet potatoes have slightly less than regular potatoes: 0.37 milligrams (3.4% RDA for men, 4.6% RDA for women).

Rather than topping your potato with sour cream, butter, and bacon bits - all of which are high in saturated fat - opt for healthy alternatives like avocado, broccoli and feta cheese, three-bean vegetarian chili, or pesto and sundried tomatoes. Black beans, salsa, and nonfat plain Greek yogurt is another high-fiber, low-fat option.

3. Sesame seeds

One tablespoon of sesame seeds contains 0.7 milligrams of zinc (6.4% RDA for men, 8.8% RDA for women).

Sesame seeds are also a source of manganese and calcium, with 0.22 milligrams (9.6% RDA for men, 12.2% RDA for women) and 87.8 milligrams (8.8% RDA), respectively.

Manganese helps the body metabolize fats and carbohydrates and plays a role in blood sugar regulation. It also helps your body absorb calcium, which is essential for building and maintaining strong, healthy bones, and ensuring your heart, muscles, and nerves are working properly.

4. Mozzarella or cheddar cheese

A 1-ounce serving of part-skim mozzarella cheese contains 0.78 milligrams of zinc (7.1% RDA for men, 9.8% RDA for women).

The same serving size of low-fat cheddar contains 0.52 milligrams of zinc (4.7% RDA for men, 6.5% RDA for women).

Dairy products, including cheese, are generally a good source of calcium, but to absorb calcium effectively, your body needs vitamin D. So try pairing your cheese with foods high in vitamin D - like salmon, tuna, fortified cereals and yogurts, beef liver, and egg yolks.

5. Hemp seeds

One tablespoon of hemp seeds contains 1 milligram of zinc (9% RDA for men, 12.5% RDA for women).

Hemp seeds add a nutty taste and subtle crunch to salads, grain bowls, smoothie bowls, oatmeal, and yogurt. You can also cook with hemp seed oil, which contains all the essential amino acids, is high in many minerals including phosphorus, sulfur, and potassium, and is rich in heart-healthy fatty acids.

6. Yogurt

A 7-ounce portion of plain low-fat Greek yogurt contains 1.2 milligrams of zinc (10.9% RDA for men, 15% RDA for women).

Yogurt is chock full of probiotics - live, gut-friendly bacteria that help to support a healthy digestive system and immune system.

As most flavored yogurts contain added sugar, it's best to stick to plain yogurt and add your own sweetness with fresh or frozen fruit, or a small drizzle of honey.

Note: Greek yogurt tends to be higher in protein and contains probiotics. Look for yogurts that say "live and active cultures" on the label.

7. Chickpeas

A ½ cup serving of cooked chickpeas contains 1.26 milligrams of zinc (11.4% RDA for men, 15.7% RDA for women).

Chickpeas can be added to salads, wraps, soups, and pasta, or smashed into a hummus dip for pita chips or crudités.

However, it's important to note that while they're an excellent source of fiber, with 6.25 grams per serving (16.4% RDA for men, 25% RDA for women), chickpeas also contain a complex sugar called raffinose, which can cause gas because it isn't easily digested.

8. Lentils

A ½ cup serving of cooked lentils contains 1.26 milligrams of zinc (11.4% RDA for men, 15.7% RDA for women).

Not only are lentils low in fat and high in satiating protein and fiber, but they also provide 179 micrograms of folate per serving (44.8% RDA). This B vitamin plays a major role in immune function and nerve health and also helps your body draw energy from food.

Folate also helps lower the risk of neural tube defects in a pregnant woman's unborn baby.

Quick tip: Try soaking dry chickpeas and lentils for a few hours before cooking them, says Andres Ayesta, MS, a registered dietitian and founder of Planos Nutrition. Many seeds, grains, legumes, and nuts contain phytic acid - a compound that binds with some minerals (including zinc) and thus blocks your body from absorbing them. Soaking these foods reduces the phytic acid content so you can absorb more zinc from your meal.

9. Cashews

A 1-ounce serving of dry roasted cashews contains 1.59 milligrams of zinc (14.5% RDA for men, 19.9% RDA for women).

Pecans, Brazil nuts, and almonds are other nuts that are good sources of zinc.

Moreover, nuts, in general, can boost your heart health by reducing inflammation and LDL cholesterol levels.

10. Chicken (dark meat)

A 3-ounce serving of dark meat chicken contains 1.99 milligrams of zinc (18% RDA for men, 24.9% RDA for women).

While dark meat chicken has a few more calories and marginally higher saturated fat than white meat, it also offers twice the amount of healthy unsaturated fat, which can help your body absorb vitamins and minerals (like zinc) more effectively.

You can also make your meal a tad healthier by removing the skin, which is high in saturated fat.

11. Squash and pumpkin seeds

A 1-ounce serving of dried pumpkin seeds contains 2.21 milligrams of zinc (20% RDA for men, 27.6% RDA for women).

Pumpkin is just one type of squash - other squash seeds from butternut squash, acorn squash, and spaghetti squash offer a comparable amount of zinc.

Note: Sprouted squash seeds come with a higher risk of foodborne illness from bacteria such as Salmonella or E. coli.

12. Pork

A 3-ounce serving of bone-in cooked pork chop contains 2.64 milligrams of zinc (24% RDA for men, 33% RDA for women).

It's worth noting that pork is considered red meat, so it can contain large amounts of saturated fat. You should limit your consumption to a maximum of two servings (or 6 ounces) of red meat per week - or half that if you have heart disease or high cholesterol.

Also, keep in mind that not all cuts are created equal when it comes to fat content - pork tenderloin is the leanest cut of pork. Other low-fat options are boneless loin roast, and boneless extra-lean ham, which all have less than 6 grams of fat.

13. Lobster

A 3-ounce serving of lobster contains 3.44 milligrams of zinc (31% RDA for men, 43% RDA for women).

Lobster also contains 62 micrograms of selenium per serving. This trace mineral has many health benefits, such as assisting with DNA and thyroid hormone production, preventing cell damage, and protecting you from infections.

14. Lamb

A 3-ounce serving of cooked lamb contains 3.97 milligrams of zinc (36% RDA for men, 49.6% RDA for women).

Not only is lamb high in protein, but it's also a good source of vitamin B12, with 2.22 micrograms per serving (92.5% RDA).

Vitamin B12 is a versatile nutrient that supports brain function, helps form red blood cells, facilitates hair and nail growth, and may also prevent birth defects.

Note: Lamb is considered a red meat and therefore should be limited to two servings per week, or half that for people with heart disease or high cholesterol.

15. Ground beef

A single 3-ounce beef patty contains 5.31 milligrams of zinc (48.3% RDA for men, 66.4% RDA for women).

Beef is also a good source of iron, with 2.48 milligrams per serving (28.5% RDA for men, 16.8% RDA for women). Iron helps to make the red blood cells that transport oxygen throughout the body.

However, beef can also be high in saturated fat, which may increase your "bad" cholesterol levels and thus elevate your risk of heart disease. For this reason, it's best to opt for cuts that are at least 90% lean, and to include this in your weekly red meat consumption, which ought to be limited to no more than 6 ounces per week

16. Alaskan king crab

A 3-ounce serving of Alaskan king crab contains 6.48 milligrams of zinc (59% RDA for men, 81% RDA for women).

King crab is also a source of omega-3 fatty acids, which may help keep your heart healthy by lowering blood pressure and enhancing blood vessel function. This family of fats may help protect against certain autoimmune diseases or benefit those with autoimmune disorders. There is some research that omega 3s lower the risk of certain cancers, however, more studies are needed.

17. Oysters

Two raw oysters contain 11 milligrams of zinc (100% RDA for men, 137.5% RDA for women).

While oysters are one of the best food sources of zinc, pregnant women should avoid eating them raw. Raw foods, like shellfish, are more likely to cause foodborne illnesses like Toxoplasma gondii, which may lead to premature birth or miscarriage.

Note: Vibriosis is a foodborne illness caused by eating raw or undercooked shellfish, and each year, approximately 80,000 people get it and 100 people die from it.

Insider's takeaway

"Zinc is found in many foods, so there isn't usually a need for supplementation if you have a varied diet that's based on whole foods," says Ayesta.

Keep in mind that the zinc in animal products is more easily absorbed by the body than the zinc from plant foods. Your body also tends to absorb more zinc when it's consumed alongside protein.

Finally, be careful not to consistently exceed the upper limit of 40 milligrams per day, says Clinthorne, as excessive zinc intake can cause a copper deficiency and other issues.