The new booster shot: 8 nutrients to boost your immunity

Our immune systems keep us healthy by fighting off pathogens—like bacteria and viruses—that often make us sick. But what about when you catch whatever your kid brought home from preschool? Or push yourself extra hard during training?

Consistent physical strain from tough workouts, a poor diet, and actually being sick all weaken your immune system. After an intense workout, like CrossFit, your body goes to work repairing muscle, activating your innate immune system.

Exercise-induced immunity strain results in the temporary suppression of the immune system, and is often the result of:

• Exercise-induced cortisol release
• Oxidative stress
• Inflammation
• Energy deficit

With regular training, we adapt to these stressors, helping us become more resilient to stress and creating a more robust immune system over time. But we need a diet rich in foods that support our immune systems to ensure optimal functioning.

We’ve rounded up foods rich in eight immunity-boosting nutrients that’ll support your immune system year-round.

1. Iron

An essential mineral, iron regulates both innate and adaptive immunity. It plays a vital role in the functioning of neutrophils—white blood cells that help fight off infection—and neutrophil extracellular traps (NETs) that also combat disease.

Because we don't produce iron naturally in our bodies, eating iron-rich foods is even more crucial. Here are some of our favorites:

• Lean red meat, turkey, and chicken
• Oysters
• White and kidney beans
• Lentils
• Spinach
• Cashews

 

2-5. Vitamins A, C, D, and E

Vitamins A, C, D, and E all play their part in your immune system and in keeping you healthy. Here's how:

• Vitamin A has antioxidant properties that can fight against free radicals that cause disease. It helps develop the immune system and aids in regulating cellular immune responses.
  
  
• Vitamin C also functions as an antioxidant and modulates the immune response. It supports cellular functions and the epithelial barrier function that fights pathogens.
  
  
• Vitamin D stimulates the production of pattern recognition receptors (PRR) that detect patterns of pathogens, antimicrobial peptides, and cytokines in your cells that regulate immune cell growth and activity.
  
  
• Vitamin E, another antioxidant, modulates immune function more effectively than most other nutrients. It also influences T cell function—white blood cells that combat germs and infections.

Multivitamins and supplements typically include vitamins A, C, D, and E. But if you want to get these nutrients through food, try:

• Spinach, kale, and other greens
• Beef
• Sweet potato and squash
• Tuna, salmon, and trout
• Citrus, like oranges and grapefruit
• Mango, watermelon, and papaya
• Vegetables, like broccoli and Brussels sprouts
• Seeds and nuts
• Milk and eggs

6. Selenium

Selenium contributes to both the innate and adaptive immune responses with selenoproteins that affect the activation, proliferation, and differentiation of immune cells.

Selenium is an immunoregulator that helps start immune responses, reduce oxidative stress, and prevent excessive responses that can cause chronic inflammation.

 

You can find selenium in:

• Seafood, like shrimp and sardines
• Ham, turkey, and chicken
• Cottage cheese
• Whole grains, like pasta, barley, quinoa, and bread
• Citrus, like oranges and grapefruit
• Mango, watermelon, and papaya
• Vegetables, like broccoli and Brussels sprouts
• Seeds and nuts
• Milk and eggs

 

7. Folate (Vitamin B9)

Folate regulates the production of antibodies and helps form healthy red blood cells. It also helps synthesize nucleic acids (DNA) that are required for proper cell division—an important mechanism for successful immune responses.

You can find folate across food groups, including wheat, vegetables, nuts, and beans:

• Fortified grains and cereals
• Wheat germ
• Spinach, lettuce, and asparagus
• Eggs
• Kidney beans and black-eyed peas
• Peanuts and sunflowers
• Rice, bread, and pasta
• Oranges, grapefruit, and bananas

8. Zinc

Zinc aids in cell development and function and acts as an antioxidant. It's also involved in cellular metabolism and helps with the enzyme catalytic activity necessary for immune function.

To get enough zinc in your diet, try adding these foods to your diet:

• Lean beef, lamb, turkey, and chicken
• Nuts, like peanuts and cashews
• Oysters, shrimp, and sardines
• Lentils and rice
• Milk and Greek yogurt
• Blueberries
• Cherry tomatoes

Nutrition and your immune system

Like most functions in our bodies, proper nutrition is also essential for a high-functioning immune system. You need to get enough of these eight nutrients to make sure your immune cells work properly—there's an inextricable link between the amount and type of nutrients and immune health.

 

When supported with proper nutrition, your immune system also destroys antigens through innate and adaptive immune cells. But when it's compromised because of nutritional deficiencies, your immune response may not function and you could lose your resistance to infection.

  

Let's eat!

No one wants to get sick. You feel like crap, likely have to skip your workouts, and don't have the energy to even leave the couch. So, don't get sick. It might not be completely unavoidable, but if you stay healthy throughout the year, you're less likely to get sick.

And the best way to do that is to always have a fully-stocked refrigerator of healthy foods that can support your immune system. Especially at the first sign of potential illness.