Fueling a Healthy Immune System in the Era of COVID-19

The other day I had the privilege of interviewing Pamela Riggs, MS, RDN, CSOWM at MarinHealth about foods people should be eating in an effort to boost their immune systems.

Rick: We all know that our immune system helps to fight off viruses, but can people actually eat their way to better immunity?

Pamela: Our immune system is a complex team of various organs, tissues and immune cells constantly working to protect us from infection, injury and disease. And during the era of COVID-19 our “team” is working harder than ever to keep us healthy and safe. In fact, as a Registered Dietitian Nutritionist at MarinHealth, I’m frequently asked if eating a healthier diet matters and, if so, what should we be eating to boost our intake of immune supporting nutrients.

The short answer is, yes, a healthier diet does matter! To start, certain nutrients can protect our immune cells from the burst of free radicals (unstable molecules that come from the fight against a virus or bacteria). Although these free radicals damage and kill invaders, prolonged exposure to them can damage our healthy cells too. Consuming a diet rich in antioxidant nutrients such as vitamin C, vitamin E, iron, zinc, copper and selenium protect immune cells by keeping free radical damage in check.

Rick: Are there other ways a nutrient rich diet helps protect us?

Pamela: A healthy diet also provides our immune system with the energy, building blocks and cofactors (assistants) it needs when it senses a foreign invader and needs to ramp up production of cells, chemicals and proteins to carry out its functions. Lean sources of dietary protein, vitamins A, D, folate, B12, B6 and minerals iron and zinc provide those building blocks and cofactors needed to mount an effective immune response.

What we eat can also influence inflammation, another way our immune system responds to a foreign invader threat. It isolates the injury and infected area and delivers immune cells, chemical messengers and antibodies to sites of injury and infection. But inappropriate activation, prolonged inflammation or the inability to turn off inflammation can lead to tissue damage and chronic disease. Omega 3 fatty acids (EPA and DHA) found in fish and fish oil have anti-inflammatory properties that can help keep inflammation in check.

Rick: So, to get the immune supporting nutrients we need, what kinds of foods should we be eating?

Pamela: To make sure you’re fueling your immune system with the nutrients it needs most, choose foods from this list:

Immune Supporting Nutrients Good Food Sources

Protein: Seafood, poultry, eggs, beans, nuts, soy, seeds

Vitamin A: Eggs, carrots, sweet potatoes, apricots, spinach

Vitamin C: Sweet red bell pepper, kiwi, strawberries, oranges

Vitamin D: Pink salmon, sardines, fortified milk, supplements

Vitamin E: Almonds, sunflower seeds or oil, peanut butter

Folate: Lentils, spinach, enriched whole grain bread

B 12: Clams, mackerel, beef

B 6: Salmon, turkey, potato with skin

Zinc: Oysters, beef, yogurt, beans, nuts

Iron: Beef, tuna, lentils, iron fortified cereal

Copper: Oysters, cashew nuts, lentils

Selenium: Brazil nuts, tuna, pork, whole wheat bread

EPA/DHA: Wild salmon, sardines, herring, supplements

Rick: Great suggestions. Is there anything we shouldn’t be eating?

Pamela: Rick, you’ve asked a good question. As much as I like to keep focused on the positive things we can do, it’s probably a good time for a little reminder about what foods to avoid or at least limit. Foods high in saturated fat (e.g. full fat milk dairy, bacon, sausage, butter, pastries, fatty cuts of meat) and refined carbohydrates and simple sugars (e.g. soda, cookies, cake, candy, white bread) tend to promote inflammation in the body. As mentioned earlier, prolonged inflammation or the inability to turn off inflammation can lead to tissue damage and chronic disease. Foods high in sugar also raise our insulin levels, promoting body fat storage and weight gain. Obesity and being overweight don’t help if you’re worried about COVID-19. Studies have found an increased risk of serious illness among those infected with COVID-19. In a recent study published in Obesity Research & Clinical Practice, researchers found that obese patients affected by COVID-19 had longer hospital stays, required more intensive and prolonged oxygen treatment and had higher markers of inflammation than non-obese patients.

Rick: Any final thoughts or advice?

Pamela: Let’s do all we can do to be well and stay well. Wear a mask, social distance, wash your hands, don’t touch your face, get regular exercise, watch your portions, and fuel your body with a diet rich in immune supporting nutrients.