It’s time to Fuel Up and start eating for immunity.
With flu season approaching and the coronavirus epidemic still very much a threat, a healthy immune system is one of the most important defenses we have to stay resilient and strong.
Our body’s immune response depends on a complex series of steps aimed at identifying, attacking and eliminating substances that invade our bodies and threaten our health. The overall immune system involves different cell types that work together to defend the body. We have innate immunity, which is the hand of the immune system that acts quickly to fight off threats but does not have the ability to specify those targets. The other hand of the system is our adaptive immunity, which takes longer to develop, but does act on specific targets and potential threats. Our adaptive immunity also has the ability to remember previous threats and act accordingly.
It’s no secret that improving lifestyle habits around exercise, sleep and nutrition can result in a host of health benefits, one of those being immune protection. Nutrient status correlates with immune status, and it is important to note that overnutrition and undernutrition can equally impair immune response and function. Overnutrition, or the consumption of excessive amounts of some nutrients, may especially inhibit our body’s immune response when paired with an inactive lifestyle. Undernutrition, or inadequate consumption of some nutrients, can be a result of too few calories or not enough intake of the vitamins and minerals we can obtain through food. It’s important to fuel our immune systems with adequate energy in the form of calories, while strategically including certain micronutrients, to be armed and ready for attack against illness.
Here are some immunity-boosting vitamins and nutrients than can help keep you healthy this flu season:
• Vitamin A is a fat-soluble vitamin that enhances immune function by helping to regulate the overall immune response. Vitamin A’s precursor, beta carotene, is a powerful antioxidant and phytonutrient. You can find vitamin A in carrots, sweet potato, butternut squash, pumpkin, spinach, apricots and dried herbs.
• Vitamin D is another fatsoluble vitamin that plays a role in both the innate and adaptive immune responses. Through sunlight, cholesterol in our bodies is converted to vitamin D. Midday sunlight exposure for 10-30 minutes several times a week can boost vitamin D levels, but this may not be possible for individuals in self-quarantine. In research studies, low vitamin D intake has repeatedly been associated with increased risk of respiratory tract infection and common cold. Look for vitamin D in mushrooms and oil-rich fish such as salmon, trout and mackerel. Because there is not a huge selection of food sources high in vitamin D, many products, such as cereal, juice and milk, have vitamin D added, or fortified. When grocery shopping, look for food labels that clearly say “fortified with vitamin D”.
• Zinc is an element that cannot be produced or stored by the body; therefore, we must get zinc through food. Zinc plays an important role in growth, development and immune maintenance. As with other nutrients, zinc deficiency is associated with increased susceptibility to disease and infection. Foods high in zinc include lean beef, lean lamb, cooked oysters, tahini, legumes, dairy foods and natural cocoa powder.
• Selenium is also a trace element that boasts a wide variety of antioxidant and antiinflammatory effects. Inadequate selenium levels lead to a greater risk for poor immune function and cognitive decline. Lentils, Brazilian nuts, spinach and most proteins such as beef, chicken, turkey, fish and eggs are all high in selenium.
• Omega-3 fatty acids are anti-inflammatory powerhouses that exert favorable health benefits on a number of biological processes, including improved immune status, enhanced cognition and optimized neuromuscular function. EPA and DHA are the most studied omega-3 fatty acids, which can be found in oily fish, such as salmon.
• Phytonutrients are foods with strong antioxidant and anti-inflammatory properties. The unique pigment that comes with a particular fruit or vegetable signifies different phytonutrient powers. All phytonutrients are equally important and work together to provide maximum health benefit, which is why it is crucial to consume a variety of fruits and vegetables every day. Phytonutrients can also be found in herbs, spices, onions, garlic, red wine and natural cocoa.
To set your immune system up to be strong and resilient, it is recommended to regularly consume a variety of the foods listed into your diet to achieve better immunity. A great starting point is to incorporate one of these foods into each meal. Try to get nutrients through food before turning to pills and powders. Scientific evidence suggests that the health benefits of fruits and vegetables are because of the interactions of phytonutrients working together to target potential physiologic threats — this can’t be replicated by supplements.
The role diet plays in promoting a strong immune system begins before you get sick — eat for immunity to prevent illness and infection this fall.
Emma Willingham is a registered dietitian who practices in an outpatient hospital clinic and through her private practice, Fuel with Emma. Willingham specializes in sports-performance nutrition, weight management and nutrition counseling, and aims to promote a resilient relationship between food, mind and body.