This post was written by Megan Bragiel RD, LDN, clinical dietitian, Parkview Health.
Our immune system is a network of pathways that help to protect our body against harmful microbes, diseases, bacteria, parasites and viruses. There are two main parts of the immune system. The first is the innate immune system that we are born with, which creates a physical and chemical barrier to protect the body from harmful invaders. Examples include the skin, mucous membranes, stomach acid, enzymes that make antibacterial compounds and the blood-brain barrier. The second is the acquired, or adaptive, immune system. It develops when exposed to invaders. It helps your body create antibodies to fight off those invaders. It also changes and adapts throughout our life to protect us from harmful diseases. Then, if the invaders strike again, the acquired immune system will remember the foreign substance and fight it off quicker.
Furthermore, many factors can affect your immune system, including exercise, sleep, stress levels, alcohol consumption, and weight, but I want to focus on diet and nutrition. So, let’s take a closer look at the role they play in supporting the function of your body’s immune system.
Balancing your gut and your plate
A balanced diet helps your cells and organs function while keeping your body healthy. The gut is a significant site for antimicrobial production and immune response. What you eat can influence your gut's microbiome, determining what microbes live in your intestines. Your body and immune system require micronutrients (vitamins and minerals) to function fully. For this reason, a healthy diet rich in fruits, vegetables, whole grains, legumes, protein, dairy and water are essential. Building a healthy plate at every meal can be a great place to start. Try choosing water or milk as your beverage, then focus on filling half of your plate with vegetables and fruits, add in protein, whole grains and healthy fat. Remember, processed, high-fat and sugary foods or beverages should be limited and only consumed in moderation.
Maximizing your micronutrients
Your diet must include several vital micronutrients for your immune cells to grow and function properly. Six essential micronutrients to boost your immune function include:
- Iron. It allows cells to mature and proliferate. Sources of iron can include red meat, leafy greens, beans, nuts and fortified cereals.
- Vitamin C. This helps stimulate the formation of antibodies as well as the production and function of white blood cells. Sources of vitamin C include oranges, kiwi, strawberries, grapefruit, tomatoes, broccoli and bell peppers.
- Vitamin A. This nutrient helps protect against infections and is an anti-inflammatory vitamin that enhances immune function. Sources of vitamin A include leafy green vegetables, tomatoes, cantaloupe, milk, eggs and fish oils.
- Vitamin D. It regulates antimicrobial proteins that help kill pathogens in your body. Sources of vitamin D can include fortified dairy, salmon, egg yolks, tuna fish and beef liver.
- Vitamin E. This is an antioxidant and helps protect the integrity of the cell membrane preventing damage from free radicals. Sources of vitamin E include wheat germ, sunflower seeds, peanut butter, pumpkin, bell pepper and leafy greens.
- Zinc. This micronutrient helps support immune response and is vital for wound healing. Sources of zinc include milk, nuts, meats, seeds, whole grains and poultry.
Additionally, a plant-rich diet high in fiber and containing pre- and probiotics can help support the growth of microbes, increasing immune cell activity and assisting your body in fighting infections. Some prebiotic foods that help maintain healthy bacteria include bananas, asparagus, onions, barley, garlic, artichokes, oats and apples. Probiotic foods that contain beneficial live bacteria that help improve digestive health include yogurt, kefir, kombucha tea, buttermilk, and fermented vegetables such as tempeh, kimchi and sauerkraut.
Strive for variety
Diets low in variety can negatively affect a person's immune system and cause nutrient deficiencies. It can be particularly challenging for some people to acquire nutrient-dense foods, especially those with increased nutrient needs. For example, groups at risk of developing nutrient deficiencies can include food insecure homes, individuals with restrictive diets, the elderly, critically ill patients, pregnant and lactating women, infants, and children. In most cases, these populations can supplement with a vitamin and mineral regimen to help fill any nutritional gaps and deficiencies. However, you should consult a health care provider before adding new supplements to your routine.
Our immune system functions best with a balanced diet that includes a range of vitamins and minerals. Not one single food or nutrient will prevent illness but incorporating a variety into a balanced diet each day will help boost your body’s immune function and its ability to fight off infections.