Nutrition is the cornerstone of health. Our body requires vitamins, minerals, and other nutrients to function optimally. Unfortunately, many of us have at least one nutritional deficiency. Even if we are exceptionally health conscious, our heavily-processed food supply and depleted soil make it difficult to obtain all the nutrients we need from diet alone.
Some of the most common deficiencies, such as vitamin D, play a pivotal role in immunity. Supporting a strong immune system remains a top focus for most, especially as cases of COVID-19 continue to rise across the country. In fact, you’ve probably seen the vitamins discussed here in recent news regarding COVID-19. Preventing deficiencies of these key vitamins and minerals can decrease our susceptibility to infection. Supplementation to boost amounts of these nutrients can help us fight infections and recover more quickly from illness. Let’s take a closer look at these critical nutrients, including their functions and benefits, food sources, and supplement options.
Vitamin A: Vitamin A has many critical functions in the body. It helps maintain vision, healthy teeth, skeletal and soft tissue, and skin. Among the micronutrients, vitamin A plays a central role in normal immune function. It has been well-known for its protective roles against infections. It helps to maintain the integrity of our mucus membranes and is also a part of our adaptive, or long-term, immune response.
Food sources: Vitamin A is only found in animal sources, but carotenoids, which convert to vitamin A in the body, are found in a variety of fruits and vegetables.
- Liver
- Fish
- Eggs
- Sweet potato
- Butternut squash
- Kale
- Carrot
- Cantaloupe
- Apricot
Supplements:
Vitamin C: Vitamin C, or ascorbic acid, is an essential micronutrient for humans. It’s necessary for the growth, development, and repair of all body tissues. It aids in the formation of collagen, enhances iron absorption, and is essential for wound healing. Vitamin C also plays a critical role in the functioning of our immune system. Vitamin C supports epithelial barrier functions against pathogens. As an antioxidant, it protects against environmental oxidative stress. Vitamin C is necessary for the immune system to mount and sustain an adequate response against pathogens and enhances microbial killing. A deficiency in vitamin C results in impaired immunity and higher susceptibility to infections. Supplementation with vitamin C appears to both prevent and treat respiratory and systemic infections.
Food Sources:
- Acerola cherries
- Rose hips
- Peppers
- Strawberries
- Orange
- Guava
- Kale
- Kiwi
- Broccoli
Supplements:
Vitamin D: Vitamin D receptors are located throughout the body, resulting in a variety of health benefits. Vitamin D supports healthy bones, regulates mood, and supports blood sugar levels and a healthy heart. One of vitamin D’s most important benefits is that on the immune system. It can modulate both the innate and adaptive immune response. A deficiency in Vitamin D has been associated with an increased susceptibility to infection, including upper respiratory infections. Vitamin D has made recent headlines in the news about COVID-19. Some research has shown that people with a deficiency in vitamin D were more likely to test positive for the virus that causes COVID-19. Other research observed high rates of vitamin D deficiency in people with COVID-19 who experienced acute respiratory failure. These people had a significantly higher risk of dying.
Food Sources:
- Fatty fish, such as tuna, mackerel, and salmon
- Fortified foods like some dairy products, orange juice, soy milk, and cereals
- Beef liver
- Cheese
- Egg yolks
Supplements:
Zinc: Zinc is known to be essential for all highly-proliferating cells in the human body. It helps to heal wounds, supports normal growth, makes proteins and DNA, and is essential for a strong immune system. In fact, a review published in 2020, ranked zinc as one of the top three vital nutrients for immunological health. Zinc enhances the activities of immune cells in the recognition and killing of foreign invaders. It also helps recruit cells to sites of infection. Therefore, zinc strengthens our immune system and helps us fights off invading bacteria and viruses. The mineral also has antioxidant and anti-inflammatory actions. Deficiencies have been associated with decreased functioning of immune cells and severe immune dysfunctions. Lower zinc levels correlated with higher inflammation in the course of infection and poorer outcome.
Given its strong immunological background, it comes as no surprise that clinical studies have started to favor zinc as part of an anti-COVID-19 approach. Researchers from Spain, reporting at a European coronavirus conference, found that hospitalized COVID-19 patients with low blood levels of zinc tended to fare worse than those with healthier levels. In another study published in September, scientists in japan measured zinc levels in the blood of 29 COVID-19 patients upon hospitalization. They identified zinc deficiency in 14% of patients who remained with mild to moderate COVID-19 and 86% of patients progressed into severe COVID-19.
Food Sources:
- Meat (particularly red meat)
- Shellfish (especially oysters)
- Legumes (chickpeas, lentils)
- Seeds (hemp, flax, pumpkin)
Supplements:
While omega-3s were not discussed in this article, they remain beneficial as the foundation of a supplement regimen. In fact, some researchers have suggested that the anti-inflammatory actions of omega-3s may help to avoid the cytokine storm of COVID-19.
