It has never been more important to support our immunity. This can be achieved through ensuring you are having an optimal intake of essential nutrients which the immune system needs each day
to function. By including these nutrients in our diets we are making sure that our immune system is ready kick into action and protect us when we need it.
The key micronutrients to support our immunity are Selenium, Zinc, Vitamin C, Vitamin D and Vitamin A. Read ahead to discover research into the key nutrients and the foods which help us to have an optimal functioning immune system.
Key nutrients for our immunity
Selenium is an antioxidant which influences inflammation and immune responses (1). Selenium is actually an essential mineral, meaning it must be obtained through our diet. This antioxidant helps lower oxidative stress in your body, which reduces inflammation and in turn enhances immunity. Oxidative stress can be caused by lifestyle factors, such as smoking, alcohol, toxins and stress.
Foods rich in selenium include brazil nuts, fish, meats, eggs, brown rice, dairy products, sunflower seeds, mushrooms, lentils and oats. A single Brazil nut per day can provide the daily recommended adult allowance of 55 mcg. Due to this, intake of brazil nuts should actually be limited to a couple of times a week.
Zinc is a mineral which is involved in influencing growth and affecting the development and integrity of the immune system. Zinc is crucial for normal development and function of cells mediating innate immunity, white blood cells and Natural Killer (NK) cells, which act to control viral infections (2).
It is highest in protein rich foods, like oysters, seafood, meats, poultry and liver. If you are vegetarian or vegan, you can obtain zinc in your diet through consuming legumes, whole grains, nuts and seeds. If your diet is rich in these foods, you should be getting enough from your diet. Although, there are certain factors which can impair the absorption of zinc, including phytates, which are anti-nutrients found in legumes. The trick is to soak your beans over night, discard the water, and then cook in fresh water, which will remove phytates and increase the absorption capability of zinc in the body.
Vitamin C, also known as ascorbic acid, is a water soluble vitamin that is essential for the growth and repair of connective tissues, bone, cartilage, blood vessels and skin. Vitamin C supports the cell-mediated immune response, which means that it activates protective responses. Vitamin C deficiency can lead to reduced resistance to certain pathogens, while a higher supply strengthens various parameters of the immune system (3).
As Vitamin C is not made in the body; we need to obtain it from external sources, such as limes, lemons, oranges, strawberries, guava, kiwi fruits, papaya, spinach, kale, tomatoes, bell peppers, broccoli, blackcurrants and brussel sprouts.
Vitamin D is now seen as a key vitamin for immunity. It can act to modulate immune responses. Deficiencies in Vitamin D are associated with increased autoimmunity, as well as an increased susceptibility to infection (4). Also known as the ‘sunshine vitamin’, Vitamin D is made when your skin gets enough direct UV light from the sun. We can also get Vitamin D through our food intake, however the sun is the most potent source.
As we are now spending more time indoors due to many of us now working from home, it is important to make sure we are getting enough Vitamin D. When you are getting less sunlight than usual throughout the winter months, a good quality Vitamin D supplement will help in keeping your levels up.
Foods rich in vitamin D include oily fish (mackerel, sardines, herring, salmon, sardines), red meat, liver, egg yolk, some fortified bread and cereals and mushrooms. Mushrooms can also synthesise this vitamin when exposed to the sunlight and contain the D2 form, not the D3 form which is in animal products.
Vitamin A is a micronutrient that is crucial for maintaining vision, promoting growth and development, and protecting epithelium and mucus integrity in the body. It is known as an anti-inflammatory vitamin because of its critical role in enhancing immune function (5).
Vitamin A is found as preformed vitamin A in foods such as liver, cod-liver oil, butter, eggs, and dairy products, and as provitamin A carotenoids (beta carotene) in plant foods such as spinach, carrots, and orange fruits and vegetables.