Table 1 Functions of various nutrients, role in immune system, effect of its deficiency and supplementation in immune-boosting foods

Zinc

Meat, spinach, oysters, yogurt, pumpkin seeds, cashews, dark chocolate, mushrooms

Acts on growth and cell replication

Structural and catalytic components of the superoxide dismutase

Abridged lymphocyte number and function, improved thymic atrophy, altered cytokine production toward oxidative stress and inflammation, enhanced infectious diseases

The higher number of T cells, decreased incidence of infections, enriched natural killer cell cytotoxicity

(Prentice 2017)

Carotene

Carrot, pumpkin, red and yellow pepper, sweet potatoes, muskmelon, apricot, mangoes, papaya, chilly, tomatoes

Antioxidant

Lower incidence of acute respiratory disorder

Poor vision and weak bones, the resistance to infection reduces

The carotene intake reduces the CPR which indicates antioxidant and immunomodulatory effect

(Khalil et al. 2021)

Folate

Cow pea, chickpea, mung bean, sunflower seed, quinoa, seafoods

Fetal development

The mechanism with which folates aid in development of mammalian cells is DNA methylation

Improper developmental effects in fetus

Folate has been reported to have a major role in proper development of mammalian cells during pregnancy; thus, during pregnancy it is recommended to consume folic acid capsules

(Farran et al. 2019)

Dietary fibre

Banana, artichoke, sprouts, lentils, oats, almonds, chia seeds

Maintains bowel movement

Strengthening mucus layer, gastrointestinal immune barrier

Constipation and colon cancer

It improves the beneficial gut microbes which can aid in easy digestion. When gut microbes ferment the dietary fibres, it produced short chain fatty acids and also in replicating the beneficial microbial load

(Beukema et al. 2020)

Anthocyanin

Berries, grapes, carrots, pomegranate, beetroot

Antioxidant

Treats hyperglycaemia, prevents oxidation

Aging and improper immunity

It treats atherosclerosis, inhibit free radical activity, and decreases inflammation and aging

(Yilmaz 2019)

Omega 3 fatty acid

Fish and other sea foods

Pro resolving mediators, aids immune system

Regulation of immune function

It affects the immunity, nervous system and also causes inflammation and irritation on the dermis

It activates both the innate and the adaptive immunity. Regulation of cellular membrane properties, such as membrane fluidity or complex assembly in lipids

(Gutiérrez et al. 2019)

Iron

Red meat, dark-green leafy vegetables (spinach, collard greens), artichokes, blackstrap molasses, tofu, quinoa, prunes

Component of hemoglobin and myoglobin and important in oxygen transfer

Involvement of Fenton reaction with the production of free radicals with antimicrobial action

Drop-in immune response, lessened lymphocyte bactericidal activity

Hypothetically rise immunity to infections, but untargeted supplementation may enhance the availability of iron for pathogen growth

(Calder et al. 2007; Prentice 2017)

Selenium

Fish, seafood, wheat germ, and brazil nut

Involved in the metabolism of fat and vitamin E

Component of glutathione peroxides

Concealment of immune function, harmed humoral and cell-mediated immunity

Improves cell-mediated immunity and builds immune response in people with deficiency, yet may deteriorate allergic asthma and injury the immune response to parasites

(Calder et al. 2007)

Vitamin A

Liver, egg, milk, and carrots

Protective action on the skin and mucus and essential role in retinal function

Inhibition of the lipid peroxidation and the generation of hydroperoxides

Impacts immune functions, and exposure to infections

Diminished danger of morbidity and mortality from contagious disease. Not beneficial in pneumonia

(Prentice 2017)

Vitamin C

Citrus fruits, tomatoes, peppers, and leafy vegetables

Increases the absorption of nonheme iron

Enzymatic cofactor with redox properties

Improved oxidative damage, enlarged incidence, and expanded contamination, decreased protection from diseases, diminished DTH response

Secured against oxidative stress, decreased duration and occurrence of pneumonia and basic cold indications

(Calder et al. 2007; Hemilä 2017; Hemilä & Chalker 2013; Prentice 2017)

Vitamin D

Fish (oil liver), egg yolk, butter, cheeses, and meats

Maintaining homeostasis of calcium and phosphorus

Expression of antimicrobial peptides

Expanded weakness to contaminations, better morbidity, and mortality, Enhanced danger of autoimmune diseases

Improved immune function in transmittable disease

(Calder et al. 2007; Medzhitov 2001)

Vitamin E

Vegetable oils, olive oil, almonds, and avocados

Protection of cell membrane–unsaturated phospholipids

Decreased lipid peroxidation

Damage humoral, T and B cell function

Enhanced DTH response and proliferation of T cell

(Meydani et al. 1990)