Compiled & Medically reviewed by 
Dr.Sanjana.V.B. Bhms. Dbrm.Cdn

 Immunity boosting vegetables & fruits

     The immunity is body’s innate way of protecting itself from infection and disease. The immune system helps the body in fighting against acute infection to serious conditions such as cancer. Diet plays a very important role in determining your immunity status.

  There are various ways to strengthen your immunity, such as: eating nutritious diet, being physically active, maintaining a healthy weight, getting adequate sleep, not smoking, and avoiding excessive alcohol use.

Immune function of your body is seriously affected by deficiency of nutrients in the food you consume or if the nutrients are not properly absorbed by the body due to some diseases of gut.

 Sleep deprivation also can lower the immune functions of your body. Obesity, smoking and alcohol abuse can lower your immunity. Stress also has detrimental effect on body’s immune function.

     Our age, sex, previous exposure to certain infections, and genetics can affect our immune system and make us more predisposed to diseases. The task of identifying these determinants or factors that regulate our immune system has become the main challenge facing precision medicine, which envisions offering patient treatments based on individual characteristics like these.

    Respiratory infections, including, influenza, the COVID-19 virus and particularly pneumonia are major causes of death in people over 65 years. There is no clear cut data available to elucidate the impact of infections in raising the death toll in old people. However, some scientists observe that this increased mortality risk correlates with a decrease in T cells in the immune system of ageing people.

 The reduction in T cells arises possibly from the thymus gland atrophy associated with old age. T cells are main warriors against infections and their decrease associated with old age; make the old population vulnerable to infections.

  As we grow old, our internal organs like the thymus or bone marrow produce less immune cells needed to fight off infections. Aging is sometimes associated with micronutrient deficiencies [vitamins and minerals], which may worsen a declining immune function. "Micronutrient malnutrition “is common in elderly.

   Vitamins A, B, C, D,E are the most important vitamins for keeping your immunity status good.  Research studies show that zinc, selenium, iron, copper, folic acid, and vitamins A, B6, C, D, and E can alter immune responses.

 We are constantly exposed to potentially harmful microbes from our environment. Our immune system protects us against these harmful microbes as well as certain diseases caused by them.

        Researchers are exploring the effects of diet, exercise, age, psychological stress, and other factors on the immune response, both in animals and in humans. 

Eat a diet high in fruits and vegetables as they have important role in boosting your immune function.

A few vegetables & fruits for improving your immunity include:

·       Broccoli

·       Citrus fruits

·       Blue berries

·       Ginger

·       garlic

·       Turmeric

·       Almonds

·       Kiwi fruits

·       Bell peppers

·       spinach

Broccoli

Broccoli is a cruciferous vegetable that belongs to the Brassica genus of plants. It's a type of flower with a thick, central stalk with grayish-green leaves and green florets which is used for its antioxidant properties.  Broccoli is a good source of vitamin C, providing over 81mg, or about 135% of your daily needs. Vitamin C is an antioxidant and immunity boosting nutrient which may protect you from infections and diseases consequent to oxidative stress. It's also a great source of vitamin A, manganese, potassium, folic acid and other B vitamins. Study  shows that a chemical present in broccoli is capable of stimulating a wide range of antioxidant defense pathways and may be able to interfere with the age-related decline in immune function." sulforaphane in broccoli reversed the decline in cellular immune function,[3,4]

Citrus fruits

Citrus fruits include:

·       Grapefruit

·       Oranges

·       Clementines

·       Tangerines

·       Lemons

·       Limes

Citrus fruits are abundant source of vitamin C which plays an important role in supporting the immune system and also acts as an antioxidant that might help protect your cells against the effects of free radicals and fight inflammation.

Citrus fruits represent an important source of dietary flavonoids including hesperidin, hesperetin, naringin, naringenin, diosmin, quercetin, rutin, nobiletin, tangeretin and others with antioxidant properties. Studies show that citrus flavonoids protect the cells against the damage of free radicals, scavenging of free radicals and thus reducing inflammation. Citrus fruits are anti-inflammatory and antiinfective due to the antioxidants and vitamin C.

Citrus fruits are rich sources of other nutrients, including potassium, folate, calcium, thiamin, niacin, vitamin B6, phosphorus, magnesium, copper, riboflavin and pantothenic acid ;all of these are immunity boosting nutrients and hence the consumption of citrus fruits is very essential to boost immunity.

Blueberries

Blueberries are perennial flowering plants with blue or purple berries. The micro nutrients in blueberries are vitamin C, vitamin K, mineral manganese, potassium, calcium and dietary fiber. Blueberries are effective antioxidants against free radical attack and oxidative stress causing inflammations. Vitamin A, vitamin C, and the various phytonutrients in blueberries function as powerful antioxidants.

Blueberries also contain copper, beta-carotene, folate, choline, and manganese, anthocyanins, vitamins, and minerals & a diverse range of phenolic compounds such as quercetin, kaempferol, myricetin, and chlorogenic acid. These contribute to the antioxidant capacity of blueberries.

Blueberries help fight infections and inflammations boosting immunity.

Ginger

 Ginger [Zingiber officinale Rosc.]  is one of the most nutritious and tasty spices that belongs to the Zingiberaceae family, and the rhizome [ the underground part of the stem most commonly called ginger]is used for consumption as a spice . 

Gingerol is a compound in ginger which imparts unique fragrance , flavor, anti-inflammatory and antioxidant properties to this spice. It has antimicrobial potential also to fight against infectious diseases [4],

 The anticancer potential of ginger is due to ingredients like gingerols, shogaol, and paradols .

However further extensive research is needed to prove the potential of ginger in cancer prevention without ambiguity.

Garlic

Garlic (Allium sativum L.) belongs to   Amaryllidaceae family.

It contains minerals like good amount of potassium, phosphorus zinc, and sulfur, moderate levels of selenium, calcium, magnesium, manganese, iron, and low levels of sodium, vitamin A and C and B-complex.

Its main bioactive compounds, include polyphenols, flavonoids, flavanols, tannins , saponins  polysaccharides , sulfur-containing compounds  alliin, allicin etc. 

 Garlic has anti-inflammatory properties and thus prevents inflammations and cancers [8].

Garlic-derived organosulfur compounds such as diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS) provide significant protection against glioblastoma cancers [11]

 Garlic has antioxidant, anti-inflammatory, and lipid-lowering effects. It has antimicrobial activity also.

 Turmeric

Turmeric help fight against infections caused by various types of microbes.

Curcumin is a compound found in turmeric which is an antimicrobial agent, limiting the replication of many different fungi, bacteria and viruses.

Research has also demonstrated that curcumin has diverse biological functions, with reported anti-cancer, antioxidant and anti-microbial properties [12]:

Curcumin can impact HIV function at several different stages of the virus lifecycle as curcumin and Curcumin A can inhibit early reverse transcription of the virus causing AIDS.

Curcumin inhibits Dengue Viruses appeared to be due to effects on cellular lipid metabolism.

Curcumin can also inhibit zika virus and its infection.

Curcumin is also a potent inhibitor of IAV, and likely exerts its effect at multiple different stages of the virus lifecycle.

 Almonds

The nutrients of almonds, including monounsaturated fatty acids, polyunsaturated fatty acids, fibre, vitamins, minerals, phytosterols, and polyphenols, provide many health benefits including anti-inflammatory and lipid-lowering properties .

Almonds are high in vitamin E and have antioxidant properties to fight against free radicals. The polyphenols and fiber content of almonds may be used as prebiotics [substrate] for growth of gut bacteria and help in  regulation of gut microbiota . Almonds also contain iron and protein that are essential to healthy immune system function.

Kiwi fruits 

Kiwi, (Actinidia deliciosa), also called kiwifruit or Chinese gooseberry, woody vine, is an edible fruit with lots of antioxidants and fibers.

Kiwi fruits are rich source of micronutrients vitamins K, E, C, folate, and potassium and low in calories. The vitamin C in kiwifruit is an effective antioxidant &fights against free radicals and prevents inflammations and protect against infections.

Kiwifruits contain a peptide called kissper that is anti-inflammatory in action [6]. 

Bell peppers 

Red bell peppers are an excellent source of vitamin C and vitamin A which can boost immunit 

Red bell peppers have antioxidants that help protect cells from oxidative damage. These include carotenoids such as lycopene, beta carotene, lutein, and zeaxanthin.

Spinach

Spinach, (Spinacia oleracea), hardy leafy annual plant of  family Amaranthaceae,  widely grown in Asia, northern Europe and the United States and used as a food item. The edible leaves are arranged in a rosette, from which a seed stalk emerges. The simple leaves are somewhat triangular or ovate and may be flat or puckered.

Spinach, (Spinacia oleracea] is used as a nutrient rich vegetable. It contains  fibers ,proteins , Vitamin A,C and K and minerals potassium,calcium , copper,iron,magnesium, manganese ,selenium and zinc. All these nutrients are immunity boosters.

Most of the carbohydrates in spinach are fibers. It contains some amount  of proteins also.

 Include more vegetables and fruits in your diet to enhance the antioxidants and micronutrients in your body which are immunity boosters.

References

1.    https://www.health.harvard.edu/staying-healthy/how-to-boost-your-immune-system

2.    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3665023/

3.    https://www.sciencedaily.com/releases/2008/03/080306133919.htm

4.    https://pubmed.ncbi.nlm.nih.gov/16169024/

5.    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7867070/

6.   https://pubmed.ncbi.nlm.nih.gov/31329250/#:~:text=Epidemiological%20studies%20associate%20regular%2C%20moderate,evidence%20from%20human%20clinical%20studies

7.     https://pubmed.ncbi.nlm.nih.gov/24168016/

8.    https://pubmed.ncbi.nlm.nih.gov/19508394

9.    https://www.cambridge.org/core/journals/nutrition-research-reviews/article/garlic-in-health-and-disease/C70F38FF67A0A21547898B2641240B8E

10.           https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7402177/

11.           https://acsjournals.onlinelibrary.wiley.com/doi/full/10.1002/cncr.22888

12.           https://pubmed.ncbi.nlm.nih.gov/26528921/

13.          https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693600/#:~:text=Curcumin%2C%20the%20primary%20curcuminoid%20compound,different%20fungi%2C%20bacteria%20and%20viruses.

14.           https://www.verywellfit.com/foods-good-for-your-immune-system-2507173

15.            https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999804/

16.            https://pubmed.ncbi.nlm.nih.gov/3354496/

17.            https://pubmed.ncbi.nlm.nih.gov/2801588/

18.            https://www.britannica.com/plant/spinach