Boost your immune system - add kiwi to your diet

Boost your immune system - add kiwi to your diet

Kiwi also called kiwifruit, is an edible berry of different species of plants in the genus Actinida native to China. They are oval shaped, with a bright green or golden flesh containing black seeds, covered with caramel colored skin. Their taste can be sweet, tart, or bold depending on how ripe they are, and they can be consumed alone raw, in fruit salad, in smoothies and juices, baked in cakes and pies (1).

Kiwis are an excellent source of vitamin C (92.7mg/100g) providing for 112% of the recommended daily value and vitamin K (40.3 μg/100g) providing for 38% of the recommended daily value. It also contains a good amount of fiber (3%) and moderate amounts of vitamin E (1.46 mg/100g) which provides 10% of the recommended daily value (2).

Additionally, kiwis are loaded with many bioactive compounds that together with its nutrient profile, bestow great health benefits to those who consume them. The following are some health benefits of kiwi fruits.

  1. Boost the immune system. Vitamins C stimulates the migration of neutrophils to the site of infection, where they engulf invading bacteria, digesting and kill them consequently. Neutrophils are a type of white blood cell that act as the first line of defense of the immune system. Therefore, dietary intake of at least 100 – 200mg of vitamin C per day is prescribed as a prophylactic prevention strategy against infections (3).

  2. Boost skin health. Vitamin C also boosts the skin’s immunity by enhancing the production of collagen, which gives structure, rigidity, elasticity, and toughness to the connective tissues of the skin. Thus, a deficiency in vitamin C called scurvy, weakens collagen structures impairing the rapid healing of wounds and reducing overall immunity. Such people are highly susceptible to infections that are fatal like pneumonia (4).

  3. Promote heart health. Kiwis contain compounds like choline, lutein, and zeaxanthin which together with vitamin C, have potent antioxidant and anti-inflammatory properties. As antioxidants, they prevent oxidation of cells by capturing reactive oxygen species (free radicals), which are unstable molecules produced during normal body processes like metabolism. A build up of free radicals is harmful to the body because they will cause more oxidation reactions to occur, which will eventually stress out the body cells and damage them, a state called oxidative stress.

As free radicals increase, nitric acid’s availability drops, and blood vessels narrow (vasoconstriction) enhancing hypertension which is a risk factor for heart disease. Free radicals also cause plaque buildup in blood vessels resulting in atherosclerosis, another risk factor for heart disease (5).

  1. Helps with digestion. Kiwis are a good source of dietary fiber which pulls water from the intestines, increasing stool bulk and easing its passage through the gut. For this reason, people suffering from constipation are encouraged to eat kiwi. Studies carried out with healthy people who ate kiwis everyday reported that they all had increased stool frequency, as well as softer stool consistency (6).

Besides, kiwis contain an enzyme called actinidin, which accelerates the breakdown of proteins, easy their digestion and absorption in the intestines. This is the reason why kiwis are used to tenderize meats (7).

  1. Promotes good vision. Kiwis protect the eyes from macular degeneration, cataracts, and vision loss. The macular which is at the center of the retina of the eyes, contain carotenoids like lutein and zeaxanthin which the body uses to make vitamin A, needed for the proper functioning of the eyes. Lutein and zeaxanthin protect the eyes by directly absorbing ultraviolet light, reducing its intensity, and consequently preventing possible damage of the eyes due to oxidation. Kiwis are a good dietary source of lutein and zeaxanthin which can supplement macular stores, enhancing a continuous stream of good vision (8).

Kiwis are great fruits, with numerous health benefits. They are generally safe though some people may experience allergic reactions like itching tongue or lips, rashes, or vomiting. Life threatening reactions are rare.

 

REFERENCES

  1. Morton, J. (1987). Kiwifruit. Fruits of Warm Climates. Julia F, 293–300.

  2. FoodData central. (n.d.). Retrieved May 14, 2022, from Usda.gov website: https://fdc.nal.usda.gov/fdc-app.html#/food-details/168153/nutrients

  3. Carr, A., & Maggini, S. (2017). Vitamin C and immune function. Nutrients, 9(11), 1211. doi:10.3390/nu9111211

  4. Hemilä, H. (2017). Vitamin C and infections. Nutrients, 9(4), 339. doi:10.3390/nu9040339

  5. Senoner, T., & Dichtl, W. (2019). Oxidative stress in cardiovascular diseases: Still a therapeutic target? Nutrients, 11(9), 2090. doi:10.3390/nu11092090

  6. Wilkinson-Smith, V., Dellschaft, N., Ansell, J., Hoad, C., Marciani, L., Gowland, P., & Spiller, R. (2019). Mechanisms underlying effects of kiwifruit on intestinal function shown by MRI in healthy volunteers. Alimentary Pharmacology & Therapeutics, 49(6), 759–768. doi:10.1111/apt.15127

  7. Lewis, D. A., & Luh, B. S. (1988). Application of actinidin from kiwifruit to meat tenderization and characterization of beef muscle protein hydrolysis. Journal of Food Biochemistry, 12(3), 147–158. doi:10.1111/j.1745-4514.1988.tb00368.x

  8. Mares, J. (2016). Lutein and zeaxanthin isomers in eye health and disease. Annual Review of Nutrition, 36(1), 571–602. doi:10.1146/annurev-nutr-071715-051110

 

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