Boosting Immunity With Watermelon

  • Muna Hassan Bachelor of science in molecular biology and Genetics Üsküdar Üniversitesi

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How does the immune system work? Our immune system is our body’s soldiers. They fight off disease, germs or any intruders that may want to access or get access to our body system. These bodily soldiers have different ways by which they exert their power, might or strength in making sure that our body is safe from any harm.

What is the immune system precisely?

You see, every day you wake up from sleep, you keep going and continue your daily life as if nothing happened there. Any time you pick up dirt with your hands and somehow into your mouth, you feel nothing happening, and your body is strong enough to hold it. You see, without that immune system in your body, in my body, we would have been falling sick more often than not. The immune system combats harmful or external agents that enter our body and tries to stabilize internal changes that could disrupt the organization of our body.

The immune system does this by fighting the pathogens, germs, and disease-causing organisms that find their way into our bodies. These could include bacteria, viruses, parasites and even fungi. Aside from this, the immune system also does a lot of other work, such as quenching the aggressive proliferation of normal cells in our system to malignant cells, like in the case of cancerous cells.  And lastly, touch-lighting and rendering harmless the harmful substances from our immediate surroundings. The immune system achieves this by elucidating an immune response.

What, then, is the immune response?

The immune system is activated via two avenues: one intrinsic or innate and the other adaptive or acquired immune response.

The intrinsic or innate is the natural immune response that an individual is born with, and it is usually the first line of defence, as it occurs instantly, all things being equal. It is regarded as a non-specific and non-memory cell. This is because it triggers a more general or overall defence mechanism, irrespective of the intruder. It is not specific in action. Examples include the skin being the first line of the barrier of defence against harmful substances in our body. In addition, the salty constituents of the sweat glands, the lysozyme in our tears, the wax in our ear and even the hair-like structures in our nose trap the microaerophilic microbes in the form of dust.

Adaptive or acquired immune response, on the other hand, is the secondary immune response. It occurs later as the coordination of acquired cells needs to be established. Unlike the innate, this is specific in action and remembers the mechanisms it initially uses to curtain invaders or harmful substances in our body. This, in particular, makes use of antibodies and body soldiers to fight foreign invaders, the antigens that the body might have previously had an encounter with. That is why they got the name ‘acquired’; that is, they acquired it from previously ‘learned’ responses.

Well, from the foregoing, one could wonder, why much emphasis is placed on the immune system. Much emphasis is placed on the immune system because there are some sets of people we regard as immuno-compromised individuals. Unlike the immuno-competent, from the name, these people possess a competent immune system; the immuno-compromise, on the other hand, are individuals with less immune response. 

Their immunity has been compromised in one way or the other. Hence, it cannot induce a competent immune response. These individuals could include but are not limited to pregnant women, nursing mothers, neonates, infants, even the elderly, and people with debilitating diseases such as HIV and cancer, just to mention a few.

Thus, it is not far-fetched to understand the importance of maintaining a good immune system.

How, then, can we, as individuals, maintain a good immune system?

One of the ways of maintaining a good immune system is through what we eat. And that is why one of the ancient philosophers says, and I quote, “Let thy food be thy medicine” so that thy medicine will not become thy food. So, from these, we realized that having a good diet and good nutrients nourishes the immune system. And one of those good immune-enhancing foods, otherwise called fruits, is watermelon.

What, then, are the nutritional benefits of watermelon?

The nutritional value of watermelon has been studied over the years. While the flesh constitutes about 68%, the rind is 30% and seed is 2%.2 Every part of a watermelon is very beneficial. It is a good source of vitamins and valuable phytocompounds that protect the immune system from different ailments such as cancer.3 It is a juice-like fruit with a tender kernel of colour varying from red to pink and abundant black seeds.2 These seeds do not only have medicinal value but are also employed to treat acute or chronic eczema.

The external hard content of watermelon called the rind also has its own uses despite the majority not considering it edible.  It is reported4 to possess Vitamin B6, alkaloid, potassium, vitamin C, citrulline, steroids, dietary fiber, triterpenes, cucurbitacin, among others. These are important phytochemicals that are not only beneficial to the immune system but also confer general well-being to an individual. 

Take citrulline for example, it helps to boost blood flow, reduce high blood pressure and enhances athletic performance. It also helps to spice up your sexual life as it alleviates the problem of erectile dysfunction. Moreover, the antioxidant effect of citrulline is very key to the circulatory system, heart and even the immune system.4

Cucurbitacin, on the other hand, possesses antidiabetic, anti-inflammatory, antitumor and atherosclerosis activity and, hence, promotes blood circulation within the immune system.5 In addition, the seed also has a high value of proteins, lipids, and carbohydrates and is a good source of fibre.3 Besides, they are employed domestically to treat urinary tract infections, catarrh, hepatic congestion, abnormal blood pressure and even used as a worm remedy.6

According to the proximate analysis conducted by Elamin Ibrahim and others7, they investigated the chemical composition and mineral content of different parts of the watermelon plant. But for the scope of this write-up, I would only concentrate my energy on the melon kernel (that’s the edible reddish to pinkish part) and seed. 

They revealed that while the seed is made up of about 16% moisture content, the kernel is made up of more than 90 %. Respectively, kernel and seed possess 15.23 and 25.6 % crude protein, 12.23 and 25.12 % lipids, 2.44 and 2.73 % carbohydrate, 101.1 and 70.9 ppm potassium, 2.51 and 2.46 µg/ml Calcium. Other important mineral content includes magnesium, cobalt, copper, manganese, lead, zinc, and iron. All these have a crucial role they play in building up our immune system.

Hydration and immune system

It is no fact that about 60-70 % of human weight is made up of water. This is to show that water is very essential in the human system. Water not only regulates digestion but also enhances absorption and metabolism, which usually is the breakdown of molecules. It is also useful in bowel movement in the case of excretion, circulation, and even the transfer of biological molecules from one site to another.8 It is for this reason that the daily intake of water has been proposed to be about 12 glasses. 

However, this is not an overhaul recommendation for everyone as water intake differs based on individual age, diet, body weight, mass, level of physical activity or demand, environmental state, weather, pregnancy, and nursing mother, among other intricate factors. When the appropriate level of water is not taken, it could lead not only to disease in some cases but even death.8

That is why, even though it is acknowledged that drinking ordinary water all the time might be challenging, it is recommended that other means be devised to satisfy this menace. One of those ways is either food or fruit. So, watermelon solves the problem immensely, with over 90% water content, as earlier established.

Eating more of these water-loaded fruits will not only flush out harmful substances via your system that otherwise weaken them but also protect you from developing kidney stones. Additionally, it has been established that when one is down with a fever, the best way to replenish the heat and water loss is via hydration.8 Therefore, it is a good habit and well recommended to incorporate watermelon in our diet.

What then are the creative ways to consume watermelon?

Watermelon can be spiced up in different ways as watermelon recipes. These include but are not limited to watermelon popsicles, watermelon salad, watermelon-infused water, watermelon cake, watermelon gazpacho, watermelon sorbet, watermelon mojito, watermelon salsa, watermelon mint lemonade, Grilled Watermelon + Avocado Salad, among others.


To round up, our immune system requires deliberate action to keep it moving and strong. Disease is inevitable with a bad immune system. Immune response could be achieved via two avenues: innate, natural or non-specific and adaptive acquired or specific immune response. However, this response can be enhanced via our diet. As the saying goes, ‘Let thy food be thy medicine so that thy medicine will not become thy food’. Watermelon is one of the important foods that can be incorporated into our diet to improve our immune response in various ways.


  1. Witkamp RF, van Norren K. Let thy food be thy medicine.when possible. Eur J Pharmacol. 2018 Oct 5;836:102–14.
  2. Elamin SI, Ali NA, Abd El Hakeem SB, Elhadi Sulieman AM. Proximae Chemical Composition of Watermelon (Citrullus vulgaris). [Internet]. Available from:
  3. AC, Ugbogu OC, Ugbogu AE, Ezeonu CS. Production of mixed fruit (pawpaw, banana and watermelon) wine using Saccharomyces cerevisiae isolated from palm wine. Springerplus. 2015 Dec 1;4(1):1–11.
  4. Lobo MG, Dorta E. Utilization and management of horticultural waste. In: Postharvest Technology of Perishable Horticultural Commodities. Elsevier; 2019. p. 639–66.
  5. Kaushik U, Aeri V, Mir SR. Cucurbitacins - An insight into medicinal leads from nature. Pharmacogn Rev. 2015;9:12–8.
  6. Amadi EN, Barimalaa IS, Blankson CD, Achinewhu SC. Melon Seeds (Citrullus vulgaris) as a Possible Substrate for the Production of Tempe. 2004.
  7. Elamin SI, Ali NA, Abd El Hakeem SB, Elhadi Sulieman AM. Proximae Chemical Composition of Watermelon (Citrullus vulgaris). [Internet]. Available from:
  8. Özkaya İ, Yıldız M. Effect of water consumption over the immune system response given during Covid-19. Magna Scientia Adv Res Rev. 2021 May 30;2(1):040–4.

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Morufat Oluwatosin Olaitan

Masters of Science – M.Sc. Microbiology (Environmental), University of Ibadan, Ibadan, Nigeria

Morufat is a Research-oriented Scientist; sulphite and inquisitive Microbiologist; an Antimicrobial Resistance enthusiast and One Health Advocate. Morufat has interned with different Public Health Organizations affiliated with Nigeria, South Africa and Australia. She is an academically certified Scientific Writer with Honours at Stanford University. She completed her Masters of Science degree with a Ph.D. Grade. She’s a First-Class Graduate of Microbiology. She has some publications to her name and serves as a Reviewer to International Research Journal of Public and Environmental Health, and Open journals Nigeria. Morufat currently lectures at the Nile University of Nigeria, located in the heart of Nigeria’s capital, Abuja. presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
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