Watermelon Benefits and Side Effects

Watermelon Benefits and Side Effects

Watermelon is a flowering plant which is believed to have originated from Africa. Like most fruits that grow in the drier parts of the world,  watermelon is very hydrating and it is also low in calories. So, it is easy to binge on watermelons without putting on extra weight.

The primary benefit of watermelons lies in their high water content. But the fruit is also loaded with other essential vitamins and minerals that can help prevent diseases and improve the overall health.

There are different varieties of watermelons that are cultivated across different parts of the world. Even the colour of the flesh varies depending on the growing environment and genetics of the particular variety. It is believed that red watermelons taste the best.

It might interest you to know that watermelons have a rich history as a fruit and as a healing agent. The earliest records of watermelon cultivation come from the Egyptian tombs that were made around 4000 years from now. Shredded pieces of evidence suggest the use of watermelon in early Greece and Rome, around 1st century BCE. Mentions of watermelon have also been found in the bible. According to Dioscorides, a famous Greek physician, watermelons can be used as a diuretic and its rind can be applied on the head to alleviate the symptoms of heat strokes.

Today, the largest producer of this fruit in the world is China. In India, watermelons are cultivated in many states, but Uttar Pradesh, Karnataka, and West Bengal account for 50% of the total production of watermelons in India.


Some basic facts about watermelons:

Scientific name: Citrullus lanatus

Family: Cucurbitaceae

Common name: Watermelon, Tarbuj

Parts used: Flesh, rind, seeds

Native region and geographical distribution: Watermelons are native to Africa but they are grown in most warmer climates all over the world.

Energetics: Cooling

  • Watermelon nutrition facts
  • Watermelon health benefits
  • Watermelon use
  • Watermelon side effects
  • Takeaway

Watermelon nutrition facts

Watermelons have about 30 calories per 100 g. About 92% of water constitutes water. However it also an excellent source of many other nutrients. It is rich in minerals such as potassium, phosphorus, calcium, and magnesium and has various vitamins such as vitamin A, B1, B2, B3 etc.

As per the USDA Nutrient Database, 100 g of watermelon contains the following values

Nutrients Value per 100 g

Water 91.45 g

Energy 30 kcal

Carbohydrate 7.55 g

Sugars 6.2 g

Fibre 0.4 g

Fats 0.15 g

Protein 0.61 g

Minerals Value per 100 g

Calcium 7 mg

Iron 0.24 mg

Magnesium 10 mg

Phosphorus 11 mg

Potassium 112 mg

Sodium 1 mg

Zinc 0.1 mg

Manganese 0.038 mg

Vitamins Value per 100 g

Vitamin A 28 µg

Vitamin B1 0.033 mg

Vitamin B2 0.021 mg

Vitamin B3 0.178 mg

Vitamin B5 0.221 mg

Vitamin B6 0.045 mg

Vitamin C 8.1 mg

Vitamin E 0.05 mg

Vitamin K 0.1 µg

Fatty Acids Value per 100 g

Saturated 0.016 g

Monounsaturated 0.037 g

Polyunsaturated 0.050 g

Watermelon health benefits

A chilled glass of watermelon can quench our thirst and keep us refreshed on a hot and exhausting day. But this fruit also has several other health benefits. It contains essential minerals and vitamins that can be beneficial to our body. Apart from all of this, watermelon is a rich source of a phytochemical called lycopene which is responsible for the bright red colour of the fruit. This phytochemical is known to have powerful antioxidant properties. Below are some of the most common health benefits of watermelons

  • Watermelon for blood pressure
  • Watermelon for sore muscles
  • Watermelon as an antioxidant
  • Watermelon for diabetes
  • Watermelon benefits for eyes
  • Watermelon for peptic ulcer
  • Watermelon for kidneys
  • Watermelon for pregnant women
  • Watermelon for Alzheimer’s
  • Watermelon prevents cancer

Watermelon for blood pressure

According to research, the rind of watermelon is rich in an amino acid known as citrulline. So why is citrulline important for our body? Studies suggest that foods rich in citrulline can help improve the systolic and diastolic blood pressure.  A group of 40 prehypertensive and hypertensive individuals was subjected to a study, where they were given 6 g of watermelon extract for 6 weeks. At the end of the study, it was concluded that watermelon extract helped reduce blood pressure.

Watermelon for sore muscles

Watermelon juice can serve as a better alternative to soft drinks, especially among athletes and people who indulge in workouts. Studies suggest that the citrulline content in watermelon can helps in reducing muscle soreness. In a clinical study, a group of athletes was given 500 ml of watermelon juice daily for a certain period of time. The study reported that the juice was very helpful in reducing muscle soreness within 24 hours.

Watermelon as an antioxidant

Antioxidants are a class of bioactive compounds which play an important role in protecting us against various diseases. They scavenge the free radicals produced in the body due to various metabolic processes and environmental factors like stress. Excess of these free radicals is responsible for a lot of health problems ranging from premature ageing to the development of chronic diseases such as cardiovascular disorders, diabetes, and cancer.

Several studies are being conducted to evaluate the potential health benefits of lycopene, an effective antioxidant present in fruits such as watermelons, guavas, tomatoes etc. Clinical studies suggest that lycopene can reduce DNA  damage caused by the presence of excessive free radicals. This DNA damage is the underlying cause of the free radical associated damage. In a random controlled trial (RCT), various quantities of lycopene supplement were given to a group of 77 healthy people for a  period of 8 weeks. At the end of the study, it was concluded that lycopene does lead to a decrease in DNA oxidative damage.

Watermelon for diabetes

Diabetes is a disease characterised by high blood sugar levels and symptoms like frequent urination, excessive hunger, and weight issues. In the long term, diabetes can also lead to complications such as cardiovascular disorders, kidney diseases etc. Hence it is essential to keep the blood sugar levels under control.

Consumption of lycopene-rich foods can reduce the glucose level in blood. In a study conducted on animal models, administration of lycopene-rich watermelon rind extract showed a reduction in the blood sugar levels. Another study indicates that watermelon seeds have certain proteins which are very effective in reducing the blood sugar levels.

Watermelon benefits for eyes

Declining eyesight is a very common problem among older people. People above 60 years of age are also susceptible to a more serious problem called age-related macular degeneration (AMD). Macular degeneration caused due to the damage to the macula, a portion near the center of the retina may lead to a complete loss of vision. Research suggests that consumption of carotenoid-rich foods along with vitamins such as vitamin A and vitamin E can help prevent age-related eye problems. Watermelons are one of the richest sources of lycopene. They are also rich in vitamin A and contain a small amount of vitamin E. Therefore, regular intake of watermelon may help keep your eyes healthy along with preventing age-related eye problems.

Watermelon for peptic ulcer

A peptic ulcer is an inflammation of the inner lining of the stomach. Peptic ulcer mainly affects the stomach and rarely it affects the esophagus Although there are various causes for peptic ulcer, oxidative damage could be one the causes of this problem. In vivo studies suggest that as an antioxidant, lycopene can be effective against gastric ulcer. As per a study, oral administration of lycopene supplements can be beneficial in alleviating the symptoms of gastric ulcer.

However, this study was on lycopene instead of watermelons. More studies are still needed to confirm the safety and efficiency of watermelon lycopene for the treatment of peptic ulcer.

Watermelon for kidneys

Kidneys are a vital organ in the body because it helps in filtering out waste from the blood. Various conditions like high blood pressure, diabetes, and urinary tract problems may adversely affect the kidneys. Untreated kidney problems could lead to chronic kidney disease and in extreme cases, kidney failure. Traditionally, watermelon has been known as a diuretic. This means that it can help remove the excess salts and toxins from the body and keep the kidneys healthy.

In a case study, a 60-year-old man who was at a later stage of the chronic kidney disease showed improvement upon regular consumption of watermelon. However, it was a single case and more studies are being conducted all over the world to understand the benefits of watermelon in preventing kidney diseases and improving kidney function.

Watermelon for pregnant women

The lycopene present in watermelons has numerous health benefits. A study was conducted on 251 women, expecting their first child, to understand the effects of lycopene consumption during pregnancy. The study focussed on two important complications that can arise in pregnant women –  preeclampsia and intrauterine growth retardation. Preeclampsia is the increase in blood pressure among pregnant women, observed mostly after 20 weeks of pregnancy which might lead to pre and post birth complications. Intrauterine growth retardation is a condition when the baby is not its normal weight during pregnancy. As per the study, oral administration of lycopene was found to reduce the chances of both preeclampsia and intrauterine growth retardation in first time pregnant women.

Watermelon for Alzheimer’s

Alzheimer’s disease (AD) is a brain disorder where the patient begins to lose their memory and gradually lose the ability to do simple chores. Although scientists are unable to fully understand what causes this disease, AD is generally associated with individual genetics and lifestyle. Researchers have found that the carotenoid lycopene could be effective in reducing the onset and progression of Alzheimer’s disease. This is attributed to lycopene’s ability to decrease oxidative damage. Another study suggests that intake of foods rich in lycopene such as watermelons can help reduce the risk of Alzheimer’s disease.

Watermelon prevents cancer

Several studies claim that lycopene present in watermelons can be used to treat various chronic diseases including cancer. It has been suggested that the antioxidant properties of lycopene make it an excellent anticancer agent. It reduces the cell and DNA damage caused by oxidative stress thereby preventing the development of cancer. Additionally, lycopene has also been found to reduce the proliferation of cancer cells and induce apoptosis (cell death) in cancerous cells. Watermelon lycopene has been reported to have inhibitory effects of several cancer cell lines including oesophagial cancer, prostate cancer, colorectal cancer, and breast cancer.

Watermelon use

Watermelons belong to the same family as cucumbers and pumpkin. So, they are considered both a fruit and a vegetable. Although most of us prefer eating only the flesh of this fruit, the entire fruit is edible. This includes the seeds and the rind which is the outer green portion of the fruit. In fact, the watermelon seeds, also known as magaz in Hindi are extensively used in cakes, confectionery, mouth fresheners, and sweets and snacks. Once the seeds are shelled and roasted, they can be directly consumed. The rind of the watermelon can be used to make curries and jam.

Watermelon side effects

Although this juicy, favourite fruit of most people has innumerable health benefits, it also comes with its share of drawbacks.

Watermelon could lead to hyperkalemia

Hyperkalemia is a serious medical condition in which the potassium levels in the body increase either due to high potassium intake or due to the inability of the body to expel it. High levels of potassium can cause muscular damage or harm the kidneys. Exceedingly high levels can lead to improper functioning of the heart. If left untreated, this could be life-threatening. Since watermelon is rich in potassium (112 mg per 100 g), overeating can lead to an increase in the potassium levels in the body.

Allergies to watermelon

People who are allergic to vegetables such as carrots may also be allergic to watermelon. Watermelons have a set of allergins including profilin and malate dehydrogenase that could cause allergic reactions in some people.


Watermelon can be consumed on a regular basis by anyone irrespective of the age and gender. This summer fruit is not only loved for its taste but also because it is power packed with nutrients that are beneficial to the body. It helps in proper functioning of different organs such as kidney, eyes, digestive organs and the heart. However, it is not advisable to eat this fruit in excess. Also, people who are allergic to carrot or other vegetables should consult their doctor before having this fruit.