西瓜消暑降血壓，但7類人應謹慎食用

In the sweltering summer, a slice of chilled watermelon is a top choice for many to beat the heat. This fruit, originally from Africa and also known as the "cold melon," "summer melon," or "water melon," is named "Watermelon" in English, which literally translates to "watery melon." In Taiwan, there are many varieties, including large red watermelons, yellow-fleshed small watermelons, seedless watermelons, and "Black Beauty" watermelons, making it a popular summer ingredient due to its refreshing taste. From a Traditional Chinese Medicine perspective, watermelon is cold in nature and sweet in taste, and is known as "natural Baihu Tang" (a traditional Chinese medicine formula). It can clear heat, relieve summer heat, quench thirst, and, due to its high water content, help promote urination.Lower blood pressureIt even has the effect of relieving hangovers, and can alleviate symptoms of inflammatory fever such as tonsillitis, sore throat, and angular cheilitis, as well as fever reduction and cooling after heatstroke.
Many people are curious about the nutritional differences between yellow-fleshed and red-fleshed watermelons. In fact, both have their advantages. Red watermelons are particularly rich in lycopene...β-caroteneWatermelon contains vitamin A, which not only has antioxidant properties but also anti-cancer effects. While yellow watermelon also contains these nutrients, the content is relatively low. It's worth noting that while many people are familiar with the high lycopene content of tomatoes, they often overlook the fact that red watermelon is equally rich in lycopene. Furthermore, its beta-carotene and vitamin A content is significantly higher than that of oranges and comparable to that of papayas. However, it's important to note that lycopene and vitamin A require the aid of fats for optimal absorption. Therefore, eating watermelon after meals not only helps to cut through the greasiness but also aids in nutrient absorption, making it more suitable than eating it on an empty stomach.
Regarding vitamin C, a concern for many, watermelon falls short of expectations, containing only 8 milligrams per 100 grams. The highest vitamin C content is not found in the red or yellow flesh, but rather in the white part between the flesh and rind, and in the seeds. As for calories, watermelon has a high water content of approximately 931 TP4T, and 100 grams of peeled flesh contains about 35 calories, which isn't considered a high-calorie fruit. However, due to its refreshing and easy-to-eat taste, people often unknowingly overeat. Just three or four slices after a meal can easily add up to nearly 100 calories, meaning the actual calorie intake is often higher than expected.
Another common question is, "Watermelon is so sweet, isn't its glycemic index (GI) very high?" Actually, judging the GI value by sweetness is inaccurate. The key is dietary fiber—fruits rich in dietary fiber, like apples and guavas, can buffer blood sugar spikes and prevent them from rising rapidly, even if they are sweet. However, watermelon has relatively little dietary fiber, so it rises quickly after entering the body.Raise blood sugarIt stimulates insulin secretion, so diabetic patients need to strictly control their intake.
Not everyone is suited to eating watermelon freely. People with weak constitutions, poor gastrointestinal function, or gastrointestinal ulcers should avoid eating it; postpartum women and post-operative patients should also limit their intake. For kidney patients, although watermelon is not considered a high-potassium fruit, three slices of watermelon contain 300 mg of potassium, so patients who need to control their potassium intake should be especially careful, and even the amount of watermelon juice consumed should be strictly limited. Diabetics should limit their intake to three slices (about 300 grams) or less at a time, and eat it no more than twice a day. In addition, there is a saying in Taiwan, "eating watermelon at midnight causes adverse reactions," which refers to the fact that eating too much watermelon on an empty stomach can easily lead to abdominal pain and diarrhea in the middle of the night. Because watermelon is cold in nature, people with weak stomachs or cold constitutions are prone to discomfort when eating it on an empty stomach; people with frequent urination should also avoid eating it too late at night to avoid the urge to urinate affecting their sleep.
When it comes to watermelon-related products, many people are curious whether the commercially available "watermelon frost" is made from watermelon. In fact, the raw material for watermelon frost does come from watermelon, but not from the flesh; it comes from the watermelon rind. After watermelon rind is left to stand for a long time, a white, frosty powder similar to mold will appear on the surface. Collecting this powder is the traditional watermelon frost, which has a cooling and heat-relieving effect. Modern watermelon frost is made by adding other Chinese medicinal herbs and can be used to treat problems such as swollen gums and stomatitis.
Finally, regarding watermelon storage, most people are used to putting it directly in the refrigerator after buying it. However, as a tropical fruit, watermelon is not suitable for low-temperature storage. Studies show that room temperature helps watermelon ripen and increases the content of antioxidants such as lycopene. Low temperatures may actually destroy nutrients. Furthermore, watermelon has a high water content, and prolonged refrigeration will cause water evaporation, affecting its taste. A US study indicated that storing watermelon at room temperature (21 degrees Celsius) in a well-ventilated area not only helps it ripen but also increases the content of lycopene and beta-carotene. Therefore, it is recommended to buy only what you can eat to avoid wasting food or losing nutrients due to improper storage.