As summer arrives, Vietnam’s fruit markets come alive with an array of unique fruits such as lychee, plum, and jackfruit. However, many people are hesitant to indulge in these treats due to concerns about experiencing “internal heat,” acne, mouth ulcers, and even itching and discomfort. But is there any truth to these beliefs? Let’s explore this topic from a nutritional perspective to gain a clearer understanding.
What is “internal heat”?
“Internal heat” is a concept not recognized in modern medicine, yet it is prevalent in everyday life. Common symptoms associated with this condition include acne, mouth ulcers, itching, frequent urination, constipation, and a feeling of restlessness.
While there is no official scientific definition, many nutrition experts believe that these symptoms may be linked to an imbalanced diet, excess energy intake, dehydration, or insufficient fiber consumption.
Do lychees cause “internal heat”?
Nutritional value of lychees: Lychees (Litchi) are tropical fruits rich in vitamin C, potassium, antioxidants, and natural sugars. On average, 100g of lychees contain approximately 66 kcal and nearly 15g of sugar. They boost immunity, improve blood circulation, and promote healthy skin.
Why lychees are considered “heating”: Lychees are high in sugars (fructose and glucose). Consuming excessive amounts can lead to a sudden spike in blood sugar levels, disrupting energy balance and resulting in sensations of heat, acne breakouts, and restlessness. The National Institute of Nutrition recommends that adults consume only 5–10 lychees per day, depending on their physique.
Note: Children who consume too many lychees, especially on an empty stomach, may experience hypoglycemia due to metabolic disorders, as observed in certain lychee-growing regions like India.
Do plums cause internal heat?
Nutrition in plums: Hanoi plums or northern plums (Prunus salicina) are packed with vitamins A and C, fiber, and antioxidants such as polyphenols and anthocyanins, which have anti-inflammatory properties and support digestion and immunity.
Do plums actually cause heat?: Contrary to folk belief, plums do not induce “internal heat.” In fact, they have a mild laxative effect and help detoxify the liver. However, consuming large quantities of plums (over 300g/day) may increase stomach acid, causing a burning sensation, discomfort, or mild acne due to high fructose levels. Individuals with sensitive skin may also experience acne breakouts.
In summary: Plums do not cause heat when consumed in moderate amounts. It is recommended to eat them with the skin to benefit from the antioxidants and avoid excessive salt and spicy condiments to minimize gastric irritation.
Does jackfruit cause acne or internal heat?
Nutritional value of jackfruit: Jackfruit is a good source of carbohydrates, vitamins C and B6, magnesium, potassium, and plant compounds like lignans and saponins, which have anti-inflammatory and anti-aging properties.
100g of jackfruit provides approximately 95 kcal – relatively high compared to other fruits – and contains a significant amount of natural sugars. Therefore, overeating jackfruit can easily lead to excess energy intake.
Does jackfruit cause “internal heat”?: Jackfruit is often labeled as “heating” due to the consequences of overeating it, which can result in bloating, indigestion, acne, or constipation if not paired with adequate water intake. However, when consumed in moderate amounts (100 – 200g/day) and with sufficient water, jackfruit is a nutritious food.
Suggestion: Consider pairing jackfruit with unsweetened yogurt or consuming it 30 minutes after a main meal to aid digestion.
How to eat these fruits without experiencing “internal heat”?
- Eat a diverse and moderate amount of fruits: Avoid overeating any single type of fruit, be it lychees, plums, or jackfruit. Rotate your choices, and aim for a total of 200 – 300g of fresh fruit per day.
- Stay hydrated: Dehydration in summer can exacerbate “internal heat” symptoms. Aim for a daily water intake of 1.5 – 2 liters.
- Incorporate cooling foods: Include cooling foods like pennywort, water spinach, winter melon, and dragon fruit to help regulate body heat.
- For those with heat-prone constitutions and acne-prone skin, avoid eating fruits on an empty stomach or combining them with spicy, fried foods.
- Individuals with high blood pressure or diabetes should monitor their consumption of sweet fruits like jackfruit and lychees to prevent blood sugar spikes.
Lychees, plums, and jackfruit do not inherently cause “internal heat” when consumed in moderation and with a balanced diet. The perception of these fruits as “heating” largely stems from improper eating habits, such as overeating, consuming them on an empty stomach, dehydration, imbalanced meals, or individual sensitivity. Instead of abstaining from these delicious summer fruits, embrace them in a mindful and moderate manner to maintain your health and enjoy the bounty of nature.
