Longan For Digestive Wellness

  • Eva Henning MSc Precision Medicine, University of Manchester, UK
  • Jasmine Le BSc (Hons) Microbiology, University of Manchester

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What is longan?

Longan, often presented in fruit form, originates from a Dimocarpus longan tropical tree. The fruit is referred to as a dragon eye; beneath the peel, there is an outer, fleshy layer and within that lies a black seed, resembling the iris and pupil of an eye. Originating from South Asia, it has been applied in traditional Chinese medicine for centuries due to the range of health benefits it promotes. One of these benefits involves assisting digestive health, which is important in facilitating nutrient transport from our food to our gut and blood. Furthermore, previous studies show that there is a direct association between the gut and brain via the gut-brain axis, so digestive health is extremely important in protecting the brain. Therefore, it's important to be mindful of what we put into our bodies. The gut can be defined as the basis of physiological health as it facilitates digestion and allows absorption of nutrients, which are central for the body to function. 

Often added to a range of foods including ice cream, smoothies, cakes and even salads, longan is a very versatile fruit. It provides the body with an array of health benefits, specifically promoting digestive health as it contains multiple favourable components. For example, studies show it displays a range of metabolites, a relative abundance of fibre, and multiple nutrients including proteins, carbohydrates, vitamin C and importantly antioxidants.¹ These bioactive compounds and their health benefits of digestive wellness, including aiding in digestion, will be discussed in this article. 

The history 

The history of longan stems back to a Chinese medical specialist named Li Shizhen who classified it as a superior fruit.¹ In the past, it had been used to treat a variety of ailments, including cardiovascular and kidney disease.² The component of logan that is utilised in traditional medicine is the pulp which alleviates a range of health complications, including tense nerves, insomnia, and the metabolism of the blood.¹ The application of longan therefore extends outside digestive wellness by alleviating disease implications. For example, the seed and pericarp components of longan have been beneficial in increasing overall health in pregnant women. This can be explained at a biological level relating to the seed extract activity. 

Nutritional profile

The seed extract of longan contains anti-gelatinase action, which is effective in preventing a range of diseases including cancer.⁴ As a diverse fruit , it can be consumed as longan juice, jelly, wine and even syrup. For example, longan wine contains a large amount of antioxidant activity at approximately 92%.⁵ The nutritional profile of longan involves an abundance of carbohydrates, fibre, amino acids, polyphenols and protein. Furthermore, other components such as polysaccharides, found within the pulp and pericarp tissues, provide anticancer properties.¹ The beneficial properties of the pulp also extend beyond nutrition as it positively impacts the brain. Studies have revealed that pulp components reduce anxiety levels, provide memory improvement and even improve insomnia .⁵ 

Digestive wellness benefits

It is consumed globally , not only because of its sweet taste similar to that of a lychee fruit, but also due to its nutritional profile which aids digestive wellness. It can be eaten in its natural form, dried, or after being modified. Longan is suggested to promote digestive wellness due to having a large abundance of dietary fibre and antioxidants, which are extremely advantageous to the gut microbiota.⁵ The fruit also contains a high mineral content, which aids hydration and is extremely important for allowing the digestive system to function efficiently. In turn, this helps to prevent bowel problems, including constipation and acute diarrhoea. Additionally, the presence of tannins in the fruit further assists gut function and influences the microbiota.⁶ The large presence of enzymes found in fruit in general, also assists the breakdown of foods within the gut, assisting digestive wellness. For example, longan contains a range of enzymes, including superoxide dismutase, catalase and glutathione peroxidase.² 

Scientific studies supporting the digestive benefits 

Importantly, it is the pulp of longan that provides digestive benefits as it promotes beneficial bacteria in the gut and safeguards the intestinal barrier.³ The presence of a protective mechanism of the intestinal barrier prevents conditions, such as inflammatory bowel disease (IBD), where the intestinal barrier becomes impaired. Prebiotics are foods that not only nurture the gut, but also enhance the microbiota, improving gut health. Previous studies have revealed the importance of polysaccharides in modulating IBD, as they protect the gut and enhance the surrounding gut environment.³ Therefore, the large abundance of polysaccharides in longan is important in digestive wellness. Other studies have found that O-phosphocholine metabolite is an important component of the fruit. This is because it aids in the production of phosphatidylcholine, which enhances  the immune system.⁷ 

Cautions - allergies and side effects

Although longan is an extremely tasty and healthy fruit, too much should not be consumed. This is because large consumption of this tropical fruit can do the opposite of promoting digestive wellness by causing indigestion. As there is a large quantity of sugar found in longan, individuals with health complications, such as diabetes, should consume the fruit with caution.⁸ Furthermore, longan contains high amounts of phenolic compounds that are predominantly found in the seed of the fruit, so mainly the pulp should be consumed .⁷ High doses of phenolic compounds have been associated with toxicity as oxidative stress builds up in the body. Therefore, further research on the toxicology of longan extract containing these compounds is needed to ensure safety during consumption.⁹ 

Is this fruit safe?

Longan does not often cause a major allergy threat due to the lack of pollen that is accompanied by the fruit, and it is also gluten-free. In support of this, very few cases exist that report allergic responses to longan, suggesting it is a safe fruit to eat.¹⁰ However, there is limited research to conclude whether or not longan is safe to be consumed by pregnant women. Although some benefits have been associated with pregnancy, it is often advised against consumption as it may lead to dehydration and other complications, so it should not be overconsumed. Another issue associated with longan is the farming of the fruit and the risk of pesticide contamination. Toxicity related to the fruit is possible due to pesticides found on the skin of longan. The skin must be consumed with caution, so be sure to thoroughly wash the skin and eat the fruit whole, or peel the skin and enjoy the pulp alone to prevent this.


The juicy sweet-tasting longan fruit is recommended for consumption because it promotes a range of health benefits including digestive wellness. As it has a large abundance of vitamin C and fibre, it is the ideal fruit to incorporate into daily meals and overall diet. The advantages of longan as a super fruit extend beyond boosting immunity as it has been proven to lower anxiety levels, stress, and some diseases including kidney issues. However, some disadvantages must be considered including the possibility of pesticide contamination stemming from farming. Despite this, it is not classified as a superfood for no reason being used in traditional Chinese medicine. The range of health benefits found in longan therefore must be considered. 


  • Zhang X, Guo S, Ho CT, Bai N. Phytochemical constituents and biological activities of longan (Dimocarpus longan Lour.) fruit: a review. Food Science and Human Wellness. 2020 Jun;9(2):95–102.
  • Huang S, Han D, Wang J, Guo D, Li J. Floral Induction of Longan (Dimocarpus longan) by Potassium Chlorate: Application, Mechanism, and Future Perspectives. Frontiers in Plant Science. 2021 Jun 7;12.
  • Bai Y, Zhou Y, Li X, Zhang R, Huang F, Fan B, et al. Longan pulp polysaccharides regulate gut microbiota and metabolites to protect intestinal epithelial barrier. Food Chemistry. 2023;422:136225.
  • Panyathep A, Chewonarin T, Taneyhill K, Vinitketkumnuen U, Surh YJ. Inhibitory Effects of Dried Longan (Euphoria longana Lam.) Seed Extract on Invasion and Matrix Metalloproteinases of Colon Cancer Cells. Journal of Agricultural and Food Chemistry. 2013 Apr 3;61(15):3631–41.
  • ‌Xuan Y, Chen Z, Zhang J, Chi Ming Huang, Zhao S, Li X, et al. Extraction, purification, structural features and biological activities of longan fruit pulp (Longyan) polysaccharides: A review. Frontiers in Nutrition. 2022 Jul 25;9.
  • ‌Molino S, Lerma-Aguilera A, Jiménez-Hernández N, Gosalbes MJ, Rufián-Henares JÁ, Francino MP. Enrichment of Food With Tannin Extracts Promotes Healthy Changes in the Human Gut Microbiota. Frontiers in Microbiology. 2021 Mar 16;12.
  • ‌Wang J, Guo D, Han D, Pan X, Li J. A comprehensive insight into the metabolic landscape of fruit pulp, peel, and seed in two longan (Dimocarpus longan Lour.) varieties. International Journal of Food Properties. 2020 Jan 1;23(1):1527–39.
  • Wu X, Huang H, Li M, Wang Y, Wu X, Wang Q, et al. Excessive consumption of the sugar-rich longan fruit promoted the development of nonalcoholic fatty liver disease via mediating gut dysbiosis. Food frontiers. 2022 Nov 29;4(1):491–510.
  • ‌Ofosu FK, Daliri EBM, Elahi F, Chelliah R, Lee BH, Oh DH. New Insights on the Use of Polyphenols as Natural Preservatives and Their Emerging Safety Concerns. Frontiers in Sustainable Food Systems. 2020 Nov 10;4.
  • Rank MA, Li JT. A CASE OF FOOD ALLERGY DUE TO LONGAN FRUIT. Annals of Allergy, Asthma & Immunology. 2007 Apr;98(4):402.

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Eva Henning

MSc Precision Medicine, University of Manchester, UK

Eva Henning is an enthusiastic intern with a strong academic background in science communication. Holding a Bachelor of Sciences from the University of Manchester, Eva continues her scientific journey by pursuing a Masters in Precision Medicine. Having gained experience in medical sciences, Eva brings a unique blend of academics and a passion for effective science communication with the general public. Eva provides readers with accurate, insightful and engaging content on a range of medical health content.

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