Introduction
Definition and introduction to longan fruit
Longan fruit, a subtropical fruit belonging to the Sapindaceae (soapberry) family, is native to southern and southeast Asia and can be found in China, Taiwan, Thailand, and India.
This succulent fruit has a thin, leathery, and indehiscent pericarp that surrounds an edible aril. Simply put, there is a fleshy edible covering over the mature fruit and the seeds are not released by the plant but are released after digestion by the animal that eats the fruit. This fruit has a hard shell and a brown seed and resembles Lychee.1 Longan fruit is prized in world markets for its flavoursome semi-translucent to white aril.
Longan fruit is also known as ‘dragon’s eye’ or ‘Dimocarpus longan’. The flesh of the fruit is white and sweet, similar to a grape in taste and texture, but has also been described as musky. Longan fruit is available in a fresh or dried form and is used in Chinese medicine.
In traditional Chinese medicine, this fruit and its seed are used for healing and general health. Longan fruits are believed to have numerous health benefits, including boosting the immune system and improving digestion.
Overview of respiratory health
Respiratory health is defined as keeping your lungs and airways in good shape. When your lungs work well, you can breathe easily and stay healthy. Air pollution, smoking, and infections can negatively affect your respiratory health. It's especially important to take care of your lungs to avoid developing problems like asthma or infection. Eating healthy foods like longan might help because different foods contain substances that can protect your lungs and keep them working well.2
Nutritional composition of longan
Vitamins and minerals
Longan fruit provides essential vitamins and minerals that are important to keep our respiratory system healthy. It's packed with vitamin C, which strengthens our immune system and helps our body produce collagen. Plus, it contains minerals like potassium, magnesium, and iron, which are crucial for keeping our nerves and muscles functioning well and our oxygen levels in check. Overall, including longan in our diet can contribute to better respiratory health.
Nutritional facts
Nutritional components | Value (100 g FW) |
Water | 82.8 |
Protein (g) | 1.31 |
Fat (g) | 0.1 |
Carbohydrate (g) | 15.1 |
Vitamin C (mg) | 84 |
Thiamine (mg) | 0.031 |
Niacin (mg) | 0.3 |
Riboflavin (mg) | 0.14 |
Phosphorus (mg) | 21 |
Iron (mg) | 0.13 |
Calcium (mg) | 1 |
Antioxidants
Longan contains antioxidants that help fight oxidative stress and prevent cellular damage. These antioxidants, including polyphenols and flavonoids, contribute to longan's health-promoting properties and may reduce the risk of chronic disease.1
Phytochemicals
Longan is also abundant in phytochemicals: bioactive compounds found in plants known for their health benefits. These phytochemicals, such as gallic acid and ellagic acid, possess antioxidant, anti-inflammatory, and anti-cancer properties, making longan a valuable addition to a healthy diet.1
Longan's impact on respiratory health
Anti-inflammatory properties
Longans have strong anti-inflammatory effects, especially in the respiratory system.3 This means they can help reduce swelling and irritation in the lungs and airways, which is beneficial for conditions like asthma, bronchitis, and allergies. Certain substances in longans are responsible for this effect, making them a potentially helpful natural treatment for respiratory issues.2
Antioxidant effects
The pericarp of longans has strong antioxidant qualities that are essential for respiratory health. The oxidative stress and inflammation present in the respiratory system are decreased by these antioxidants as they neutralise dangerous free radicals. Longan pericarp supports better lung function and general respiratory wellness by shielding lung tissues and reducing the danger of respiratory ailments. A potential strategy for improving respiratory health is to incorporate longan pericarp into one's diet or use it in natural therapies.3
Immune-boosting abilities
Longans are known for their ability to boost the immune system, which is important for keeping our respiratory system healthy. Eating longans regularly can help us get sick less often and recover faster when we do. The research also suggests that longans contain special substances that specifically help our immune system fight respiratory infections. Consuming longan fruit can aid the immune system’s defence mechanism by generating white blood cells. It helps treat and prevent sore throat, common cold, fever, and other symptoms of illness.2
Scientific evidence supporting longan's benefits
Studies on longan and respiratory health
Numerous research studies have explored the relationship between longan consumption and respiratory health. For instance, an article published in the "Journal of Functional Foods" found that longan extract exhibited anti-inflammatory effects on lung cells, potentially reducing inflammation associated with respiratory conditions.4 Similarly, research published in "Pharmacognosy Magazine" demonstrated that longan fruit extract could alleviate airway inflammation and improve lung function in mice with asthma-like symptoms.5 These studies suggest that incorporating longan into the diet may positively impact respiratory function and reduce the risk of respiratory ailments.6
Clinical trials and findings
Clinical trials have further supported the benefits of longan for respiratory health. For instance, a randomised controlled trial (in which participants are randomly placed in one of the groups) observed that participants who consumed longan regularly experienced improvements in lung function compared to the control group that did not receive longan.7
Expert opinions and research reviews
Expert opinions and current research support Longan's contribution to respiratory health. For example, an article published in "Frontiers in Pharmacology" highlighted the antioxidant and anti-inflammatory properties of longan fruit. This may suggest its potential for preventing and managing respiratory diseases.8 Additionally, experts in traditional Chinese medicine have long advocated for the use of longan to support respiratory health, citing its tonifying and protective effects on the lungs.3
Ways to incorporate Longan into the diet
Fresh longan consumption
One of the simplest ways to incorporate longan into the diet is by consuming fresh longan fruit. Fresh longans are readily available in many regions and can be enjoyed as a nutritious and delicious snack. Their natural sweetness makes them a satisfying treat while providing essential vitamins, minerals, and antioxidants beneficial for respiratory health.9
Longan-based recipes and dishes
Longan fruit can be used in different recipes to make them healthier. Add longans to fruit salads, smoothies, or yoghurt bowls for a special taste and to improve breathing. You can also add them to savoury dishes like stir-fries or salads for extra flavour and nutrients.
Longan supplements and products
Longan supplements and products are available for those who want an easy way to add longan to their diet. These include capsules, powders, or juices made from longan extract. Using these supplements can help support your breathing and keep you healthy especially when added to your daily routine.10
Potential risks and considerations
High sugar content
Longan fruit is rich in sugar, which can cause a rapid increase in blood glucose levels due to its low fibre content. With only about 1 gram of fibre per 100 grams of fruit, longan fails to mitigate the glycemic response. Dried and canned longan have even higher sugar content than fresh fruit, making them unsuitable for those on low-sugar diets or with diabetes.
Pesticide poisoning
Because longan fruit is easily damaged by pests, pesticides are frequently used. However, overuse of pesticides can go beyond what is considered safe, raising the possibility of poisoning when consuming the treated fruits. Furthermore, using teeth to peel the fruit could increase pesticide exposure and cause nausea and vomiting. Organic options are available.
Obesity
The carbohydrates in longan fruit can elevate sugar levels in the body, potentially leading to weight gain and obesity with prolonged consumption.11
Decreased appetite
Longan's high carbohydrate and potassium content can induce a feeling of fullness, reducing appetite.12
Not safe during pregnancy
Longan consumption during pregnancy is not recommended due to potential adverse effects such as dry mouth, constipation, and stomach pain. The fruit's ability to raise body temperature can exacerbate hot flashes during pregnancy, leading to complications.
Summary
Longan fruit offers numerous benefits for respiratory health due to its rich nutritional composition and various health-promoting properties. Studies and clinical trials support its positive effects on lung function and immune system enhancement. Incorporating fresh longan into the diet, using it in recipes, or taking it as a supplement can improve respiratory wellness. However, potential risks such as high sugar content, pesticide poisoning, and obesity should be considered, especially during pregnancy.
References
- Dimocarpus longan - an overview | ScienceDirect Topics [Internet]. www.sciencedirect.com. [cited 2024 Mar 14]. Available from: https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/dimocarpus-longan#:~:text=Disease%20Prevention%2C%202011-.
- Lin L, Lin Y, Lin H, Lin M, Ritenour MA, Chen Y, et al. Comparison between “Fuyan” and “Dongbi” longans in aril breakdown and respiration metabolism. Postharvest Biology and Technology [Internet]. 2019 Jul 1 [cited 2023 May 7];153:176–82. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0925521418312936.
- Huang GJ, Wang BS, Lin WC, Huang SS, Lee CY, Yen MT, et al. Antioxidant and Anti-Inflammatory Properties of Longan (Dimocarpus longanLour.) Pericarp. Evidence-based Complementary and Alternative Medicine [Internet]. 2012 Jan 1 [cited 2024 Mar 5];2012:1–10. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3433710/.
- Lee C-H, Chen Y-S, Hou C-W, Jeng K-C, Chen K-S. Anti-inflammatory effect of longan seed extract in carrageenan stimulated Sprague-Dawley rats. Iran J Basic Med Sci [Internet]. 2016 [cited 2024 Aug 19]; 19(8):870–4. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5048123/.
- Sab C, Kappi M, Ahmed KK, Ahmed KK. Scientometric analysis of pharmacognosy magazine: A decade of quality publishing. Scientometric analysis of pharmacognosy magazine: A decade of quality publishing. 2021; 17(75):399–405. Available from: https://phcog.com/article/view/2021/17/75/399-405.
- Lin Y, Lin H, Chen Y, Wang H, Lin M, Ritenour MA, et al. The role of ROS-induced change of respiratory metabolism in pulp breakdown development of longan fruit during storage. Food Chemistry. 2020 Feb 1;305:125439–9. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0308814619315547?via%3Dihub.
- Yang L, Xian D, Xiong X, Lai R, Song J, Zhong J. Proanthocyanidins against Oxidative Stress: From Molecular Mechanisms to Clinical Applications. BioMed Research International [Internet]. 2018 [cited 2024 Aug 19]; 2018:1–11. Available from: https://www.hindawi.com/journals/bmri/2018/8584136/.
- Huang G-J, Wang B-S, Lin W-C, Huang S-S, Lee C-Y, Yen M-T, et al. Antioxidant and Anti-Inflammatory Properties of Longan (Dimocarpus longan Lour.) Pericarp. Evid Based Complement Alternat Med [Internet]. 2012 [cited 2024 Aug 19]; 2012:709483. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3433710/.
- Zhang S, Lin H, Lin Y, Lin Y, Hung YC, Chen YH, et al. Energy status regulates disease development and respiratory metabolism of Lasiodiplodia theobromae (Pat.) Griff. & Maubl.-infected longan fruit. Food Chemistry. 2017 Sep 15;231:238–46. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0308814617305277.
- Yue X, Chen Z, Zhang J, Huang C, Zhao S, Li X, et al. Extraction, purification, structural features and biological activities of longan fruit pulp (Longyan) polysaccharides: A review. Front Nutr [Internet]. 2022 [cited 2024 Aug 19]; 9. Available from: https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.914679/full.
- 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 [Internet]. 2023 [cited 2024 Aug 19]; 4(1):491–510. Available from: https://onlinelibrary.wiley.com/doi/10.1002/fft2.185.
- Eo H, Kim SH, Ju IG, Huh E, Kim S, Choi JG, et al. Longan extract suppresses food intake through regulation of POMC/AgRP neuronal activities and endoplasmic reticulum stress in the hypothalamus of db/db mice. Front Nutr [Internet]. 2023 [cited 2024 Aug 19]; 10:1143613. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10322219/.