Lychee and Its Contribution to Respiratory Health

A particular fruit that has been gaining a lot of attention recently all around the world is the lychee fruit (also known as Litchi chinensis). Native to the tropical areas of China and Southeast Asia, the lychee fruit belongs to the soapberry family (Sapindaceae) and is composed of inedible pink-red, scaly skin, white pulp and a large seed in its centre. It is most typically eaten fresh, however, the fruit can also be used in ice cream, juices, wine and jellies.¹ This fruit is becoming more and more popular worldwide due to its distinct sweet flavour, as well as for its richness in important nutrients that we need to keep us healthy. Specifically, this fruit has shown promise to effectively help keep our lungs healthy.² 

Keeping our lungs and our respiratory system healthy is of utmost importance. Our lungs are central in keeping our whole body functioning properly, as every organ in our body relies on our respiratory system. This is because our lungs collect oxygen from the air we breathe in and provide it to every organ, as well as expelling any toxic waste gases (such as carbon dioxide) out of our body. This process is crucial in making sure our organs keep functioning the way they should. When our lungs are compromised, then our whole body’s health can be affected, in turn impacting our overall quality of life.³ Hence, it is vital to keep our lungs healthy, and one way to do so is through what we eat.⁴ The lychee is becoming an excellent example of a fruit to eat to maintain our respiratory health.² This article will detail the nutritional composition of the lychee fruit, and how its various nutrients can help keep our lungs healthy.

Nutritional composition of the lychee fruit 

The lychee is packed full of nutrients which help keep our lungs healthy. The following vitamins and minerals are those which are found most abundantly in the fruit and which have been shown to benefit our respiratory system: 

• Vitamin A
• Vitamin C - The most abundant vitamin found in lychees 
• B-complex vitamins - Examples include thiamine, niacin and folates
• Potassium
• Copper
• Manganese
• Magnesium 
• Zinc
• Selenium

Other vital compounds found within lychees are natural plant compounds called polyphenols such as flavonoids, which have been proven to be beneficial for our lung health. The most important examples found within lychees include epicatechin and rutin.^5,6 

How do lychee nutrients help keep our lungs healthy? 

The antioxidant properties of lychees

Many of the nutrients found within lychees are known to be “antioxidants”. In fact, lychees are known to contain higher levels of antioxidant nutrients compared to other fruits.⁷ 

An antioxidant is a substance that protects our body from an abundant amount of compounds called reactive oxygen species (ROS). ROS are highly reactive substances which can either be naturally produced via normal cellular processes all around the body, or through exposure to external toxins (such as cigarette smoke and air pollution).⁸ Moderated levels of ROS are important for us, as they interact with other compounds all over our body in important processes which allow our organs to function properly. However, too many ROS can instead interact with too many bodily processes that they should not be interacting with in the first place, leading to dysfunctions within such processes. Too many ROS can also damage our DNA (the genetic material found within our cells), which as a consequence can cause our cells to stop functioning properly and die. This negative consequence of abundant ROS is called oxidative stress.⁸ When oxidative stress occurs within our lungs, this can cause them to stop functioning properly, in turn affecting our whole body’s health and making us more susceptible to developing a lung disease.⁹ 

The specific nutrients of lychees that are well-known for their antioxidant capabilities are polyphenols like flavonoids. These substances can scour our lungs, searching for ROS, and when found they interact with ROS to stop them from disrupting important lung processes and preventing DNA damage in lung cells. Hence, the polyphenols'  antioxidant capabilities help protect the function of our lungs and keep our respiratory system, and in turn our whole body, healthy.^5,6 Other nutrients within lychees that have antioxidant properties include the vitamins A and C, as well as the minerals copper, zinc, manganese, magnesium and selenium.   

The anti-inflammatory properties of lychees

Inflammation is a natural bodily response that occurs when a part of our body is harmed - for instance, sustaining an injury or developing an infection. An inflammatory response signals our immune system (our natural self-defence system) about what harm is occurring and where in the body. This signal allows cells of the immune system to target the harm and eliminate it. Hence, inflammation is an essential process which helps alert our body to injuries to get rid of them. However, it is equally important for inflammation to then stop once the harm has been dealt with. If instead inflammation persists and does not go away, even after the harm has been eliminated, this can lead to chronic inflammation, which can cause a variety of issues for us.¹⁰ Specifically focusing on the lungs, chronic inflammation can lead to a variety of consequences that negatively impact our respiratory health:¹¹ 

• It can damage our healthy lung cells, resulting in an impairment of their function
• It can limit airflow into the lungs
• It can limit how much oxygen we absorb into our blood from the air we breathe in. This in turn can cause hypoxemia (low amount of oxygen in our blood) and hypoxia (low amount of oxygen in our organs)

Various nutrients in the lychee fruit are known to be anti-inflammatory, which is a term given to any substance which helps lower inflammation levels in our body after an infection or injury has been eliminated. Such nutrients include all the vitamins mentioned above, polyphenols like flavonoids, and the minerals copper and potassium.¹² 

Moreover, the antioxidant capacities of the lychee nutrients (detailed in the section above) all help in the reduction of inflammation and the prevention of chronic inflammation. This is because oxidative stress is known to make us more susceptible to developing chronic inflammation,¹³ hence the antioxidants which reduce our chances of oxidative stress in turn also help regulate our inflammation levels.¹² 

Potential benefits for respiratory conditions

The antioxidant and anti-inflammatory nutrients of lychees can help prevent us from developing serious lung conditions. Examples of the most common lung conditions include:

• Chronic obstructive pulmonary disease (COPD) – This disease is in the top 3 biggest causes of death worldwide
• Asthma - Over 300 million people worldwide suffer from this disease¹⁴ 
• Lung cancer – The type of cancer that causes the most deaths overall compared to other cancers

Both oxidative stress and inflammation play a key role in the development of all the serious lung conditions listed above.^9,11 Hence, the antioxidant and anti-inflammatory vitamins, minerals, and polyphenols of lychees all help prevent us from developing these life-threatening lung conditions and instead promote a healthy respiratory system. 

Is lychee safe for everyone to eat?

Lychees are considered generally safe to eat. Consumption in moderation, for instance as one portion of your 5-a-day fruit and vegetables, should be safe for the majority of people. However, it is important to note that some people could experience allergic reactions after eating lychee fruit. Examples of symptoms include:^15,16

• Itchiness
• Sore throat
• Swelling of gums
• Ulcers in the mouth 
• Fever
• Hives
• Swelling of the tongue and lips
• Breathing difficulties 

However, as stated above, allergic reactions to lychees are rare, and consumption of the fruit in moderation is typically safe. 

Summary

Lychees are sweet-tasting fruits, native to the tropical areas of China and Southeast Asia, which have been gaining attention in the medical field for their various essential nutrients and how such nutrients can preserve good health. In particular, the antioxidant and anti-inflammatory properties of their vitamins, minerals, and polyphenols have been shown to keep our lungs functioning properly, as well as protect us from life-threatening lung conditions such as asthma, COPD and cancer. Hence, adding lychee to your 5-a-day fruit and vegetable portions would greatly benefit your respiratory health. It is important to note, however, that, like any other food, lychees must be consumed in moderation, to avoid any adverse reactions.