Overview
Respiratory health is the absence of disease in our lungs and airways. Many of us do not realise the importance of respiratory health until we experience a breathing problem. The lungs provide oxygen to the rest of the body and remove carbon dioxide to keep all of our organs functioning. Genetics, disease, and the environment all affect the health of our lungs. Food may not seem like an obvious factor in looking after our respiratory health, but research suggests that certain foods can have benefits for our airways, such as pineapple. Pineapple contains enzymes, vitamins, and antioxidants which help guard against respiratory diseases, from the common cold and asthma to more serious diseases.
Read on to discover how the compounds found in pineapple help to keep our airways healthy.
Nutritional components of pineapple
Pineapples contain many vitamins and minerals which help keep our whole body healthy, but some compounds found in this tropical fruit are particularly beneficial for our respiratory health, such as vitamin C, antioxidants, and enzymes.
Vitamin C
Vitamin C, also known as ascorbic acid, has many functions throughout the body, including protecting cells and keeping them healthy, helping control infections, and aiding in wound healing. Its functions are mainly due to its antioxidant properties.
Bromelain
Bromelain is a mixture of enzymes found only in pineapple. Bromelain is thought to reduce inflammation caused by infections or injuries and has also been said to help reduce pain.1 It has been used as a traditional medicine for centuries in some cultures, for example, in Central and South America, where it is touted as an indigestion remedy and anti-inflammatory. Bromelain is not found in high enough concentrations in pineapple to act as a medicine, but it still has health benefits when consumed this way. Bromelain extract is available in tablet form as a supplement to treat conditions such as sprains, tendinitis, sinusitis and minor muscle injuries and sometimes as a topical solution to treat burns.2 Bromelain’s therapeutic effects make it a promising potential alternative to traditional medicines.
Antioxidants
Antioxidants are chemicals that help protect our cells by preventing damage from free radicals. Free radicals are highly reactive molecules produced by the oxidation of food when it gets digested. Free radicals cause cell damage, and a build-up of them causes oxidative stress, which can lead to diseases such as heart disease, cancer, and Alzheimer’s.3 Pineapples are rich in two types of antioxidants: flavonoids and phenolic acids. Flavonoids are compounds found in many plants, such as fruits and vegetables. They have many health benefits, including anti-inflammatory, anti-viral, antioxidant and even anti-cancer properties. Phenolic acids are the main source of antioxidants in our diet and are easily absorbed by the body in the small intestine. They help prevent damage from free radicals and have anti-inflammatory effects, helping to prevent a range of diseases.4
How pineapple supports respiratory health
Role of vitamin C in immune function
Vitamin C is famed for its immune-boosting effects. One way it does this is by helping to increase the production and proliferation of white blood cells, the cells of the immune system that fight pathogens.5 Consuming pineapple can help to stave off respiratory viruses and infections such as the common cold and flu.
Vitamin C also acts as an antioxidant, preventing oxidative stress in the body. Oxidative stress causes us to feel run down and puts us at higher risk of becoming unwell, so consuming plenty of Vitamin C can help fight free radicals, prevent oxidative stress, and, therefore, keep us feeling healthy.
Bromelain's anti-inflammatory properties
This cocktail of enzymes unique to pineapple is an inflammation-fighting hero. Studies have found that bromelain can reduce swelling and bruising, as well as healing time and pain after surgery. In mainland Europe, bromelain is commonly used to bring down swelling in the sinuses and nasal passages after ear, nose, or throat surgery or trauma.2
It is these anti-inflammatory effects that are thought to be responsible for pineapple’s ability to ease symptoms of colds and allergies, by reducing swelling in the airways and sinuses. This can be especially beneficial for people with allergies, as it can help them to breathe easier.
Although it might seem counterintuitive to consume pineapple when you have a sore throat due to its acidic taste, which can irritate an already sore throat, the enzymes in pineapple can actually help to reduce the swelling and congestion in the throat, easing the associated pain and discomfort. Bromelain also has antiviral properties, so it may help to fight off the infection that is causing the sore throat.6
Bromelain has been used as a treatment for inflammatory and autoimmune disorders. Several autoimmune diseases affect the lungs, such as lupus, mixed connective tissue disease, and rheumatoid arthritis, among others. The broad term for these autoimmune conditions that affect the lungs is autoimmune interstitial lung disease (ILD), which is a progressive disease where the body’s own immune system starts to attack the lungs, causing inflammation and scarring of the lung tissue. Symptoms include a dry cough, difficulty breathing and shortness of breath. The powerful anti-inflammatory effects of bromelain can help ease these symptoms by reducing the inflammation in the lungs.7 Bromelain has also been shown to have immunosuppressant effects, which can help fight against autoimmune diseases.8
Bromelain's mucolytic properties
Bromelain also has mucolytic properties, meaning it breaks up mucus, making it easier to remove from the lungs.9 Mucus causes congestion in the chest and sinuses, thus consuming pineapple can help to break it up, making it easier to expel from the body, relieving symptoms of colds, flu, and allergies. Bromelain is especially useful if you have a stubborn cough; we cough when the body is trying to expel an irritant from the airways, and when we are unwell, this is usually mucus. By coughing, we attempt to dislodge the mucus from the airways and clear it out of our system. Bromelain helps to break the mucus down, making it easier to expel from the body. When the mucus has been cleared, the coughing will ease.
Antioxidants and their impact on respiratory tissues
Antioxidants help to fight free radicals. In the lungs, free radicals can damage the lung cells, leading to poor respiratory health and even cancer. It is important to gain antioxidants from our diet, as the amount that our body naturally produces is limited, and some types of antioxidants, such as vitamin C, cannot be made by the body, so must be gained from our diet.
Research and studies
Most studies focus on bromelain extract in isolation. It is uncertain whether the level of bromelain found naturally in pineapple is enough to reap its health benefits, but bromelain supplements, which contain much higher concentrations, are available.
Antimicrobial effects of bromelain
In addition to its anti-inflammatory effects, bromelain has also been shown to possess antimicrobial properties, meaning it kills or prevents the growth of microorganisms. Some studies have found that antibiotics are more effective against respiratory diseases such as influenza virus (flu), sinusitis, and chronic bronchitis when taken alongside bromelain.10
Anti-inflammatory effects of bromelain: preventing asthma, allergies, and sinusitis
Bromelain has many therapeutic benefits, but its anti-inflammatory actions seem to be the most prominent. As previously discussed, bromelain has been a successful treatment for autoimmune disorders. Aside from this, the bromelain in pineapples has been effective against asthma, allergic reactions, and sinus inflammation. It modulates the immune system, causing white blood cells to release cytokines (immune system signalling molecules) and enzymes which inhibit the actions of proteins that cause asthma and allergic reactions.8
Bromelain has also been shown to help manage sinus infections.10 Sinusitis is when the lining of the sinuses becomes swollen due to an infection. Sinuses are the cavities in the nose, cheeks, and forehead which make mucus. The mucus gets drained out of the nose in order to clear any bacteria, allergens or other pathogens.11 In a study on children with severe sinusitis, bromelain reduced the duration of symptoms and aided complete recovery better than traditional medicines. In adults, bromelain has been shown to provide complete relief from breathing difficulties and nasal mucosal infections (any infection that causes the lining of the nose to be swollen and inflamed, such as sinusitis).8
Anti-inflammatory effects of bromelain: preventing cancer
Inflammation is an important factor in cancer development. Reducing inflammation can, therefore, prevent cancer from developing and inhibit its progression. In a study on rats, bromelain caused a large decrease in the amount of inflammatory mediators (chemicals in the immune system that trigger inflammation).9 Bromelain also helps to stimulate tumour necrosis factor (TNF), a chemical messenger in the immune system that helps to protect the body from tumours.12 Consuming bromelain can help to reduce the risk of cancers, including lung cancer. However, there is not sufficient bromelain present in fresh pineapple to gain these effects.
Effect of bromelain on COVID
Bromelain has been shown to be effective at fighting the SARS-CoV-2 virus as both a supporting treatment and preventative treatment.6 Bromelain’s immunosuppressive effects mean it is able to slow down the development of COVID-19 infection by preventing inflammatory messengers from producing inflammatory cells that help the COVID-19 virus grow. Bromelain also breaks down the enzyme that SARS-CoV-2 binds to, limiting the virus's chances of reproducing and proliferating throughout the body.8 However, this evidence only comes from in vitro studies and computer simulations. Further testing is required on animal and human cell models before we can be sure of the therapeutic effects of bromelain against COVID-19.6
Incorporating pineapple into the diet
Pineapple is a delicious and diverse fruit that is easy to include in the diet. Widely available as fresh, ready-chopped, tinned, frozen, dried, candied, and juice, pineapple can be easily consumed as a snack or incorporated into recipes to gain its health benefits. Including pineapple in your diet will have a range of health benefits, especially for your respiratory system. Do note, though, that this is not medical advice, and eating pineapple cannot counteract an unhealthy lifestyle. You should always aim to eat a varied, balanced diet.
Fresh and frozen pineapples have almost exactly the same nutritional value, as frozen pineapple is usually picked and frozen at the peak of freshness. This may differ if you freeze frozen pineapple yourself. Contrary to what many people believe, tinned pineapple is also just as good for you as fresh, as long as it is canned in water and not sugar syrup. If it has been tinned in a sugar syrup, the nutrients are still present, but there is a higher sugar content, which pushes up the calories. Fresh pineapple is a better choice for people with a blood sugar condition such as type 2 diabetes. The only real downside to tinned pineapple is that it is lower in vitamin C, and therefore, if you want to boost your vitamin C intake, fresh pineapple is the better option.13 Both frozen and tinned pineapple tend to be cheaper than fresh pineapple and, therefore, is a more cost-effective way to benefit from its nutrients.
Recipe ideas
Pineapple can be enjoyed on its own or used in a host of dishes, from salads and curries to cakes and sorbets. Pineapple is also a great addition to smoothies, and both fresh and frozen work well. Try blending pineapple with a banana, lime juice and a splash of water for a refreshing, summery smoothie. You can also incorporate Greek yoghurt or flax seeds/chia seeds to increase the protein content of the smoothie. Spinach also works well with pineapple in smoothies, which is a good way to get more of your 5-a-day in, and get other vital nutrients such as iron and calcium.
Dried pineapple also makes for a good on-the-go snack, however it tends to be expensive, and the drying process can compromise its nutritional value. Dried pineapple is also high in sugar, so should be consumed in moderation as part of a balanced diet.
Potential risks and considerations
Allergic reactions
Allergy to pineapple is rare but does affect some people. It is the bromelain in pineapples that causes the allergic reaction. People with this allergy will get a localised rash accompanied by itching and swelling. If you are allergic to pineapples, you can get the health benefits by eating other fruits high in vitamin C and antioxidants, but unfortunately, you will not be able to reap the benefits of bromelain. You can undergo allergy testing to discover what exactly you are allergic to in pineapples - some people are allergic to a different protein found in pineapples called profiling.
Interactions with medication
Bromelain can interact with certain medications, potentially reducing their effectiveness. These include blood thinners, such as warfarin and clopidogrel and non-steroidal anti-inflammatories (aspirin, ibuprofen, naproxen, etc.) However, some medications are actually absorbed better and have a greater effect when taken alongside bromelain. These include certain antibiotics, antidepressants, sedatives, blood pressure medications, chemotherapy drugs and opioids like codeine.9
Fresh pineapple does not contain enough bromelain to have a significant effect on these medications, so it is usually fine to eat pineapple alongside them. It is always best to check with your doctor before considering taking bromelain supplements, as it could be dangerous to start taking these with any of the above medications.
Moderation in consumption
Pineapple and pineapple juice should be consumed in moderation as part of a balanced diet. Pineapple is high in natural sugars and acid, which can cause tooth decay. Additionally, if you are prone to mouth ulcers, it may be best to steer clear of pineapple as the acid can irritate and worsen ulcers. The naturally occurring sugars in pineapple also mean you should be careful about consuming it if you are watching your blood sugar levels, for example, if you have type 2 diabetes.
Lifestyle factors for respiratory health
Although pineapple has been proven to have benefits to our respiratory health, it is important to remember other lifestyle factors that help to maintain healthy lungs, such as regular exercise to improve your lung capacity and the strength of the muscles around your lungs, and hydration, which is as important for the lungs as it is the rest of the body. Drinking plenty of water helps to keep the mucus that lines the lungs thin, which makes it easier to cough up the mucus and helps the lungs to function better. It also helps to keep the lung lining moist, which is vital for proper oxygen transport and for capturing and clearing away any pathogens and allergens that we breathe in. Having dry lungs causes the lining to dry out, which weakens the respiratory system and puts you at risk of illness and allergens. Dry lungs can also cause shortness of breath, wheezing, and fatigue.14
As mentioned before, pineapple cannot cancel out the effects of unhealthy habits such as smoking. Smoking causes free radicals to build up in our lungs, damaging the lung cells and potentially leading to cancer. Although pineapple can go some way to reducing the effects of free radical damage, it cannot completely counteract or reverse the effects of smoking.
Summary
Pineapple contributes to enhanced respiratory health in a number of ways. Its high vitamin C content supports the immune system, helping to stave off respiratory diseases; antioxidants combat oxidative stress, protecting the lungs from damage caused by free radicals and environmental pollutants, and the anti-inflammatory effects of bromelain help to reduce inflammation in the lungs and airways, easing symptoms of respiratory diseases and potentially preventing the growth of cancerous tumours. Bromelain dietary supplements are available on the market, however these will not provide you with the other nutrients found in pineapple, like vitamin C, antioxidants, and fibre.
As always, a holistic approach is the best way to keep the respiratory system healthy. This can be achieved by eating a healthy diet with a range of fruits and vegetables, getting regular exercise, staying hydrated, avoiding smoking and, where possible, avoiding exposure to pollutants.
In conclusion, consuming pineapple alongside a healthy lifestyle may help to enhance respiratory health due to its nutritional components and anti-inflammatory and antioxidant properties.
Note: It's important to consult with a healthcare professional before making significant changes to your diet, especially if you have existing health conditions or concerns.
References
- ‘Bromelain’. NCCIH, https://www.nccih.nih.gov/health/bromelain. Accessed 7 Dec. 2023.
- ‘Bromelain Information | Mount Sinai - New York’. Mount Sinai Health System, https://www.mountsinai.org/health-library/supplement/bromelain. Accessed 7 Dec. 2023.
- Lobo, V., et al. ‘Free Radicals, Antioxidants and Functional Foods: Impact on Human Health’. Pharmacognosy Reviews, vol. 4, no. 8, 2010, pp. 118–26. PubMed Central, https://doi.org/10.4103/0973-7847.70902.
- Ali Ghasemzadeh. ‘Flavonoids and Phenolic Acids: Role and Biochemical Activity in Plants and Human’. Journal of Medicinal Plants Research, vol. 5, no. 31, Dec. 2011. DOI.org (Crossref), https://doi.org/10.5897/JMPR11.1404.
- Carr, Anitra C., and Silvia Maggini. ‘Vitamin C and Immune Function’. Nutrients, vol. 9, no. 11, Nov. 2017, p. 1211. PubMed Central, https://doi.org/10.3390/nu9111211.
- Hikisz, Pawel, and Joanna Bernasinska-Slomczewska. ‘Beneficial Properties of Bromelain’. Nutrients, vol. 13, no. 12, Nov. 2021, p. 4313. PubMed Central, https://doi.org/10.3390/nu13124313.
- Autoimmune Interstitial Lung Disease | Columbia Surgery. https://columbiasurgery.org/conditions-and-treatments/autoimmune-interstitial-lung-disease. Accessed 8 Dec. 2023.
- Varilla, Carolina, et al. ‘Bromelain, a Group of Pineapple Proteolytic Complex Enzymes (Ananas Comosus) and Their Possible Therapeutic and Clinical Effects. A Summary’. Foods, vol. 10, no. 10, Oct. 2021, p. 2249. www.mdpi.com, https://doi.org/10.3390/foods10102249.
- Chakraborty, Arka Jyoti, et al. ‘Bromelain a Potential Bioactive Compound: A Comprehensive Overview from a Pharmacological Perspective’. Life, vol. 11, no. 4, Apr. 2021, p. 317. PubMed Central, https://doi.org/10.3390/life11040317.
- Rathnavelu, Vidhya, et al. ‘Potential Role of Bromelain in Clinical and Therapeutic Applications (Review)’. Biomedical Reports, vol. 5, no. 3, Sept. 2016, pp. 283–88. www.spandidos-publications.com, https://doi.org/10.3892/br.2016.720.
- ‘Sinus Infection: Common Causes & How To Treat It’. Cleveland Clinic, https://my.clevelandclinic.org/health/diseases/17701-sinusitis. Accessed 8 Dec. 2023.
- Idriss, H. T., and J. H. Naismith. ‘TNF Alpha and the TNF Receptor Superfamily: Structure-Function Relationship(s)’. Microscopy Research and Technique, vol. 50, no. 3, Aug. 2000, pp. 184–95. PubMed, https://doi.org/10.1002/1097-0029(20000801)50:3<184::AID-JEMT2>3.0.CO;2-H.
- ‘Is Canned Pineapple Actually Healthy?’ LIVESTRONG.COM, https://www.livestrong.com/article/530229-the-nutritional-difference-between-canned-fresh-pineapple/. Accessed 8 Dec. 2023.
- Olien, Darin. WHY YOUR LUNGS NEED HYDRATION. https://darinolien.com/why-your-lungs-need-hydration/.