Papaya (Carica papaya) is a popular fruit due to its nutrient density and tasty flavour.1 However, often people eat the flesh of the fruit but don’t eat the seeds. Many people do not know that the seeds of papaya are not only edible but boast an impressive nutritional profile. Papaya seeds contain: a range of vitamins,1 fibre,2 healthy fatty acids3 and antioxidants such as flavonoids and polyphenols, and have many potential health benefits.4 Though, there may be some things that you need to consider before deciding to start consuming them.
So let's take a look at the benefits and drawbacks of including papaya seeds in your diet and their impact on your health.
Papaya seeds nutritional value
There is a wide range of important nutrients in Papaya seeds.1
Fibre
Fibre is a major component of papaya seeds. Increasing your fibre intake has been shown to cause a reduction in cholesterol and blood pressure.2,3 There is also an association between reduced risk of stroke and/or diabetes and high fibre intake.2,6 Having plenty of fibre in your diet may also help you to maintain a healthy weight.6, 7
Monounsaturated fatty acids
High amounts of beneficial monounsaturated fatty acids are found in papaya seeds - for example oleic acid.3
Diets rich in monounsaturated fatty acids could be beneficial to people who have type 2 diabetes. One study they found that this type of diet could decrease very low density lipoprotein cholesterol by 7.5%, with patients meeting the treatment goal for diabetes.9
Antioxidants
Papaya contains health-boosting antioxidants. Flavonoids and polyphenols are two compounds that perform this antioxidant role in papaya seeds.4
They act to reduce oxidative stress, decreasing your chance of developing chronic disease and help protect the immune system by acting against free radicals which can cause disease in the body.4,10
Potential health benefits of papaya seeds
Papaya seeds have been associated with several health benefits which are largely due to the nutrients they contains.1,2,3,4
Anticancer properties
Some research suggests Papaya seeds may have anticancer effects. A lab study showed that papaya seed extract protected against cancer development and had an anti-inflammatory effect.4,10,11
A lab based study showed that human colon cancer cell growth was reduced when cells were exposed to black papaya seeds.12
Another study demonstrated black papaya seed extracts to have a potent anticancer effect against some hepatocellular carcinoma (a type of liver cancer) in rats.13
Though these results demonstrate the potential of papaya seeds in combating cancer, more studies are required to see whether papaya seeds affect the growth of cancer in humans.
Fighting infections
There is some evidence that certain parasites and fungi can be killed by papaya seeds.14,15
One lab based study demonstrated that papaya seeds exerted an antifungal effect against 3 specific fungal strains. This included Candida albicans which causes yeast infections in humans.14
One study suggested that papaya seed extract may be able to prevent threadworm (pinworms) eggs hatching and may be able to kill the lava.15
Though evidence is currently relatively sparse, papaya seeds should not be relied upon to treat infections. More larger-scale studies are required to look at papaya seeds effectiveness against parasitic and fungal infections in humans.
Protecting the liver and kidney
Papaya seeds antioxidants also may potentially help to prevent damage to your organs such as the liver and kidneys.4,16,17 A few animal studies have demonstrated the benefits of papaya seeds on liver and kidney function.
Your liver is an important organ for breaking down substances in the body and filtering the blood.18 Whilst your kidneys remove excess fluid and waste both play an essential role in your health.19
Papaya seed extract may help to prevent damage to the kidneys, this was demonstrated in a rat study where rats were given a toxic medicine. Papaya’s antioxidants may act on the cellular level by blocking oxidative damage, therefore preserving the health of the kidneys.16
Papaya seeds have also been found to have a protective effect in liver health. In another study, rats were fed papaya seeds for 12 weeks and they were found to protect against damage to the liver.17
Promotes gut health
Seeds contain lots of fibre and papaya seeds are no exception.2,20
Adding more fibre to your diet may help to regulate your bowel movements as fibre is not digested in your gastrointestinal tract. It adds more weight to your stool as it moves through your intestine. It has been shown that adding more fibre to your diet increased how often bowel movements occurred in people suffering from constipation21,22.
Increasing the amount of fibre you eat may also promote digestive health in other ways as well. Studies demonstrate that additional dietary fibre may help to alleviate hemorrhoid symptoms,23 helping to aid treatment of peptic ulcers,24 and even have a protective effect against inflammatory bowel disease.25
Protective effects on the brain
Some studies have suggested that papaya seeds may have neuroprotective effects on the brain.
In one such study, mice were given either papaya seed extract or pulp of papaya and both were found to have some beneficial neuroprotective effect yet the papaya pulp had greater effect.26
Papaya seeds also have a protective effect against oxidative stress, which may be useful for some neurodegenerative conditions like Alzheimer’s.26,27 However, there is a lack of studies conducted in humans so this isn't conclusive.
Skin benefits
Papaya seeds contain bioactive compounds (BAC’s) like antioxidants and phenolic compounds giving them potential in cosmeceutical products. Particularly BAC’s that may aid wound healing.28
One animal study on Papaya seeds has found that papaya seeds promote wound healing in the skin of rats.29 Though there are few studies on this effect.
Things to consider
Whilst eating papaya seeds may have a range of beneficial effects, there are some possible health concerns associated with their consumption.
Potentially reduce fertility
Animal studies have suggested that papaya seeds may decrease fertility.
One example of this was a study in which monkeys were given papaya seed extract in large doses which led to the development of azoospermia (no sperm found in the semen).30 Similar results were also observed in studies on rats,31,32 with reversal of the effect being seen in 30-45 days of ceasing treatment.32
Though the dose of papaya seed extracts given in these studies was far in excess of what the majority of people eat.30,31,32
However, these studies were only performed in animals and human studies would be required to confirm that the effects are the same.
Large servings could be harmful
Benzyl isothiocyanate is a compound found in a range of cruciferous vegetables and has also been found in papaya seeds.12,33
Whilst this compound has shown to have potential cancer prevention properties according to some lab based studies, other research reports that larger servings may be harmful.12
One rat study demonstrated that benzyl isothiocyanate can lead to significant DNA damage.34
Another rat study showed that it had a detrimental effect on cells in the bladder of rats.35
It is important to remember that these studies used highly concentrated benzyl isothiocyanate and were performed on animals.34,35 Therefore, more studies are needed on more realistic servings of papaya seeds in humans to evaluate these risks.
Allergic reactions
As with any food there is a possibility of an allergic reaction to papaya, in papaya this is often a response to the enzyme papain. It has been suggested that there is an association between this response and an allergy to natural latex rubber.36 In very rare instances there may be a life threatening reaction (anaphylaxis) in people who are allergic to papain.37
Summary
- Papaya seeds contain lots of key nutrients like fibre, vitamins, antioxidants and monounsaturated fats.
- Research has shown that papaya seeds may improve digestive health, have antiparasitic and antifungal effects, have a protective effect against cancer, kidney health, liver health, and skin health and have protective effects on the brain.
- However, many studies are reliant on lab and animal studies so talk to your doctor if you have any concerns about your health.
- Some lab and animal studies have found that, in concentrated doses, papaya seeds could have damaging effects on DNA and cells and reduce fertility in people AMAB (assigned male at birth).
- There aren’t many human studies that demonstrate these same disadvantages in human health and the doses in these studies are typically very high.
- Enjoying papaya seeds in moderation and limiting yourself to a couple of servings a day ensures these problems can be avoided.
References
- Zhou Z, Ford R, Bar I, Kanchana-udomkan C. Papaya (Carica papaya L.) flavour profiling. Genes [Internet]. 2021 Sep [cited 2023 Dec 4];12(9):1416. Available from: https://www.mdpi.com/2073-4425/12/9/1416
- Santana LF, Inada AC, do Espirito Santo BLS, Filiú WFO, Pott A, Alves FM, et al. Nutraceutical potential of carica papaya in metabolic syndrome. Nutrients [Internet]. 2019 Jul 16 [cited 2023 Dec 4];11(7):1608. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6682863/
- Santana LF, do Espirito Santo BLS, Tatara MB, Negrão FJ, Croda J, Alves FM, et al. Effects of the seed oil of carica papaya linn on food consumption, adiposity, metabolic and inflammatory profile of mice using hyperlipidic diet. Molecules [Internet]. 2022 Oct 8 [cited 2023 Dec 4];27(19):6705. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9570947/
- Gazwi HSS, Soltan OIA, Abdel-Hameed SM. Cakes fortified with papaya seeds effectively protects against CCl4-induced immunotoxicity. Environ Sci Pollut Res Int [Internet]. 2023 [cited 2023 Dec 4];30(51):111511–24. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10625515/
- Ghavami A, Banpouri S, Ziaei R, Talebi S, Vajdi M, Nattagh‐Eshtivani E, et al. Effect of soluble fiber on blood pressure in adults: a systematic review and dose–response meta-analysis of randomized controlled trials. Nutr J [Internet]. 2023 Oct 13 [cited 2023 Dec 4];22:51. Available from:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10571351/
- Saklayen MG. The global epidemic of the metabolic syndrome. Curr Hypertens Rep [Internet]. 2018 [cited 2023 Dec 4];20(2):12. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5866840/
- Offringa LC, Hartle JC, Rigdon J, Gardner CD. Changes in quantity and sources of dietary fiber from adopting healthy low-fat vs. Healthy low-carb weight loss diets: secondary analysis of dietfits weight loss diet study. Nutrients [Internet]. 2021 Oct 16 [cited 2023 Dec 4];13(10):3625. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8539701/
- Santana LF, do Espirito Santo BLS, Tatara MB, Negrão FJ, Croda J, Alves FM, et al. Effects of the seed oil of carica papaya linn on food consumption, adiposity, metabolic and inflammatory profile of mice using hyperlipidic diet. Molecules [Internet]. 2022 Oct 8 [cited 2023 Dec 4];27(19):6705. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9570947/
- Effects of a low-fat diet compared with those of a high-monounsaturated fat diet on body weight, plasma lipids and lipoproteins, and glycemic control in type 2 diabetes. The American Journal of Clinical Nutrition [Internet]. 2004 Nov 1 [cited 2023 Dec 5];80(3):668–73. Available from: https://www.sciencedirect.com/science/article/pii/S0002916522035766
- Forman HJ, Zhang H. Targeting oxidative stress in disease: promise and limitations of antioxidant therapy. Nat Rev Drug Discov [Internet]. 2021 [cited 2023 Dec 5];20(9):689–709. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8243062/
- Li ZY, Wang Y, Shen WT, Zhou P. Content determination of benzyl glucosinolate and anti–cancer activity of its hydrolysis product in Carica papaya L. Asian Pacific Journal of Tropical Medicine [Internet]. 2012 Mar 1 [cited 2023 Dec 5];5(3):231–3. Available from: https://www.sciencedirect.com/science/article/pii/S1995764512600303
- Mahrous NS, Noseer EA. Anticancer potential of Carica papaya Linn black seed extract against human colon cancer cell line: in vitro study. BMC Complement Med Ther [Internet]. 2023 Jul 29 [cited 2023 Dec 5];23:271. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10385885/
- Kyei-Barffour I, Kwarkoh RKB, Acheampong DO, Brah AS, Akwetey SA, Aboagye B. Alkaloidal extract from Carica papaya seeds ameliorates CCl4-induced hepatocellular carcinoma in rats. Heliyon [Internet]. 2021 Aug 20 [cited 2023 Dec 5];7(8):e07849. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8387916/
- Singh O, Ali M. Phytochemical and antifungal profiles of the seeds of carica papaya l. Indian J Pharm Sci [Internet]. 2011 [cited 2023 Dec 5];73(4):447–51. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3374564/
- Cabral ERM, Moraes D, Levenhagen MA, Matos RAFD, Costa-Cruz JM, Rodrigues RM. In vitro ovicidal and larvicidal activity of Carica papaya seed hexane extract against Strongyloides venezuelensis. Revista do Instituto de Medicina Tropical de São Paulo. 2019;(61).Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6880996/
- Naggayi M, Mukiibi N, Iliya E. The protective effects of aqueous extract of Carica papaya seeds in paracetamol induced nephrotoxicity in male wistar rats. Afr Health Sci [Internet]. 2015 Jun [cited 2023 Dec 5];15(2):598–605. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480493/
- Shaban NZ, El-Kot SM, Awad OM, Hafez AM, Fouad GM. The antioxidant and anti-inflammatory effects of Carica Papaya Linn. seeds extract on CCl4-induced liver injury in male rats. BMC Complement Med Ther [Internet]. 2021 Dec 30 [cited 2023 Dec 5];21:302. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8719404/
- Cleveland Clinic [Internet]. [cited 2023 Dec 5]. Liver: what it does, disorders & symptoms, staying healthy. Available from: https://my.clevelandclinic.org/health/articles/21481-liver
- Cleveland Clinic [Internet]. [cited 2023 Dec 5]. Kidneys: location, anatomy, function & health. Available from: https://my.clevelandclinic.org/health/body/21824-kidney
- Cleveland Clinic [Internet]. [cited 2023 Dec 5]. The 6 best seeds to eat. Available from: https://health.clevelandclinic.org/the-6-best-seeds-to-eat
- Bharucha AE, Lacy BE. Mechanisms, evaluation, and management of chronic constipation. Gastroenterology [Internet]. 2020 Apr [cited 2023 Dec 5];158(5):1232-1249.e3. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7573977/
- Guo K, Yao Z, Yang T. Intestinal microbiota-mediated dietary fiber bioavailability. Front Nutr [Internet]. 2022 Oct 28 [cited 2023 Dec 5];9:1003571. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9651179/
- Anderson JW, Baird P, Davis RH, Ferreri S, Knudtson M, Koraym A, et al. Health benefits of dietary fiber. Nutr Rev. 2009 Apr;67(4):188–205. Available from: https://pubmed.ncbi.nlm.nih.gov/19335713/
- VOMERO ND, COLPO E. Nutritional care in peptic ulcer. Arq Bras Cir Dig [Internet]. 2014 [cited 2023 Dec 5];27(4):298–302. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4743227/
- Pituch-Zdanowska A, Banaszkiewicz A, Albrecht P. The role of dietary fibre in inflammatory bowel disease. Prz Gastroenterol [Internet]. 2015 [cited 2023 Dec 5];10(3):135–41. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4607699/
- Naz F, Sajid S, Yueda L, Yang Z, Naheed S. A comparative study of anti-aging effects of Carica papaya (Pulp and seeds) on D-galactose-induced brain aging in albino rats. J Clin Transl Res [Internet]. 2022 Sep 28 [cited 2023 Dec 5];8(5):434–44. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9706316/
- Panzarini E, Dwikat M, Mariano S, Vergallo C, Dini L. Administration dependent antioxidant effect of carica papaya seeds water extract. Evid Based Complement Alternat Med [Internet]. 2014 [cited 2023 Dec 5];2014:281508. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3984819/
- García-Villegas A, Rojas-García A, Villegas-Aguilar M del C, Fernández-Moreno P, Fernández-Ochoa Á, Cádiz-Gurrea M de la L, et al. Cosmeceutical potential of major tropical and subtropical fruit by-products for a sustainable revalorization. Antioxidants [Internet]. 2022 Feb [cited 2023 Dec 5];11(2):203. Available from: https://www.mdpi.com/2076-3921/11/2/203
- Nayak BS, Ramdeen R, Adogwa A, Ramsubhag A, Marshall JR. Wound‐healing potential of an ethanol extract of Carica papaya (Caricaceae) seeds. Int Wound J [Internet]. 2012 Feb 1 [cited 2023 Dec 5];9(6):650–5. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7950972/
- Lohiya NK, Manivannan B, Mishra PK, Pathak N, Sriram S, Bhande SS, et al. Chloroform extract of Carica papaya seeds induces long-term reversible azoospermia in langur monkey. Asian J Androl. 2002 Mar;4(1):17–26. Available from: https://www.researchgate.net/publication/11455974_Chloroform_extract_of_Carica_papaya_seeds_induces_long-term_reversible_azoospermia_in_langur_monkey
- Manivannan B, Mittal R, Goyal S, Ansari AS, Lohiya NK. Sperm characteristics and ultrastructure of testes of rats after long-term treatment with the methanol subfraction of Carica papaya seeds. Asian J Androl [Internet]. 2009 Sep [cited 2023 Dec 5];11(5):583–99. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3735006/
- Uche-Nwachi EO, Mitchell CV, McEwen C. Steroidogenic enzyme histochemistry in the testis of sprague dawley rats following the administration the water extracts from carica papaya seed. Afr J Tradit Complement Altern Med [Internet]. 2010 Oct 2 [cited 2023 Dec 5];8(1):69–78. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3218444/
- Mastuo T, Miyata Y, Yuno T, Mukae Y, Otsubo A, Mitsunari K, et al. Molecular mechanisms of the anti-cancer effects of isothiocyanates from cruciferous vegetables in bladder cancer. Molecules [Internet]. 2020 Jan 29 [cited 2023 Dec 5];25(3):575. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7037050/
- Kassie F, Pool-Zobel B, Parzefall W, Knasmüller S. Genotoxic effects of benzyl isothiocyanate, a natural chemopreventive agent. Mutagenesis. 1999 Nov;14(6):595–604. Available from: https://pubmed.ncbi.nlm.nih.gov/10567035/
- Masutomi N, Toyoda K, Shibutani M, Niho N, Uneyama C, Takahashi N, et al. Toxic effects of benzyl and allyl isothiocyanates and benzyl-isoform specific metabolites in the urinary bladder after a single intravesical application to rats. Toxicol Pathol [Internet]. 2001 Oct [cited 2023 Dec 5];29(6):617–22. Available from: http://journals.sagepub.com/doi/10.1080/019262301753385942
- Vandenplas O, Vandezande LM, Halloy JL, Delwiche JP, Jamart J, Looze Y. Association between sensitization to natural rubber latex and papain. J Allergy Clin Immunol. 1996 Jun;97(6):1421–4. Available from: https://pubmed.ncbi.nlm.nih.gov/8648044/
- Benedé S, Pérez-Rangel I, Lozano-Ojalvo D, Molina E, Ibañez MD, López-Fandiño R, et al. Anaphylaxis induced by a drug containing lysozyme and papain: influence of papain on the IgE response. Int Arch Allergy Immunol. 2014;165(2):83–90. Available from: https://pubmed.ncbi.nlm.nih.gov/25359082/
