Volume 41 Number 2

Clinical Question

What is the best available evidence on the use of topical coconut products in wound management and the treatment of skin conditions?

Summary

Despite the wide use of topical coconut products for medicinal purposes in tropical geographic regions, only a limited number of clinical studies reporting its effectiveness in treating skin conditions and no studies reporting its use in wound management were identified is this rapid review. Level 1 evidence^1,2 demonstrated that topical virgin coconut oil (VCO) is associated with improvements in signs and symptoms of xerosis^1,2 and psoriasis³ in adults, and mild-to-moderate dermatitis in children⁴. There is some evidence that VCO improves scores of skin immaturity in preterm neonates^5,6. Currently no evidence is available on the use of topical coconut products for healing human wounds.

Clinical practice recommendations

All recommendations should be applied with consideration to the wound, the person, the health professional and the clinical context.

• Topical VCO could be considered for the treatment of mild-to-moderate xerosis (Grade B).
• Topical VCO could be considered for the treatment of psoriasis in the absence of access to topical corticosteroid therapy (Grade B).
• Topical VCO could be considered for the treatment of mild-to-moderate atopic dermatitis in children (Grade B).

Sources of evidence

This summary was conducted using methods published by the Joanna Briggs Institute (JBI)^7–11. The summary is based on a systematic literature search combining search terms related to wounds and skin conditions with terms related to coconut palm. Searches were conducted in Embase, Medline, Global Health, and Allied and Complementary Medicine databases, and in 10 healthcare journals from low- and middle-income countries for evidence published up to May 2021 in English. Studies were assigned a level of evidence (Table 1) based on JBI’s hierarchy^7–11. Recommendations are made based on the body of evidence and are graded according to the system reported by JBI^7–11.

Table 1. Levels of evidence

Background

Various parts of the coconut tree have been used for a multitude of purposes in traditional medicine for thousands of years, to the extent that the plant is often called the “tree of life”¹⁶. Products derived from Cocos nucifera Linn: Arecaacae include coconut water, oil from coconut milk or copra (dried kernel), dried coconut shell and husk fibre^17,18. The most used coconut product, virgin coconut oil (VCO), is extracted directly from coconut flesh and contains medium chain fatty acids that have surfactant qualities^1,19,20. Another tested product, coconut shell liquid smoke (CS-LS) is produced by burning coconut shells at 400˚C resulting in a solution arising from condensation of vapour of wood smoke¹⁴. Coconut shells contain the highest antioxidant properties of any parts of the coconut¹⁴.

Laboratory testing and biochemical analysis of these products have identified a number of useful properties – anti-inflammatory, antimicrobial, antifungal, antioxidant, antineoplastic and analgesic^{17,18,20–24}. When applied topically, VCO provides barrier protection for the stratum corneum and reduces transepidermal water loss (TEWL), promoting skin moisturisation^19,20,24,25. When used on wounds, VCO and other coconut-derived products are reported to promote collagen synthesis and faster epithelisation^15,20,24.

Evidence

Evidence from animal studies

Evidence on the wound healing effect of coconut comes from animal studies. Results from three studies^13–15 are provided as examples of the significant amount of laboratory work on this topic. In the first study¹³, undertaken in India, VCO was applied daily for 10 days to open dermal wounds in rats. There were three groups of six rats each – a control group, a group treated with 0.5ml VCO, and a third treated with 1ml VCO. Time to complete epithelisation and composition of granulation tissue (e.g., collagen and fibroblasts) were among the outcome measures. In terms of both time to complete epithelisation and total collagen content, groups 2 and 3 were statistically significant compared to the control (p<0.05), 1ml being more effective than 0.5ml¹³ (Level 5).

The second study¹⁴ was conducted in Indonesia to evaluate the healing activity of CS-LS for burns. Thirty-six mice were randomised into three groups (n=12/group) – CS-LS, normal saline 0.9% (NaCl), and 10% povidone iodine. The burn wounds were left open, with treatment applied twice daily for 25 days. Wound contraction was measured on days 1, 5, 10 and 25 after burn induction. The CS-LS group showed the fastest wound contraction of the three groups by day 5 (p<0.001). On day 10 there was a statistically significant difference to the povidone iodine group (p<0.001) and on day 25 there was a statistically significant difference to the NaCl group (p<0.05)¹⁴ (Level 5).

In the third study¹⁵, VCO for treating diabetic ulcers was explored with a rat population. Rats with ulcers were divided into four groups – non-treated, non-diabetic rats (n=18), non-treated diabetic rats (n=18), diabetic rats receiving 1ml VCO applied daily for 14 days (n=18), and diabetic rats receiving silver sulfadiazine cream applied daily for 14 days (n=18). Wound closure rates were measured on days 5, 10 and 14. Diabetic ulcers treated with VCO had statistically significantly faster closure rates (p<0.05) compared with diabetic ulcers receiving no treatment on all days. On days 5 and 14 there was a statistically significant difference between the VCO and the silver sulfadiazine cream groups (p<0.05), favouring VCO¹⁵ (Level 5).

Evidence from human studies

Evidence on effectiveness for treating wounds

No evidence on topical coconut products for use in treating human wounds was identified.

Evidence on effectiveness for treating skin conditions

Xerosis in adults

Two blinded RCTs^1,2 provided evidence for using VCO to relieve xerosis (dry skin) in adults. The first RCT¹ was conducted on 34 individuals with mild-to-moderate xerosis to determine the effectiveness and safety of VCO compared with mineral oil when used as a therapeutic moisturiser. The solutions were applied to the legs twice daily for 14 days. Skin hydration and skin lipids were tested to measure effectiveness while TEWL and skin pH were the quantitative measures for safety. Xerosis was evaluated for dryness, scaling, roughness and pruritus by both an investigator using Wehr’s Grading and by participants using a visual analogue scale. Data were collected at baseline, day 7 and day 14. Participants also evaluated side effects (e.g., erythema, stinging or itching). Both treatments were comparable in terms of outcome measures for effectiveness and safety. By the end of the study 81% (13/16) of the participants in the VCO group showed improvement of at least one level in xerosis grading compared to 72% (13/18) of the mineral oil group¹ (Level 1).

The second RCT² compared VCO to virgin olive oil (VOO) for relieving xerosis and eliminating Staphylococcus aureus from skin in adults with atopic dermatitis (n=52). One group was treated with VCO and the other with VOO, with oils massaged gently into the skin twice daily at two skin sites displaying no clinical signs of infection. Outcome measures were skin cultures, photography and the objective component of the SCORAD severity index (O-SSI). Assessment occurred at baseline and at 4 weeks. At 4 weeks, the VCO group improved more significantly on the O-SSI compared to the VOO group (p=0.004)². Of the VCO group, 77% (20/26) were positive for S. aureus on entry to the study compared 46% (12/26) in the VOO group. Following treatment, only 5% (1/12) of the VCO group remained positive versus 50% (6/12) of the VOO group. The relative risk for VCO was 0.1 compared to 10.1 for VOO (p=0.00; 95% confidence interval [CI], 0.01–0.73, number needed to treat [NNT]=2.2) (Level 1).

Psoriasis in adults

Two studies provided evidence on the use of coconut oil for treating psoriasis. In an RCT (n=40)³, adults with scalp psoriasis were randomised into three groups to assess the effectiveness of relatively bland emollients: 5% coal tar solution plus coconut oil (1:1); 10% urea, 10% lactic acid, 10% propylene glycol plus 10% liquid paraffin (in a cream base); and VCO alone. All three groups showed comparable significant improvement over time, showing 57%, 64.4% and 58.3% clearing of symptoms respectively (p<0.01) without adverse effects. The authors noted that topical corticosteroids have demonstrated substantially higher response and clearance rates than this study found³ (Level 1).

An observational study (n=31)¹² explored the use of VCO applied twice daily for 8 weeks to psoriasis lesions in adults. Erythema, scaling and plaque elevation were evaluated every second week using photography and a clinical assessment of symptom clearance. At the completion of the study 16% of participants (5/31) had complete clearance. Scaling was observed to be most reduced in the 4–6-week period of treatment, while erythema and plaque elevation were most improved in the 6–8-week period. No adverse effects were experienced¹² (Level 3).

Dermatitis in children

One RCT⁴ (n=117) compared the effectiveness of topical VCO to that of topical mineral oil for children (aged between 1–13 years) with mild-to-moderate atopic dermatitis. For both treatment groups, 5ml of oil was applied twice daily. Impact on epidermal function was measured using a clinical assessment tool (SSI) and by measuring TEWL and skin capacitance, all measured at baseline and 2, 4 and 8 weeks. On the SSI measure the VCO was significantly more effective than the mineral oil (mean reduction in symptoms 68.23% versus 38.13%, p<0.001). The VCO also produced significantly effective results in terms of the TEWL over the 8-week period compared to the mineral oil group (decrease in TEWL 70.7% versus 35.36%). In terms of the emollient effect of the two oils, a statistically significant difference between the two became apparent at 8 weeks of treatment (p=0.03). No adverse effects were reported in the VCO group, while five children in the mineral oil group required “rescue” treatment with topical corticosteroids⁴ (Level 1).

Treatment of immature skin in preterm neonates

Two non-blinded RCTs^5,6 investigated application of VCO to preterm neonates to promote skin maturity. In both studies, skin maturity was assessed on days 7, 14 and 21 using the Neonatal Skin Condition Scale (NSCS) that includes evaluation of dryness, erythema and skin breakdown. In both studies, babies with existing skin conditions (e.g., infection or rash) were excluded^5,6.

In the largest RCT (n=2,294)⁵, preterm neonates (<37 weeks) were randomised to a treatment group receiving 5ml VCO applied four times daily or to a control group receiving massage only (no topical treatment). Babies receiving VCO had statistically significantly better NSCS scores than the control group at days 7, 14, 21 and 28 (p<0.01) and were significantly less likely to experience a decrease in skin maturity (p<0.01) or hypothermia (p<0.01), without increase in adverse events including rash or accidental slippage of the baby. However, parents were significantly more likely to rate the intervention as cumbersome (2% versus 0.3%, p<0.001) (Level 1).

In the second RCT⁶, 72 preterm babies (n<30 weeks) received either no topical emollient (n=36) or 5ml/kg VCO applied twice daily over the body (excluding face, scalp and around medical devices). After 3 weeks of treatment, NSCS score declined for the babies in the control group but remained stable for those receiving VCO (p=0.01). There was no significant difference in adverse events including skin irritation or temperature instability⁶ (Level 1).

Due to methodological limitations of these studies, more evidence is required to recommend VCO for routine care of immature neonate skin. However, available research suggests that the practice is safe to explore^5,6.

Table 2. Summary of clinical evidence for topical coconut products

Considerations for use

• When used as a skin moisturiser, VCO is applied to adults and children by rubbing directly on skin and/or lesions, usually twice daily^1,2,4,12,22.
• Topical application of VCO for mild-to-moderate skin conditions is associated with a lower rate of adverse effects than topical corticosteroids^4,12.
• To apply VCO to the immature skin of very preterm neonates, stroke the oil onto skin for 2–3 minutes without massage during routine care to avoid excessive handling⁶.

Conflict of Interest

The authors declare no conflicts of interest in accordance with International Committee of Medical Journal Editors (ICMJE) standards.

The method for development of WHAM (Wound Healing and Management unit at Curtin University, Perth) evidence summaries is consistent with methodology published in Munn Z, Lockwood C, Moola S. The development and use of evidence summaries for point of care information systems: a streamlined rapid review approach. Worldviews Evid Based Nurs 2015;12(3):131–8 and other resources on rapid evidence summaries published by the JBI as cited above. WHAM evidence summaries undergo peer-review by an international multidisciplinary Wound Expert Reference Group. WHAM evidence summaries provide a summary of the best available evidence on specific topics and make suggestions that can be used to inform clinical practice. Evidence contained within this summary should be evaluated by appropriately trained professionals with expertise in wound prevention and management, and the evidence should be considered in the context of the individual, the professional, the geographic and clinical setting and other relevant clinical information.

Funding

The authors received no funding for this evidence summary.

Copyright © 2021 Wound Healing and Management Unit, Curtin University.

Author(s)

Robin Watts AM, PhD, MHSc, BA, Dip NEd, FRCNA
Emeritus Professor, School of Nursing, Midwifery and Paramedicine, Wound Healing and Management (WHAM) unit, Curtin University, Perth, WA, Australia

Teresa Solomon BA, Grad Dip Lib Sc ALIA
Curtin University, Perth, WA, Australia

Emily Haesler* PhD, BN, P Grad Dip Adv Nurs, FWA
Adjunct Associate Professor, School of Nursing, Midwifery and Paramedicine, Wound Healing and Management (WHAM) unit, Curtin University, Perth, WA, Australia
Email Emily.haesler@curtin.edu.au

* Corresponding author

References

1. Agero AL, Verallo-Rowell VM. A randomized double-blind controlled trial comparing extra virgin coconut oil with mineral oil as a moisturizer for mild to moderate xerosis. Dermatitis 2004;15(3):109–16.
2. Verallo-Rowell VM, Dillague KM, Syah-Tjundawan BS. Novel antibacterial and emollient effects of coconut and virgin olive oils in adult atopic dermatitis. Dermatitis 2008;19(6):308–15.
3. Kaur I, Saraswat A, Kumar B. A comparison of three therapeutic modalities in scalp psoriasis and a review of literature. Indian J Dermatol 2003;48.
4. Evangelista MT, Abad-Casintahan F, Lopez-Villafuerte L. The effect of topical virgin coconut oil on SCORAD index, transepidermal water loss, and skin capacitance in mild to moderate pediatric atopic dermatitis: a randomized, double-blind, clinical trial. Int J Dermatol 2014;53(1):100–8.
5. Konar MC, Islam K, Roy A, Ghosh T. Effect of virgin coconut oil application on the skin of preterm newborns: a randomized controlled trial. J Trop Pediatr 2020;66(2):129–35.
6. Strunk T, Pupala S, Hibbert J, Doherty D, Patole S. Topical coconut oil in very preterm infants: an open-label randomised controlled trial. Neonatol 2018;113(2):146–51.
7. Munn Z, Lockwood C, Moola S. The development and use of evidence summaries for point of care information systems: a streamlined rapid review approach. Worldviews Evid Based Nurs 2015;12(3):131–8. doi:10.1111/wvn.12094. PMID: 25996621.
8. Aromataris E, Munn Z, editors. JBI manual for evidence synthesis. Joanna Briggs Institute; 2021. Available from: https://synthesismanual.jbi.global
9. Joanna Briggs Institute (JBI) Levels of Evidence and Grades of Recommendation Working Party. New JBI grades of recommendation; 2013. Available from: https://jbi.global/sites/default/files/2019-05/JBI-grades-of-recommendation_2014.pdf
10. Joanna Briggs Institute (JBI) Levels of Evidence and Grades of Recommendation Working Party. Supporting document for the Joanna Briggs Institute Levels of Evidence and Grades of Recommendation; 2014. Available from: https://jbi.global/sites/default/files/2019-05/JBI%20Levels%20of%20Evidence%20Supporting%20Documents-v2.pdf
11. Joanna Briggs Institute (JBI) Levels of Evidence and Grades of Recommendation Working Party. JBI levels of evidence; 2013. Available from: https://jbi.global/sites/default/files/2019-05/JBI-Levels-of-evidence_2014_0.pdf
12. Tepeng K, Rivera F. Virgin coconut oil for psoriasis. J Am Acad Dermatol 2006;54(3):AB210.
13. Nevin KG, Rajamohan T. Effect of topical application of virgin coconut oil on skin components and antioxidant status during dermal wound healing in young rats. Skin Pharmacol Physiol 2010;23(6):290–7.
14. Tarawan VM, Mantilidewi KI, Dhini IM, Radhiyanti PT, Sutedja E. Coconut shell liquid smoke promotes burn wound healing. J Evid Based Complement Altern Med 2017;22(3):436–40.
15. Soliman AM, Lin TS, Ghafar NA, Das S. Virgin coconut oil and diabetic wound healing: histopathological and biochemical analysis. Eur J Anat 2018;22(2):135–44.
16. DebMandalm M, Mandalm S. Coconut (Cocos nucifera L.: Arecaceae): in health promotion and disease prevention. Asian Pacific J Trop Med 2011;4(3):241–7.
17. Dua K, Sheshala R, Ling T, Ling S, Gorajana A. Anti-inflammatory, antibacterial and analgesic potential of Cocos nucifera Linn.: a review. Med Chem (Los Angeles) 2013;12(2):158–64.
18. Vaughn AR, Clark AK, Sivamani RK, Shi VY. Natural oils for skin-barrier repair: ancient compounds now backed by modern science. Am J Clin Dermatol 2018;19(1):103–17.
19. Ayanlowo O, -Adeife OC, Ilomuanya M, Ebie C, Adegbulu A, Ezeanyache O, Odiase O, Ikebudu V, Akanbi B. African oils in dermatology. Dermatol Ther 2021 Apr 30:e14968. doi:10.1111/dth.14968. PMID: 33928725.
20. Chew YL. The beneficial properties of virgin coconut oil in management of atopic dermatitis. Pharmacog Rev 2019;13(25):24–7.
21. Lima E, Sousa C, Meneses L, Ximenes N, Santos Junior G, Vasconcelos G, Lima N, Patroninio M, Macedo D, Vasconcelos S. Cocos nucifera (L.) (Arecaceae): a phytochemical and pharmacological review. Braz J Med Biol Res 2015;48(11):953–64.
22. Alves AQ, da Silva VA, Goes AJS, Silva MS, de Oliveira GG, Bastos IVGA, de Castro Neto AG, Alves AJ. The fatty acid composition of vegetable oils and their potential use in wound care. Adv Skin Wound Care 2019;32(8):1–8.
23. Kh H, Kuttinath S, Rammohan R. First description of antibacterial and in vitro wound healing properties of Cocos nucifera tomentum. Asian J Pharm Clin Res 2019;12(5):118–22.
24. Lin TK, Zhong L, Santiago JL. Anti-inflammatory and skin barrier repair effects of topical application of some plant oils. Int J Mol Sci 2018;19(1).
25. Karagounis TK, Gittler JK, Rotemberg V, Morel KD. Use of “natural” oils for moisturization: review of olive, coconut, and sunflower seed oil. Pediatr Dermatol 2019;36(1):9–15.