WHAM evidence summary: effectiveness of topical coconut products
Robin Watts, Teresa Solomon and Emily Haesler
Keywords skin conditions, topical coconut, coconut oil, wound management, low- and middle-resource countries
For referencing Watts R et al. WHAM evidence summary: effectiveness of topical coconut products. WCET® Journal 2021;41(2):32-35
What is the best available evidence on the use of topical coconut products in wound management and the treatment of skin conditions?
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 evidence1,2 demonstrated that topical virgin coconut oil (VCO) is associated with improvements in signs and symptoms of xerosis1,2 and psoriasis3 in adults, and mild-to-moderate dermatitis in children4. There is some evidence that VCO improves scores of skin immaturity in preterm neonates5,6. 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 hierarchy7–11. Recommendations are made based on the body of evidence and are graded according to the system reported by JBI7–11.
Table 1. Levels of evidence
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 fibre17,18. The most used coconut product, virgin coconut oil (VCO), is extracted directly from coconut flesh and contains medium chain fatty acids that have surfactant qualities1,19,20. 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 analgesic17,18,20–24. When applied topically, VCO provides barrier protection for the stratum corneum and reduces transepidermal water loss (TEWL), promoting skin moisturisation19,20,24,25. When used on wounds, VCO and other coconut-derived products are reported to promote collagen synthesis and faster epithelisation15,20,24.
Evidence from animal studies
Evidence on the wound healing effect of coconut comes from animal studies. Results from three studies13–15 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 RCTs1,2 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 RCTs5,6 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 excluded5,6.
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 explore5,6.
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 daily1,2,4,12,22.
- Topical application of VCO for mild-to-moderate skin conditions is associated with a lower rate of adverse effects than topical corticosteroids4,12.
- 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.
The authors received no funding for this evidence summary.
Copyright © 2021 Wound Healing and Management Unit, Curtin University.
Robin Watts, Teresa Solomon and Emily Haesler
本总结是采用乔安娜•布里格斯研究所（JBI）公布的方法进行7-11。本总结以系统性的文献检索为基础，并结合使用伤口和皮肤病相关的检索术语和与椰子树相关的术语。在Embase、Medline、Global Health、补充医学文献数据库（Allied and Complementary Medicine）等数据库中进行了检索，并在中低收入国家的10种医疗保健杂志中检索了截至2021年5月以英文发表的证据。根据JBI的等级划分，对研究进行了证据水平（表1）的划分7-11。建议是根据大量证据所提出的，并根据JBI报告的系统进行评分7-11。
这些产品的实验室测试和生化分析已确定了许多有用的性能 - 抗炎、抗菌、抗真菌、抗氧化、抗肿瘤和镇痛性能17,18,20-24。外用VCO可为角质层提供屏障保护，减少经皮水分丢失（TEWL），促进皮肤保
关于椰子伤口愈合效果的证据来自动物研究。本文提供了三项研究13-15的结果，作为关于这个主题的大量实验室研究工作的示例。在印度进行的第一项研究13中，每天在大鼠的开放性皮肤伤口上涂抹VCO，持续10天。研究分为3组，每组有6只大鼠 - 对照组、使用0.5ml VCO的治疗组，以及使用1ml VCO的治疗组。完成上皮化的时间和肉芽组织（如胶原蛋白和成纤维细胞）的形成是结果指标。在完成上皮化的时间和总胶原蛋白含量方面，与对照组相比，第2组和第3组均具有统计学意义（P<0.05），1 ml比0.5 ml更有效13（5级）。
第二项研究14是在印度尼西亚进行，旨在评价CS-LS对烧伤的愈合活性。36只小鼠被随机分为三组（n=12/组） - CS-LS、0.9%生理盐水（NaCl）和10%聚维酮碘。烧伤伤口保持开放，每日治疗两次，持续25天。在烧伤诱导后的第1、5、10和25天测量伤口收缩情况。到第5天，CS-LS组表现出三组中最快的伤口收缩情况（P<0.001）。在第10天，与聚维酮碘组相比显示出具有统计学意义的差异（P<0.001），在第25天，与NaCl组相比显示出具有统计学意义的差异（P<0.05）14（5级）。
在第三项研究15中，使用大鼠群体探究了VCO治疗糖尿病溃疡的问题。将患有溃疡的大鼠分为4组 - 未治疗的非糖尿病大鼠（n=18），未治疗的糖尿病大鼠（n=18），持续14天每天涂抹1 ml VCO的糖尿病大鼠（n=18），以及持续14天每天涂抹磺胺嘧啶银乳膏的糖尿病大鼠（n=18）。在第5、10和14天测量伤口闭合率。与未接受治疗的糖尿病溃疡相比，在研究期间的所有天数内，接受VCO治疗的糖尿病溃疡均表现出具有统计学意义上更快的闭合率（P<0.05）。在第5天和第14天，VCO组和磺胺嘧啶银乳膏组之间具有统计学意义的差异（P<0.05），VCO效果更佳15（5级）。
在最大型的RCT（n=2,294）5中，早产儿（<37周）被随机分配至每日四次涂抹5 ml VCO的治疗组或仅接受按摩（无外用治疗）的对照组。接受VCO治疗的婴儿在第7、14、21和28天的NSCS评分在统计学上显著优于对照组（P<0.01），并且出现皮肤成熟度下降（P<0.01）或体温过低（P<0.01）的可能性明显降低，包括皮疹或婴儿意外滑倒在内的不良事件没有增加。但家长们认为干预措施较为麻烦的可能性更高（2%与0.3%，P<0.001）（1级）。
在第二项RCT6中，72名早产儿（n<30周）接受了不使用外用润肤剂（n=36）或每日两次在全身（不包括面部、头皮和医疗器械周围）涂抹5 ml/kg VCO的治疗。治疗3周后，对照组中婴儿的NSCS评分有所下降，但接受VCO治疗的婴儿的评分保持稳定（P=0.01）。不良事件（包括皮肤刺激或温度不稳定性）无显著差异6（1级）。
WHAM（珀斯科廷大学伤口愈合与管理课程）证据总结的开发方法与Munn Z, Lockwood C, Moola S发表的现场医护信息系统（一种简化的快速审查方法）证据总结的开发和使用，Worldviews Evid Based Nurs 2015；12（3）:131-8，以及上文引用的JBI发表的关于快速证据总结的其他资源的方法一致。WHAM证据总结经过国际多学科伤口专家参考小组的同行评审。WHAM证据总结提供了关于特定主题的最佳可用证据的总结，并提出了可用于指导临床实践的建议。本总结中包含的证据应由经过适当培训的具有伤口预防和管理专业知识的专业人士员进行评价，并应根据个人、专业人士、地理和临床环境以及其他相关临床信息考虑证据。
版权所有© 2021 科廷大学伤口愈合和管理课程。
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
* Corresponding author
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