April 2025 Issue
Ask the Expert: Manuka Honey
By Toby Amidor, MS, RD, CDN, FAND
Today’s Dietitian
Vol. 27 No. 4 P. 6
Where’s the Current Research Stand?
Q: My clients have been asking about the health advantages of consuming Manuka honey. Is there any research showing potential health benefits?
A: Manuka honey is a type of honey—not a brand—that’s uniquely sourced and produced in New Zealand, where the native Manuka tea tree (Leptospermum scoparium) lives. Manuka honey has numerous properties demonstrated in vitro, including antioxidant, antiviral, and anti-inflammatory, as well as some in vivo research evolving.1,2 This article will focus on research related to wound healing, respiratory, and gut health.
What Is Manuka Honey?
Manuka honey is more viscous compared with traditional honey and has a sweet flavor with a cream-to-caramel color. The honey is derived from the nectar of the sweet-smelling flower of the Manuka tree, which is capable of photosynthesis not only in their leaves like other plants but also in their nectaries. This honey provides amino acids, B vitamins, vitamin C, minerals, and carbohydrates, as well as phenolic acids like flavonols.2 The bioactive properties of Manuka honey are a result of bees taking the unique nectar of the single source (monofloral) flower of the Manuka tree. The potent properties of the honey are known as the Unique Manuka Factor (UMF).4
The Unique Manuka Factor
Over 25 years ago, New Zealand beekeepers recognized the need for a standardized system to certify the unique properties of Manuka honey and founded the Unique Manuka Factor Honey Association (UMFHA). This independent trade association works with producers and brands to certify that they adhere to a unique quality system to guarantee potency, authenticity, shelf life, and freshness. The UMF certification verifies the presence of all key factors in Manuka honey, ensuring that consumers get a product that’s true to its label.
In addition, UMFHA-led research has identified more than 2,000 natural components in Manuka honey, including methylglyoxal and leptosperin. Methylglyoxal provides in vitro antibacterial properties, while leptosperin is an anti-inflammatory compound found only in Manuka flower nectar and can only be created by nature.3
Every batch of UMF-certified honey goes through a Four Factor Quality Assurance Test to verify its potency, authenticity, shelf life, and freshness. This includes the following:
• MGO for potency. The potency measure of methylglyoxal (MGO) antibacterial properties. The higher the MGO, the stronger the concentration of MGO.
• Leptosperin for authenticity. Measuring leptosperin ensures the authenticity of the honey as the compound is only found in the Manuka flower nectar.
• DHA for shelf life. Dihydroxyacetone (DHA) is slowly converted to MGO in high-quality Manuka honey. The higher the DHA content, the longer the life of the MGO content. Manuka honey must have more than 70 mg/kg DHA to be UMF certified.
• HMF for freshness. The honey is tested for hydroxymethylfurfural (HMF), which is naturally present in Manuka honey and indicates the freshness of the honey. The compound is destroyed if the honey has been overheated or stored too long.
Manuka honey can be enjoyed drizzled on fruit, yogurt, and oatmeal; however, its bioactivity degrades when overheated or cooked, so hot beverages should be slightly cooled before adding.5
The Research
Initial research identified Manuka honey may support wound care and recent published studies continue to support this.4,6 Research also supports the benefit of Manuka honey in respiratory health in some cases. A 2022 in vitro published study examined the effect of Manuka honey and azithromycin to help treat Mycobacterium abscessus, a pathogen that causes both pulmonary and skin and soft tissue infections.7 Researchers observed improved growth inhibition for azithromycin with manuka honey against all M. abscessus subspecies compared with control of tobramycin and Manuka honey. No improved activity was observed for tobramycin and Manuka honey against any of the M. abscessus isolates tested. Researchers concluded that the addition of Manuka honey can potentially enhance the antibiotics. Additional systematic review and meta-analysis suggest potential benefits in upper respiratory tract infections,8,9 plus a pilot study investigating the effects of Manuka honey sinus rinse compared with traditional sinus rinse in cystic fibrosis patients is currently underway.10
With regards to gut health, one published study concludes that from in vitro, animal, and pilot human studies, certain kinds of honey could have prebiotic capability to lead to changes in the gut microbiome. However, the specific bioactive components responsible for its prebiotic effect still need to be identified by further research.11 A second in vitro study found potential for honey to act as an antibacterial agent in reducing counts of infection-causing bacteria, including Salmonella, E. coli, and Clostridiodes difficile; however, being in vitro, it can’t speak to in vivo effects.12 Some additional research in vivo has found no effect on the reduction of similar pathogenic strains nor any increase in beneficial microbes like Lactobacillus.13 As such, there is currently a lack of conclusive evidence on the effects of Manuka honey on gut health, including dysbiosis, and more research is needed.
Recommendations for RDs
There’s a growing body of evidence showcasing the potential benefits of Manuka honey. RDs can educate clients on the unique sources New Zealand honey and how to select an authentic brand. As too much added sugar is a concern for most Americans, RDs should also explain to clients who wish to consume Manuka honey how to incorporate small amounts of it into a well-balanced diet.
— Toby Amidor, MS, RD, CDN, FAND, is founder of Toby Amidor Nutrition (tobyamidornutrition.com) and a Wall Street Journal bestselling author. She’s written 11 cookbooks, including the Health Shots: 50 Simple Tonics to Help Improve Immunity, Ease Anxiety, Boost Energy, and More. She’s also an award-winning media dietitian, spokesperson, and nutrition expert for FoodNetwork.com and a contributor to U.S. News and other national outlets.
References
1. Carter DA, Blair SE, Cokcetin NN, et al. Therapeutic Manuka honey: no longer so alternative. Front Microbiol. 2016;7:569.
2. Sunan Wang, Yi Qiu, Fan Zhu. An updated review of functional ingredients of Manuka honey and their value-added innovations. Food Chemistry. 2024;440:2024.
3. Unique Manuka factor. Unique Manuka Factor Honey Association website. https://www.umf.org.nz/unique-manuka-factor/umf-four-factor-quality-testing
4. Lane JA, Calonne J, Slattery H, Hickey RM. Oligosaccharides isolated from MGO Manuka honey inhibit the adhesion of pseudomonas aeruginosa, Escherichia coli O157:H7 and staphylococcus aureus to human HT-29 cells. Foods. 2019;8(10):446.
5. Suga N, Yakemoto C, Okano Y, Sakamoto K, Kato Y. Thermal stability of Manuka honey specific ingredients and heat processing applications in cooking. Journal of Cookery Science of Japan. 2021;54(4):186-192.
6. Jodidio M, Schwartz RA. Honey therapies for dermatological disorders: more than just a sweet elixir. Int J Dermatol. 2024;63(4):422-430.
7. Nolan VC, Harrison J, Cox JAG. Manuka honey in combination with azithromycin shows potential for improved activity against Mycobacterium abscessus. Cell Surf. 2022;8:100090.
8. Abuelgasim H, Albury C, Lee J. Effectiveness of honey for symptomatic relief in upper respiratory tract infections: a systematic review and meta-analysis. BMJ. 2021;26:57-64.
9. Paul IM, Beiler J, McMonagle A, Shaffer ML, Duda L, Berlin CM Jr. Effect of honey, dextromethorphan, and no treatment on nocturnal cough and sleep quality for coughing children and their parents. Arch Pediatr Adolesc Med. 2007;161(12):1140-1146.
10. Roberts AEL, Xanthe C, Hopkins AL, et al. A pilot study investigating the effects of a manuka honey sinus rinse compared to a standard sinus rinse on sino-nasal outcome test scores in cystic fibrosis patients. Pilot Feasibility Stud. 2022;8(1):216.
11. Schell KR, Fernandes KE, Shanahan E, et al. The potential of honey as a prebiotic food to re-engineer the gut microbiome toward a healthy state. Front Nutr. 2022;9:957932.
12. Hammond EN, Donkor ES. Antibacterial effect of Manuka honey on Clostridium difficile. BMC Res Notes. 2013;6:188.
13. Palma-Morales M, Huertas JR, Rodríguez-Pérez C. A comprehensive review of the effect of honey on human health. Nutrients. 2023;15(13):3056.