Manuka honey (MH) helps prevent infections and promotes wound healing when used externally.
MH can help fight bacterial infections and has been used in dressings to promote wound healing. Methylglyoxal, a compound present in MH, is thought to have bacteriostatic effects. In vitro and animal studies have shown that MH has anti-inflammatory and anti-ulcer effects. Small studies in humans suggest its benefits against gingivitis and inflamed nasal sinuses. But it was found ineffective in improving oral mucositis following radiation in head and neck cancer patients. Larger studies are needed.
Small studies suggest the value of MH in wound healing.
Topical use of MH was shown to be effective against bacteria.
Clinical trials have not been conducted.
MH was ineffective in lowering cholesterol.
Clinical trials are lacking. Excessive use of honey may cause increase in blood sugar levels.
Gastrointestinal tract problems
Clinical trials have not been able to confirm if MH has a significant effect on the levels of beneficial bacteria in the gut.
Case studies and anecdotal reports have described MH as being effective in treating infected wounds that were non-responsive to standard treatment.
Clinical trials are lacking.
Radiation-induced oral mucositis
Clinical trials did not find any benefit of MH in reducing radiation-induced oral mucositis, but one study found that it reduced bacterial infections.
One small study suggested regular consumption of MH to be effective in reducing buildup of plaque and gingivitis. Large-scale studies are needed.
Although MH has antibacterial effects, patients should not self-medicate with honey products. Any infection should be examined by a physician or a qualified healthcare professional for proper care.
The sugar content in honey may raise the blood glucose level of diabetics.
In rodents, a 50% concentration of MH applied to the ear following a surgical procedure of the eardrum resulting in inflammation leading to facial paralysis and hearing loss.
Manuka honey (MH) is collected from beehives around the Manuka (Leptospermum scoparium) bush that is indigenous to Australia and New Zealand. It has been used as food and as a topical treatment for wounds, burns and ulcers. Studies done in vitro and in animal models show that MH has antibacterial (1)(25)(26), anti-inflammatory (9)(27), antioxidant and anti-ulcer (27) effects. Methylglyoxal, one of the constituents, is the major bactericidal factor (21). MH was also found effective against several antibiotic-resistant bacteria (28)(29)(30), and may potentially be useful against rapidly increasing antibiotic resistance.
Small studies suggest its utility against gingivitis (2), chronic rhinosinusitis (32), as an adjunct in the management of corneal oedema (24), and as an adjunctive oral hygiene agent in children (33). However, randomized trials did not find MH to be more effective compared to standard treatments against catheter-associated bacterial infections (6), in healing venous leg ulcers (20) or eyelid surgical wounds (31). MH has also been used to increase levels of beneficial bacteria and relieve gastrointestinal problems, but was not found useful in healthy subjects (7). It also did not reduce cholesterol levels in subjects with hypercholesterolemia (8).
The anticancer potential of MH has not been investigated yet. But it was ineffective in alleviating radiation-induced oral mucositis in randomized trials involving patients with head and neck cancer (19)(22), although one study reported a reduction in bacterial infections (22). Larger studies are needed to determine the therapeutic value of MH.
Fungal and bacterial infections
Gastrointestinal tract problems
Mechanism of Action
Flavonoids present in MH demonstrated anti-inflammatory, antimicrobial, and anticancer properties (13). Methylglyoxal, a phytochemical, is the major bactericidal factor and also promotes free radical generation (14)(21). MH was shown to reduce the motility of Pseudomonas aeruginosa, a gram negative bacterium and an opportunistic pathogen, by suppressing genes associated with its flagella, thereby reducing its virulence (34). It also inhibited the formation of biofilm, a complex polysaccharide structure produced by some bacteria such as Clostridium dificile, which confers on them resistance to antibiotics (30). The anti-ulcer effects of MH are likely by increasing gastric mucosal levels of glutathione peroxidase and superoxide dismutase; and by reducing inflammatory cytokines including tumor necrosis factor (TNF-alpha), Interleukins 1-beta and 6 (27).
In addition, MH honey was shown to enhance the effects of antioxidants in animal studies (15) as well as promote wound healing by modulating production of cytokines (4) and by lowering pH on wound surfaces (5)(16). Some products MH list its antibacterial potency by a Unique Manuka Factor (UMF), which is equal to the inhibitory potential of a phenolic solution of same strength (7). However, the clinical relevance of this measurement is unclear.
Individuals allergic to honey should avoid this product.
May increase blood glucose levels.
In a rodent model, a 50% concentration of MH applied to the ear following myringotomy caused severe inflammation leading to facial paralysis, vestibulotoxicity, and hearing loss (23).
Chemotherapy: Theoretically, MH may interfere with certain chemotherapeutic agents due to its antioxidant effects.
Herb Lab Interactions
The sugar in MH may raise the blood glucose level in diabetics.
Weston RJ, Mitchell KR, Allen KL. Antibacterial phenolic components of New Zealand manuka honey. Food Chemistry. 1999;64(3):295-301.
Yao L, Datta N, Tomás-Barberán FA, Ferreres F, Martos I, Singanusong R. Flavonoids, phenolic acids and abscisic acid in Australian and New Zealand Leptospermum honeys. Food Chemistry. 2003;81(2):159-168.