Manuka Honey - Medical grade or from a jar?

From wives tales to modern day:  
Using honey for wounds is nothing new. From ancient egyptian texts to roman times its properties have been extolled as an aid to healing and for reducing inflammation. For many a miracle cure, for the more scientific it is a case that the high sugar (84%) low pH environment created by honey will aid debridement and help to decontaminate wounds to enable the wound to progress from inflammation through to the proliferative. 

Honey (of all types) offers the wound several benefits due to its ‘natural’ high sugar content which creates an osmotic effect in the wound, a low pH which inhibits microbial proliferation, and some key enzymes which create an antimicrobial effect related to the release of low levels of hydrogen peroxide. In fact this ‘peroxide  effect’ is similar to that adopted by neutrophils in defence of pathogens during inflammation. 

Manuka honey from New Zealand is considered 'gold standard' for wound management since research led by Dr. Peter Molan at the University of Waikato began to explore its properties as an antimicrobial and debridement aid. The research identified that honey derived from nectar from the Manuka bush (Leptospermum scoparium) had an additional antimicrobial effect independent of that associated with standard mixed floral honey being independent of the pH, Enzymes and sugars. In 2008 Maveric et al reported that they had found methylgloxal to be the chemical responsible. The level of antimicrobial effect being directly proportional to the concentration of methylgloxal in the honey. A method of testing potency of antimicrobial effect was registered to give batches of Manuka honey a rating and guarantee of the presence of this unique manuka factor or UMF®. Some manufactures will choose to use an NPA statement or logo instead of the UMF®  mark. NPA stands for non-peroxide activity and can be used to demonstrate that the product has been tested similarly to  guarantee an antimicrobial activity that is maintained without the presence of glucose oxidase. 

So why not just use it from a jar?
Manuka honey is one of the worlds most expensive honeys. For comparison a few years ago a tonne of standard mixed floral honey may have cost you around £5,000 per tonne with an equivalent amount of Manuka honey being nearer £50,000. Unfortunately where there is money to be made there is also the temptation for fraud. In May 2015 the Grocer magazine reported on a commissioned special investigation into the Manuka honey market in the UK and found that only 1 in 7 of the jars they tested were positive for the presence of methylgloxal at a level matching the NPA or UMF® rating on the label. Furthermore they stated that the maximum volume of Manuka honey being shipped out of New Zealand in one year was less than 2,000 tonnes, whereas the shelves around the UK appear to be stocked with over 11,000 tonnes. 

Risk and reward: 
Despite its potent and evidenced antimicrobial effect even Manuka honey is not immune to harbouring bacterial spores. When cold gamma sterilised (to preserve valuable antimicrobial enzymes) spores are rendered inert while the potent antimicrobial effect is preserved. This is the standard process for medical grade honey which will normally be sterilised in batches that will be guaranteed through a batch number and expiry date. The expiry date does not apply to the efficacy of the honey itself, but the guarantee that the packaging (if stored as advised) will ensure sterility to that point.

Pasteurisation is used for honey intended for consumption and being a heating process will inhibit some of the enzymes that we consider beneficial for assisting wound management. When eating honey we deliver it into an environment that is  hostile enough to deal with many bacterial threats through digestive and immune system. Its a good job as pasteurisation is ineffective at inhibiting spores of some of the most pathogenic bacteria we face, specifically Clostridium botulinum. Most adults will have become immune to proliferation of this dangerous pathogen, but if ingested by children under one year of age the consequences can be lethal. This is why most honey meant for consumption will be labelled as not suitable for children under 1 year of age. 

​When using a jar of food grade honey for wound management there is a risk of contamination, regardless of the rating of the honey. Evidence of such complications are scarce, but such infection or contamination that delays healing may not even be recognised by the clinician, it may be considered simply as a failure of the wound to progress for a period of time. While we research this a little more it is worth considering the image below. The plates were used as part of a study looking at the efficacy of a range of honeys against equine wound pathogens. (Pollock and Regan). The plate on the left was a the growth resulting from a 'value' range of honey where more species proliferated than had been inoculated.

If you wish to use honey from a jar for wound management there is nothing to stop you. However, if you are a clinician you have a duty of care to your patients and clients. That means that you are obliged to do no harm, however small the risk. Only medical grade, cold gamma sterilised honey (Manuka or otherwise) will have all its benefits preserved while guaranteeing it safety through a batch number system. The fear is that it is more expensive to buy as a medical product but if you consider buying 15g versus a whole jar, you'll find the its the Jar that costs you more! 

Click here to read the 2015 article from "The Grocer" 

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