Sunday, 24 June 2012

Manuka honey in medicine, part 3

Professor Peter Molan, Honey Research Unit, University of Waikato in New Zealand, looks at the use of manuka honey as a medicine.

As well as rapidly clearing infection, honey has been demonstrated in clinical usage to have several other therapeutic actions that are of great benefit. It very rapidly causes pus and dead tissue to lift off messy wounds, so surgical debridement or the use of enzymes (which are generally too expensive to use) are not necessary to get a clean wound bed to allow healing to begin.
It actively stimulates the healing process, so that rapid healing occurs and skin grafting is not needed. It rapidly soothes inflammation and thus decreases the exudation of serum from wounds, and decreases swelling and painfulness.

Trials are currently being conducted on the use of manuka honey to reduce the inflammation that results from radiotherapy.

The rapid clearance of inflammation in wounds by honey also gives healing without scarring. This is because part of the inflammatory process is the stimulation of fibroblasts to produce scar tissue to repair the wound, and prolonged inflammation gives over-stimulation, so excessive amounts of scar tissue are produced.

One of the factors that has slowed the uptake of the use of honey in clinical practice has been the practical difficulty of handling a very sticky substance that, when it warms up to body temperature, becomes quite watery and runs off wounds.
But technology has now been developed that makes honey easy to apply to wounds in the form of manufactured dressings. These are not only convenient to use but also increase the effectiveness of the honey on the wound. Because the water content of honey is strongly bound up with the sugar molecules, there is very little wetting of dressings applied to cover honey on a wound, so much of the honey, when it becomes runny at body temperature, gets squeezed out sideways, leaving very little remaining to exert its therapeutic effects.

If, however, the dressing is impregnated with honey before it is applied to the wound, then a larger amount of honey can be kept on the wound. There are two wound dressings impregnated with manuka honey on sale in the UK.

One consists of a triple layer of low adherent knitted viscose impregnated with manuka honey. The other consists of a mechanically bonded M-type calcium alginate fibre dressing impregnated with manuka honey.

 The calcium alginate fibres convert to a sodium alginate gel when wound exudate is absorbed, which has the advantage when used on an exuding wound of not only containing the exudate cleanly within the dressing but also of preventing the honey from being flushed out of the dressings, as can happen with the viscose dressings.

Both of these types of dressing are CE marked products. A further development, expected to be on sale in 2006, consists of manuka honey gelled with sodium alginate in the form of a sheet of non-sticky, rubbery material that has a very large capacity to absorb wound exudate.

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