Manuka honey is widely touted as a panacea, though there is no evidence for most of the claims. But its value for wound dressing is well established and there are promising signs it may improve gut health.
Over the next 20 hours, as much as half of his blood was drained. Washington was a great believer in bloodletting to cure or prevent illness, but the modern view is that it, more than any other single thing, caused his death.
With the benefit of hindsight, it is easy to dismiss his treatment as superstitious and primitive, even barbaric. Yet bloodletting is an ancient practice – in the Middle Ages leeches did the job – that doesn’t entirely belong on the historical rubbish heap. It has re-emerged in modern medicine as a highly effective way to increase blood circulation and break up blood clots in plastic surgery and other microsurgery.
Old cures have a habit of coming back into vogue. Of particular interest in this country is the use of manuka honey. Manuka (Leptospermum scoparium) was widely used by pre-European Maori as a source of rongoa, or traditional medicine: early settlers recorded an infusion of the bark being used externally and internally as a sedative or to treat scalds and burns. Ash made from the burnt bark was applied to treat skin diseases; vapour from leaves boiled in water was used for colds; inner bark was boiled and the liquid used as a mouthwash.
Now, honey made by bees that have foraged on manuka has been credited with such an endless list of curative and medicinal properties that it’s at risk of becoming the new elixir of life. It has been claimed to be the answer to acid reflux; acne and eczema; staphylococcal infections (including methicillin-resistant Staphylococcus aureus (MRSA), the notoriously intractable hospital superbug; tooth decay; gingivitis; irritable bowel syndrome (IBS) and inflammatory bowel disease; and allergies, including sinusitis.
It is widely, if not always persuasively, touted as a general tonic that will stimulate the immune system and nip a sore throat in the bud, make you sleep better and give you younger-looking skin (a new book claims a paste of oats, yogurt and honey will soothe and absorb excess oils on the skin).
It’s worth mentioning that none of these claims has been submitted to rigorous scientific scrutiny by way of properly designed double-blind, placebo-controlled trials. Indeed, many fly in the face of accepted scientific belief: honey is a particularly problematic sweetener for people with IBS; a qualified health professional experienced in dietary management of IBS would never suggest honey as a sweetener without first checking their patient’s response to it.
By contrast, claims about the contribution of manuka honey to gut health have come under analysis. Plant & Food Research recently conducted a laboratory-based study to investigate the effect of a New Zealand honey product on gastrointestinal health. Auckland company Manuka Health produces a formulation under the trademarked name Manuka Honey with CycloPower – a combination of manuka honey solids with alpha-cyclodextrin, a type of soluble fibre that takes the form of six sugar units bonded together in a ring shape, with a hollow centre.
Molecules become trapped in the middle of the sugar ring, making alpha-cyclodextrin (the CycloPower of the brand name) a vehicle for potentially delivering the active components of manuka honey to different gut locations.
Plant & Food Research gut microbiologist Shanthi Parkar and colleagues used a simulated model of the human gut to investigate what effect CycloPower would have on the delivery of the active components of manuka honey into the gut and on gut bacteria. They found the addition of the alpha-cyclodextrin to manuka honey prevented the honey sugars (glucose and fructose) from being digested in the upper gut and allowed them to travel further through the digestive system. Levels of DHA (one manuka honey component) were higher, and the valuable organic compound methylglyoxal (MGO) in the honey was seen only in the upper gut digestion model. Nonetheless, Parkar observed positive changes in the digestive outputs and gut bacteria that would typically favour better gut health. “There’s a lot more to do,” says Parkar. “This is really just preliminary, but it is very exciting.”
The one claim in the health benefits lists that does have the support of both history and science is the value of manuka honey as a dressing for burns, wounds and ulcers. Honey has been used for thousands of years for healing wounds. Egyptian medical manuscripts dating back to 1550BC detail the use of concoctions for the treatment of wounds that included honey because of its antibacterial and other healing properties. Interestingly, honey was similarly used in India long before the time of Christ.
In ancient civilisations, honey was even selected from different floral origins for different ailments. Indeed, Aristotle in 350BC and Discorides in AD50 both recommended that honey collected in specific regions and seasons could be used for treating different ailments.
Honey was used in British hospitals and homes as late as the 1970s to assist with wound healing; the practice seems to have been handed down through generations by word of mouth, though practice of tailored honey treatment had been all but forgotten, according to a 2016 review in the Journal of Wound Care.
As effective antibiotics became readily available and new sterile dressing materials and protocols were developed, honey fell out of favour for wound care. But new scientific evidence is boosting its chances of a comeback.
According to University of Waikato associate professor in chemistry Merilyn Manley-Harris, manuka honey has a different type of bioactivity from normal honey. “Normal honey is antibacterial because it produces hydrogen peroxide when it is exposed to wounds; it is also dehydrating and slightly acidic.
“Manuka honey has the latter two properties but does not show much hydrogen peroxide activity; instead, it contains abnormally high levels of a strongly antibacterial compound called methylglyoxal, and it has been demonstrated to be very effective in wound healing.”
European honeybees were probably introduced to New Zealand in 1839 by Mary Bumby, the sister of a Methodist missionary, who brought two hives ashore when she landed at the Mangungu Mission Station in Hokianga. But it took more than a century for the health benefits of our honey and the value to our agricultural sector of the bees’ pollination services to be fully recognised.
More than any other single person, Peter Molan was responsible for getting the health benefits of manuka honey recognised. Born and raised in Cardiff, Wales, Molan came to New Zealand in 1973, when he was 30, and taught at the University of Waikato for 41 years. He heard Maori legends about the medicinal properties of manuka and investigated its wound-care potential. Molan established a Honey Research Unit and methods to evaluate the antibacterial activity of manuka honey, known as the unique manuka factor (UMF).
The antibacterial effects of the honey are believed to be the result of its high methylglyoxal content (of up to 800mg in every kilogram of honey). Molan researched and wrote extensively about manuka honey, describing its antibacterial, deodorising and anti-inflammatory effects and its capacity for debriding dead tissue and stimulating new tissue growth. His work revived international interest in the healing properties of honey in the 1980s, which led to a resurgence in global interest in honey for wound healing, which was a boon for manuka honey producers.
The European honeybee (Apis mellifera) was introduced for its ability to produce honey, but bees quickly became important for their role in pollination of crops, says David Pattemore, a pollination scientist at Plant & Food Research.
From apples and carrots to clover pasture and kiwifruit, the European honeybee is the quiet workhorse of New Zealand agriculture. Each year, about 100,000 honeybee hives are transported around New Zealand to pollinate kiwifruit vines.
Honeybees are also used as pollinators in the commercial production of apples, pears and stone fruit and in the big vegetable seed industry, which produces carrot, onion and radish seeds for domestic and export markets.
Honeybees also provide pollination services for the production of seed for clover – the favoured pasture of dairy herds – and for brassica forage crops for cattle. “The value of pollination services in the economy is doubled, probably more than doubled, if you consider the contribution towards clover in dairy pastures,” says Pattemore.
New Zealand faces a unique situation when it comes to pollination, as most of our crops are not native species, so we depend on Apis mellifera to pollinate them. “They’re very generalist flower visitors,” says Pattemore, “so they’re happy to visit whatever flowers they can, to get the nectar and pollen they need to sustain the colonies. That makes them very useful for pollination.”
In recent years the beekeeping industry has boomed, largely thanks to the demand for manuka honey. “The number of hives in New Zealand has increased from about 300,000 to close to 700,000 within the space of 10-15 years, which is a huge increase. And that’s driven by the price of manuka honey, which is so great that the amount of money you can make from a single hive that’s collecting a good manuka crop far outweighs the best price you can get from both pollinating kiwifruit and also collecting an ordinary honey crop,” says Pattemore.
One flow-on benefit of new companies diving into the manuka honey market has been the impact on land use. Hamilton-based Three Peaks, for example, which collects its honey from hives located in the North Island’s volcanic central plateau, is working with Horizons Regional Council in Manawatu-Whanganui on a number of environmental initiatives. Horizons land manager Grant Cooper says removing livestock from erosion-prone hill country and replacing animals with manuka will, in conjunction with pest control, reduce the quantities of sediment and nutrients ending up in waterways.
“By destocking highly erodible land and replacing pasture with permanent woody vegetation, soil erosion can be decreased by 80-90%,” says Cooper. “This will lead to less sediment entering waterways … fewer nutrients and bacteria in water, more carbon sequestration and increased biodiversity.”
An estimated 100,000ha of hill-country land suited to manuka planting and harvesting for honey production are located in the Horizons region. “These are typically sites that are difficult for other uses, such as commercial forestry, due to harvest access or underlying geography,” says Cooper.
However, Pattemore warns there are still some big questions to be answered for the honey industry in New Zealand. “One of those is understanding the stocking rates of hives for honey production. Hypothetically, if you were already at the maximum stocking rate, so the bees were removing all the nectar that could be removed by bees, doubling the number of hives would reduce the overall honey harvest by much more than half, and many hives would fail to collect any honey surplus at all. There’s a very fine balance to be struck with stocking rates and we don’t know when we’re going to reach it.”
Clearly, too, pumping up production of a high-sugar foodstuff is at odds with efforts to reduce our sugar intake. With an eye on the wider economic benefit, it may be smarter to focus on the health benefits of manuka honey rather than simply producing honey for consumption.
This article was first published in the July 1, 2017 issue of the New Zealand Listener.