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Honey's healing touch

Antibacterial properties could make the nectar an effective treatment for sores that refuse to mend.

September 10, 2007|Karen Dente | Special to The Times

With the rise in cases of diabetes, more and more people will suffer from foot ulcers that do not heal and may end up needing amputation because treatment of chronic wounds is so difficult.

Today, an alternative treatment based on a remedy used since antiquity is getting increased attention -- smearing wounds with honey.

Manuka Honey, a medicinal honey harvested from beekeepers in New Zealand, is now being marketed for application on wounds. In June, Health Canada approved it under the brand name Medihoney for use as a wound dressing and antimicrobial. In July, the Food and Drug Administration cleared it for use in wounds and burns in the U.S.

The effects of treating wounds with honey have been noted mostly in anecdotal reports and case histories, making it hard for scientists to know whether the remedy compares favorably with standard wound dressings such as hydrogels, silver-impregnated gauzes or topical antibiotics.

But in recent years, larger studies have shown promising results, and more are underway.

"In the last few years, a lot of good science has been done in the area," says Shona Blair, a microbiologist at the University of Sydney, Australia, who studies the antibacterial properties of honey.

Chronic wounds -- most commonly diabetic foot ulcers but also burn wounds, venous pressure ulcers, arterial leg ulcers and bedsores -- are a growing medical problem. An estimated 3 million people in the U.S. suffer from pressure ulcers, or bedsores. Each year, an estimated 100,000 diabetics will lose a limb through amputation, mostly as a result of nonhealing wounds. With diabetes on the rise, doctors expect to see a lot more diabetic foot ulcers.

Acute wounds are usually treated by keeping them moist and sterile, which promotes the innate wound-healing ability of the body. But in patients with underlying conditions such as diabetes, a small crack in the skin often fails to heal and can develop into a chronic wound.

Such a wound runs a great risk of becoming infected, which in turn reduces the chance of healing -- a vicious cycle that can lead to severe infection, even down to the bone. Chronic wounds are sometimes treated surgically, by removing dead skin to promote healing. Patients are also treated with off-loading orthotic shoes to prevent applying pressure on the wound, but these are cumbersome and rarely efficiently used.

The honey treatment involves putting it on bandages and applying it to wounds. Because there is a concern among some physicians that untreated honey may carry a risk of botulism -- a rare but fatal disease caused by contamination -- companies such as Comvita, which markets Medihoney, irradiate the product to sterilize it.

There are several possible ways that honey helps wounds heal, researchers say.

Honey, rich in sugars, provides a hyperosmotic environment -- meaning it will suck the water out of bacteria, killing them. (Such a hyperosmotic environment is the principle behind making preserves from fruit and regular sugar.)

Honey is antibacterial in other ways, too. During its creation, worker bees add an enzyme -- glucose oxidase -- to the nectar they've collected. When the honey is applied to a wound, it is exposed to oxygen in the air, and the glucose oxidase produces hydrogen peroxide -- bleach -- killing the bacteria.

Honey, Blair adds, seems to be active against troublesome antibiotic-resistant strains such as methicillin-resistant Staphylococcus aureus -- an important thing, because chronic wounds are often colonized by such bacteria. She's tested various Australian and New Zealand honeys against bacterial strains obtained from hospitals and found that even the strains most resistant to antibiotics failed to grow and were killed in the presence of honey.

Peter Molan, a New Zealand biochemist at the University of Waikato, has reported that Manuka honey, named after a New Zealand tree, can stop bacterial growth even when diluted up to 56 times. And in studies in piglets and rats he's found that honey has anti-inflammatory properties, stimulating skin to grow into a wound, advancing its closure.

Patient case histories also provide evidence that honey can help wounds heal. In 2001, Dr. Jennifer Eddy, associate professor at the department of family medicine at the University of Wisconsin, was treating a patient with an extreme case of diabetic foot ulcer. It had refused to heal despite treatment with conventional remedies: surgical debridement (or removal of dead tissue) antibiotics, hydrogel dressings and use of an off-loading orthotic.

The foot was infected down to the bone. With the threat of amputation looming, Eddy treated the patient's wound with honey, smearing it on the bandage and applying it to the wound.

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