One way honey is classified is according to the origin of its floral nectar—by the species of plant from which it was collected. On supermarket shelves, you might find clover honey, orange-blossom honey, lavender honey, and others. One lesser-known honey sold in natural-foods stores or by mail is manuka honey, produced by bees collecting nectar from the manuka tree (Leptospermum scoparium) in New Zealand. This small tree is native to New Zealand and southeast Australia and is found growing in dry areas. It is an evergreen species in the myrtle family, a family also known for eucalyptus, cloves, and allspice. The manuka tree has small leaves and bears white or pink flowers.
The honey is gathered from hives placed in areas where the manuka trees grow wild. Manuka honey has a different look and taste than honey derived from other flowers—it is caramel-colored with a distinct flavor, and it does not have the overly sweet smell of regular honey. The texture is thick and rich with a very pleasant aftertaste. Manuka honey has attracted a following of people who attribute a variety of healthful properties to this unusual substance. It is featured in entire product lines, from soap and lip balm to throat lozenges.
The department of biological sciences at the University of Waikato, in New Zealand, is home to the Waikato Honey Research Unit, a group of scientists who are investigating the value of manuka honey for infected wounds. Its website explains that regular honey has antibacterial properties—benefits resulting from the low levels of hydrogen peroxide it naturally contains. Depending on its nectar origin, the antibacterial activity of honey can vary a hundredfold. Manuka honey is unique in that it contains high levels of nonperoxide antibacterial compounds, allowing it to heal wounds better than honeys containing peroxide. Products sold as “active” manuka honey should contain a greater concentration of these nonperoxide antibacterial compounds and thus be more powerful for this purpose. To consistently measure these nonperoxide antibacterial compounds, the research unit developed an activity rating for manuka honey (known as Unique Manuka Factor, or UMF) on a scale ranging from 12 to 18, with the highest score having the most powerful antibacterial activity. The UMF factor for an individual manuka honey brand can be found on the brand’s website and often on its label.
Stephen Dahmer, M.D., family medicine attending physician at the Continuum Center for Health and Healing at the Beth Israel Medical Center in New York City, notes his experience with manuka honey: “As a physician practicing in Whanganui (a district on the North Island of New Zealand), I saw remarkable results achieved by patients applying manuka honey as treatment for leg and skin ulcers, diabetic ulcers, pressure sores, wounds, and rashes, some of which were formerly unresponsive to other traditional medical treatments.”
Less research has been done on manuka honey as an ingestible treatment, although manufacturers claim that its antibacterial properties help cure the causes of sore throats, colds, and ulcers. While such statements are anecdotal and not scientifically tested, there is agreement that manuka honey is delicious, so with the exception of a honey allergy (or for children younger than 12 months, who should not be fed honey), the worst that can come from trying it is the enjoyment of a nice snack.
Manuka honey is an unusual form of this sweet food, with evidence of medicinal properties. However, in medicine, skeptics abound, and what is needed are scientifically rigorous clinical trials to determine its value in improving human health, particularly for conditions where this gentle food might be preferable to another type of therapeutic intervention.
Michael J. Balick, Ph.D., is the director of the Institute of Economic Botany at the New York Botanical Garden.