The Antibacterial Properties of Honey

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Honey has been successfully used as medicine for at least 5000 years, its known use beginning with a Sumerian tablet dated at about 3000BC prescribing honey for the treatment of an infected skin ulcer. But only in the last 60 years have the antibacterial properties of honey been studied and documented by modern science. Due to its natural antimicrobial properties, honey has been clinically shown to have an inhibitory effect on no fewer than 23 known pathogens, among them the bacteria that cause meningitis, septicemia, tooth decay, ear infections and, most recently, stomach ulcers caused by Heliobacter pylori. Four natural characteristics of honey are responsible for its antibacterial properties: its osmolarity, acidity, hydrogen peroxide production, and its floral nectar component.

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It is a fundamental principle of nature that water moves across a permeable membrane from regions of high concentration to regions of low concentration. Being a supersaturated sugar solution, honey has a very low concentration of water and therefore a high osmolarity. When honey comes into contact with bacterial cells, the water within the cells will seek to reach equilibrium by moving across the cellular membrane into the honey. In this way, water is drawn out of the bacterial cells, and the bacteria are killed by simple dehydration.

Bacteria thrive at pH levels that are close to neutral or slightly acidic, such as the natural pH of human skin of about 6.1. With a pH of about 4, honey is an acidic substance and creates an inhospitable environment for bacterial growth.

Hydrogen peroxide (H2O2) will kill bacterial cells by oxidation, and is commonly used for the purpose. Pure H2O2, however, is chemically unstable and rapidly degrades to water when exposed to heat and light. Honey, on the other hand, is highly stable but will naturally produce H2O2 in small amounts from the oxidation of glucose when exposed to a pH between 5.5 and 8.0, the normal pH of human skin. By this mechanism, honey is able to supply a steady dose of H2O2 when applied to the skin.

Most plants have natural defence systems against invading pathogens, and this is where the floral nectar component of honey comes into play. Using natural flavonoids still not fully identified by science, floral nectar itself has antibacterial properties that are part of the plant’s immune system.

These four properties, taken together, make honey a powerful, natural antimicrobial substance that will not lead to resistant strains of bacteria or harm beneficial bacteria that are part of the natural fauna of the human body. After 5000 years of use, the antibacterial properties of honey are finally beginning to be understood, and certainly warrant further study.