The nutraceutical benefit, part iii: honey.

The ancient Egyptians and Greeks used honey as a medicine to treat wounds and various gastrointestinal diseases. Modern scientists have dismissed the notion of natural food for healing due to lack of scientific basis. In recent years, much attention has focused on natural food as nutraceuticals that have been used for treatment of illness and diseases in ancient times. The mechanism of the effect of honey on human health has gradually become apparent in a number of studies. Another bee product, propolis (bee glue) is a strong adhesive made of resinous material derived by bees from plant juices and used to seal holes in their honeycomb. Because propolis has properties similar1 to honey, we focus on the health effects of honey. Honey is the nectar and saccharine exudation of plants gathered, modified, and stored in the comb by the honeybee, Apis mellifera. Honey contains approximately 80% carbohydrates (35% glucose, 40% fructose, and 5% sucrose) and 20% water, serving as an excellent source of energy. Also, it contains more than 180 substances, including amino acids, vitamins, minerals, and enzymes.2 Its pH is approximately 4.0. The most active medical effect of honey is its antimicrobial property. The mechanism of this function relates to its high osmolarity,3,4 acidity,3 and content of inhibines, such as hydrogen peroxide,5 flavonoids, and the phenolic acids (caffeic and ferulic acid).6 However, the antimicrobial ability of honey differs depending on its floral source.7 Kanuka, manuka, ling, and kamahi honeys are likely to produce honey with high antimicrobial properties. The antimicrobial agent in some honeys is predominantly hydrogen peroxide5 and is formed by glucose oxidase synthesized by the bee. In other honeys, the antimicrobial agent is a non-peroxide compound derived directly from the flower. Hence, not every type of honey has equally effective antimicrobial properties. The antimicrobial properties of honey were tested in several studies. Wahdan showed that, in 21 types of bacteria, such as Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa, and 2 types of fungi in vitro, honey neutralized more pathogens in a dose-dependent fashion than did a control sugar solution, consisting fructose and glucose at an 80% concentration, similar to that in pure honey.6 Undiluted honey completely inhibited growth of all 21 types of bacteria, whereas control sugar solution inhibited only 18 types. At half the dilution, the growth of 18 bacteria strains was retarded or completely inhibited by the honey, whereas only 12 strains were inhibited by the sugar solution. Jeddar et al. showed that honey at a concentration of 40% was bactericidal to various gram-negative and gram-positive bacteria, in particular Salmonella shigella, E. coli, and Bibrio cholera.8 Honey has been traditionally used in the treatment of wounds. This healing effect has been shown in some studies, in which honey-treated gauze was used to treat superficial burns, these studies also compared healing time of the honey-treated gauze with silver-sulfadiazone gauze9 and amniotic-membrane dressing.10 Results showed that honey-treated gauze was associated with faster (7 versus 13 d) healing than the other treated gauzes. For the treatment of infected wounds direct application provides the most successful results because a higher concentration provides the greater antimicrobial effect. In an experimental animal model, the wound treated with pure, unboiled, commercially available honey healed significantly faster than that treated with saline as a control in mice as determined by the decrease in wound size and the thickness of granulation.11 Honey has been used for the treatment of various gastrointestinal diseases for a long time. The effect was confirmed in a study, in which an oral rehydration therapy (ORT) solution containing 5% honey was given to infants and children suffering from bacterial gastroenteritis caused by organisms such as Salmonella, Shigella, and E. coli.12 The results showed that recovery time, i.e., the duration from starting treatment to the passage of normal soft stool, was significantly faster in patients given ORT solution containing honey than in those given control ORT solution containing equal concentration of glucose (58 versus 93 h, P , 0.05). Conversely, in non-bacterial gastroenteritis, honey had the same effect as control ORT solution on the duration of the diarrhea. Honey also has been used for the treatment of dyspepsia and of gastric and duodenal ulcers,13 which appears to be caused mainly by infection with Helicobacter pylori. Somal et al. showed that total inhibition of growth of H. pylori, isolated from gastric ulcers and incubated in vitro, by manuka honey occurred even at a 5% concentration, whereas the control sugar solution, containing the same sugar and gluconic acid concentration as found in pure honey, showed no inhibition.14 Because H. pylori produces catalase, an inhibitor of glucose oxidase, the antibacterial effect of honey on H. pylori is not likely due to hydrogen peroxide. Hence, the antibacterial effect of honey on H. pylori may be due to the phytochemical content rather than to hydrogen peroxide or osmolarity, although an osmotic effect has been shown to be effective in killing H. pylori.15 In addition to the antibacterial effect on H. pylori, honey has been reported to have a protective effect on acute gastric mucosal lesions induced by 50% ethanol.16 Based on these data, honey can provide an effective and cheap therapy for infected wounds and infectious gastrointestinal disease. However, because honey is a natural mixture of carbohydrates, honey may be contaminated with Clostridium botulimun, resulting in infant botulism,17 and honey can cause an allergic reaction. Hence, investigators who use honey should be aware of these potential complications associated for such treatments.