Q. What is MGO™?
A. MGO™ is a trademarked system for testing the level of Methylglyoxal, a compound identified as the active ingredient responsible for the anti-bacterial action of Manuka honey. The discovery that Methylglyoxal is manuka honey's "active ingredient" was made by Professor Thomas Henle, head of the Institute of Food Chemistry at the Technical University of Dresden.
Q. What is MGO™ Certification?
A. This is the independent testing and certification of the Methylglyoxal level in an anti-bacterial product based on Manuka honey. The higher the MGO™ level, the greater the antibacterial effect.
Q. What is the level of Methylglyoxal in other honeys?
A. Some honeys have no Methylglyoxal reading at all. Most of them tested so far have as much as 3-8 mg/kg. Some New Zealand Manuka honeys have been found to contain Methylglyoxal levels as high as 700 mg/kg, 70 times the level of other honey.
Q. As long as it is Manuka honey, it has Methylglyoxal, right?
A. Not necessarily. Methylglyoxal is a compound present in pollen from Manuka trees, which have a short flowering period. Because of this, factors such as other plants flowering nearby, hive placement and harvest timing, can dilute Methylglyoxal levels. Correct processing of products is also crucial. That's why testing and certification of Methylglyoxal levels in products is one of the most reliable guarantee of effectiveness.
Q. I thought there was already a system for measuring the anti-bacterial effectiveness of Manuka honey?
A. Manuka honey's anti-bacterial properties have been known for some time. These have been demonstrated by the UMF system (Unique Manuka Factor) which shows these properties in terms of the honey's ability to kill bacteria growing in a laboratory situation. However, with the identification of Methylglyoxal as the active ingredient, exclusively responsible for unique non-peroxide activity of Manuka honey, it is more exact and reliable to test for this.
Q. Who does the tests and how do I know I can rely on MGO™ certification?
A. MGO™ Manuka honey testing and certification is carried out independently by an authorised laboratory in New Zealand. The New Zealand assay has been cross-validated with the test method used by the Institute of Food Chemistry at the Technical University of Dresden.
Only approved laboratories are authorised to conduct tests and certify MGO™ levels in Manuka honey products. Only certified products can carry the MGO™ certification label, which is protected by trademark.
Q. What do scientists know about Methylglyoxal?
A. Numerous studies have been done about the effects of Methylglyoxal using synthetically-produced Methylglyoxal (with impurities) in a laboratory, rather than how the human body responds to a naturally-occuring compound in various foods. Honey containing a high level of Methylglyoxal kills bacteria on contact (this is the basis of Manuka honey products developed especially as wound dressings).
Some laboratory studies show Methylglyoxal has a cytotoxic effect (kills cancers), some show Methylglyoxal can modify DNA and proteins, and others discuss a positive effect from the formation of chemo-protective compounds. So far the negative effect of Dietary Methylglyoxal has not been registered. Futher studies are planned to clarify how Methylglyoxal reacts within the body.
Q. How safe is Manuka honey containing Methylglyoxal?
A. Methylglyoxal is known to kill bacteria and may also have an effect on other cells. However, Methylglyoxal has been ingested for decades as a naturally-occuring compound in food without any negative consequences becoming apparent.
People with medical conditions such as diabetes must of course be careful with any honey because of its sugar content.
Answers to these questions have been provided by Professor Dr Thomas Henle, PhD, head of the Institute of Food Chemistry at the Technical University of Dresden, who led the research team which identified Methylglyoxal as the dominant antibacterial constituent of manuka honey from New Zealand. Professor Henle is a world-leading chemist in understanding how carbohydrates in food change in response to certain conditions. He has published more than 80 scientific papers in peer-reviewed journals since 1991.
Professor Henle is joint Editor in Chief of the journal"European Food Research and Technology", president of the German Society of Food Chemistry, a member of the Scientific Advisory Board of the Federal Institute for Risk Assessment, and a referee of the German Research Society.
The Technical University of Dresden is one of the oldest and most prestigious German Universities, located in Saxony (http://tu-dresden.de).
The university's Institute of Food Chemistry is a world leader in food analysis, in particular analysis of compounds resulting from glycation reactions and carbohydrate degradation (a process which proteins and carbohydrates undergo during food processing and storage).
The university's skill base attracts major multi-nationals to collaborate in research. New Zealand dairy giant Fonterra interchanges staff and students with the university to carry out research.
Q: What first prompted you and your research team to consider Methylglyoxal as the compound responsible for Manuka honey's antibacterial properties?
A: I must admit that until about 3 or 4 years ago, I had not heard anything about Manuka honey and its spectacular antibacterial properties. Our main research interest was in reactions occurring during food processing, the identification of amino acid and carbohydrate degradation compounds and so on. In this context, we investigated several food items for their content of carbohydrate degradation products, so-called dicarbonyl compounds, which are important precursors for protein modifications which can be used as indicators to control heat treatment. We came into honey research more or less by chance, when we quantified these compounds for the first time in a number of honey samples commercially available in Germany. Among them was one sample of Manuka honey we found in a local drugstore in which we quantified surprisingly high amounts of methylglyoxal - more than hundred-fold higher than local honeys. Based on this, we started systematic investigations and became aware of the non-peroxide anti-bacterial activity of Manuka honey and the fact, that - despite several attempts - the molecular background of this phenomenon was still unknown.
Q: To what extent is Methylglyoxal responsible for the non-peroxide anti-bacterial activity in manuka honey?
A: Our studies show methlyglyoxal is exclusively responsible for the non-peroxide antibacterial activity of manuka honey. There may be some synergistic effects, for instance resulting from polphenols or not yet identified compounds, which may make methylglyoxal even more effective in honey compared to solutions of methylglyoxal in water. But without methylglyoxal, there probably would be no antibacterial activity at all.
Q: Is MGO™ the best measure for consumers to rate the unique antibacterial activity of manuka honey?
A: Based on our studies, the amount of methylglyoxal directly correlates with the antibacterial properties of Manuka honey samples. From a scientific point of view, the amount of methylglyoxal therefore can be used to rate the antibacterial activity.
Q: Is Methylglyoxal safe for humans to consume?
A: It cannot be overlooked that methylglyoxal is discussed in several reports in the literature in connection with possible pathophysiological consequences. However, all of these studies refer to endogenously formed methylglyoxal, resulting from intracellular reactions during aging or diseases such as diabetes or uremia. At present, there is no study which shows any adverse effect caused by exogenously or dietary methylglyoxal supplied via food items such as Manuka honey. It still remains open, whether dicarbonyl compounds such as methylglyoxal are resorbed when passing through the gastrointestinal tract. From a scientific point of view, any possible risk from consuming methylglyoxal via Manuka honey is considerably lower than its proven benefit.
Q: Is it possible in future that widespread MGOTM tests will provide a basis for substantiating (or not) the health claims made for honey products?
A: For substantiating a real health claim, intervention studies with human volunteers or patients are necessary. As soon as a direct structure-function relationship is shown, meaning for instance that a certain amount of methylglyoxal in honey can be made responsible for a biological effect in vivo, it should be possible to take methylglyoxal as the hallmark for the certain claim.
Q: What is the minimum methylglyoxal content (mg/kg) required for manuka honey to be effective against a wide range of harmful pathogens?
A: We are currently working on that issue. The minimum concentration may vary for various micro-organisms and, as mentioned above, may also be effected by other compounds present in the honey. In our studies, we found for pure solutions a concentration of around 70 to 100 mg methylglyoxal per litre is the minimum concentration needed to inhibit E. coli and S. aureus.
Q: Would you rate manuka honey with Methylglyoxal content 100mg/kg and higher as a true functional food?
A: Yes.
