What is Methylglyoxal (MGO)?
Methylglyoxal (MGO) is a naturally occurring organic compound found in certain honeys, known for its potent antimicrobial properties. The concentration of MGO directly correlates with the antibacterial strength of the honey, a feature that distinguishes specific varieties from conventional honey. In Manuka honey, MGO is formed over time from the conversion of another compound called dihydroxyacetone (DHA), which is present in high concentrations in the nectar of Leptospermum flowers. This conversion process during the honey's maturation, influenced by factors like temperature and storage, is why MGO levels can vary even within the same type of honey.
Honeys with High Levels of Methylglyoxal
When discussing which honeys contain methylglyoxal, Manuka honey is the most famous example, but it is not the only one. Other honeys derived from the Leptospermum plant species native to Australia and New Zealand also possess significant MGO content. The specific concentration of MGO can differ dramatically based on the Leptospermum species, geographical location, and harvest conditions. Australian Manuka honey, for example, is sometimes harvested from varieties of Leptospermum that produce exceptionally high levels of MGO.
Examples of high-MGO honeys include:
- Manuka Honey: The quintessential high-MGO honey, with concentrations often ranging from 100 mg/kg up to over 1000 mg/kg for premium, medicinal-grade varieties. Its potent antibacterial effects are directly linked to this high MGO content.
- Australian Leptospermum Honeys: Researchers have identified several Australian Leptospermum honey varieties with potent MGO levels, with some samples showing concentrations exceeding 500 mg/kg. Some Australian honeys, like certain varieties of Jarrah, are also recognized for high antimicrobial activity, although not always dependent on MGO.
Honeys with Trace Amounts of Methylglyoxal
In contrast to Leptospermum honeys, most conventional and multi-floral honeys contain very low or trace amounts of methylglyoxal. Their primary antibacterial effect comes from hydrogen peroxide, produced by the enzyme glucose oxidase added by bees. This is why these honeys are not rated or marketed based on MGO concentration. While some studies have measured small amounts of MGO in these honeys, the levels are insignificant compared to Manuka and other potent Leptospermum varieties.
Examples of low-MGO honeys include:
- Acacia Honey: Often light in color and mild in flavor, containing minimal levels of MGO.
- Clover Honey: One of the most common honeys, which typically contains only trace amounts of MGO and relies on peroxide activity for its mild antimicrobial effects.
- Multi-floral Honeys: Gathered from a variety of flower sources, these honeys have highly variable MGO content, but generally remain at very low levels, ranging from 0.4 to 5.4 mg/kg in one study of Italian honeys.
Comparing Honeys by Methylglyoxal Content
To illustrate the vast difference in MGO concentration, the table below compares Manuka honey with other common honey types.
| Honey Type | Typical MGO Concentration (mg/kg) | Primary Antimicrobial Factor | Notes on Potency |
|---|---|---|---|
| Manuka Honey | >100 to 1200+ | Methylglyoxal (MGO) | Highly potent, non-peroxide activity. Higher ratings like MGO 850+ indicate higher potency. |
| Australian Leptospermum | Highly variable, >500 mg/kg possible | Methylglyoxal (MGO) | Some varieties rival or exceed Manuka in potency. |
| Jarrah Honey | Trace amounts | Non-MGO compounds | Strong antibacterial properties unrelated to MGO. |
| Clover Honey | Minimal/Trace | Hydrogen Peroxide | Mild antibacterial effect, widely available. |
| Italian Honey (Multi-floral) | 0.4 to 5.4 | Primarily Hydrogen Peroxide | Low MGO content with standard peroxide activity. |
| Eucalyptus Honey | Low to moderate | Peroxide and other phytochemicals | MGO presence is not the primary determinant of potency. |
Conclusion
While almost all honey contains trace amounts of methylglyoxal, the high concentrations responsible for significant non-peroxide antibacterial activity are characteristic of Manuka and other honeys derived from the Leptospermum plant species. The MGO content in these specific honeys is a critical marker of their potency, leading to grading systems like the MGO rating. Consumers seeking high levels of methylglyoxal for wellness or medicinal purposes should look for Manuka or Australian Leptospermum honeys, with higher MGO numbers indicating greater antimicrobial strength. It is also important to note that the presence of MGO should not overshadow the risks associated with its consumption for specific groups, such as those with blood sugar issues, and consultation with a healthcare professional is always advised. For a deeper dive into the science, a review of studies on Manuka honey and MGO is available from the National Institutes of Health.
Key Takeaways
- Manuka is the High-MGO Standard: Manuka honey from New Zealand is the most recognized variety with consistently high levels of methylglyoxal (MGO), a potent antibacterial compound.
- Other Leptospermum Varieties Also Count: Honeys from Australian Leptospermum plants can also contain significant MGO, with some batches exceeding New Zealand Manuka in potency.
- MGO Comes from DHA: The high MGO content in Leptospermum honeys is formed during the honey's maturation from a precursor compound, dihydroxyacetone (DHA), found in the nectar.
- MGO Levels are Quantified: The MGO rating on honey labels indicates the milligrams of methylglyoxal per kilogram, with higher numbers correlating to greater antibacterial potency.
- Most Honeys Have Minimal MGO: Conventional honeys, such as clover and acacia, contain only trace amounts of MGO, with their primary antibacterial activity coming from hydrogen peroxide.
- MGO is Not the Only Factor: Some honeys, like Jarrah, have strong antibacterial properties that are not primarily dependent on MGO content.
- Choose Based on Your Needs: Lower MGO honey is suitable for daily, general use, while higher grades are used for targeted wellness or medicinal purposes.
FAQs
Q: What is the main difference between Manuka honey and other types? A: The key difference is the high level of methylglyoxal (MGO) in Manuka honey, which gives it a powerful non-peroxide antibacterial effect that is not found in most other honeys.
Q: How is MGO measured in honey? A: MGO is measured in milligrams per kilogram (mg/kg). The MGO number on a label, such as MGO 400+, indicates a minimum of 400 mg of methylglyoxal per kilogram of honey.
Q: Are there any risks associated with high MGO levels in honey? A: For most healthy individuals, moderate consumption is safe. However, high levels of MGO have been linked to potential risks in some studies, particularly concerning diabetic complications. Infants under one year old should not be given any honey.
Q: Does all Manuka honey have a high MGO rating? A: No, the MGO content in Manuka honey can vary greatly. Factors such as the specific Leptospermum subspecies, the beekeeper, and maturation time all play a role in the final MGO concentration.
Q: Can multi-floral honey ever have high MGO content? A: It is highly unlikely. While multi-floral honeys may contain trace amounts, high MGO is specifically derived from the nectar of Leptospermum flowers, which is the defining characteristic of Manuka and related honeys.
Q: What is the difference between MGO and UMF ratings? A: MGO is a direct measure of methylglyoxal content. UMF (Unique Manuka Factor) is a comprehensive quality trademark that includes MGO along with other markers like dihydroxyacetone (DHA) and leptosperin, providing a broader assessment of authenticity.
Q: Does cooking with Manuka honey destroy the MGO? A: While moderate heating for short periods may not significantly impact MGO levels, prolonged high-temperature cooking can degrade the active compounds in honey. For maximum benefits, it is best to add high-grade Manuka honey to warm foods rather than boiling hot ones.
Q: Can I use Manuka honey for external applications, like wounds? A: Yes, medical-grade Manuka honey is often used for topical applications on cuts, burns, and ulcers due to its potent antibacterial properties. Its ability to combat infections and promote healing has been well-documented.
