The Uniqueness of Manuka Honey
All honey has some form of antibacterial property, mainly due to hydrogen peroxide. However, this compound is sensitive to light, heat, and body fluids, causing its antibacterial effect to break down. The nectar from the Manuka bush (Leptospermum scoparium) gives the resulting honey its special attributes that remain stable under various conditions. This unique feature is known as Non-Peroxide Activity, or NPA.
What is NPA in manuka?
NPA stands for Non-Peroxide Activity. It is a term used to describe the antibacterial power of Manuka honey that is independent of the hydrogen peroxide typically found in other types of honey. This special, stable antibacterial activity is what gives Manuka honey its medicinal reputation. The core component responsible for NPA was later identified as methylglyoxal (MGO).
The Discovery of NPA and Its Modern Measurement
In the 1980s, scientist Dr. Peter Molan discovered that some Manuka honey maintained its antibacterial activity even after the hydrogen peroxide was neutralized. This stable activity was dubbed Non-Peroxide Activity. The original method for testing NPA involved an agar well diffusion method, comparing the honey's effect on bacteria to that of a phenol solution. For example, a honey with NPA 10+ had the same antibacterial effect as a 10% phenol solution. While this method is still used in some places, it has largely been superseded by more modern chemical testing.
Today, the most common and accurate method for determining the potency of Manuka honey is by measuring its methylglyoxal (MGO) content. The MGO is generated from dihydroxyacetone (DHA), a compound naturally present in the nectar of the Manuka flower. Because MGO concentration is directly correlated with NPA, a conversion equation is used to calculate the NPA grade from the MGO test results. The higher the MGO level, the higher the NPA and the stronger the honey's antibacterial effects.
NPA vs. MGO: Decoding the Differences
While NPA and MGO are closely related, they represent different measurements in the context of Manuka honey grading. Understanding their relationship is crucial for consumers.
- NPA (Non-Peroxide Activity): This was the original, descriptive term for Manuka honey's unique antibacterial property. Historically measured via bioassay against a phenol standard, it is now typically calculated based on the honey's MGO content. NPA ratings are often shown as a number followed by a plus sign (e.g., NPA 10+).
- MGO (Methylglyoxal): This is the key bioactive chemical compound directly responsible for Manuka honey's non-peroxide antibacterial effect. MGO is measured in milligrams per kilogram (mg/kg), or parts per million (ppm), and is a direct, reliable chemical marker. The higher the MGO number, the more potent the honey.
Other Grading Systems: UMF
In addition to NPA and MGO, you may also see the UMF (Unique Manuka Factor) trademark on Manuka honey labels. UMF is a more comprehensive quality system that verifies multiple signature markers found in Manuka honey, including MGO, Leptosperin, and DHA, to ensure authenticity and purity. UMF ratings correlate with NPA levels; for example, UMF 10+ corresponds to NPA 10+ and a specific MGO level.
Comparison of Manuka Honey Grading Systems
| Aspect | NPA (Non-Peroxide Activity) | MGO (Methylglyoxal) | UMF (Unique Manuka Factor) |
|---|---|---|---|
| What it Verifies | The overall stable antibacterial effect, non-hydrogen peroxide related. | The specific antibacterial compound, methylglyoxal. | Authenticity and purity based on multiple signature markers, including MGO, DHA, and Leptosperin. |
| Measurement | A phenol-equivalent percentage (e.g., 10+). | Milligrams per kilogram (mg/kg) or parts per million (ppm) (e.g., 263+). | A quality trademark rating based on a holistic assessment (e.g., 10+). |
| Status | Historical term, now typically calculated from MGO test results. | The modern, scientifically accurate chemical test for potency. | A comprehensive, certified standard for New Zealand Manuka honey. |
The Benefits of High NPA Manuka Honey
The benefits attributed to Manuka honey are directly linked to its NPA level. A higher NPA rating, corresponding to a higher MGO concentration, indicates stronger antibacterial and anti-inflammatory properties. This makes high-grade Manuka honey particularly useful for:
- Wound and Skin Care: Applied topically, it can help treat minor cuts, scrapes, and burns by providing a moist, acidic environment that promotes healing and fights infection.
- Sore Throat Relief: Its antibacterial properties can help soothe sore throats and fight the bacteria causing the discomfort.
- Digestive Health: When ingested, it can support gut health by maintaining a healthy bacterial balance.
How to Choose the Right Manuka Honey
When selecting a Manuka honey, focus on the potency rating displayed on the label. Look for these key indicators to ensure you are getting an authentic, high-quality product:
- MGO Rating: This is the most direct and accurate measure of antibacterial strength. Check the number (e.g., 263+, 514+, 829+) to gauge potency.
- UMF Certification: If the honey is certified by the Unique Manuka Factor Honey Association, you can be confident in its authenticity and that it has been independently tested for MGO, Leptosperin, and DHA markers.
- Authenticity Markers: For Australian Manuka honey, look for labeling that adheres to standards set by the Australian Manuka Honey Association (AMHA).
Conclusion
In essence, what is NPA in manuka? It is the non-peroxide antibacterial activity, a stable and potent property that distinguishes Manuka from other honeys. While NPA was the historical name, the underlying cause is the compound methylglyoxal (MGO). Today, MGO is the primary indicator of potency, and higher MGO ratings correlate directly with higher NPA and UMF grades. By understanding these grading systems, consumers can make informed choices about purchasing authentic Manuka honey with the desired level of antibacterial strength for their specific health and wellness needs.
