2011 Study: Nutrients and Minerals in Mamaki

A 2011 mamaki study published in the Journal of Food Composition and Analysis  is probably more interesting to propeller heads than to the average tea connoisseur, even if the connoisseur is a mamaki fanatic. Titled Nutrient and mineral composition of dried mamaki leaves (Pipturus albidus) and infusions, it provides a plethora of statistics but no clear conclusions. Nevertheless, the numbers will probably be used as a foundation for future, more exciting research, so I’ll put them in graphic format here so they’ll be a little more engaging. And perhaps we’ll pickup some patterns that are not easily seen in the raw data.

Mamaki v Lipton v Green

In summary, nutrient values varied widely between leaves harvested in winter and summer, but some nutrients that were high during one season were low in the other and visa versa, so things seem to average out. Dried mamaki leaves (before tea) had significantly higher levels of nutrients than other commercial teas that were compared.

Mamaki Mineral Seasonal Variation

However, the nutrient levels in the tea itself declined so substantially that it generally compared less favorable to other teas. The one exception was calcium which stayed higher than all the others.

What’s it all mean?

  • Eat the leaves as suggested in this video? That might be a good idea.
  • The tea is valuable only for those who want additional calcium? Not necessarily…

The study itself hints at issues that may influence nutrient measurements…like the resistance of leaching due to the influence of other minerals. It seems obvious from earlier studies—and hundreds of years of anecdotal experience—that there is more going on with the mamaki plant than the numbers in this study can convey.

This study continues in the footsteps of the 2007 study by distinguishing between varieties of mamaki. In fact, they further subdivide the the original four varieties into more due to the size of leaves and their depth of color. But for clarity here, I’ll stick with the four main varieties. I’ve also personally witnessed the tripling and quadrupling in leaf size in the same plant between harvests simply due to a better rainy season and more nutrients added to the soil.

Mamaki Varieties

The overall impression of the next chart is that mamaki generally has a high percentage of calcium and potassium. While it’s probably way too anal to think about such things in the real world, tea drinkers that use the hybrid variety are getting a stronger dose of calcium from summer-harvested leaves and stronger dose of potassium from winter-harvested leaves.

Macro-Mineral Content of Mamaki Tea Varieties

The next chart shows similar seasonal variation in the hybrid variety with manganese being stronger in the winter and is apparently displaced by lots of boron in the summer.

MIcro-Mineral Content of Mamaki Tea Varieties

In the two charts above, note how the hybrid variety on mamaki tends to stand out with the highest numbers. The researchers must have noticed that because the hybrid variety was isolated to create the following two charts. The interesting take-away from this next chart is that a tea-drinker especially focused on potassium may want to further hone in on whole leaves from the hybrid variety.

Macro Minerals in Whole, Crushed or Ground Mamaki Tea

On the other hand, making mamaki tea from ground leaves (tea bags) seems to be the best way to get the widest variety of micro-minerals like boron, copper and zinc.

Micro Minerals in Whole, Crushed or Ground Mamaki Tea

The next chart is the most amazing one on this site at this time.  Just a glance shows that dried mamaki leaves have a much higher mineral content than the four others compared. But take a closer look. The numbers on the y-axis are logarithmic…they increase by orders of magnitude. Now the superior mineral level of mamaki leaves become astonishing! The difference is so pronounce that this logarithmic chart doesn’t do it justice. But when I used a standard non-logarithmic chart, the mamaki bars extended beyond the page and the other bars where so small that they were invisible.

Macro-Minerals in Mamaki v Other Tea Leaves

So let’s revert back to some numbers to help us fully grasp the difference.

Dried mamaki leaves compared to the next highest scoring dried tea leaves tested

  • 218 times the phosphorus of echinacea
  • 185 times the potassium of echinacea
  • 1696 times the calcium of red raspberry
  • 2813 times the magnesium of echinacea
  • 46 times the sodium of echinacea

What the heck!

  • Is mamaki that much superior at drawing minerals out of the soil?
  • Is there simply more mineral availability in Hawaii’s volcanic soil compared to wherever the other teas were raised?
  • Were the other teas raised with Round-up (glyphosate) which limits mineral uptake from the soil?

We just don’t know. This may be a good future study for the University of Hawaii.

But the preceding data pertains to dried leaves. Is that proof enough that the whole world should give up their other namby-pamby teas in favor of a rocket-fueled mamaki variety? Apparently not. Given the previous extraordinary data, the following chart is a let-down for mamaki tea drinkers. The mineral-rich leaves apparently don’t release those minerals into boiling water as readily as do other teas. Mamaki tea comes in average at best for mineral content.

Macro-Minerals in Mamaki v Other Teas

What’s going on?! My wild hypothesis is that mamaki tea should ideally be steeped for a much longer period to coax out its mineral richness. This study put the tea leaves in boiling water and allowed them to steep in a covered container for 30 minutes.  I wonder what would happen if…

  • the leaves were allowed to “cook” a bit while boiling the water
  • the leaves were allowed to steep longer than 30 minutes
  • the mineral-content of the tea was tested after allowing the tea (with leaves) to set in the refrigerator for three or more days

New mamaki tea drinkers are always amazed at (1) the dark maroon color of the tea and (2) how long a container of brewed tea can set in the fridge without souring. The last two charts in my article on the 2007 study shows antioxidant levels stabilizing after 24 hours and then staying consistent for two more days. I hope a future study will extend out for a longer period of time. I’ve had refrigerated mamaki tea that tasted just as good a week later as it did when it was freshly brewed. So I wonder if mamaki’s mineral riches are being slow-released the entire time. If the theory holds, the short shelf life of the other teas might be correlated to the poor mineral content of their dried leaves.

So this study raises at least three questions to be answered in future studies…

  1. What is the explanation for the astonishingly high mineral content of dried mamaki leaves?
  2. What influence do different boiling, steeping, and storage times have on the mineral content of mamaki tea?
  3. How long does the antioxidant potential of mamaki tea extend beyond the three days tested in the 2007 study.

In the introduction to this article, I suggested that most of the data in this study is relevant only to propeller heads. But I think that even everyday mamaki tea drinkers can appreciate what a good stepping stone this study will be if it leads to future studies that answer these three questions.

 

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