Transcript: How Much Hibiscus Tea is Too Much?
Over-the-counter antacids are probably the most important source for human aluminum exposure in terms of dose. Maalox, for example, taken as directed, can exceed the daily safety limit more than 100-fold, and nowhere on the label does it say to not take it with acidic beverages such as fruit juice. Washing an antacid down with orange juice can increase aluminum absorption 8-fold, and citric acid was worse—the acid found naturally concentrated in lemon and limes.
Just as sour fruits can enhance the absorption of iron, which is a good thing, through the same mechanism they may enhance the absorption of aluminum, raising the question what happens when one adds lemon juice to tea? Previously, I concluded that the amount of aluminum in tea is not a problem for most people because it’s not very absorbable, but what if you add lemon? No difference between tea with lemon, tea without lemon or no tea at all in terms of the amount of aluminum in the bloodstream, suggesting that tea drinking does not significantly contribute to aluminum actually getting inside the body. They’re talking about black tea, green tea, white tea, oolong tea, what about the red zinger herbal tea, hibiscus? The reason it’s called sour tea is because it has natural acids in it like citric acid—might that boost the absorption of any of its aluminum? Well, a greater percentage of aluminum gets from the hibiscus into the tea water, but there’s less aluminum overall. The question is, does the aluminum then get from the tea water into our body? We don’t have that data so to be on the safe side we should assume the worst—that is hibiscus tea aluminum, unlike green and black tea aluminum, is completely absorbable. In that case, based on this data and the World Health Organization weekly safety limit we may not want to drink more than 15 cups of hibiscus tea a day, but that’s based on someone who’s about 150 pounds. If you have a 75 pound 10-year-old, a half gallon a day may theoretically be too much. And more extensive testing more recently suggests levels may reach as high as twice as much, so no more than about two quarts a day for adults, or a quart for kids every day or for pregnant women. And hibiscus tea should be completely avoided by infants under 6 months—who should only be getting breast milk—as well as kids with kidney failure, who can’t efficiently excrete it.
The study also raised concern about the impressive manganese level in hibiscus tea. Manganese is an essential trace mineral, a vital component of some of our most important antioxidant enzymes, but we probably only need about 2 to 5 milligrams a day, and 4 cups of hibiscus tea can have as much as 17, averaging about 10. Is that a problem?
Women given 15 cups a day for 4 months, if anything, only saw an improvement in their anti-inflammatory, anti-oxidant enzyme activity. This study using 20 a day similarly showed no adverse short-term effects, and importantly showed that retention of dietary manganese is regulated. Our body’s not stupid; if we take too much in, our body decreases the absorption, and increases the excretion. So even though tea drinkers may get 10 times the manganese load, 10 or 20 milligrams a day, the levels in their blood is essentially identical. So there is little evidence that dietary manganese poses a risk. That was regular tea, though, we don’t know about the absorption from hibiscus, so to err on the side of caution we should probably not routinely exceed the reference dose of 10 mg per day, so that’s only about a quart a day for adults, a half quart for a 75 pound child. So that’s actually changed my consumption. Given the benefits of the stuff, I was using it as a substitute for drinking water, so like 2 liters a day, and I was blending the hibiscus petals in, not throwing them away, effectively doubling aluminum content, and increasing manganese concentrations by about 30%. So given this data I’ve cut back to no more than a quart of filtered a day.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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