 Over-the-counter antacids are probably the most important source for human aluminum exposure in terms of dose. Melox, for example, taken as directed, can exceed the daily safety limit more than 100-fold, and nowhere on the label does it say not to take with acidic beverages such as fruit juice. Washing antacid down with orange juice, for example, can increase aluminum exposure 8-fold, and citric acid was worse, the acid found naturally concentrated in lemons 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 and tea is not a problem for most people, because it's not very absorbable. But what if you add a 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, the lemon juice or not. Now 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 the hibiscus tea aluminum, unlike green or black tea aluminum, is completely absorbable. In that case, based on the state and the World Health Organization weekly safety limit, we may not want to drink more than like 15 cups of hibiscus tea a day. That's based on someone who's about 150 pounds, but so if you have a 75-pound or 10-year-old, a half gallon of tea a day may be theoretically too much. And more extensive testing more recently suggests levels may be as high as twice as much, so no more than about two cups a day for, excuse me, two quarts a day for adults, or a quart a day for kids every day, or pregnant women. And hibiscus tea should be completely avoided by infants under six months, who should only be getting breast milk anyway, 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, vital component of some of our most important antioxidant enzymes, but we probably only need two to five milligrams a day, and four cups of hibiscus tea can have as much as 17, averaging about 10. Is that a problem? Well, women given 15 a day for four months, if anything, only saw an improvement in their anti-inflammatory antioxidant enzyme activity. This study, using 20 a day, similarly showed no adverse short-term effects, and importantly showed that the retention of dietary manganese is regulated. Our body is not stupid. If we take too much in, our body decreases the absorption and increases the excretion. So even though tea drinkers may drink 10 times more manganese, get 10 times more a day, 10 or 20 milligrams a day, the levels in their blood is essentially identical. So there's little evidence that dietary manganese poses a risk. That was regular tea, though. We don't know about the absorption from hibiscus. So there on the side of caution, we should probably not routinely exceed the reference dose of 10 milligrams per day. So that's only about a quart a day for adults, half a quart for a 75 pound child. So that's actually changed my family's consumption. Given the benefits of the stuff, I was using it as a substitute for drinking water, so like, you know, two 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 about a quart of filtered hibiscus tea a day.