Q. I try to avoid aluminum as much as possible after reading that it was toxic to the brain. I was astonished to learn recently that tea is high in aluminum. I drink 4 or 5 cups of hot tea a day during cold weather and in the summer I drink glass after glass of iced tea.
I would have a hard time giving up tea, but I am worried about the aluminum exposure. Please clarify this confusing story.
A. There is evidence that tea may have higher concentrations of aluminum than many other beverages.
That is because aluminum is found naturally in soil and can be concentrated in tea leaves, depending upon various factors such as acidity in the ground, growing conditions, fertilizers and type of tea. A study in the journal Natural Resources (online, Sept. 2011) notes that:
“Tea leaves (Camellia sinensis) are among the most conspicuous vegetal species recognized as aluminum accumulators, reaching contents up to 10,000 mg·kg. Commercial teas, in spite of the fact of being produced from young leaves shoots, contain relatively high concentrations of aluminum, becoming a potential source of bioavailable aluminum in the diet. Matsumoto et al. have reported concentrations around 30,000 mg·kg-1 of aluminum in old tea dry leaves. Ruan and Wong mentioned concentrations of aluminum in some tea varieties from 468 to 930 mg·kg.
“For many years aluminum has been considered innocuous for human beings, since most chemical forms are not damaging for living organisms. However, if pH soil values are low, aluminum tends to form chemical species that are potentially absorbed by plants, especially tea, and become toxic for living organisms. In this sense, there has been controversy on the impact of this metal on biological systems particularly in the last years. Concerning human health recent studies have demonstrated that bioavailable aluminum is related to some diseases such as Alzheimer, Parkinson, and dialysis encephalopathy.”
The Mexican researchers who conducted this study found that both black and green tea infusions had concentrations of aluminum that were “higher than the level accepted in Mexico for drinking water…”
There is growing evidence that aluminum is indeed problematic for the brain and other biological systems. A recent article in the Journal of Alzheimer’s Disease (online, Feb. 20, 2014) summarizes one perspective thusly:
“Industrialized societies produce many convenience foods with aluminum additives that enhance various food properties and use alum (aluminum sulfate or aluminum potassium sulfate) in water treatment to enable delivery of large volumes of drinking water to millions of urban consumers. …Mechanisms that underlie the risk of low concentrations of aluminum relate to (1) aluminum’s absorption rates, allowing the impression that aluminum is safe to ingest and as an additive in food and drinking water treatment, (2) aluminum’s slow progressive uptake into the brain over a long prodromal phase, and (3) aluminum’s similarity to iron, in terms of ionic size, allows aluminum to use iron-evolved mechanisms to enter the highly-active, iron-dependent cells responsible for memory processing. Aluminum particularly accumulates in these iron-dependent cells to toxic levels, dysregulating iron homeostasis and causing microtubule depletion, eventually producing changes that result in disconnection of neuronal afferents and efferents, loss of function and regional atrophy consistent with MRI findings in AD [Alzheimer’s disease] brains. AD is a human form of chronic aluminum neurotoxicity. The causality analysis demonstrates that chronic aluminum intake causes AD.”
Despite this rather gloomy assessment, there is some good news about tea and aluminum. It turns out that tea also contains reasonably high concentrations of an amino acid called L-Theanine. A recent study in Drug and Chemical Toxicology (March 24, 2014) reports that L-Theanine has “neuroprotective effects.” The authors studied the negative impact of aluminum on rat brains and concluded that:
“Aluminium induction also caused histopathological changes in the cerebral cortex, cerebellum and hippocampus of rat brain which was reverted by pretreatment with L-Theanine. The present study clearly indicates the potential of L-Theanine in counteracting the damage inflicted by aluminium on rat brain regions.”
So, although tea is high in aluminum, perhaps the fairly high levels of L-Theanine in tea counteract the potentially negative effects of the aluminum. Because we are tea lovers ourselves, we are not likely to give up our morning cup because of aluminum content.
You may want to pay more attention to your antiperspirant than your tea bag, however. All antiperspirants are quite high in aluminum. That’s because the FDA requires aluminum in such products to stop sweating. There is quite a lot of controversy about how much aluminum is absorbed through underarm skin. Until recently we suspect that the FDA assumed there was little, if any, absorption. But drugs can be absorbed through this sensitive tissue. In fact, there is a commercial on television for a product called Axiron. It is a topical testosterone solution that is specifically applied to underarms, suggesting that drug absorption from this area is efficient.
There have been reports of aluminum absorption from antiperspirants. Women who shave their underarms may be especially susceptible to this effect.
Until the issue of aluminum is resolved, we like to use alternate solutions for preventing body odor. One we learned about several years ago was milk of magnesia (MoM). At first we tried pouring it into our palms and then sloshing in on our underarms. It worked, but it was messy. That is why we developed our People’s Pharmacy Milk of Magnesia Roll-On Deodorant. It is convenient and avoids the most common ingredient in antiperspirants, aluminum cholorohydrate
Instead of giving up tea, just try to reduce your exposure to aluminum from other sources. If you have used milk of magnesia as a deodorant, please comment below and let us know how it has worked for you.