"Is There Too Much Aluminum in Tea?"
Aluminum is the third most abundant element on Earth, and may not be good for our brain—
something we learned studying foundry workers exposed to high levels.
Though the role of aluminum in the development of brain diseases like Alzheimer’s is controversial,
to be prudent, steps should probably be taken to lessen human exposure to this metal.
There are a number of aluminum-containing drugs on the market
like antacids, which have the highest level,
though aluminum compounds can also added to processed foods
as anti-caking agents in pancake mix,
melting agents in American cheese, meat binders, gravy thickeners,
rising agents in some baking powders, and dye-binders in candy.
So it’s probably better to stick to unprocessed, natural foods.
However, if you cook those natural foods in an aluminum pot,
a significant amount can leach into the food, compared to cooking in stainless steel.
If you do the same thing with tea, though,
you get a few milligrams of aluminum regardless of what type of pot you use,
suggesting the aluminum is in the tea itself.
And indeed back in the 1950s,
it was noticed that tea plants tend suck up aluminum from the soil,
but like anything, it’s the dose that makes the poison.
According to the World Health Organization,
the provisional tolerable weekly intake–
our best guess at a safety limit for aluminum–
is 2 mg per healthy kilogram of body weight per week,
which is nearly a milligram per pound,
so someone who’s around 150 pounds probably shouldn’t ingest
more than 20 mg of aluminum per day.
Up to a fifth of intake may come from beverages,
so what we drink probably shouldn’t contribute more than about 4 mg a day,
which is the amount found in about 5 cups of green, black, or oolong tea.
So should we not drink more than 5 cups of tea a day?
Well, it’s not what we eat or drink; it’s what we absorb.
If you just measured how much aluminum was in tea,
it would seem as though a couple cups could double our aluminum intake for the day,
but if you measure the level of aluminum in people’s bodies after they drink tea, it doesn’t go up.
This suggests that the bioavailability of aluminum in tea is low,
possibly because most of the extractable aluminum in brewed tea is strongly bound
to these large phytonutrients that are not easily absorbed from the gastrointestinal tract,
so it just passes right through,
our intestines get flushed away without actually getting inside our body.
Probably more than 90% of the aluminum in tea is bound up.
But what about studies like this showing a large spike in aluminum excretion
through our urine after drinking tea compared to water?
The only way for something to get from our mouth to our bladder
is to first be absorbed into our bloodstream,
but they weren’t comparing the same quantity of tea and water.
They had the study subjects chug down like 8-1/2 cups of tea,
or just drink water at their leisure,
so the tea drinkers peed a lot more, period,
so the aluminum content was no different really, tea versus water,
suggesting that gross aluminum absorption from tea is unlikely
and that only little aluminum is potentially available for absorption.
So though as few as 4 cups of tea could provide 100% of one’s daily aluminum limit,
the percentage available for absorption in the intestine may be less than 10%.
Therefore, it is unlikely that moderate amounts of tea drinking can have any harmful effects on humans.
However that’s for people with normal aluminum excretion.
For example, tea may not be a good beverage for children with kidney failure,
since they can’t get rid of the aluminum as efficiently.
For most people, though, tea shouldn’t be a problem.
Though if you drink tea out of a can, buy undented cans,
as the aluminum in dented cans can leach into the liquid
boosting aluminum levels by a factor of 8 sitting on store shelves for a year.