In my videos on tea, I caution not to drink with meals,

because it can inhibit the absorption of iron from foods

anywhere from 26 to 99 percent,

perhaps depending on the brewing time, brand, or how strong it is.

What about the inhibition of food iron absorption by coffee?

When I was first looking this up, I ran across this study

on the effects of discontinuing coffee intake

on the iron status of Guatemalan toddlers.

I’m thinking they must be talking about breastfeeding mothers

or something, but no, coffee is one of the first liquids

given to infants in Guatemala.

I did not know that!

Anyway, the inhibition of food iron absorption by coffee.

A cup of coffee reduced iron absorption from a hamburger meal

by 39 percent, as opposed to a 64 percent decrease with tea.

So, not as bad as tea, but still significant blockage.

And just like with the tea, the stronger the coffee,

the more iron absorption was impeded.

In terms of timing, no decrease in iron absorption occurred

when coffee was consumed an hour before a meal,

but waiting an hour after the meal

to drink the coffee didn’t seem to help,

which can be probably explained by the fact

that it may take up to nearly two hours

to clear a meal from the stomach;

so, starting an hour in,

the coffee can catch up to the food.

Now, you can reverse the effect of tea or coffee

by adding orange juice to a meal, or even better an orange,

or any source of vitamin C-rich food.

The vitamin C boosts iron absorption,

which is good for people who are borderline anemic,

but for many, the blockage of iron absorption from coffee

may actually be a good thing.

Iron is a double-edged sword.

On the one hand, iron is an essential element

vital for blood production.

On the other hand, iron is a potent pro-oxidant.

So, maybe the reduced risk of type 2 diabetes

associated with coffee consumption is due to the inhibition

of iron absorption by coffee.

See, the risk of type 2 diabetes increases with the increase

in the amount of ferritin in your blood,

which is a measure of your iron stores.

So, higher iron stores, higher diabetes risk.

It’s the same thing with the risk

of gestational diabetes during pregnancy.

So, you need to make sure you’re getting enough iron,

but not building up too much iron in your body.

How do we know it’s cause and effect?

Because if you randomize diabetics

like old-fashioned bloodletting,

but instead of leeches, they just donate blood

a couple times to lower their iron stores,

and those in the blood donation group

had better blood sugar control, better insulin secretion,

less insulin resistance.

Iron depletion improves artery dysfunction

in type 2 diabetics as well.

It’s the same thing with gout.

Does inhibition of iron absorption by coffee reduce

the risk of gout? Let’s find out.

Near-iron deficiency-induced remission of gouty arthritis.

They took gout patients and maintained their iron stores

at the lowest level possible without causing anemia and…

gouty attacks markedly diminished in every patient,

with effects ranging from a complete remission

to a marked reduction of incidence and severity of gouty attacks.

Here's the attack rates before and after.

So, maybe that’s one reason coffee consumption

is associated with lower risk of gout.

It blocks some of the iron uptake.

Increasing evidence suggests that iron is also involved

in multiple diseases of aging, including Alzheimer's disease,

Parkinson’s disease, and heart disease.

In terms of iron and Alzheimer’s,

they think it’s iron’s potential to effectively “rust” brain tissue

by producing free radicals that may cause neurodegeneration,

contributing to Alzheimer’s disease pathology

at numerous levels, so much so that there is interest

in trying to treat Alzheimer's disease by targeting iron.

High body iron stores may also be associated with shorter telomeres,

which is a biomarker of biological aging.

And for those of you thinking, well if I had high iron stores,

I’d probably know about it.

Only 5 percent of patients with elevated iron report

ever being told by a doctor that this was the case.

To prevent too much iron accumulation, regularly drinking tea

with meals will do it, found to decrease the amount

of bloodletting you have to do for people

with a genetic iron overload disease.

But you’d want to do the opposite— drink tea only apart from meals—

if you were at risk for iron deficiency anemia.

Besides tea and coffee, there are other beverages

that can block iron absorption.

Peppermint is right up there with black tea,

chocolate milk would do it too,

and chamomile blocks iron about in the same range as coffee.

So, if your iron stores are high, these are great mealtime choices.

If you’re struggling to get enough iron,

you wouldn’t want to regularly drink these with meals.

We think it’s the polyphenol phytonutrients.

So, what about herbs and spices?

They’re packed with polyphenol goodness.

Now, this study was done basically in a test tube,

not in real people, but there is this case report

of iron deficiency anemia due to high-dose turmeric.

A physician treated himself for an osteoarthritis flare

with capsules of turmeric extract and he was anemic,

couldn’t get his iron up despite taking iron supplements.

But two weeks after stopping the turmeric,

his blood count and iron levels were all back to normal.

So, on one hand, those presenting to doctor’s offices

with iron deficiency anemia should be asked about supplement use;

at the same time, the ability of turmeric

to glom on to intestinal iron may lead to it being useful

in states of iron overload.