Do Coffee and Caffeine Inhibit Iron Absorption

Caffeinated foods and beverages have become staples in most modern-day diets.
Coffee is among the most popular, with 80% of US adults drinking it (1, 2).
Caffeine is a natural stimulant. However, some claim it interferes with the absorption of certain nutrients, such as iron.
As a result, some people have been advised to avoid coffee and caffeine.

Here’s everything you need to know about how coffee and caffeine affect iron absorption.
Coffee and Caffeine Can Inhibit Iron Absorption
Several studies have found that coffee and other caffeinated drinks can reduce iron absorption.
One study found that drinking a cup of coffee with a hamburger meal reduced iron absorption by 39%. Drinking tea, a known inhibitor of iron absorption, with the same meal reduced iron absorption by a whopping 64% (3).

Another study found that drinking a cup of instant coffee with a bread meal reduced iron absorption by 60–۹۰% (۴).
What’s more, the stronger the coffee or tea, the less iron absorbed (3).
However, caffeine alone does not seem to be the main substance interfering with iron absorption.
In fact, one study found that caffeine itself only binds to about 6% of the iron from a meal. Given that this is a relatively small amount, other factors must affect iron absorption (5).

Furthermore, regular coffee consumption may also have an effect on iron storage levels.
However, it’s important to remember that the effects of coffee and caffeine on iron absorption seem to depend on when you drink your coffee. For example, drinking coffee one hour before a meal had no effect on iron absorption (7).
Other Substances Affect Iron Absorption
Caffeine is not the only substance known to interfere with iron absorption.

The polyphenols found in coffee and tea are thought to be major inhibitors of iron absorption.
These include chlorogenic acid, which is found mainly in coffee, cocoa and some herbs. Also, tannins found in black tea and coffee inhibit iron absorption (4, 8).
These compounds bind with iron during digestion, making it more difficult to absorb (9, 10).
Their effect on iron absorption is dose-dependent, meaning that iron absorption decreases as the polyphenol content of the food or beverage increases (9, 11).

The Type of Meal Affects Iron Absorption
Iron absorption is complex and affected by many dietary factors.
Evidence suggests that the type of food you eat has a greater influence on iron absorption than the effect of drinking coffee or caffeinated drinks.
Certain types of foods enhance iron absorption, while others inhibit it. The type of iron you consume is also important.
Iron is present in food in two forms — heme and non-heme iron.