Most of the advice you see online for people who have anemia involves eating foods rich in iron. But you may also have read or heard that some foods can inhibit your iron absorption and make you more iron deficient. Let’s take a look at some of these claims.
The science
When I first wrote this article years ago, I’d just heard on the news that even though spinach was really rich in iron, it also had an ingredient that could block you from absorbing iron.
Well, that sucked. I pictured myself eating a nice juicy steak along with some spinach and feeling even more exhausted after the meal than I had before. Or maybe I’d take my doctor-advised iron supplement and it would do me no good because I’d eaten spinach for lunch.
Then I did some research. I found loads of blogs advising me that all sorts of foods could block iron absorption! And they had links to websites with medical names! It had to be true, right? And so I published my own article with several of these claims.
But scientists have been studying this issue ever since. And it turns out a lot of what I heard just wasn’t the whole story. None of it was completely false. But sometimes getting half the story is worse than getting none at all.
Foods and Anemia
Foods that Boost Iron Absorption
First of all, it turns out there’s at least one food that actually boosts your iron absorption: Vitamin C. You can squeeze a lemon wedge into your iced tea with an iron-rich lunch.
Or you can take a Vitamin C supplement. If you’re looking for one, I like Country Life Vitamin C chewable tablets. They have a better flavor than most brands and not so much of the chalky texture.
A supplement that does inhibit iron absorption
There is one supplement and food item you need to be aware of, for sure: calcium. Calcium does interfere with iron absorption. But there’s a strategy for making it work: you just need to take calcium supplements and iron supplements at different times of the day.
You should also be aware of calcium in food form. For example, the calcium in cheese could make a cheeseburger less helpful for your iron levels than a hamburger without it.
Foods to avoid… or not?
1. Spinach
As I said above, this whole learning journey started with a report that spinach contains oxalic acid, and OA can binds with the iron and keep your body from using it.
It turns out spinach does inhibit iron absorption, just not enough to worry about. And it’s not the OA that’s the problem – it’s the calcium and some other ingredients.
2. Red wine
It’s true that red wine inhibits iron absorption a little bit, at least compared to white wine. But again, it’s not significant enough to worry about:
Our findings indicate that the inhibitory effect of phenolic compounds in red wine is unlikely to affect iron balance significantly.
3. Coffee
Sorry to be the bearer of bad news, but coffee really can interfere with iron absorption. But only if you drink it along with or just after a meal:
No decrease in iron absorption occurred when coffee was consumed 1 h before a meal, but the same degree of inhibition as with simultaneous ingestion was seen when coffee was taken 1 h later.
So drink coffee in between meals, being sure to leave at least an hour on either side of your meal.
4. Black and green teas
It turns out both herbal and black and green teas can interfere with iron absorption when you’re getting it from plant sources, but they don’t block it from meat.
Our findings demonstrate that herb teas, as well as black tea, coffee and cocoa can be potent inhibitors of Fe absorption. This property should be considered when giving dietary advice in relation to Fe nutrition.
But again, the trick is to drink tea in between meal:
Recommendations with respect to tea consumption (when in a critical group) include: consume tea between meals instead of during the meal; simultaneously consume ascorbic acid and/or meat, fish and poultry.
5. Soy proteins
Soy protein isolate definitely blocks iron absorption:
The soy products tested in this study have a pronounced inhibitory effect on the absorption of nonheme iron.
Soybeans in general also inhibit it:
We conclude that there are two major inhibitors of iron absorption in soybean-protein isolates, phytic acid and a protein-related moiety contained in the conglycinin (7S) fraction.
It’s not clear if other forms of soy also block iron. One study seemed to find that some forms of it may actually help with iron absorption, but they were unable to reach any conclusions because some of the data didn’t make any sense.
