[vanderZwan]

You're probably thinking of the type of iron they add to breakfast cereals, which is the mineral kind you don't absorb. Also, you wouldn't absorb it anyway because calcium-rich food (like, I dunno, milk) block the absorption of iron. There was an episode on a Dutch TV show where they investigated this, and they found you could actually make Special K flakes follow a magnet when floating it in water.

The episode is among the few that you cannot stream from their own website, but it's, still on YouTube[0]. I am pretty sure legal threats from Kellogs had to do with tgat, because the week after the episode in question aired, people on that program were forced to publically apologise for joking that Kellogs was putting crusher bicycles in their cornflakes. Also, Kellogs actually took out a full-page ad stating that they don't and that the people on that show were slandering.

The corporation doth protest to much, methinks.

[0] https://www.youtube.com/playlist?list=PL2AC0E0D930B52A07

[klodolph]

Your body can absorb metallic iron, because it will react in your stomach and change to Fe2+, which you can absorb just fine. For a different type of experiment, you can try mashing Special K in a mortar and pestle and use a magnet to extract the iron. This is fine, because your body can actually absorb this!

It’s also misinformation that your body won’t absorb iron because of calcium intake, it’s just that calcium inhibits iron absorption somewhat, and only short-term, it doesn’t stop it completely. It’s not that well understood.

[vanderZwan]

Any source on that? I'm just basing my statements on what the GP who was consulted in the linked episode stated, and while she's not exactly a specialist on the subject she does know a little bit more about nutrition than the average person on the street.

> [mineral iron] it will react in your stomach and change to Fe2+

Wouldnd't the presence of an acid-neutralizing ingredient like milk negatively affect this process?

> it’s just that calcium inhibits iron absorption somewhat, and only short-term, it doesn’t stop it completely.

Could you be a bit more precise when you say "short-term"? If it basically reduces absorption for the current meal the point of it defeating iron absorbtion is still valid.

[klodolph]

> Any source on that?

Personal correspondence with a nutrition PhD. Not going to identify for unrelated reasons.

> Wouldnd't the presence of an acid-neutralizing ingredient like milk negatively affect this process?

Milk is acidic in the first place. In either case, it doesn’t raise the pH of your stomach very much.

> Could you be a bit more precise when you say "short-term"?

Short enough that the effect is gone before you finish digesting the meal.

https://www.ncbi.nlm.nih.gov/m/pubmed/21462112/

From what I gather, there were some studies that claimed that calcium interferes with iron absorption, and it’s clear that it does, but it might not have much of an effect on nutrition.

[vanderZwan]

Thanks, appreciate the follow-up!