Cereal fillers

When I read words like “enriched” and “added iron/calcium/etc” on a packet, I can’t help but wonder where the added nutrients come from. How are they produced, and are they the best things for my body?

A recent e-newsletter from Raw Pleasure featured this YouTube clip about how to establish the fact that there are little bits of metallic iron in your favourite breakfast cereal:

My first reaction: Thank goodness I don’t eat packaged cereal!
My second reaction: What does this actually mean?
[yes, I am becoming a healthy skeptic in my old age :)]

While I could believe that cereal manufacturers would add iron filings to cereals, and that FSANZ would let them, I couldn’t believe that no major action had taken place or been publicised about the issue. This particular YouTube video is dated May 2009, with other similar videos being created as early as 2007. I move in healthful circles; why had I not heard about this before? Surely it meant this was not such a big deal. All the same, something just didn’t sit right with me…

Most of us know that iron is an important mineral for our body, and some of us are acutely aware of this because of personal experience with anaemia. I first suffered from iron-deficient anaemia when I was 16: I was so tired that I couldn’t drag myself out of bed. Iron is essential for regulating cell growth, cell differentiation, transporting oxygen around the body and immunity.

Although I know metallic iron is related to the iron you find in wholefoods, like cacao, seaweed and spinach, the burning question in my mind was: “can this form of iron be readily absorbed into our bodies?” In other words, is it as bioavailable?

So what are these filings? Consumer knowledge of iron filings in cereal dates back to at least 1984, starting with an experiment by Dr Babu George.

Where iron filings are used in food, these are known as “food grade iron filings”. What does this mean? Basically, they are powdered iron filings. These powdered iron filings are also known as “reduced iron”. This is iron in its metallic, or elemental, state and that doesn’t sound too appetising to me.

Are iron filings used in Australian cereals? The first thing that I wanted to establish was whether or not reduced iron is used to fortify Australian cereals. Given that the cross-section of YouTube clips I viewed appeared to be from Europe and the US, I kind of hoped this was only happening elsewhere.

I investigated labels from three popular Australian cereal manufacturers to find out as to whether or not they list the form of iron they use. I won’t name them here, but I will say that only one of the manufacturers included details on their website regarding the form of iron fortification used — and it was indeed reduced iron.

Now I knew that this issue was relevant to Australians.

How readily are these iron filings absorbed into the body? On the face of it, the first real research article I found, Iron Absorption From Elemental Iron-Fortified Corn Flakes In Humans. Role of Vitamins A and C, appeared to be exactly what I was after. It clearly detailed research into the relative absorption of different forms of iron, found that the absorption of reduced iron could be encouraged to an acceptable rate, and reached the conclusion that supplementation with this relatively inexpensive substitute is the most cost effective way to supply populations with the iron they need.

Wait a minute. Did this study recommend a low-grade, poorly absorbed form of iron fortification in cereals? Because it’s cheap? Seriously, why bother?

A closer look at the first page revealed it was a study sponsored by none other than a cereal manufacturer with a direct interest. This piqued my curiosity.

Dr Tim O’Shea put together this useful reference regarding minerals and how available they are to our bodies. Note that metallic iron is not highly bioavailable.

So is there another place the iron could be broken down? Digestion starts in your mouth and it continues past your stomach to your small intestine, with the aid of your pancreas, liver and gall bladder. Iron absorption happens in the duodenum, the first section of your small intestine, and this converts iron from its ferric (Fe3+) to its ferrous (Fe2+) form.

So where does the body convert metallic iron to its ionic form? All I could find were explanations on how plants make that conversion for us but, given the fact that numerous studies do show limited absorption from metallic iron, I assume that our stomach acids are strong enough to work on the surface of the iron filings to create a small number of iron ions.

Still feeling that iron filings might not be the greatest thing to eat, I looked further.

What stops iron filings from rusting in our food? When iron is exposed to oxygen, it rusts. To keep metallic iron from rusting in domestic & industrial applications, it is either coated (eg. with zinc, grease) or mixed with another element (eg. carbon). Food grade filings are powdered, which would leave more of their surface available to oxidisation. I couldn’t find anything online that mentions how food grade filings are protected from rust, or who produces reduced iron for food — but I assume that something must be added to them, or I would expect the distinctive taste to come through in our food.

I did have the thought that perhaps there just isn’t enough iron added to our foods for a significant flavour change following rusting, however a number of studies online mention the fact that the more absorbable ferrous sulphate is often avoided as an additive because of its taste — so that makes me think that there is sufficient metallic iron added to warrant a taste change on rusting.

If manufacturers follow the WHO recommendation to use twice the amount of reduced iron as they would ferrous sulphate if they choose the former as a fortificant, I would think that rust and, hence rusty flavour, would be even more pronounced. [And, yes, I was surprised to note that the WHO supports the use of metallic iron as a supplement in any form.]

So, aside from not being readily absorbed into our bodies, are iron filings actually bad for us to eat? Dr Thomas Levy discusses the issue of enriched food in the May 2002 issue of “Health e-Bytes”, telling us that iron filings are toxic to our bodies. While Dr Levy talks in general about the ills of fortified foods, including the fact that they are so processed that they are stripped of their base nutritional value before fortification, he doesn’t mention how or why iron filings are so toxic/dangerous to our health.

This 2010 article from Dr Joseph Mercola also warns us to avoid fortified foods altogether. Like Dr Levy, he stops short of explaining the specifics of why reduced iron is such a baddie, but he makes an excellent point: would any of us actually choose to feed our child a pinch of iron filings every morning? I know I wouldn’t.

Articles and studies regarding iron toxicity (like this one from The Eck Institute of Applied Nutrition and Bioenergetics and this one from Cornell University) mention potential causes of toxicity as being cast iron cookware, occupation, and over-consumption. My limited understanding of iron metabolism leads me to believe that iron toxicity does not necessarily result from the amount our bodies absorb in the duodenum: the harmful effects of iron toxicity could also relate to the ways in which metallic iron is stored and eliminated from the body.

To conclude, when elements are extracted from nature in non-bioavailable forms and reinjected into food, it is akin to molecular gastronomy: reducing food down to its most infinitesimal level. And when food is reduced to this level, it is not balanced.

I am also concerned about the possibility of added “filler”/mixer to prevent rusting in reduced iron. If a compound ingredient (eg. tomato sauce) makes up less than 5% of the total weight of a food product in Australia, it is lawful for a manufacturer not to include information about it. This is, of course, unless there is a known major allergen included. The problem with this is that many additives, including fillers, that produce reactions are not formally recognised as allergens (for an example, read Jennifer’s story about additives 627, 631 & 635).

The form of added minerals and their fillers is not necessarily obvious. The most effective defence against eating unwanted additives is to avoid processed foods altogether.

Nature incorporates so many excellent nutrients in our foods and in beautiful balance. Many of the cofactors for nutrient absorption are already in the wholefoods we eat, so long as the environments in which our foods thrive are not nutrient-deficient to start with. For this reason, I would include a variety of whole, organic and free range foods from a variety of sources in your diet.

If you are worried about whether or not your iron intake is sufficient, a good place to start looking is your own lifestyle. Is the problem to do with having sufficient iron in your diet, or is it about the level of absorption by your body? Iron absorption is hindered by caffeine intake and low levels of vitamin C, iron competes with other minerals for absorption (meaning: your intake of other minerals also needs to be balanced), and a low sleep/high stress lifestyle leads to poor absorption of all nutrients.

What I have presented here is my interpretation of a rudimentary internet forage — and possibly a little too much insight into how my brain works. I am really keen to learn more. If you have thoughts or feelings on this topic, or can shed more light, please leave a comment.

Yours in mindful eating,

H 🙂

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Addenda

24 July 2012: I removed the paragraph linking to a set of University of Oregon lecture notes after the comment from Pete Richter [below] because it didn’t make a point either way. The equations did not approximate the full action of digestion in the stomach, or the interaction of food enzymes/cofactors in digestion, and HCl does not wholly represent gastric juices, which vary in strength and composition from person to person.

20 June 2018: after discovering broken links, I removed my 4 November 2011 addendum about the supplement Adya Clarity. I still have not met a single person who has used it.

Some further reading on bioavailability of iron and factors that enhance/inhibit its absorption:

J D Cook, S A Dassenko, P Whittaker; Calcium supplementation: effect on iron absorption, The American Journal of Clinical Nutrition, Volume 53, Issue 1, 1 January 1991, Pages 106–111, https://doi.org/10.1093/ajcn/53.1.106

Richard F. Hurrell; Preventing Iron Deficiency through Food Fortification, Nutrition Reviews, Volume 55, Issue 6, 1 June 1997, Pages 210–222, https://doi.org/10.1111/j.1753-4887.1997.tb01608.x
[PDF accessible from: http://doc.rero.ch/record/290231/files/nutritionreviews55-0210.pdf]

Birgit Teucher, Manuel Olivares, Héctor Cori; Enhancers of Iron Absorption: Ascorbic Acid and other Organic Acids, International Journal for Vitamin and Nutrition Research, 74, 2004, Pages 403-419, https://doi.org/10.1024/0300-9831.74.6.403.
[PDF accessible from: https://www.researchgate.net/profile/Manuel_Olivares/publication/7991048_Enhancers_of_Iron_Absorption_Ascorbic_Acid_and_other_Organic_Acids/links/565660d808ae1ef9297a01e7.pdf]

>See also: Science Direct’s research summary on iron overload