In our previous article, we talked about the pieces or iron people add to their food to top up their plasma levels.

But it is really the case?

Would this mean that by cooking exclusively in cast iron cookware you are ingesting far more iron than you should?

Dietary Iron

Iron is essential to our survival. Iron is an essential component of haemoglobin (a protein found in the red blood cells that carries oxygen from the lungs to the rest of your body and gives blood its red colour), and myoglobin (an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue. It functions as an oxygen-storage unit, providing oxygen to the working muscles), another protein that provides oxygen. Much of the remaining iron is stored in the form of ferritin or hemosiderin (a degradation product of ferritin) in the liver, spleen, and bone marrow.

Iron levels are under tight control, as we have seen in previous article that too high concentrations of iron are damaging to health.

Iron also supports muscle metabolism and healthy connective tissue, and is important for healthy brain development and growth in children, and for the normal production and function of various cells, enzymes and hormones. It is also involved in DNA synthesis. Thus, it would be expected that any deficiencies would cause health problems. It is estimated that 1.6% of the US population do not ingest enough iron through their diet. In fact, iron-deficiency anaemia is the most common nutritional deficiency worldwide. Usual symptoms include extreme fatigue, lethargy, lightheadedness, and difficulties with concentration and focus. Iron deficiency is thus associated with poor physical, cognitive, and immune development and poor immune function. It affects all ages, but the populations at greater risk of deficiencies include children, and women who are pregnant or menstruating. Injuries and heavy bleeding can also lead to iron losses. Extreme stress or anxiety can also reduce the absorption of dietary iron by the intestinal cells.

Infections, cancer and certain inflammatory disorders may also lead to anaemia of chronic disease, also known as ‘anaemia of inflammation’ (e.g., rheumatoid arthritis, inflammatory bowel disease, and haematologic malignancies). In people with anaemia of chronic disease, inflammatory cytokines upregulate hepcidin. As a result, iron homeostasis is disrupted and iron is diverted from the circulation to storage sites, limiting the amount of iron available for the synthesis of red blood cells, a process known as erythropoiesis.[2]

If we understand how iron is stored in the body then it makes more sense when looking at different forms of iron available in our diet. Following a certain type of restricting diet may also lead to lower intake of iron. Calorie-restricting diets and strict vegetarian and vegan diets may also be low in iron if they rarely cook from scratch.[1] Only half of all women in the UK do not consume the 8.7 mg/day RNI.[3] Therefore, this is a nationwide (and potentially worldwide) problem.

Haem and non-haem iron

Haem and non-haem iron, also known as heme and non-heme iron, are the two forms of iron available in our diet.

Plant contain non-haem iron (iron they pull from the soil*. White beans contains 8 times more iron than chicken. Most beans deliver 3 mg, and nuts around 1-2 mg ). Animal meat and seafood are the richest source of haem iron (oysters provide 8 mg per serving, beef liver 5 mg, and poultry 1 mg)). Meat contains both non-haem (due to consumption of plants) and haem iron. Therefore, our human diet should provide plenty of non-haem and sufficient levels of haem iron.

Many foods are ‘fortified’ with iron and used forms of iron in supplements include ferrous and ferric iron salts, such as ferrous sulfate, ferrous gluconate, ferric citrate, and ferric sulfate.[4] Iron-only supplements usually deliver many times the recommended daily intake, with many providing 65 mg of iron , about 260% of the Daily Value — DV (US). or over 600% the recommended national intake — RNI (UK). The DV is 18 mg and RNI is 8.7 mg per day for men and postmenopausal women, and 14.8 mg per day for premenopausal women).[2] Therefore, supplementing with iron must be done under tight supervision.

Currently, enriched bread and cereal products provide most the RNIs.[5] Foods participating to topping up iron levels include beans and pulses, eggs and fish.

* Iron as a metal is extracted from the earth crust from mines. Iron is one of the most abundant metals in the earth's crust, however its availability to plant roots is very low. Plants are only able to absorb iron from the rhizosphere, the most biologically active part of the soil around plant roots.

Food combining

Spinach is very rich in non-haem iron; however, it also contains polyphenols which prevents the absorption of dietary iron. Therefore, they are not recognised as a good source of iron.

All food and drinks containing polyphenols will thus reduce the absorption of iron and these include teas and coffee. Do not drink tea within 1 hour of a meal if you have been diagnosed with iron-deficiency anaemia or deficient in iron.[5]

Should I supplement with iron or not?

Adults with normal intestinal function have very little risk of iron overload from dietary sources of iron [7]. Exceeding an intake of more than 20 mg/kg iron by taking supplements or medicines can lead to gastric upset, constipation, nausea, abdominal pain, vomiting, and faintness, especially when not taken with food.[7,8]. Any dose over 25 mg elemental iron can also reduce zinc absorption and plasma zinc concentrations. Overdoses of iron can lead to multi-system organ failure, coma, convulsions, and even death.[2]

Supplementing with iron is not suitable for people on Levodopa (a drug given to patients with Parkinson’s disease), Levothyroxine (a drug given to patients with hypothyroidism, goitre, and thyroid cancer) : iron supplements reduce the amount of Levodopa and Levothyroxine available to the body and, thus, diminish its clinical effectiveness. Iron-containing supplements should be taken 4 hours away from Levothyroxine.

Omeprazole and other proton-pump inhibitors, antacids and other drugs preventing the release of stomach acid will effectively reduce the absorption of non-haem iron. Identifying the cause of heartburn and reflux (GERD) is a better form of treatment than reducing the levels of gastric acid, which is also essential to digest proteins and many more foods, which can lead to a wide-array of conditions like bloating, intestinal discomfort, inflammatory disorders and associated malnutrition, as well as food intolerances, and on the long-run autoimmunity.

To maximise intake of iron, a healthy diet seems to be the best option (as always and for a continuous intake of nutrients and health-preserving antioxidants). It should:

• Include a variety of fruits and vegetables of as many colour as possible; whole grains, beans and pulses; and, some fermented products like sauerkraut, kimchi, yogurt and cheese.

• Include a varied selection of protein foods such as organic pasture-raised offal and lean meats (beef, lamb, poultry, venison, games, and seafood), eggs, beans and pulses, nuts and seeds, and some soy products.

• Include none to little alcohol.

• include plenty of antioxidant-rich foods, which also include teas and coffee (keep black tea and coffee away from meals); raw, unprocessed and unsweetened berries, (açaí and haskap, among many others) in powder form or frozen added to smoothies or foods; fresh berries; spices.

• Include nutrient-dense foods to keep you satiated and less inclined to overeat and over-consume calories by snacking and consuming too many empty calories, which keep you wanting more by disturbing blood sugar balance.

What about those iron stuff?

Let’s see the story of the Lucky Iron Fish, a product that is growing in interest the world around. Lucky Iron Fish was created by Christopher Charles, who was shocked to discover how endemic anaemia — the most common nutritional problem globally — was in Cambodia while working there in 2008. Following the advise of the World Health Organization (WHO) reporting iron deficiency to be the primary cause of anaemia[9], it was easy to come to conclusion and propose a higher intake of iron to reduce the number of Cambodians with anaemia.

This is what Kate Mercer, Lucky Iron Fish vice president of marketing and communications, told News Deeply, “We’ve done several studies in Cambodia and have found that although some results are inconsistent, overall there is great scientific support for using the Lucky Iron Fish as an easy and affordable way of increasing the dietary iron in food.”

This statement is solely based on the WHO and not so much on studies implicating Cambodian citizens.

It is assumed that iron levels can be increased by cooking on cast iron cookware and so an idea to modernise this idea by developing a piece of cast iron to place in food while cooking — the birth of Lucky Iron Fish.[10]

While one piece only can cost ad much as an entire set of cast iron pans it may not be the best option for the many.

But let’s go back to Cambodia for one second.

“Iron deficiency is a very common cause of anaemia globally, but dozens of other causes exist,” says Dr. Reina Engle-Stone, a specialist in public health nutrition at the University of California.

The causes of anaemia can be varied but there was a flaw in the ‘studies’ backing up the design of Lucky Iron Fish and national aim to distribute free iron supplements. There was no evidence of numbers decreasing. Iron-deficiency anaemia is still a problem in Cambodia. The reason being the majority of anaemia cases in Cambodia are related to genetic defects (e.g., Haemoglobinpathy E), where smaller than normal red blood cells are present.

So, Lucky Iron Fish or similar products may be useful in people following highly-restrictive diets and may benefit from adding it to their cooking food. But for that, they would have to cook from scratch. Typically, highly-restrictive diets (calorie-restrictive diets, strict vegetarians and vegans) are a problem in themselves as they mostly revolve around ultra-processed manufactured food products that are already health disasters in plastic-wrapped plastic/aluminium trays; offering little health benefit and very little nutrients (but a tsunami of non-food products and various chemicals).

Cast iron cookware can transfer 8 mg of iron to cooking food (depending on length of cooking). Using cast iron can thus be an ideal solution to increase iron levels in the body; however, this will not make a bad diet better.

Dr. Reina Engle-Stone response to Lucky Iron Fish’s ability to increase iron levels in some women in Cambodia: “There will never be a single solution, simple or not, to a complex problem like anaemia. On the other hand, we cannot do nothing just because we don’t have all the solutions.”

References

1. Young, I. et al. (2018). Association between haem and non-haem iron intake and serum ferritin in healthy young women. Nutrients. 10(1), 81. doi.:10.3390/nu10010081

2. Source: National Institute of Health (NIH). (2022). Iron: Fact Sheet for Health Professionals.

3. Thane, C Bates, C. Prentice, A. (2003). Risk factors for low iron intake and poor iron status in a national sample of British young people aged 4–18 years. Public Health Nutrition. 6(5), pp. 485–496

4. Murray-Kolbe, LE. Beard, J. (2010). Iron. In: Coates, PM. et al. 2nd eds. Encyclopedia of Dietary Supplements. 2nd ed. London and New York: Informa Healthcare. pp. 432-438.

5. Finnamore, HE. et al. (2014). Top dietary iron sources in the UK. The British journal of general practice : the journal of the Royal College of General Practitioners. 64(621), pp. 172–173. doi.:10.3399/bjgp14X677761

6. Nelson, M. Poulter, J. (2004). Impact of tea drinking on iron status in the UK: A review. Journal of Human Nutrition and Dietetics : The Official Journal of the British Dietetic Association. 17(1), pp. 43-54. doi.:10.1046/j.1365-277x.2003.00497.x

7. Aggett, PJ. (2012). Iron. In: Erdman JW, Macdonald IA, Zeisel SH, eds. Present Knowledge in Nutrition. 10th ed. Washington, DC: Wiley-Blackwell; pp. 506-520.

8. Institute of Medicine. (2001). Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc : A report of the panel on micronutrients. Washington, DC: National Academy Press.

9. Source: http://www.who.int/topics/anaemia/en/

10. Source: https://en.wikipedia.org/wiki/Lucky_iron_fish (sorry for this, but when you are looking for mainstream biased info, that site always delivers!)