Updated: Aug 21, 2019
Iron = spinach = Popeye = strength
That’s all we know about this fundamental element which is abundantly present in almost all life forms. But it’s far more complex than simply eating spinach and getting iron. Let’s break it down into what we really need to know to get enough iron through food.
Iron is the basic component of hemoglobin (the blood pigment) and myoglobin (the muscle pigment). So without iron we are basically no blood and no muscle (kinda like the white walkers in game of thrones!).
An average adult stores about 1-3 g of iron in his/her body.1
We have no mechanism in place to excrete excess iron! Yes, so basically we have a large turnover of stored iron in the body (liver-muscle-blood) with iron being lost only though blood loss (menstruation in females mainly) and loss of dead cells (<1%).1
And so, the daily requirement for iron is only 2-4 mg (slightly higher in menstruating or pregnant women) which can be easily met through diet. 1
Then why is iron deficiency so common? Why do so many take iron supplements?
Only up to 10% of dietary iron can only be absorbed from a regular vegetarian diet. But there are few hacks to increase this number that we will talk about later!
Iron can be absorbed only in its ferrous state (Fe2+) and the acidic pH of the stomach is essential to maintain this state.2 When the acidic pH is altered due to antacids or drugs (omeprazol, ranitidine etc.), iron absorption is reduced.
Calcium (and its compounds) inhibits iron absorption. Dietary calcium doesn’t seem to affect iron absorption except in cases of dairy products.3 Short term calcium supplements have also shown to reduce iron absorption, but the long-term studies are inconclusive.4
Ascorbic acid (Vitamin C) is very much essential is the absorption of iron. Most green leafy vegetables have ascorbic acid to aid iron absorption. Also, addition of lemon, orange, guava, amla etc. to iron rich diet, will further increase the bioavailability.1 The ideal requirement will be 1g of citric acid (or ascorbic acid) to a meal containing 3 mg of iron.2
Iron, unfortunately, has many enemies called anti-nutrients which inhibit its absorption. These are phytates, coffee, tea and polyphenols. Ascorbic acid overcomes the phytates to some extent.2
Animal muscle protein is also an excellent facilitator for iron absorption. Addition of chicken, fish, eggs, or meat to the diet with veggies increases iron bioavailability.1
Hepcidin: the iron regulator: Hepcidin is a peptide produced by the liver that negatively regulates iron absorption. Increased hepcidin levels reduce iron absorption and decreased hepcidin levels increase iron absorption and accumulation. During chronic inflammatory conditions (RA, cancer, chronic stress, etc.), Interleukin-6 (IL-6) is released as a part of the inflammatory process. IL-6 increases hepcidin production and causes anemia in those suffering from chronic inflammation.
Iron deficiency is easy to occur in both impoverished and affluent societies, albeit due to different reasons. In addition, oral iron supplements are not tolerated well by a large majority and long term consumption is not without some extreme side-effects.
So how can we ensure adequate iron levels are maintained?
Never consume milk and milk products with regular meals. Always have them at an interval of 2 hours before or after meals. Similar precautions to be taken with consumption of coffee, tea and herbal tea.
add vitamin c rich food (lemon, orange, guava, amla, grapefruit) with iron rich foods. Remember that plant sources of iron are far more important than animal sources because we consume them much more in quantity.
If you are taking antacids regularly stop it! And try to look for a permanent solution to your problems. These quick fixes do more damage than good in the long run.
Cooking process: Animal sources are not altered much during the cooking process however, plant iron changes.
Soaking followed by pressure cooking (especially lentils and beans) increases iron availability and absorption to 50%.6
90% of iron is lost during refining of grains (to produce flour). Always use whole grain flour (whole grain bread etc.).
Stewing, frying, parching or boiling for vegetables for long time reduces mineral content in general. Three-fourths of the iron content is lost if spinach is boiled for more than 3 minutes. Steaming, pressure cooking, or blanching help conserve not only the iron but also the water soluble vitamins (like vitamin C).7
Cooking in iron pots releases absorbable iron in the food.8 However, it should be noted that after cooking the content should be immediately transferred to another bowl because long-time contact with iron surface can change the colour of the cooked food.
Animal sources are all rich in iron and readily available for absorption. However, among plant sources, the iron density, % availability and dietary value differs and as shown below:9Excellent sourcesVery good sourcesGood sources
Spinach, swiss chard, cumin, parsley, turmeric
Jaggery*Greens, asparagus, bok choy, mustard greens, turnip greens, leeks, chilli pepper, lettuceSoyabean, lentils, sesame, kidney beans, olives, black beans, tofu, pumpkin seeds, brussel sprouts, beets, kale, broccoli, cabbage, thyme, oregano, squash, basil, fennel, black pepper, tomatoes, cloves
*Jaggery is a product of sugarcane, widely used in India. The manufacturing process concentrates iron in it (10-13 mg/ 100mg of jaggery). Addition of ascorbic acid to it further increases iron availability.
Treat any cause of chronic bleeding. (eg: menorrhagia, piles, stomach ulcers etc.)
Even after these diet hacks, if iron deficiency persists, there is a problem with absorption. Herbal medicine, homeopathy and ayurvedic medicine help improve intestinal absorption is general and should be considered for such cases.
Get treated for chronic inflammatory conditions. Parasites in the intestines (like hookworms, pin-worms, Helicobacter pylori.) can also cause iron deficiency.10 Homeopathy and ayurvedic treatments are more natural and cause no side-effects (Mainly they do not alter stomach pH thereby no influencing iron absorption).
If you are taking calcium supplementation, it might be advisable to talk to your doctor about possible interactions with iron absorption. Consider naturally incorporating calcium in the diet or if not, avoid combining the two in the same meal.
Again, iron is abundantly present in our food and with small tweaks in the diet, you can maximize the bioavailability. The challenge here is to first get treated for any condition that causes iron depletion or malabsorption.
Let’s make iron deficiency a thing of the past! 🙂
1 Abbaspour N, Hurrel R, Kelishadi R. Review on iron and its importance to human health. J Res Med Sci 2014. 19: 164-174.
2 Teucher B, Olivares M, Cori H. Enhancers of iron absorption: ascorbic acid and other organic acids. Int J Vitam Nutr Res 2004. 74: 403-19.
3 Lynch SR. The effect of calcium on iron absorption. Nutr Res Rev 2000. 13: 141-58.
4 Lönnerdal B. Calcium and iron absorption–mechanisms and public health relevance. Int J Vitam Nutr Res 2010. 80: 293-9.
5 Nemeth E & Ganz T. Regulation of iron metabolism by Hepcidin. Annu rev Nutr 2006. 26 323-342.
6 Pereira E et al. Effect of different home-cooking methods on the bioaccessibility of zinc and iron in conventionally bred cowpea (Vigna unguiculata L. Walp) consumed in Brazil. Food Nutr Res 2016. 60. 10.3402/fnr.v60.29082.
7 Kimura M & Itokawa Y. Cooking losses of minerals in foods and its nutritional significance. J Nutr Sci Vitaminol 1990. 36 Suppl 1:S25-32.
8 Geerligs PD, Brabin BJ, Omari AA. Food prepared in iron cooking pots as an intervention for reducing iron deficiency anaemia in developing countries: a systematic review. J Hum Nutr Diet. 2003.16: 275-81.
10 Cassat J & Skaar E. Iron in Infection and Immunity. Cell Host Microbe 2013. 13: 509–519.