Most of us have been told that iron, especially in the form of spinach (think Popeye!) ‘gives us muscles and makes us strong’! Although I’m sure vegetables were the last thing I was thinking about when I was five! However, when it comes to understanding the importance of iron’s role and making sure we have a healthy intake of it- how does your knowledge and diet weigh up?!
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The human body contains 2-4mg of iron (men usually and naturally have higher levels); approximately two-thirds is found in Haemoglobin (Hb).
Haemoglobin is a protein found in our red blood cells that: carry oxygen around our body, mygoglobin in our muscles and it also gives it its red colour; myogloblin accepts, stores, transports and releases oxygen.
The body uses iron to make Hb. A protein called transferrin binds to iron and transports it around the body. Without enough iron, our organs and tissues become starved for oxygen.
Iron-Deficiency Anemia By: Ed Uthman Flickr
Ferritin is another protein that helps store iron by binding to it; approximately 25% of our iron is stored as ferritin.
It’s found in our liver, spleen, skeletal muscles and bone marrow. Only a small amount is found in the blood, but this is an indicator of how much is stored in our bodies; low ferritin levels are indicative of iron deficiency which causes anaemia.
Functions Of Iron
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If iron stores are low, Hb production slows down, therefore the transport of oxygen is diminished resulting in fatigue, dizziness and lowered immunity.
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Our immune system depends on it for efficient functioning; the production of new enzymes is dependent on iron, which is important when we are recovering from illness or strenuous exercise.
Required For DNA Synthesis
Iron is required for the function of many proteins involved in cell cycle and DNA synthesis, e.g. Ribonucleotide Reductase.
Production of red blood cells; they help carry oxygen around the body.
Consequences of Low Iron
- Iron deprivation can result in harmful effects, in particular to our: cardiovascular, respiratory, brain and muscle function.
- Iron depletion occurs when iron stores are low or exhausted and further decreases can produce iron deficiency anaemia. Iron deficiency anaemia is the most common consequence of a lack of dietary iron.
- Iron deficiency is the most common nutritional deficiency in the world. Mclean et al 2008, showed that it affects nearly 2 billion people globally; a significant problem in the developed world affecting approximately 50% of the global population and 74% of non-pregnant women.
Why Women Are At An Increased Risk?
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- Menstruation with long and/or heavy periods.
- Eating disorders and/or various ‘restrictive dieting regimes’.
- Following a vegan or vegetarian lifestyle with improper instruction.
- Consecutive pregnancies/ bleeding during deliveries.
All women should be given dietary information to maximise iron intake and absorption regardless of whether they are vegan/vegetarian or following a ‘typical’ balanced diet.
Groups At Risk Of Iron Inadequacy
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- Pregnant women
- Infants and young children (needed for physical and mental growth)
- Frequent blood donors
- People with colon cancer or heart failure
- People with G.I disorders or that have had G.I surgery
- Vegetarians/vegans/fussy eaters
Signs And symptoms of Iron Deficiency
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- A sore tongue
- Reduced endurance
- Unusually pale skin
- Frequent infections
- Restless leg syndrome
- Memory problems/difficulty focusing
- Brittle nails/ concave or spoon-shaped depression in the nails
Iron DRV’s (UK)
Average adult woman:
(19-50yrs) = 14.8mg/Day (inclusive of pregnant women).
*Breasting feeding could require up to an extra mg per day.
Average adult man:
(19+) = 8.7mg/day
NB: Please refer to your own country’s nutrient guidelines; quantities may vary.
- These DRV’s take in to account that with normal iron metabolism only approximately 5-10% of dietary iron is absorbed through diet and supplements.
- Children and adolsences having growth spurts may find their intake of iron isn’t adequate.
- The iron in breast milk has a high bioavailability. Unfortunately not in amounts that are sufficient to meet the needs of infants older than 4 to 6 months. This is why children older than 6 months should not be exclusively breast fed.
- On average, 1mg of iron/day is lost through faeces, sweat, urine and the exfoliation of old skin cells.
- Women of child bearing age lose on average 20mg/month through menstruation- but this can vary.
- Blood donors can lose approximately 200-250mg of iron with each donation.
Types Of Iron In Our diet
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Is iron found in ‘meat’. Its bio-availability is greater and is generally unaffected by other food components.
The bioavailability is approximately 14-18%* from mixed diets that include vitamin c and substantial amounts of meat and seafoods.
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Is iron found in foods of vegetable origin or fortified foods and is the main form of dietary iron.
The bio-availability is lower and is therefore harder for your body to absorb. The bioavailability is approximately 5-12% (1).
Some Common Foods That Contain Iron
Have a look and see if you can roughly calculate what your current iron intake is!
Factors That Can Increase & Affect Overall Iron Absorption
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- The absorption of iron is affected by the presence of other foods in our guts, e.g.
calcium, tannins, phenols, protein (inclusive of eggs & milk) and phytates (phytic acid) which all hinder iron absorption.
We should all avoid drinking caffeinated teas, coffee and milk around meal times, especially if we’re taking iron supplements.
Photo by: Julia Khusainova Flickr
- Vitamin and iron are best friends! Vitamin C helps to increase of the absorption is iron, particularly non-haem, e.g. drink a glass of orange juice with your morning porridge!
Our Diets & ‘Supplementation’ For Health And Well-Being
- Purchasing cookbooks can help inspire new ideas to make sure you keep your meals nutritious, varied and ‘iron rich’. 🙂
- Some studies have shown, including this article (found in the Journal of Food Science), that cooking in cast iron pots/pans can possibly increase the amount of iron in your food, especially when cooking high-acids foods, e.g. applesauce or tomato-based recipes. Apparently the greater the acidity of the food and the longer you cook it= the more iron that is transferred into the food; it’s a nice thought, but this would be hard for us to measure!
- If you are embarking on a vegetarian or vegan diet, it’s a good idea to talk to your GP, a dietitian or a recognised nutritionist to make sure you have all the facts & avoid ill health. If you do suffer from, e.g. ‘heavy’ periods, an underlying G.I problem, or have a limited budget, it might also be a good idea to speak to a health professional about possible supplementation to lower your risk of iron deficiency anaemia.
- If you are diagnosed with iron deficiency anaemia, your GP might prescribe iron supplementation or iron therapy; even an oral contraceptive pill to decrease menstrual blood loss during periods.
We should consult with our health care provider before taking loads of extra supplementation, especially if you are taking prescribed medications, regardless of whether it’s iron or, e.g. vitamin A, zinc or calcium. Firstly, to make sure we are going to do ourselves any harm, e.g. unsupervised use of iron supplements can reduce the absorption of other essential nutrients (such as zinc and calcium) and secondly they can recommend the ones with the most bio-availability and that may cause the least amount of gastrointestinal effects etc.
Unfortunately, taking mineral supplements, especially iron can cause undesirable side effects…
Possible Side effects of iron supplementation:
- tummy ache
These types of side effects can make compliance poor and will have knock-on effects on your well-being.
So having read my article, hopefully you are just a few informed choices away from improving your health….
…As everyone has a responsibility to themselves to source and eat a healthy diet, regardless of their food likes and dislikes…
…Because it’s all too easy to just assume that we are getting enough iron, but the reality is that it’s all too easy to not get enough!
Article written by: Lynn Risby BSc Nutritionist
Feature image by: Miserablespice Flickr
1. Am J Clin Nutr May 2010 vol. 91 no. 5 1461S-1467S
3.Foods Standards Agency (2002) McCance and Widdowson’s The Composition of Foods, Sixth summary edition. Cambridge: Royal Society of Chemisty
4.Foods Standards Agency (2002) Food Portion Sizes, 3rd Revised edition edition. London:TSO