The iron debacle - should you be worried about your iron levels in the absence of meat consumption?

First of all … what is iron? 

Iron is first and foremost, a mineral. It is an essential element for blood production, but in more complex terms, it is a part of hemoglobin, which is a protein that carries oxygen from our lungs and throughout our bodies, working to help our muscles store and use oxygen. Iron is also part of many other proteins and enzymes. 

That being said, our bodies need the right amount of iron. The RDI (recommended daily intake) of iron for adults (over 18 years old) is 8mg for males and 15mg-18mg for women (variation depending which country) and (8mg for women over 50). Reason for these variables in recommended intakes is due to women's monthly menstrual cycles. Obviously once a woman reaches her menopausal time in her life, her absence of monthly bleed means her intake of iron is on the lower end. These intakes can vary further if women’s bleeds are significantly heavy and or if you are partaking in regular intense exercise causing a high sweat loss. 

Symptoms of low iron can often go unnoticed, in particular to the busy lifestyles that we lead today, we can often pawn these symptoms off to other causes. Alternatively,  in extreme cases, it can cause anemia. Ultimately, common symptoms include;

• Extreme fatigue

• Weakness

• Pale skin

• Headache, dizziness or lightheadedness

• Cold hands and feet

• Brittle nails

Much more uncommon, but in rare cases, ongoing overdoses of iron intake can lead to the following symptoms; 

• weakness

• weight loss

• abdominal pain

• high blood sugar levels

• hyperpigmentation, or the skin turning a bronze color

• a loss of libido, or sex drive

• in males, reduction in the size of the testicles

• in females, reduced or absent menstruation

In time, iron overdose can cause the following conditions to develop:

• arthritis

• liver disease or cirrhosis (permanent scarring) of the liver

• enlargement of the liver

• diabetes

• hypothyroidism

• heart disease

• Pancreatitis

Veganism, Vegetarian and Plant Based diets alike have been long scrutinised over the regular absence of Iron in their diets. In which case, I have always found it intriguing, considering my experience has been quite the opposite. At 16 years old I had my bloods done and I can remember being told I was very close to being diagnosed anemic. I remember feeling cold often, very tired and very pale in my face. From then on I was on and off prescribed iron tablets whenever I could feel that sensation of low iron coming forth. However, 5 + years being Plant Based, and my iron troubles have since left the building. My blood tests have continuously come back better than ever. 

So what is it about a diet without meat that creates this narrative? 

Well there are two types of iron. Heme and Non Heme. Heme iron is only found from animal proteins from the likes of  meat, poultry, seafood, and fish.  Non-heme iron, by contrast, is found in plant-based foods like grains, beans, vegetables, fruits, nuts, and seeds. However, heme,  derived from hemoglobin and myoglobin of animal food sources is the most easily absorbable form , whereas non-heme iron is less well absorbed. 

There are also aspects to a plant based diet that contribute to absorption inhibitors such as phytate (in legumes and grains). Therefore, with the decrease in absorption from non-heme iron, alongside a diet high in inhibitors, then yes that makes iron absorption seem difficult. Not to mention, if you exercise strenuously and or are on your menstrual cycle, then an iron deficiency appears more prominent than a meat eater with higher absorption. 

HOWEVER.. 

Why is there so much research in iron deficiency in the animal intake population as well ? Because CONTEXT, IS, KEY. With 1.6 billion of the population suffering from anemia (Mclean, et.al, 2009) and at least 2 billion with iron deficiency. With 10 million just in the United States (Clark, 2008), which is ironically in the top three largest meat eating populations in the world. 

As a vegan/vegetarian, elements to consider include that non-heme iron, when iron stores are low, absorption is far more responsive than heme iron. Not to mention that plant based intakes have been researched to show to regularly have an increased intake of vitamin C , a key nutrient to iron absorption. Additionally, other iron absorption inhibitors include milk, eggs, caffeine, wine, and calcium. In which are common elements to a western diet. 

A study conducted in Germany in female vegans in 2004, showed 42% of the 75 participants were under the 18mg p/day mark, 53% were over and the mean daily iron intake was higher than the recommended intake (Walden, et.al, 2004). In comparison, a recent study conducted in NZ, Auckland  of females  (total of 165 participants), resulted in 55.8% under the recommended daily intake of iron (Lim, et.al, 2020).  Mind you, this study did try to distinguish that the lack of iron was due to the decreased intake of meat movement, although that could not be confirmed. However, it potentially shows that regardless of meat intake or not, there is still an opportunity to be iron deficient. Whether a vegan or plant based intake becomes more of a risk for deficiency, is room for debate and highly dependent on context. I should also mention that the German study also clarified that fortified iron products were less accessible in their country and are now much more prominent in western society. 

Other potential denominators include blood loss during the menstrual cycle.  Therefore, a woman with a heavier cycle may require additional iron intake. That being said, there is strong correlation to a high consumption in dairy products, and an increase in PMS symptoms. Therefore, a vegan/plant based intake, may have a positive impact on the heaviness of one's monthly bleed. Which could work in one's favour in terms of meeting adequate iron intake. 

Simon Hill, an Australian nutritionist, discusses his academic findings in regards to plant based iron intake. One of these findings include that despite our bodies being more able to absorb heme iron, our bodies are better able to regulate absorption of non-heme iron to prevent it from rising to harmful levels. Therefore, an increased absorption rate is not always a good thing. For instance, levels too high in heme iron are shown to promote production of harmful molecules that make LDL-C more likely to get lodged in the artery wall (De Valk & Marx, 1999). Fang, et al. (2015), shows in their meta-analysis that for every 1mg of heme iron consumed p/day, subjects would increase their risk of cardiovascular disease by 7%. This is even after controlling their saturated fat intake. For reference, a 250g of sirloin steak contains about 5mg of heme iron. 

Therefore, we cannot presume that adhering to a vegan, plant based, vegetarian intake, that contains a wide variety of wholefoods, is detrimental to meeting our daily needs of iron intake. Infact, in context, it can be beneficial. 

List of Plant Based foods high in iron

• tofu

• legumes (lentils, dried peas and beans)

• wholegrain cereals (in particular, iron-fortified breakfast cereals)

• green vegetables such as broccoli or Asian green

• nuts, especially cashews

• dried fruits such as apricots

• seeds such as sunflower seeds or products such as tahini.

Plant based foods that increase absorption

• citrus fruits

• kiwifruit

• strawberries

• tomatoes

• capsicum

• broccoli

• cabbage

• spinach.

Plant based foods that inhibit absorption 

tannins or polyphenols
- herbal tea, coffee, wine, cocoa (fine to consume just give space in between meals)

Note**Excessive amounts of zinc and calcium are known as inhibitors however isn't usually something to be concerned with, as it is only in excessive amounts. You will find that most of your iron rich foods will have traces of these in them as well. 

References

https://www.medicalnewstoday.com/articles/166455#symptoms

https://medlineplus.gov/iron.html

 Lim, K., Beck, K. L., Von Hurst, P. R., Rutherfurd-Markwick, K. J., & Badenhorst, C. E. (2020). Iron deficiency and risk factors in pre-menopausal females living in Auckland, New Zealand. Asia Pacific journal of clinical nutrition, 29(3), 638-647.

Waldmann, A., Koschizke, J. W., Leitzmann, C., & Hahn, A. (2004). Dietary iron intake and iron status of German female vegans: results of the German vegan study. Annals of nutrition and metabolism, 48(2), 103-108.

De Valk, B. and Marx, J. J. M. (1999). Iron, atherosclerosis, and ischemic heart disease. Archives of Internal Medicine, 159(14), 1542–8. 

jamanetwork.com/journals/jamainternalmedicine/article-abstract/485095

Hurrell, R. and Egli, I. (2010). Iron bioavailability and dietary reference values. American Journal of Clinical Nutrition, 91(5), 1461S–7S.

academic.oup.com/ajcn/article-abstract/91/5/1461S/4597424

Cook, J. D. (1990). Adaptation in iron metabolism. American Journal of Clinical Nutrition, 51(2), 301–8. 

academic.oup.com/ajcn/article-abstract/51/2/301/4695161

Fang, X. et al. (2015). Dietary intake of heme iron and risk of cardiovascular disease: A dose-response meta-analysis of prospective cohort studies. Nutrition, Metabolism and Cardiovascular Diseases, 25(1), 24–35. 

www.sciencedirect.com/science/article/pii/S0939475314002889

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