Iron deficiency due to a vegetarian diet?

Iron is a vital trace element and is involved in numerous processes in the body, such as the transport of oxygen in the blood. A sufficient supply through food is necessary to maintain iron reserves. Unfortunately, this does not always seem to be easy, as iron deficiency is the most common nutrient deficiency worldwide. A vegetarian or vegan diet is often suspected of promoting a deficiency. Here you can find out what is true about this theory.

Table of contents:

• What is iron deficiency and how does it arise?
• What deficiency symptoms are typical?
• How long does it take to correct an iron deficiency?
• Where does the belief come from that vegetarians are more likely to suffer from iron deficiency?
• Are vegetarians really more likely to suffer from iron deficiency than meat and fish eating people?
• Should vegetarians eat meat again if they have an iron deficiency?
• Where do vegetarians get iron?

What is iron deficiency and how does it arise?

Iron deficiency occurs when there is too little iron in the blood and this can have various causes. On the one hand, the supply through diet may be too low and on the other hand, bleeding may be the reason why the body's iron requirements are not met [1].

Did you know that about 25% of the world's population suffers from iron deficiency?

Reduced absorption can be caused by, for example, an unbalanced diet, certain food components, diseases of the intestinal mucosa, medication or surgery . Iron deficiency due to bleeding in women is often associated with heavy menstruation ; but bleeding in other parts of the body can also lead to iron loss [1].

To a certain extent, losses are completely normal and do not have a health problem, as the body loses about 1 mg of iron daily through stool, urine and sweat [2].

Therefore, an inadequate iron supply is problematic

As the central atom of hemoglobin (red blood pigment) and myoglobin (muscle protein), iron is responsible for oxygen transport . With the help of iron, the inhaled oxygen is first bound to the hemoglobin, which then supplies all cells in the body with oxygen via the bloodstream. The body also needs iron for the development of various cell types and cell growth , as well as for DNA production and the defense against infections . If there is not enough iron available, a variety of symptoms of deficiency occur [1, 2].

What deficiency symptoms are typical?

Hair loss, cracked corners of the mouth, itching and dry skin, and pain when swallowing can indicate an iron deficiency. In the later stages, headaches, paleness, tiredness, and listlessness are often observed [1]. If you notice such symptoms, you should consult a doctor to clarify your iron supply status.

If you have these symptoms, you should have your iron status checked.

How long does it take to correct an iron deficiency?

The time it takes for iron stores to fill up can vary greatly from individual to individual , depending on how much iron is still stored in the body when the deficiency is diagnosed and how well iron is absorbed. If the deficiency is caused by internal bleeding, this must be localized and stopped so that a lot of iron is not lost again and again. Treatment with iron tablets should be carried out for at least 3-6 months , as it takes quite a long time for the stores to be filled up [3]. However, an iron-rich diet should also be maintained after that. You often hear that vegetarians in particular are undernourished, but what is the truth behind this myth?

Where does the belief come from that vegetarians are more likely to suffer from iron deficiency?

Iron from animal foods (heme iron) is much easier for the body to use than iron from plants (non-heme iron). While heme iron is absorbed at around 20%, the absorption rate of plant iron is around 5%. This is because the latter is bound and in a triple positively charged form (Fe ³⁺ ) and must be converted, while animal iron (Fe ²⁺ ) can simply be used by the body as it is [2]. However, the iron status is more relevant than the bioavailability when it comes to absorbing plant iron. If the body's own stores are barely full, the iron can be absorbed more easily than if there is already sufficient iron in the body [4].

Bioavailability indicates the extent to which a substance is released from a food compound and absorbed into the body. Other substances that are supplied (via food) can partially promote or inhibit absorption [6].

Are vegetarians really more likely to suffer from iron deficiency than meat and fish eating people?

Many studies have examined the iron levels of vegetarians and meat eaters , but no clear trend could be determined. The European Prospective Investigation into Cancer and Nutrition Oxford study, which included 43,000 women, including vegetarians and non-vegetarians, showed that both groups had similar iron intakes and hemoglobin concentrations [4].

A study conducted by the California Polytechnic State University in San Luis examined the iron intake of 39 female students aged 18-22. 66% of vegetarians and 65% of non-vegetarians did not reach the recommended daily allowance for iron. However, there was no statistically significant difference in iron intake . However, iron intake through food is not directly related to actual iron status. Since plant-based iron is less bioavailable, the authors assume that the iron status of vegetarians is lower. [4, 5]. In contrast, iron is absorbed more from food when iron reserves are low [2].

How iron stores affect absorption

In a Spanish study, iron parameters in the blood of vegetarians and vegans were examined. Iron deficiency was found primarily in women; diet and the time since they had been vegetarian made no difference . Long menstruation and the use of hormonal contraceptives, on the other hand, were associated with low transferrin saturation. This is an important parameter in the diagnosis of iron deficiency [7].

Should vegetarians eat meat again if they have an iron deficiency?

The studies cited above already indicate the answer: No, that is not necessary. If someone decides not to eat meat for various reasons, then it is important to adjust the food selection so that the body is supplied with all the important nutrients in sufficient quantities .

Vegetarian food pyramid

A vegetarian diet that offers a balanced combination of fruit, vegetables, nuts, pulses, whole grains, etc. can fill the iron stores just as well as a mixed diet containing meat. However, pregnant and breastfeeding women have such an increased need (20-30 mg / day) that it is hardly possible to get enough iron from a purely vegetarian diet . In this case, however, dietary supplements can also be taken - after consulting a doctor [2].

Where do vegetarians get iron?

The diet

When following a vegetarian diet, it is particularly important to know where your iron sources are in order to reduce the risk of a nutrient deficiency. In addition to rich sources, substances that inhibit or promote the absorption of the trace element are also of great importance. In an iron-rich meal, the consumption of absorption inhibitors should be kept as low as possible, but beneficial substances are desirable.

Some plant-based sources of iron [8]:

Tabular list of some vegetarian iron suppliers

These substances inhibit iron absorption [2, 4, 7]:

• Lignin, oxalic acid, phytate / phytic acid and phosphate (in: cereals and legumes; phosphate also in processed dairy products and soft drinks)
• Tannin (in: black tea, coffee, red wine)
• Calcium salts
• Animal proteins (milk protein and egg proteins)
• Some medications

Foods that inhibit iron absorption

Since grains and pulses are valuable sources of iron, it is advisable to soak or germinate them to reduce the phytate content. The sourdough process is also a way to reduce iron losses through accompanying substances. [2, 4]

These substances promote iron absorption [2, 4, 7]:

• Vitamin C (e.g. in: peppers, cabbage, citrus fruits)
• Organic acids such as citric and lactic acid
• Vitamin A and beta-carotene
• The amino acids methionine and cysteine

Foods that promote iron absorption

Conclusion

Iron plays a role in the body that should not be underestimated. As the central atom of hemoglobin and myoglobin, the mineral is involved in the distribution of oxygen in the body, among other things. Unfortunately, it is only found in certain foods and is absorbed into the body in very small quantities. Studies have shown that iron deficiency, which is mainly found in vegetarians, is a myth. Nevertheless, plant-based iron (non-heme iron) is less well absorbed into the body than animal-based iron (heme iron). It is therefore particularly important for vegetarians to familiarize themselves with plant-based sources of iron and to know about substances that increase or decrease bioavailability. If you do not like certain iron-containing foods or have allergies, dietary supplements can help to meet your needs. However, you should only take these after consulting a doctor.

 

Sources

[1] Reiter, Andrea and Feichter, Martina, 2017: Iron deficiency, https://www.netdoktor.de/laborwerte/eisen/eisenmangel/#:~:text=Alle%20NetDoktor-Inhalte%20werden%20von%20medizinischen%20Fachjournalisten%20%C3%BCberpr%C3%BCft.%20Bleeding%20can%20lose%20a%20lot%20of%20iron%20very%20quickly. Retrieved on 01.07.2021

[2] Federal Institute for Risk Assessment, 2008: Questions and answers about iron in food, https://www.bfr.bund.de/de/fragen_und_antworten_zu_eisen_in_lebensmitteln-28383.html#:~:text=Eisen%20ist%20ein%20lebensnotwendiges%20Trace%20element,von%20H%C3%A4moglobin%20und%20den%20Sauerstofftransport. Retrieved on 01.07.2021

[3] Gynecologists on the Net, n.d.: Iron deficiency anemia: therapy, https://www.frauenaerzte-im-netz.de/erkrankungen/eisenmangelanaemie/therapie/ Retrieved on 01.07.2021

[4] Saunders, Angela V., Craig, Winston J., Baines, Surinder K. and Posen, Jennifer S., 2013: Iron and vegetarian diets, in: the medical journal of australia, Volume 199, Issue 4, Pages 11-16, https://www.mja.com.au/journal/2013/199/4/iron-and-vegetarian-diets?inline=true Retrieved on 01.07.2021

[5] Hawk, Susan N., Englehardt, Kimberly G. and Small, Cindi, 2012: Risks of iron deficiency among vegetarian college women, in: Health, Volume 4, Issue 3, https://www.scirp.org/html/1-8201551_18325.htm Retrieved on 01.07.2021

[6] Spektrum Akademischer Verlag, n.d.: Bioavailability, https://www.spektrum.de/lexikon/ernaehrung/bioverfuegbarkeit/1124 Retrieved on 01.07.2021

[7] Gallego-Narbón, Angélica, Zapatera, Belén and Vaquero, Pilar, 2019: Physiological and Dietary Determinants of Iron Status in Spanish Vegetarians, in: Nutrients, Volume 11, Issue 8, https://www.mdpi.com/2072-6643/11/8/1734 Retrieved on 01.07.2021

[8] Center for Health, n.d.: List of the foods richest in iron, https://www.zentrum-der-gesundheit.de/pdf/tabelle_eisenreiche-lebensmittel.pdf Retrieved on 01.07.2021