Do vegetarians have a greater risk of iron deficiency?
Vegetarians refuse to eat the meat of a slaughtered animal for a number of reasons. In the Dutch diet, meat is considered to be an important source of easily absorbed iron, which is why people often think that vegetarians run a higher risk of iron deficiency than meat eaters.
Iron is an essential element in our food. A deficiency has negative effects on physical and mental performance. Too much iron can be damaging to our health.
Both meat eaters and vegetarians need to eat various foods in reasonable amounts in order to function optimally.
How much iron do we need in our food? An adult male needs an average of 9 mg a day; a female needs 15 mg a day. How is iron absorbed in the body? Animal sources are more easily absorbed than vegetable sources. Combinations of foodstuffs can stimulate absorption of vegetable sources. What is the function of iron? It has, amongst others, an important role in the transport of oxygen. What are the consequences of iron deficiency? Many vague symptoms and decrease in performance levels. What are the consequences of surplus iron? Damaging to health.
The body is very economic with iron. Just a small amount is excreted, along with urine, sweat and feces; the majority is reused again and again. The amount that needs to supplemented daily is therefore small, about 1 milligram, depending on age and gender. Of the amount of iron generated in a healthy adult, only 10% is absorbed through the intestinal wall, therefore the normal daily amount of iron needed in the diet for adult males is about 9 mg and for adult females in the reproductive period about 15 mg. In the event of iron deficiency, or when there is an increased demand for iron, the digestive system caters for an increased absorption of the iron available. Babies, toddlers and people with anemia can absorb as much as 20-80% of iron from their food. During pregnancy, an increased absorption of iron comes about of 10-40%. In healthy males, the need for iron is only increased upon blood loss (each litre of blood comprises about 500 mg of iron). Females have more difficulty in keeping their iron levels balanced out. Menstrual blood, particularly, causes the daily requirements in females to be higher than those in males. After the menopause, the iron metabolism in females is comparable to that in males.
The presence of iron in our diet is very scattered in two forms: heam-iron and non-heam iron. Iron from vegetable sources (non-heam iron) is less easily absorbed than iron from animal sources (heam-iron). The bioavailability of non-heam iron is poor owing to the presence of phytates, oxalates, carbonates, phosphates and dietary fibre, which interfere with iron absorption. Other foods, which inhibit iron absorption, are milk, eggs and tea. For this reason, the general opinion for a long time was that vegetarians should be wary of iron deficiency. However, research has shown that inhibition of iron absorption through fibres, phytaes and suchlike can be a very important factor. In recent years it has become evident that a combination of non-heam iron and vitamin C neutralises this inhibition.
The importance of iron
Iron is a metal that is essential to the human metabolism. The transition from organic (Fe2+) iron to inorganic (Fe3+) iron or vice-versa brings about a transport of electrons. In this way, iron can function as iron donor or recipient in numerous biological reactions. The best known of these is the function of oxygen transporter throughout the blood. Other processes are also very important, such as transport of electrons in the mitochondria ('cell respiration'), oxidative phosphorylation and the DNA synthesis. Iron also forms part of molecules which need to protect the body from damaging by-products of oxygen.
A large portion of iron is stored in the liver, the spleen and in bone marrow. Just a small amount is needed daily for the numerous enzyme systems. When there is a danger of iron deficiency, the body is very economic with its iron reserves. An iron deficiency does not occur just like that. When an iron status is too low, we can speak of three stages. In the first stage, the iron reserves have been exhausted and there are no specific symptoms to be seen. The second stage is that of latent iron deficiency which goes hand in hand with decreased performance levels. Finally, anemia comes about. In this case, there is insufficient red blood pigment in the red corpuscles and the oxygen emission in the tissues is lower. This causes performance levels to further decrease and leads to increased susceptibility to infections because the immunological response has weakened. Iron deficiency also influences other bodily functions: loss of appetite as a result of a lower secretion of abdominal juices and slower growth rate in children. Many vague complaints such as: paleness, fatigue and weakness, slight temperature increase, ringing in the ears and headache.
Surplus of iron
The amount of iron available determines how much will be absorbed. When (too) much iron has been ingested in food, the amount that has not been absorbed will be excreted in the feces. Research has, however, also shown that a surplus of iron could be damaging to health in connection with possible toxic influences and an increase in cardio-vascular diseases.
Vegetarians eat neither the meat of animals nor fish. They do consume animal products, such as milk, cheese and eggs. The reasons why people do not eat meat vary considerably. Often there is a combination of reasons. Some vegetarians refuse meat for ethical reasons. They are so abhorred at the slaughter of animals that they become vegetarians. Economical, religious and health aspects can also play a role in the choice to become vegetarian. Other vegetarians stop eating meat through such motives as rejection of factory farming, waste of food or the amount of hormones present in meat. The so-called 'new vegetarians' view meat as an unnecessary, less healthy form of food. The idea of "living a little healthier" is their main motivation. A diet in which there is more room for vegetable, fulfilling, non-manipulated products and in which there is less room for meat is - in a nutshell - their new eating pattern. As meat and meat products in The Netherlands are a source of iron, vegetarians wonder more and more whether they are getting sufficient iron in their diet.
Iron deficiency in vegetarians?
A vegetarian who eats in accordance with the Guidelines for Good Nutrition, gets sufficient iron via his food. In order to absorb sufficient iron, amongst others, it is of great importance that a vegetarian chooses a fulfilling alternative for meat,. The amount of iron that a vegetarian needs to 'compensate' is 30% of the daily recommended amount, that is the average amount of iron that a meat eater gets daily from his meat consumption. Apart from 'meat substitutes', vegetarians often eat more vegetable products, many of which are also an important source of iron. Vegetarians also make a conscious decision for an eating pattern which deviates from the norm. This encourages many of them to look for information on healthy eating. This gives them an advantage over many meat eaters.
Let's have a look at the iron content of a number of different products.
Iron content per 100 grams product.
Filet of pork
The table shows the huge diversity of iron levels in the different products. In order to absorb sufficient iron from their food, both meat eaters and vegetarians need a varied diet. To illustrate: a vegetarian male needs to absorb 2,7 mg of iron daily from meat substitutes. According to the table, that is, for example, a normal portion of tahoe, 100 grams, yields 2,2 mg of iron along with a handful of nuts in a salad, 10 grams, yields 2,7 mg of iron.
A female needs a higher amount of iron and generally speaking, she eats smaller portions than a male. In this way she needs to go to more trouble to get sufficient iron. This applies to both female meat eaters and vegetarians. A vegetarian woman needs to absorb about 4,5 mg of iron (30% of 15 mg) daily from meat substitutes. On top of the male's menu, she can, for example add 25 grams tutti frutti to yoghurt, which yields 0,8 mg of iron. A little lettuce on her bread, 25 grams, yields 1 mg of iron, which together amounts to 4,5 mg. This should cover the daily requirement. Iron from vegetable sources (non-haem iron) is, however, not as easily absorbed as iron from animal products (see "iron absorption').
It is important for vegetarians to consider the following tips. If these tips are followed, they will lead to better iron absorption.
Consumption of vegetables and/or fruit with each meal is recommended.
Consumption of tea, milkproducts, red wine and coffee with or soon after the meal is not recommended as these inhibit iron absorption.
Good alternatives are fruit and vegetable juices, herbal tea, vegetable bouillon or water.
It is more advisable to consume milk and dairy products between meals because calcium inhibits the absoption of iron.
Consumption of loose wheat bran is even totally discouraged for this reason.
On the basis of the aforementioned information it can be concluded that vegetarians do not have an increased chance of iron deficiency once the guidelines of the RGV are followed. Drinking milk enriched with iron or taking iron supplements are, in our opinion certainly not necessary. A surplus of iron can even be damaging.