On the Menu: Too much, too little: problems to iron out
Getting the right amount of iron is easier said than done, but check out your diet before reaching for supplements
Foods rich in iron. Photograph: Thinkstock
Iron is an essential component of two oxygen-carrying proteins, haemoglobin and myoglobin. Most of our iron is found in the haemoglobin of red blood cells, where it transports oxygen to cells and produces energy. Myoglobin is found in our muscles, where it stores oxygen as fuel for the working muscle.
Inadequate iron can leave us feeling exhausted and it can compromise our cognitive ability and immune function too. The National Irish Teens Survey, carried out by the Irish Universities Nutrition Alliance in 2007, found that almost three out of every four teenage girls and almost one in five teenage boys were not getting enough iron in their diets.
In Europe too, iron deficiency is considered to be one of the main nutritional deficiencies affecting many vulnerable groups such as pregnant women, infants and fussy eaters, athletes, teenagers and, in particular, vegetarians.
As a vegetarian or vegan, your choices are limited to foods containing less readily absorbed non-haem iron. This type of iron is found in wholemeal bread, green leafy vegetables, legumes and foods fortified with iron. Eating a food containing vitamin C, such as citrus fruits, kiwis, strawberries and fresh vegetables such as broccoli, peppers and kale, will improve the amount of iron absorbed from the non-haem vegetarian meal.
Vegetarians’ recommended intake of iron is 1.8 times that of non-vegetarians so they need to know how to make up for the lack of easily absorbed iron in red meat such as beef, lamb, pork, chicken and seafood. Otherwise, their risk of iron deficiency increases. Continually combining certain foods with drinks that contain tannin can also decrease iron absorption. A cup of tea or coffee is best enjoyed after your vegetarian meal, not with it or immediately after.
Iron deficiency impairs mood, ability to concentrate and physical performance, and can lead to anaemia. Symptoms of iron deficiency include fatigue, poor circulation, depression, reduced recovery from exercise, reduced physical and mental performance and anaemia. The less well-known problems include a defective immune system, loss of fertility, difficulty in swallowing, and confusion.
As a safety net some vegetarians take an iron and vitamin B12 supplement. This is not a bad thing, as long as it’s needed. Many teenagers and young women find it difficult to achieve adequate iron intake, especially during pregnancy.
Considering the health adverse effects of low iron status in pregnancy, it is vital that supplementation is provided to those who need it.
Unfortunately, the side effects of iron supplementation are common and include constipation, impaired mineral absorption and an increased risk of haemochromatosis in susceptible women.
Irish people are genetically susceptible to hereditary haemochromatosis. The Food Safety Authority estimates that the disorder may affect as many as one in 100 people. Its report, the Scientific Recommendations for a National Infant Feeding Policy, recommends that a working group should be established to discuss in more detail the importance of iron in pregnancy. Its intention is to devise recommendations around supplementation in order to protect the health of both mother and infant.
In the meantime it suggests that women should focus on their diet to get sufficient iron. It also advocates that, given our genetic susceptibility to develop haemochromatosis, a family history of the disorder should be ruled out before any iron supplements are taken.
Haemochromatosis causes the body to absorb too much iron. The liver normally has a small store of iron but when surplus iron is stored there, it becomes enlarged and damaged. Additional iron can also be stored in the joints, skin, pancreas, heart, testes and ovaries.
Treatment involves the regular removal of blood to get rid of the excess iron from the body.
Initial symptoms are vague; they include lethargy, and stomach and joint pain. As the condition progresses, diabetes can occur, along with bronzing of the skin that looks like a perpetual tan, cirrhosis of the liver, poor memory, depression and disease of the heart muscle. If the knuckles of just the first two fingers of the hand are arthritic, this is very suggestive of haemochromatosis.
The surplus iron in the body cannot be modified by diet alone. Removing blood regularly has a greater effect on excess levels, but there are certain dietary recommendations and strategies that help reduce iron in the body.
Foods to avoid
Beef, lamb and venison contain more haem iron than pork or chicken. Limit your portion sizes and enjoy red meat three times a week, choosing more chicken, fish and vegetarian options for the remainder of the week. Avoid liver and offal and foods such as pate.
Don’t take ascorbic acid or vitamin C in supplement form. Vitamin C occurs naturally in vegetables and fruits. Enjoy one fruit rich in vitamin C a day, with another of your choice. Try to eat such fruit as a snack, not with meals. Avoid breakfast cereals and other foods that are fortified with iron.
Alcohol enhances the absorption of iron. Avoid heavy drinking. In combination with the high body iron levels in haemochromatosis, it can increase the risk of liver damage and cirrhosis.
Betacarotene is one of more than 100 carotenoids that occur naturally in plants and animals. Carotenoids are yellow to red pigments that are contained in foods such as apricots, beetroot, carrots, red grapes, peaches, prunes, spinach, sweet potatoes and butternut squash. Betacarotene enables the body to produce vitamin A and some research suggests it can increase the absorption of iron. Like vitamin E, betacarotene is an excellent antioxidant, but the best source of this nutrient is food. There is no need to exclude or cut down on any of the foods that naturally contain betacarotene, just avoid vitamin A supplements.
Foods to include
Eggs contain a compound called phosvitin which has the capacity to bind iron. Some scientists believe it may be responsible for the low bioavailability of iron from eggs.
More research is necessary but if your cholesterol is normal, you can enjoy up to seven eggs a week. If your cholesterol is high, you are best reducing this to between four and six eggs a week, including what you find in baked foods.
Calcium, like iron, is an essential mineral, which means the body gets this nutrient from diet. Calcium is found in foods such as milk, yogurt, cheese, canned sardines and salmon, tofu, broccoli, almonds, figs, oranges and rhubarb. It inhibits the absorption of both non-haem and haem iron. Include three servings of dairy a day or the equivalent of fortified soya, rice and nut milks, and boost your levels further by other sources.
Polyphenols or phenolic compounds include chlorogenic acid found in cocoa and coffee. Phenolic acid found in apples, peppermint and some herbal teas, and tannins found in black teas and walnuts, have the ability to inhibit iron absorption. Include these foods and drinks two hours prior to, during or just following your main iron-rich meal to help inhibit absorption.
Phytate is a compound contained in higher fibre foods. Small amounts can affect iron absorption. Phytate is found in walnuts, almonds, sesame, edamame beans, lentils and peas. Include these foods in meals to help decrease iron bioavailability.
Oxalates are compounds derived from oxalic acid and found in foods such as spinach, kale, beets, nuts, tea, wheat bran and rhubarb. The presence of oxalates in spinach explains why the iron in spinach is not absorbed. Try to include these foods in normal portions when enjoying red meat if you have haemochromatosis.
Paula Mee is a dietitian and a member of INDI. She works at Medfit Proactive Healthcare. See medfit.ie; @paula_mee
Thursday, June 5th, is National Haemochromatosis Awareness Day. See haemochromatosis-ir.com; tel. 01-8735911 firstname.lastname@example.org