Lack of iron is one of the most common mineral deficiencies in the world, with most cases going unrecognized. If your doctor has diagnosed iron-deficiency anaemia, don’t stop taking your iron tablets until your low iron or haemoglobin level is corrected and your doctor says it’s time to stop. Iron has many important effects in the body. As well as carrying oxygen around the body with red blood cells, iron is also involved in making energy, reducing tiredness and fatigue, healthy cell division, for clear thinking and concentration, and for optimum immunity against bacterial, viral and yeast infections.
What happens if you stop taking iron pills?
If your doctor has prescribed iron tablets, then you either have low iron stores (measured via a protein called ferritin) or this has progressed to cause iron-deficiency anaemia. Iron deficiency anaemia is associated with a low level of haemoglobin (the red blood pigment) in the circulation and with making red blood cells that are smaller than normal.
If you stop taking your iron pills then nothing will happen immediately. You may even feel a bit better if the iron tablets were causing indigestion or constipation (in which case switch to a different formulation, see below). If your iron deficiency was due to a low dietary intake and you don’t start eating more iron-rich foods (eg red meat, dark green leaves) then stopping your iron tablets means the iron deficiency will slowly creep up again and you will start to feel increasingly tired and lacking in energy.
Red blood cells, which contain iron to carry oxygen around the body, last within the circulation for around 120 days and are then filtered out (for example by the spleen) and replaced. If there is insufficient iron to meet the requirements of the new red blood cells, then symptoms of iron deficiency will re-appear within 3 to 4 months – sooner if you have increased iron requirements (eg pregnancy) or increased iron losses (eg heavy periods).
As your iron levels fall further, you will become more prone to infections such as colds and Candida, fatigue easily, and have difficulty thinking straight. Stopping your iron tablets can also lead to headaches and restless legs syndrome as iron-deficiency anaemia develops. Iron deficiency anaemia can also reduce fertility.
Don’t stop taking your iron tablets
If you are thinking of stopping your iron tablets because of side effects, you may find that iron pills which supply iron in the form of ferrous bisglycinate, ferrous fumarate or ferrous gluconate are more gentle, and less likely to cause nausea or constipation than ferrous sulphate.
Iron-rich spa water is also available as a liquid iron tonic, as are iron-rich syrups and tablets from herbal sources.
Iron tablets are best taken on an empty stomach (washed down with juice) if possible, to maximise absorption. If this makes you feel sick, however, take them with a little food – just a few bites will help.
Vitamin C increases the absorption of iron supplements when taken at the same time, so it is a good idea to wash down iron supplements with fresh fruit juice such as orange juice.
Don’t wash down iron supplements with tea or coffee, as these contain tannin polyphenols which can reduce iron absorption by up to 39% if taken together or within an hour of each other.
How iron absorption is regulated
Your intestines have a clever mechanism to ensure you only absorb as much iron as you need from your diet – whether in food or supplements. This system works on the fact that gut lining cells are shed every three to five days. Iron absorbed from the gut (mostly in the duodenum) is stored in these gut lining cells (enterocytes) bound to ferritin protein and, once the ferritin is saturated, no more iron is absorbed from food or supplements. If you are iron deficient however, your intestinal lining cells will keep absorbing iron.
Iron can only leave the intestinal lining cell stores and enter your circulation if it is passed on to another iron-binding protein called transferrin, which travels within your circulation. If your circulating transferrin saturation is optimal – because your iron levels are good – iron will stay in the gut lining cells and are naturally shed within a few days as the lining cells are replaced with new ones.
This highly tuned process helps to ensure that the amount of iron in your circulation does not rise too high. It also accounts for the fact that higher dose iron supplements can cause intestinal side effects such as dark motions, diarrhoea or constipation, because their iron stays in the gut rather than being absorbed into the body.
Some people inherit an ability to bypass this mechanism and absorb too much iron, causing a condition known as haemochromatosis.
Symptoms of iron deficiency
If you stop taking your iron tablets, it’s important to ensure you continue to get good dietary intakes of iron, or you will soon develop iron deficiency again.
Women are more at risk of iron deficiency than men, because of blood losses during menstruation. This can result in a low-grade iron deficiency that is enough to impair immunity and cause tiredness and poor work performance, reduced fertility and headache without causing frank iron-deficiency anaemia.
If unrecognised and allowed to progress, lack of iron quickly leads to the production of red blood cells that are significantly smaller and paler (due to lack of haemoglobin) than normal. This iron-deficiency anaemia is associated with generalized skin itching, concave brittle nails, hair loss, sore tongue, cracking at the corners of the mouth, profound exhaustion, reduced appetite and difficulty in swallowing. The affected person will look very pale with a fast pulse, dizziness, shortness of breath and can lead to angina and even a heart attack.
Food sources of iron
Diet should always come first, and good sources of iron include shellfish, red meats, sardines, wheatgerm, wholemeal bread, egg yolk, green vegetables, dried fruit, bread made from fortified flour, and fortified breakfast cereals. Haem iron (found in meat products) is absorbed two to three times more efficiently absorbed into your gut lining cells than inorganic iron from plant sources such as spinach, enriched cereals and supplements.
To make things slightly more complicated, inorganic iron exists in two oxidation states: ferrous (Fe2+) and ferric (Fe3+) which have separate uptake mechanisms. Ferric iron – the form in which most plant-derived iron is obtained – is less well absorbed due to low solubility at the pH found in your small intestines. Vitamin C increases absorption by converting ferric iron to ferrous iron. Avoid over-boiling vegetables as this decreases their iron availability by up to 20 per cent as well as destroying any vitamin C present.
Iron deficiency is common
Iron intakes have fallen over the last 30 years due to decreased meat consumption and energy intake. People who are most vulnerable to iron deficiency anaemia include:
- Infants if exclusively breast-fed
- Menstruating women
- Pregnant women
- Those following a plant-based diet
- People with a high intake of phytates from unleavened bread (which blocks iron absorption)
- People with inflammatory bowel disease
- The elderly.
If your doctor has recommended that you take iron tablets, it is important to keep taking them.
If you decided to take an iron-containing multivitamin yourself, because you don’t eat much in the way of iron rich foods, don’t let this study put you off taking them.
However, if you have persistent symptoms such as tiredness or fatigue, do seek medical advice to find out the cause. This is especially important if you are female and experience heavy or prolonged periods.
Your doctor can confirm whether or not you have iron deficiency through a blood test to assess your red blood cells, and to measure levels of your iron storage protein, ferritin. Iron deficiency anaemia is not a diagnosis you should make on your own as it’s important to know the underlying cause.
If you eat plenty of iron-rich foods then select a multivitamin that does not contain iron as you will absorb all that you need from your food.
Iron Supplements Dose
The EU RDA for iron is 14 mg for adults, while the US DV is 18mg. The upper safe level for long-term use from supplements is just 17mg per day. However, much higher doses are prescribed for short-term use when iron-deficiency is confirmed (eg 200mg ferrous fumarate providing 65mg elemental iron). These higher doses of iron are best taken under medical supervision.
Iron supplements can cause side effects such as nausea, indigestion, diarrhoea or constipation, and black stools (due to the formation of ferrous oxide which is black in colour). Having black stools is often considered a desirable side effect as it shows you are taking a high enough dose for excess to appear in the stools.
Excess iron is toxic, especially for children, and it is important to keep iron supplements well away from small children as eating just a few can be fatal. If a young child eats an iron tablet seek urgent medical advice or go to A&E.
Do iron supplements cause cancer?
Lack of iron is one of the most common mineral deficiencies world-wide, so I read with despair the recent headlines suggesting that iron levels found in iron supplements ‘could damage the body within just 10 minutes’. This study does not reflect what happens in the human body, however, as the researchers added a strong iron solution to blood vessel cells grown in a laboratory. Not surprisingly, these cells rapidly showed signs of damage as iron on its own is highly oxidant. We know that – it’s why iron rusts so quickly in the presence of oxygen.
Luckily, the human body is a bit more sophisticated than that. Within the circulation, iron is bubble-wrapped in an array of protective carrier proteins – including haemoglobin, ferritin and transferrin – to which it is tightly bound and unavailable for interaction with blood vessel lining cells. Only a tiny amount of iron remains unbound and that which is buffered by other components of the circulation with antioxidant properties which were not present in this study.
If you have iron-deficiency anaemia, don’t let this study or the scary headlines put you off taking your iron supplements or prescribed medicines until your iron deficiency has been corrected and your doctor tells you to stop taking your iron pills.
Image credits: vkuslandia/shutterstock; avarand/shutterstock; @ccfoodtravel/flickr
Hi Doc. My iron went from 111 to 34, while taking 2 iron pills a day. The doc bumped me up to a third and my iron went up to 66 after two months. She just took me off all of the iron supplements. Won’t my iron just tank again? I’m a vegetarian. Seems weird that she would take me off of it after it had dropped so much while I was on it. That’s why I’m not a doctor.
Hi Netti, Do ask your doctor if you are concerned as they will have a reason for doing this. In the meantime, ensure your diet is optimal for iron sources, and perhaps take a supplement designed for vegetarians that includes iron. Plant based liquid supplements are available. Best wishes, Sarah B
I have been prescribed iron tablet. It was absolutely fine until the first full dose finished. When I start taking the 2nd package.. I started getting nauseated after taking them and bitter taste in my mouth.
This has happen before as well and I stopped taking them.
Does anyone else have this problem?
Hi Binita, Do go back to your doctor who can check if you still need the iron supplements – your increased sensitivity to their taste can mean you are less iron deficient. If you do still need them, a different form of iron may suit you better. Taking them with fresh orange juice can boost absorption and improve taste. Best wishes, Sarah B
Hi, my ferritin level is a 15, it fluctuates from 15-35 depending if I’m on my period or not. I’ve been told to feel optimal levels it should be 70+. I have heavy periods which I think is because of endometriosis. I’m waiting to see a Gyno. My GP recommended I take Feramax iron capsule which is 150mg of elemental iron. I’ve been taking it almost 2 months and my levels are still 15! I have awful symptoms daily, such as fatigue, brain fog, thining hair, back pain, rib pain, shortness of breath, depression, itchy skin & just overall not well. Could the iron capsules be making me feel worse? Can I take the iron capsules 2-3 times a week n consecutive days? I’m not feeling better on them!. Im debating if I should stop taking it? Should I push to get an iron infusion? I recently started eating red meat 1-2 times a week and increasing other plant based iron sources. However because I suspect I have endometriosis I can’t eat red meat often. I’m not sure what I should do??
Hi Sahar, diet should always come first, so it’s good that you are eating some meat and plant based iron sources. If you are feeling so bad, do co back to your doctor as different forms or iron are available. Feramax contains iron in the form of a poysaccharide iron complex which is usually well tolerated. Feramax is also available in a powder format which may suit you better. Other ‘gentle’ iron forms include ferrous bisglycinate, ferrous fumarate or ferrous gluconate. Oral treatment is usually preferable to iron infusions which can cause a number of unpleasant side effects. At present, your symptoms are consistent with iron deficiency so it’s important to get this sorted, so do see your doctor. I hope you feel better soon. Best wishes, Sarah B
Thank you for your reply! I went to the pharmacy today and the Pharmacist recommended Proferrin Iron Supplement 11mg which is made with heme iron polypeptide. She advised to me this is absorbed better than Feramax. What are your thoughts on Proferrin? Do you think I should make a switch?
Also, do you think the back pain, shortness of breath, along with other symptoms is due to my low ferritin levels?
Hi Sahar, Do follow the advice of your pharmacist. If you are experiencing back pain or other symptoms, do see your doctor as you need to find out why your ferritin levels are so low, and the underlying cause of your anaemia. Best wishes, Sarah B
Of all the information i have been reading in last 3 months regarding iron deficiency and absorption processes that was the clearest and most useful, thank you. I have been astonished by how few women – particularly vegetarian – are being checked for iron deficiency, as it seems to be so common plus the more I read the more dangerous undiagnosed iron deficiency appears to be. By the time i saw my doctor my heart felt literally ready to burst! I wonder if like me, women spend months or longer assuming the very unpleasant symptoms including fatigue, palpitations, chest twinges, faintness, brain fog, etc are simply down to menopause… the effects of which seem to be strangely similar to iron deficiency, which perhaps merits investigation.
My biggest issue has been ascertaining what are NOT inhibitors of non heme iron as almost everything bar vitamin c appears to block absorption, so it’s hardly surprising that a couple of years after becoming vegetarian my iron levels were so severely depleted. I also ate a lot of cheese with my meals, which blocked any iron i might derive from the other, healthy, food on my plate. And of course having tea or coffee anywhere near to meal times had the same effect. I had no idea of any of this and still wouldn’t if I hadn’t started researching for myself. I’m having difficulty planning my diet around taking my prescribed iron supplements, to ensure i don’t consume any inhibitors 3 hours before or after my supplement. I don’t know how I’ll cope once I stop taking supplements, if ever, as the absorption/inhibitor issue seems to be so convoluted on a vegetarian diet.
Anyway, thanks again for your great explanation and particularly for dispelling fears about iron supplements breaking down cells.
Glad it was useful – I usually find taking supplements with fresh orange juice makes a huge difference. Best wishes, Sarah B
1 1/2 years ago my hgb was at 7.4 No cause found. My doctor had me take iron supplements for a year and
my hgb increased to 15 but my ferritin was only up to 34 so the doctor said to take the iron every third day. My hemoglobin is now at 16.4 but my ferritin is still only 45. They want it over 50. I have been taking tbe iron about once a week but the hemoglobin being high now is scaring me. What should I do?
Hi Kay, Ferritin shows how much iron you have stored and available for future use (although ferritin can be raised due to other reasons). Once anaemia is corrected, then ferritin slowly rises as your iron stores are replenished. The normal range for haemoglobin is 12 to 15.5g/dl for women (13.5 to 17.5g/dl for men) although individual labs vary slightly and it’s not uncommon for readings to vary by 1g/dl either way as part of measurement error. The normal ferritin range for women is 12 – 150 ng/mL (12 to 300ng/ml for men). Do see your doctor again to discuss your concerns – you may be able to manage your iron intake through diet alone, for example. There is a list of iron-rich foods on my post on Iron HERE. I hope that helps. Best wishes, Sarah B
I am taking iron tablets and tonic for hair fall with doctors advise. But I felt that my tooth become fade. Is it temporary side effect? Is there is any remedies for this?
Hi Vino, I’m not quite sure what you mean. Could you share more about what you are experiencing? Do speak to your doctor if you are experiencing side effects, too. Thanks, Sarah B
My daughter has been taking 150mg elemental iron due to severe anemia (she’s 15 with heavy periods) I read that it takes around 6 months to resolve but after taking it for 5 weeks her dr tested her blood and said she’s fine and to stop taking it. I’m not sure I’m comfortable with that as I thought haemoglobin took 120 days to renew so how can it be better that fast (but I’m not a dr!). Any thoughts?
Hi Wendy, although red blood cells survive in the circulation for an average of 120 days, the bone marrow responds to correction of iron deficiency quite quickly and increases its production of immature red blood cells (reticulocytes) within 7 to 10 days, and blood haemoglobin levels can normalised within six to 8 weeks. Iron treatment is generally continued until levels of ferritin and transferrin saturation are within the normal range. The heavy periods need to be sorted, however, or the anaemia will recur. Ask if she needs to be referred to a specialist to check for common bleeding disorders such as von Willebrand’s disease which affects an estimated 1 in 100 people, including as many as one in six women with persistent heavy periods. However, only around 1 in 10,000 are ever diagnosed (by checking blood clotting and measuring levels of von Willebrand’s blood clotting factor). [If diagnosed, then it is easily treated eg using a nasal spray called desmopressin which increases natural production of von Willebrand’s factor. Those with the condition will also need treatment with von Willebrand’s factor to cover them during future surgical procedures.] If her blood clotting is normal, then hormonal treatments such as the Pill can greatly reduce menstrual blood losses. Diet is also important, of course, and you can find information in iron rich foods in my post in iron. Hope that helps. Best wishes, Sarah B
I have been anemic for a decade. I’m 44 and have had very heavy periods and I’m on a ppi. I have been exhausted for 10 years pretty much and hated taking iron so I would take it for a few months and go off for years. Last year in April my mother in law said I looked dead. Yes, I was upset but I went to the dr and my hemoglobin was 9.7 and ferritin was 4. I took iron for 6 weeks and stopped it. One month later out of the blue I got thousands of PVC’s. 7 k a day plus NSVT on the heart monitor. I asked my ep dr if my low iron had anything to do with this and he said no. I was miserable for 3 months. Every 4th beat was a pvc. Finally I listened to my girlfriend who was begging me to take my iron. I hated iron because of the side effects. Low and behold I listened to her and within 3 days they were completely gone. Completely gone!!!!! Since then my hemoglobin was 12.8 and ferritin under 30 and I still can’t get off the iron. When I do all my symptoms Come back. Shortness of breath, fatigue, body aches , foggy thinking and PVC’s. Plus they found inflammation on my heart a few months ago. I went so long without iron and my body was just tired….now my body is do dependant on it. Do you know why that is?
Hi Stacy, It is important to find out why you keep getting low on iron – it may be because of hidden losses, or because you have a common blood clotting disorder that causes heavy periods, for example. Hopefully your doctor has ruled these out. If there are no obvious medical causes for recurrent iron-deficiency anaemia, the most likely cause is dietary – do you eat much meat? Having vitamin C with iron rich plant foods boosts absorption of plant-based iron. There is more info on dietary iron on my post on iron benefits. Hope that helps, best wishes, Sarah B
My iron level was 2 and hemoglobin 7.6. I
Took iron twice a day for a couple of years. For ten months prior I had trouble swallowing – it was painful to eat food and finally I asked for my iron to be checked not knowing that there was a connection. Five days later I was able to eat again . They never tried to find out why it was so low. Last check my iron was 99 so I quit taking it. Recently I passed a mirror and thought I looked yellow. My eyelids were quite white. I started taking iron again – just once a day and within days my finger nails look better and my skin is a normal color. I’m 51 and right now can’t say it’s excessive bleeding from periods. If I have another blood test I’m guessing that it will show iron being okay because I started taking it again. I have had diarrhea a lot and maybe that caused an iron issue? I also have heart fluttering and am tired a lot. Wish they would try to figure out the source.
Hi Tamelia, Do go back to see your doctor and request tests to find out why you are anaemic. It could be dietary if you don’t eat much red meat, but it could also relate to medical conditions. Given that you have heart flutters, diarrhoea and tiredness, your doctor should be willing to perform basic blood tests and refer you to a specilist. If not, you have a right to request a second opinion from another doctor. Best wishes, Sarah B
Dr. Brewer, I have been take ferrous sulphate for the past two months. (325 mg)
During this period, I have noticed severe lower back pain and pain on both sides of my waistline. Advil does not help. Could my pain be a side effect of taking ferrous sulphate? If so, how long will it take to get out of my system if I stop taking it today? Thank you,
Hi Michael, Iron tablets can cause abdominal pain, but this is usually epigastric – around the stomach, just below the ribs, rather than low back pain. The leaflet inside your pack will describe side effects associated with that particular formulation. Do see your doctor ASAP for a check up and review, and to find out exactly why you are lacking in iron in case your symptoms are related to the cause. Hope that helps. Best wishes, Sarah B
Hi there, the iron supplement prescribed by my doctor has 150 mg of iron! My last blood work showed my hemoglobin at 7 and I was quickly put on that. I had no symptoms of anemia other than my hair falling out for several months and I had recently had trouble waking up in the morning. I have heavy periods, so I think my doctor is trying to build up my reserves with this high dose. How long is it safe to stay at the dose?
Hi Wendy, In general when hemoglobin is so low, your doctor will want to find out why – eg blood losses (such as heavy periods), not making enough blood, or iron deficient diet. Having decided that you need iron, then the oral dose of prescribed elemental iron for treating iron-deficiency anaemia (under medical supervision) is 100mg to 200mg daily. This is usually given as ferrous sulfate. A tablet of 300mg ferrous sulfate provides 60mg ferrous iron (the sulfate bit is relatively heavy). Your doctor will monitor you for your Hb response, and for side effects. If you are concerned then do talk to your doctor. Hope that helps, Best wishes, Sarah B
My daughters Dr. Said she needs to take 325mg of fureouss sulfate and that is 65 mg. Is that 1 tablet of 65mg that will provide her with 325mg of us? I’m afraid of giving her to much. I think I did the first day but the second day we cut back.
Hi Deondria, When iron is prescribed to treat proven iron deficiency, then doses higher than the usual recommended daily amount are needed until the deficiency is corrected. WIth ferrous sulphave, a 300mg tablet will typically provide around 60mg iron – the extra weight is made up from the sulphate part of the molecule. If your doctor has prescribed the iron, then take it as directed on the pack. If you have bought your own, or are in any doubt about how much your daughter should take, don’t be afraid to ask your doctor or a pharmacist for guidance. Your daughter will probably have her iron levels rechecked after a couple of months or so, depending on how low her levels were. Hope that helps. Best wishes, Sarah B
Hi! Curious of your thoughts on this. I’m a 50 yr old female my doc ran blood work for my thyroid and minerals and said my iron was low and put me on an iron supplement. After several months my iron was still low so we increased my iron supplement, then suddenly it was high and my doctor said to stop taking it. I have had extreme hair loss over the last several months and I trying to determine if the increase in iron and then the sudden stopping of the supplement could be the cause??? I am hypothyroid and have adrenal fatigue. I take many supplements including B, C, D, K, iodine, Omega, ashwaghanda, magnesium etc. etc.
Hi Paula, while low iron can cause hair loss, the more likely cause now that your iron levels are correct is the fact that you are also hypothyroid. Once this has been corrected, hair growth should improve. Ensure continuing good intakes of dietary iron and you may find that caffeine-containing shampoos help too (more info on these HERE). Best wishes, Sarah B
I have heard that if you are low on iron, a gold ring will make a grey line when ran across your skin. Any idea if that’s true?
That’s not one I’ve heard before! A quick search on-line suggests it is an old wives’ tale and any black line probabliy results from a reaction between ‘dirt’ on the ring and oil on the skin. The only accurate way to know if you have iron deficiency is to ask your doctor to request a blood test if you have symptoms such as tiredness all the time, paleness or recurrent infections. Interesting one! Thanks.
Thanks! From some self experiment, it has seemed like getting more iron makes the line go away. But one person a rule does not make. Thanks for getting back to me. 🙂
Hello Dr. Brewer
I remember a few years ago I had my blood drawn so I could enroll into a life insurance policy. They told me at the time that I had severe hemolysis, which apparently had ties to anemia. The first thing that popped into my head was that my mother also has anemia, and she always has iron pills readily available.
I don’t think I have anemia…at least based off the symptoms you established in this article. That being said, I do think I fall short in my iron intake. Just for clarity, are you saying that it would make the most sense to associate iron rich foods into my diet first before incorporating iron based supplements, or are you saying that it would be easier to take an iron supplement considering it is easier to manage the iron intake?
This was a great read, and you did very well in explaining the importance of iron in our diet. I will definitely be reading more both here and on your other site! I read up on 25 foods that would help toward reducing my blood pressure. I just wanted to let you know how happy I was to see mangos on that list! You just gave me an excuse to eat my favorite fruit more often…so long as it is in season, of course! Again, great information!
Hi Jorge, Hemolytic anaemia is different to iron-deficiency anaemia, but can lead to iron imbalances due to the excessive break down of red blood cells. You should get checked again and find out the underlying cause if it it still happeneing. Diet should always come first, so talk to your doctor about whether you need iron tablets before taking them. Go mangoes!
Years ago I read that people over the age of sixty shouldn’t take iron. Is that true?
Most peopel over the age of 50 need a lower dose of iron – especially women who have stopped menstruating. Multivitamins designed for 50+ take this into account. Excess iron can be harmful but overall, lack of iron is the bigger public health problem.
Hi Dr. Brewer, really enjoy reading your educational nutritional posts. I had my iron ckd recently and iron, UIBC, TIBC & Transferring Saturation % were all at the lower end of the “normal range,” however my Ferritin was 160. Above normal range of 13-150. Just was wondering if you had any insight as to what might be causing this or what I might try doing differently to correct? I have food sensitivitis to gluten, corn, & dairy products. And have gut issues including UC in lower intestines. I do take numerous vitamins which includes a whole food iron supplement that I take 2x a week.
Hi Deb, A raised ferritin can be due to a number of causes related to inflammation – including having ulcerative colitis. As it is only slightly raised this is the most likely explanation, but your doctor can assess your overall health, liver and kidney function and decide how often to monitor it. Levels vary from lab to lab and generally, over 200 mcg/L is considered raised in women, and 300 in men.