Ironing It Out: Linking Diabetes with Iron Intake

If you’re old enough, you might remember those Geritol ads on television, proclaiming that everyone could be suffering from "iron-poor blood." But, in general, iron is one of those minerals that doesn’t get much respect. It’s just not that exciting—unless you happen to be iron deficient.


Iron is one of the most abundant minerals on earth. In the human body, it’s needed as part of enzymes and proteins involved in carrying oxygen to cells and for regulating cell growth. Two-thirds of the iron in our bodies is found in hemoglobin, which is a protein in red blood cells that carries oxygen to our tissues. (In case you’re wondering, hemoglobin A1c, or HbA1c, is a measure of how much glucose is attached to hemoglobin.) The rest of the iron in our bodies is found in myoglobin, a protein that delivers oxygen to muscle tissues, as well as in proteins that can store iron for future needs.

There are two forms of iron: heme iron, which is found in animal foods, such as red meat, fish, and poultry, and nonheme iron, found in plant foods, including lentils, beans, molasses, and spinach. Eating foods rich in vitamin C can enhance absorption of nonheme iron, while calcium, tannins (found in tea and other foods), and phytates (found in beans and other foods) may inhibit nonheme iron absorption. Here are the Recommended Daily Allowances for iron for adults: 18 milligrams (mg) for women of childbearing age, 8 mg for postmenopausal women, and 8 mg for adult men. So, as we age, our iron needs decrease.

Iron deficiency is a global problem, affecting about 80% of the world’s population, while 30% of the population has iron deficiency anemia. Pregnant women, infants, toddlers, teenage girls, women of childbearing age, and people with kidney and gastrointestinal disorders are at risk for iron deficiency anemia. That pretty much leaves healthy teenage boys, men, and postmenopausal women who aren’t at risk.

You might be wondering what the link is, then, between iron and diabetes. First, there’s evidence now that women who consume too much heme iron (the kind found in animal foods) have as much as a 28% increased risk of developing Type 2 diabetes. This research, published last year, is based on a study of over 85,000 middle-aged women over a 20-year time frame. Another study from 2004 showed similar results: About 33,000 healthy women with high iron stores followed for 10 years had a significant increase in the incidence of Type 2 diabetes. The thought is that high iron levels may cause damage to muscle tissue, thereby decreasing the body’s ability to move glucose from the blood into cells and also interfering with insulin production. (By the way, there’s evidence that 50% to 80% of people with hemochromatosis, a disorder of iron absorption, go on to develop Type 2 diabetes.)

Secondly, there’s new evidence that women with Type 2 diabetes who consume a high amount of heme iron and red meat have up to a 50% increase in the risk of coronary heart disease. The authors of this study admit that foods rich in heme iron (such as red meat) can also be high in saturated fat, which we already know is linked with heart disease. They also point out that foods high in heme iron don’t necessarily “cause” heart disease; they’re just “associated” with heart disease. All in all, though, they suggest that it’s not a bad idea for people with Type 2 diabetes to cut back on their intake of heme-iron–rich foods. Maybe this information will encourage you to go easy on the steaks and burgers and try more meatless meals, such as beans and rice or lentil soup!

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  • Anna

    But beans, rice, and lentil soup raise blood sugar. That isn’t such a good idea.

  • dinu

    beans is high fiber content diet. It release sugar into blood slowly.. good food for dm…

  • Kevin

    Any food that contains calories will be broken down and converted into sugar and used by the body, the rate depends on hard it is for the body to break down the food. Unused sugars will be stored as fat therefore even a low fat diet can cause a person to store excess fats and be a health risk. Basically you cannot beat a well balanced diet combined with exercise, in type 2 diabetes diet and exercise are the key and if you are Irish like me getting rid of some excess iron also helps so I will be having more beans and steaks



  • acampbell

    Hi Debra,

    To the best of my knowledge, the link between iron and diabetes pertains primarily to Type 2 diabetes. If your question relates to how much iron you need, the recommendation for post-menopausal women is 8 milligrams per day.

  • Lani

    You mostly addressed heme iron….would you please address nonheme iron consumption for ones who mostly eat vegetables and a little fish.
    Thank You,

  • acampbell

    Hi Lani,

    If you’re eating a mostly vegetarian diet with a little animal protein thrown in, you’re likely getting most of your iron from nonheme iron (the kind found in plant foods). Luckily, people who eat mostly plant foods tend to get enough iron — as long as they’re eating a variety of foods. The RDA for iron for premenopausal women is 18 milligrams and for postmenopausal women, it’s 8 milligrams. Adult men also need just 8 milligrams of iron per day. There’s some evidence that vegetarians may need up to twice as much iron in their diet since nonheme iron isn’t as well absorbed as heme iron. My advice is to make sure you eat a variety of foods that contain iron (fortified oatmeal and cold cereal, soybeans, lentils and other beans, tofu, spinach) but also make sure you eat a food rich in vitamin C also (citrus fruits, tomatoes, cantaloupe, peppers, etc.). Don’t take an iron supplement without talking with your health-care provider. And if you are concerned about iron deficiency or anemia, your provider can do certain blood tests to determine this.

  • jeorge

    Vegetarians may find it a bit more difficult to get the iron they need, but some may not understand the reason why. There are two forms of iron: heme, which comes from animal sources, and non-heme, which comes from plant sources.

  • Jack

    I am pre-diabetic and have been able to stave off a diabetic diagnosis with diet and exercise. I probably right next to that line, however, so I’m looking for more things I can do.

    Our well water has a lot of iron. So much so that we have installed an iron filter system. Prior to the system, our water was orange and stained the fixtures black over time. Since the filter system was installed, our water is clear (most of the time), but still stains fixtures, only not as badly.

    How does iron disolved in well water affect iron in the body? Is this a good thing? Or a bad thing?

  • acampbell

    Hi Jack,

    From what I’ve read, iron in the water supply can contribute up to 5% of the body’s daily requirements. That being said, even small amounts of iron in the water can leave stains on fixtures, laundry, etc It’s likely not a bad thing unless you happen to have a condition called hemochromatosis in which too much iron builds up in the body. Also, it’s doubtful that the iron in your water is enough to “induce” diabetes in you. The key ways to reduce your risk for diabetes are to aim to lose 5% to 10% of your body weight (if you’re overweight), eat a diet of whole grains, lean protein, and healthy fat, include nuts and low-fat dairy (shown to help prevent diabetes) and of course, stay active!

  • deanna

    I was diagnosed last August with an iron deficiency and have been taking 2 iron supplements daily since that time. Jan. 1 I was diagnosed with diabetes type 2. I’ve always been at high risk for diabetes (sister who is type 1, father who had type 2, high blood pressure since age 24, hypothyroid since age 25, high cholesterol and taking Lipitor) so we’ve been checking my A1C levels and blood glucose for the past 10 years. Back in June, my A1C was 5.8, and even after being diagnosed, which a blood glucose spike of 400, my A1C was 6.8… I had only one symptom of diabetes – blurry vision – which is highly unusual and has all my doctors puzzled. I’m 41 and had begun meeting regularly with a personal trainer once my iron levels began to rise back in October. I had lost 7 pounds by Christmas and was feeling great. I have been thinking it was the Lipitor that brought this on, but now I’m wondering about the iron supplements. I just had an appointment with my hematologist last Thursday and will know by the end of this week whether or not I can stop taking those supplements (which we lowered to 1/day once I was diagnosed) if my ferritin level is high enough. Now I’m highly suspicious!

  • Dorothy Koester

    I have been type 2 diabetic for quite a few years and taking Metformin three times daily. Recently I was found to be iron deficent. Iron supplement was prescribed daily for me. When my iron level was checked two weeks later my iron level had dropped another couple of tenths. I did a stool culture and that came back with no blood. My iron supplement was increased to twice daily. I also take lisinopril from high blood pressure. Can the diabetes be connected to the low iron levels?

  • acampbell

    Hi Dorothy,

    I’m not aware of a link between low iron and diabetes, or metformin causing low iron levels. Iron deficiency is generally caused by blood loss (say, from an ulcer or intestinal bleeding), a low intake of iron in the diet, use of antacids or medicines to treat acid reflux, and certain malabsorption disorders, such as celiac disease. It’s good that your stool culture was negative for blood, but you should pursue with your doctor other possible causes, like celiac disease, for example.

  • Nicole

    Hi I’m type 1 diabetic, my sugar have been higher than normal and I just fond out I have low iron, I was wondering do you think low iron can make my sugar high? I’m also pregnant 27 weeks.

    Thank you for your time

  • acampbell

    Hi Nicole,

    I think it’s more likely that the hormones released during pregnancy are causing some insulin resistance, which is why you’re seeing higher blood glucose readings. And low iron levels are common, too, as your iron needs increase during pregnancy.

  • gisellewilding

    Iron is a strong interest of mine and there is a link between high iron intake (such as pregnancy supplements) and cot death and also in brain cognitive decline.

    Some supplement have disgustingly high levels of iron and cot death is far rarer in Asian babies and breast fed babies.

    You may need more iron in pregnancy but the body releases it stores from the ferritin.Levels look lower because of this and because blood volume increases at 28 weeks and then come the toxic supplements.

  • Bonnie

    Can type 1 diabetes be controlled with taking calcium citrate, zinc and magnesium. Thank you.

  • acampbell

    Hi Bonnie,

    No, Type 1 diabetes is controlled by taking insulin, meal planning (usually in the form of carbohydrate counting), and physical activity. Calcium, zinc and magnesium are essential nutrients, but they have little, if any, effect on blood glucose control.

  • Jason Wang

    The article does not mention how nonheme iron affects glucose levels for diabetics. If the iron from meat products should be avoided, what about iron from plants?

  • acampbell

    Hi Jason,

    To the best of my knowledge, the research indicates that it’s only heme iron that is linked to an increase in diabetes risk.

  • Roger Oakes

    My wife is type 2 diabetic, and she also has a history of anemia. In going through this and related information it would appear that the anemic condition would minimize the incidence of type 2 diabetes. That is, an anemic person would be less likely to eventually see type 2 diabetes, since their blood usually contains less iron.
    I’m concerned about our daughters. They are also anemic, similar to their mother, and I’d like to believe they won’t be susceptible to diabetes. But since there is definite proof of a relationship between iron levels and diabetes, I’m trying to investigate options. The information about hemochromatosis was interesting since it shows a genetic link.
    One other question – which type of iron, heme or non-heme, is usually present in supplements such as Fergon, ferrous gluconate? My wife did take Fergon when she was younger and I’ve wondered if it introduced heme iron to her system.

  • acampbell

    Hi Roger,

    You pose an interesting question in terms of your daughters’ risk of diabetes due to anemia. Just keep in mind that they may be at an increased risk because of your wife’s Type 2 diabetes, as well. This does not mean that they will inevitably get diabetes, but it’s a good opportunity to encourage a healthy lifestyle with them. Also, Fergon contains ferrous sulfate, which is a form of nonheme iron.

  • andrew balfour

    My mother who has turned seventy two weeks ago and has type 2 diabetes has been really struggleing for six months with no energy and no appetite.Her doctor prescribed iron tablets as her iron level was low and her blood count.
    She has also been to hospital and had two camera scans to see if there was an internal bleed.It came back that she had no internal bleed.Ive since got her on Floradix which she has been taking since the 19th of Febuary.
    There doesnt seem to be any improvement and there is no drive in her to do anything and no real appetite.
    Has anybody any idea?
    Many thanks

  • acampbell

    Hi Andrew,

    I’m wondering if your mother needs to go back to her doctor for further evaluation. Fortunately, there is no sign of internal bleeding, but there can be other causes of iron deficiency and fatigue, including kidney disease, nutrient deficiencies, gastrointestinal issues (like celiac, Crohn disease, etc.), and medications that interfere with iron absorption. She might also benefit from meeting with a dietitian to review her eating plan and make sure she’s getting a balance of nutrients and enough calories. Be careful about giving her Floradix if she is also taking iron pills prescribed from her doctor; too much iron is unsafe. Finally, you might also consider her mental state: Depression and anxiety can also be causes of fatigue and poor appetite, which, in turn can lead to an inadequate intake of nutrients (including iron). It can also take a while to build up iron stores, so it may be too soon to see an improvement in her symptoms. But perhaps a talk with her doctor is in order.

  • Andrew

    Many thanks for the reply and the information.
    Andrew Balfour

  • Olga King

    Iron is NOT a nutrient, it is a poison. Iron replaces copper in the blood and tissue proteins and accumulates in multiple locations of the body, causing destruction and accelerating aging. Bio-available copper must be replenished to restore health and longevity – to repair the DNA damage.

    “The ability of copper to easily accept and donate electrons explains its important role in oxidation-reduction (redox) reactions and the scavenging of free radicals.”

    Restated, copper deficiency causes a complete breakdown of the blood’s ability to eliminate iron from the body. Loosely bound iron breaks off from the blood proteins and accumulates in various locations of the body, which then acidify those locations causing serious life threatening disease states such as cancer, cardiovascular disease, diabetes, obesity, inflammation, immune deficiencies, neurological dysfunction, tissue and organ destruction, and many other diseases and symptoms, and an early death.

  • acampbell

    Hi Olga,

    To clarify, iron IS an essential nutrient. The body cannot survive without it. But like many minerals, too much iron can be harmful and cause oxidative damage in the body. Also, iron needs to be balanced out with copper and zinc levels.

  • Nicole Christopherson

    In 1996 my mother was diagnosed with type 2 diabetes. recently her doctor has put her on levemir. when she started her levemir at 10mg/l her blood was between 130-150 when testing in the morning. her doctor has since raised her daily levemir to 14mg/l and now her blood sugar reading has gone up to 170-200. her diet hasn’t changed. could iron be causing this to happen?

  • acampbell

    Hi Nicole,

    In my opinion, it’s unlikely that iron is causing your mother’s blood glucose to be higher. There are probably many other (and more common) factors, such as a change in food intake, for example, or an overall change in her diabetes. A little detective work may be in order, such as finding out if she is taking the prescribed amount of her insulin, where she is injecting, if she has changed her food intake (like eating a snack before bed), etc. I’d suggest talking to her doctor about what he thinks, or even meeting with a diabetes educator who can review all of the above factors (and more) to help determine the likely cause.

  • Kc62

    My father is 77. Also a type 2 diabetic. Just recently was told he was anemic. His Alc is 7.5. The doc only said take a multi with minerals in it, but didn’t say how much? He takes so many pills now for high blood pressure, cholesterol , insulin. Also for acid reflux. Doc doesn’t seem to he to concerned other than take a Centrum with iron ? I think the antacids might be a big issue also with absorbing? Any advice?

  • acampbell

    Hi Kc62,

    Anemia in the elderly is a cause for concern, as studies show that it’s linked a with a loss of physical functioning. Also, it’s important to find out what’s causing the anemia in the first place, such as kidney issues, poor nutrition, internal bleeding, or cancer, for example. Yes, antacids can interfere with iron absorption, so any kind of vitamin or iron supplement should be taken apart from the antacid. A multivitamin/mineral supplement, by the way, may not contain enough iron to correct the anemia. You should find out how severe the anemia is, discuss possible causes, and ask about the best way to treat it. Iron supplements and injectable drugs (Procrit and Epogen) are available as treatments.

  • Dennis

    Is there any relation between iron pills, say 325 mg a day, and blood sugar control?

  • Bea

    I have just been diagnosed with being pre-diabetic, and low on iron ( have been described to take two tablets a day) and i’m high on Cholosterol . how can I change my diat to prevent becoming diabetic ( my father had Diabetis 2) and not to have such a high Cholesterol level anymore. Saying that i already don’t eat butter nor do i use cream.
    Thank you for taking the time

  • acampbell

    Hi Dennis,

    I haven’t come across any evidence linking iron supplements with changes in blood glucose. The best way to find out, though, is to check your blood glucose more frequently than usual if you are taking supplements, and let your doctor know if you see that they’re affecting you.

  • acampbell

    Hi Bea,

    For many people with prediabetes, losing a little weight (if you need to) can make a big difference in whether you go on to develop diabetes or not. Studies show that losing between 5% and 7% of body weight can help prevent diabetes. Cutting back on portions, eating more fresh fruits and vegetables (and fewer fatty, fried foods), and eating leaner protein foods, like chicken and fish, can help. These steps can also help lower your cholesterol. I’d suggest that you make an appointment with a dietitian for more specific guidance, however. Also, don’t forget about physical activity: Aim to do something, like walking, for at least 30 minutes a day.

  • Marilyn

    I am a 60 year old woman and have Beta Thalassemia Minor. Two years ago I was told I had pre-diabetes. My Ferritin levels have gone up to 1500 in the past. I started phlebotomy sessions about eight months ago to see if they could remove much of the iron in my body and take it down to a more manageable level of 300-400. Since having blood removed, I have found that my A1c level has dropped dramatically. In fact my last one was 5.5 which is in the normal range. I am still getting blood drawn once a month (16 oz) and will do so until my ferritin level is lower. It would be interesting to see if what is happening to my A1c would happen to others if they had regular phlebotomy sessions. What do you think?

  • acampbell

    Hi Marilyn,

    Your A1C level is essentially a snapshot of your blood glucose control over a period of 2–3 months. Removing blood can “artificially” lower your A1C, meaning that doing so is not really a true reflection of your diabetes control. Your blood glucose levels could still be high in between blood draws, and remember that it’s the prolonged high blood glucose levels that can damage blood vessels and nerves, increasing the risk for complications.

  • annelise

    I logged onto the internet tonight to get some insight on why , all of a sudden , after having hba1c results of 6.5 on average for years on end, I now battle with daily blood sugar levels ranging from 12 to 22! I have low iron, my muscles cramp and my white bloodcell count shows i have an infection somewhere in my body and i am constantly tired.
    Then iread this article and instead of understanding my problem, i am even more in the dark! Do i take calsium or vit c supps? Both inhibit absorbtion from what i can see? I need advise. Plse help!

  • acampbell

    Hi annelise,

    Calcium can interfere with iron absorption, but that doesn’t mean that you should stop taking a calcium supplement. You should, however, take your calcium supplement at least two hours apart from taking iron supplements or eating an iron-rich meal. Vitamin C actually helps with iron absorption, so there isn’t an issue taking vitamin C and iron together.

  • Cande

    I am a 71 year old diabetic2 female that was found to be anemic because of iron deficiency. A week ago I was given Venofer(Iron IV). Since then I cannot get my blood glucose to go below 134, before it was 101, 98. 84 100, had not gotten as high as it is now since diagnosed as Diabetic2. What do I do, I am still eating healthy like I was before blood glucose starting going up. Is there someone out there that has gone thru this or is going thru it now. And I am so exhausted every day, I can’t stand it. Any advice for me?

  • dora k

    I want to know how the intake of iron can affect the glucose level in the blood.

  • acampbell

    Hi dora k,

    I’ve been unable to find any link between dietary iron and blood glucose levels, other than the research showing that a high heme (animal-source) iron intake is linked with an increased risk of diabetes. If you are taking (or thinking of taking) an iron supplement, you should first discuss with your doctor and then check your blood glucose maybe a little more than you usually do to see if and how iron may affect your blood glucose.

  • acampbell

    Hi Cande,

    I’m not very familiar with Venofer, but a quick search revealed that it possibly could increase blood glucose levels. I’m not sure if this is temporary or not. You should discuss this with your doctor. If your blood glucose levels are consistently running much higher than usual, ask your doctor about the best way to treat this (for example, starting on a new diabetes medicine or increasing the dose of one that you’re currently taking). Depending on how high your blood glucose levels are running, you may feel very fatigued. However, your fatigue can also be due to your iron deficiency, which, hopefully, will be soon resolved. Continue to eat healthfully and as much as possible, fit some physical activity into your day. But certainly discuss your symptoms with your doctor.

  • Steve Parker

    I am a type 1 diabetic, I have low iron, so I received
    An IV infusion of Iron. Since the infusion my
    BS have been 200 and higher , this only happened
    After the IV iron injection . Can the iron increase
    My BS that much ? Diet has not changed .
    Thanks..,,,, Steve

  • acampbell

    Hi Steve,

    I wasn’t able to find too much information about iron infusions affecting blood sugar levels, although I did come across one study — in hamsters — that showed increased blood sugar after being given iron. Have you discussed this with your doctor? You mentioned that your diet did not change, but were there other factors that might have affected your blood sugar, such as illness, a decrease in physical activity, etc.? If you regularly receive iron infusions and notice an increase in blood sugar afterwards, the best course of action is to plan for this and increase your insulin doses accordingly. Keep a record of your blood sugar readings for a while after receiving an infusion to note any patterns — doing so can make it easier to adjust your insulin.

  • NeoAnd

    I am a wife of a diabetic. My husband recently had an iron profile which was all abnormal. Have an appointment to discuss with GI. In the last week we have noticed his blood sugars in the 140-150. This is not like him. He had been running 95-100. Am I to assume this is related? Iron deficiency and elevated blood sugars.

    • acampbell

      Hi NeoAnd,
      There may be a link between “abnormal” iron levels and higher blood sugars. Has your husband changed his eating or activity habits in any way? However, any kind of “stress” on the body can also cause blood sugar levels to rise. Hopefully the GI doctor can provide some answers; but in the meantime, you or your husband may want to contact his primary-care provider and let him or her know about his higher blood sugar levels.