Print 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!

Comments:

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

Posted by: Anna | Jul 27, 2007 12:34 AM

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

Posted by: dinu | Jan 21, 2009 07:55 PM

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

Posted by: Kevin | Jul 28, 2009 07:02 PM

WHAT ABOUT IRON WITH TYPE 1 DIABETES. POST MENPAUSAL WOMAN OF 55 YEARS OLD WHO HAS HAD TYPE 1 DIABETES FOR 44 YEARS

Posted by: DEBRA | Jan 07, 2010 11:55 AM

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.

Posted by: acampbell | Jan 08, 2010 09:32 AM

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

Posted by: Lani | Jan 08, 2011 02:24 PM

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.

Posted by: acampbell | Jan 11, 2011 09:05 AM

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.

Posted by: jeorge | Feb 05, 2011 02:54 AM

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?

Posted by: Jack | Aug 16, 2011 06:29 PM

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!

Posted by: acampbell | Aug 18, 2011 08:21 AM

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!

Posted by: deanna | Jan 29, 2012 11:29 PM

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