We need iron. Without enough iron, we'll get sick. But too much iron can kill us.
As with so many things relating to our health, it's a balancing act.
Most people who eat meat get sufficient iron. Some foods these days are also supplemented with iron. The chocolate syrup Bosco was designed to get children to consume more iron. Cooking in iron pots, especially cooking acid foods, adds iron to our diet. Multivitamins designed for younger people contain iron (especially those for pregnant women, as the fetus consumes a lot of iron).
Hence nonpregnant Western people who aren't vegetarians usually get enough iron from their diet. People in Third World countries who don't get much meat, however, are often iron deficient.
Heme iron, or the iron that is in hemoglobin, the oxygen-carrying molecule in red blood cells, is absorbed even more efficiently than the nonheme iron that you get when you eat vegetables or take an iron-containing multivitamin pill. So eating meat, especially red meat and liver, should ensure that you get enough iron.
Vitamin C will increase the absorption of iron, and large amounts of calcium or whole grains will decrease it.
Those of us over 60 probably remember all those ads for "tired blood" in the 1950s and 1960s that implied that older people were tired because they didn't have enough iron and needed to supplement with Geritol.
So should we all try to get as much iron as possible?
There is some evidence that high iron levels contribute to heart disease, and most "senior vitamins," designed for people who are at an age at which heart disease is more likely, don't have any added iron. Some people think that losing blood every month helps to protect younger women from heart disease. This protection is lost after menopause.
Iron levels have other interesting effects on our health.
Like us, most bacteria require iron in order to grow. Our bodies are smart, and they apparently know this. So when we get an infection, our bodies start reducing the iron in our blood, especially when we have a fever.
The bacteria, in turn, try to develop ways to snatch the iron away from the proteins that carry it around and store it in our cells. Hence taking iron supplements when you have an infection is probably not a great idea.
So why am I babbling on about iron? Because there are two different iron-level conditions that are relevant to diabetes. The first is hemochromatosis, a genetic disease found most commonly among people with Celtic ancestry.
Hemochromatosis makes you absorb too much iron, and the high iron levels attack many organs in the body, including the beta cells. So people with the hemochromatosis gene are at very high risk of getting diabetes. Some people absorb enough iron that their skin turns slightly brown, and if they develop diabetes, it's sometimes called bronze diabetes because of the bronzed color of the skin.
The other condition is the exact opposite, a form of anemia, or too little hemoglobin in your blood. It occurs when you don't absorb enough iron or when you lose iron because you've lost a lot of blood. Without iron, you can't make hemoglobin, and without hemoglobin, you can't make enough red blood cells.
This condition is called, not surprisingly, iron-deficiency anemia.
A test for both these conditions is the ferritin test. Ferritin is the protein that the body uses to store iron, and it's a good indicator of overall iron levels in the body. Low ferritin could mean iron-deficiency anemia. High ferritin could mean hemochromatosis.
There's another wrinkle to the iron story and diabetes. Iron-deficiency anemia can make your hemoglobin A1c test higher than it should be on the basis of your daily blood glucose measurements. A recent study showed that increases in A1c levels often found in late pregnancy are in fact caused by iron-deficiency anemia rather than by increases in blood glucose levels.
Conversely, if you find you have iron-deficiency anemia and you treat it with iron supplements, your A1c will go down.
The reason that iron-deficiency anemia makes the A1c decrease is not clear. It may be related to the red blood cell lifespan. Some people think it's related to oxidative stress.
And although iron-deficiency anemia makes the A1c go up, hemolytic anemias make the A1c go down. Hemolytic anemia is any kind of anemia that destroys the red blood cells, as this reduces the lifespan of the cells and hence results in abnormally low A1cs.
The interpretation of the A1c test assumes the red blood cells live an average of 120 days. In fact, the actual lifetime of red blood cells even in healthy people can vary from person to person, which may be one reason some people seem to get A1c results that are either higher or lower than what they expect on the basis of their home blood glucose readings.
So many things can affect our health, and so many things can affect the lab tests we use to monitor our health.
I think the important thing is to remember that no lab test is 100% accurate for all patients under all conditions. If you get an abnormal lab test, don't panic. Sometimes it helps to have the test repeated, just in case it was lab error. Other times it's simply a suggestion that something might be wrong. Then you can work on what you think might have caused the positive lab test and see if that fixes the problem.
If you have reasons to think you might have hemochromatosis (Celtic or Scandinavian ancestry; relatives with hemochromatosis), it would be a good idea to get a test for ferritin. If you have reasons to think you might be anemic (fatigue, pale skin, rapid heartbeat, especially if you're vegetarian), it wouldn't hurt to ask your doctor for the same test.
If you don't have either and your A1c continues to differ from what you think it should be, you might just be someone whose red blood cells live longer or for a shorter time than average.