If you are a strict vegan, pregnant, have experienced blood loss, had recent surgery, or have chronic kidney disease, you may be prescribed iron. If you are undergoing cancer treatment, anemia is a frequent complication both at diagnosis and during treatment, with iron deficiency being the most common cause of anemia. 

Nearly 50% of all cancer patients with solid tumors and blood cancers have some degree of iron deficiency, so there is a good chance you may need iron supplementation.

Anemia often starts slowly, so you may not even notice symptoms at first. As your hemoglobin level gets lower, you may experience shortness of breath, dizziness, chest pain, swelling in the hands or feet, pale skin or nail beds, and extreme fatigue.  

Most doctors or nutritionists will prescribe an iron supplement to help with anemia. This is especially true during treatment because it can be challenging to eat iron-rich foods consistently. The recovery of circulating iron in the body is slow when you depend on food alone.

Once you increase your iron intake, it usually takes at least six months to improve your blood count and replenish your body’s iron stores, so be patient. If your dietary efforts aren’t successful, then consider supplementation. Before you run to the drugstore for some iron, you need to know that anemia has several causes, including vitamin B12 or folate deficiency. Your doctor can run routine blood tests— serum iron, TIBC, and ferritin—to determine if you are indeed iron deficient. I urge you to take this additional step because if you take iron and don’t need it, you increase cancer risk in general. The body regulates iron levels by adjusting the rate of iron absorption from the digestive tract. But if iron levels get too high, you can develop iron overload, which may contribute to the initiation of cancer and tumor growth. (Nat Rev Cancer, May 2013) 

In examining more than 1,000 older Americans in the Framingham Heart Study, researchers found that only about 3 percent had deficient iron levels in their blood or stored in their bodies, but 13 percent had levels considered too high. If you take iron to treat iron-deficient anemia, be sure always to remind your doctor to retest you for iron deficiency periodically to determine if you need to continue taking it. Often, doctors forget they prescribed it, and people remain on iron supplementation for too long. You don’t want to risk iron overload.

If you want to improve iron stores with diet, the best iron sources are liver, meat, fish, and poultry because they contain heme iron, which is most easily absorbed by the body. Iron-enriched grains, green leafy vegetables, and potatoes have a fair amount of iron, but the iron tends to be poorly absorbed by your body when you eat these foods. To boost your absorption of iron from vegetable sources, you might try adding just a few chunks of free-range, organic meat to a vegetarian dish if your dietary habits allow for this. Also, because vitamin C promotes iron absorption, add more vitamin C-rich foods like citrus fruits or juice, broccoli, cabbage, and tomatoes to your iron-boosting diet. Preparing your meals in cast iron cookware (the iron leaches into the food when heated) will also increase your meals’ iron content. 

Iron is also added to our foods. In the United States, the Food and Drug Administration (FDA) approved the use of a form of iron (ferric EDTA) as a food additive to a variety of sauces, including soy sauce, sweet and sour sauces, teriyaki sauce, as well as fortified breakfast cereals, bars, and grain-based products. The levels in our foods are safe (according to The European Food Safety Authority (EFSA J, Jan 2010). So be aware that if you eat processed foods, you are getting additional iron.

If you find out that you are low in iron and want to try supplementation in the more natural form, desiccated liver is not a good option. Unfortunately, liver contains a fair amount of copper, which studies suggest is an essential factor for the growth of tumors in humans. You’d be better off sticking to plain old over-the-counter-iron. 

The most common side effects of iron supplementation include constipation, cramping, and stomach upset. To reduce these unpleasant side effects, you need to either increase your absorption of iron from your iron supplement by taking some vitamin C or by starting with half the recommended dose of iron at mealtimes. For even better iron absorption, avoid taking iron with vitamin E or zinc. Drinking plenty of fluid, maintaining a high fiber diet, eating flax seeds, and taking a natural senna laxative may encourage regularity. Finally, avoid over-the-counter antacids like Tums— iron is poorly absorbed in a low acid environment.