In honor of Nutrition Month, I’d like to discuss the 23 feet of narrow tubing you carry with you everywhere you go. No, not your earbuds and computer cables. Your small intestine!
Segmented into three regions (duodenum, jejunum and ileum), your small intestine is the largest site of nutrient absorption in your body and its health is key to your health. Lined with velvety fingers of cells, called villi, the small intestine presents over 250 square meters (2700 square feet) of absorptive surface. This large surface area allows for the uptake of proteins, fats, carbohydrates, vitamins and minerals from your daily meals.
Healthy villi maximize their surface area, standing up like microscopic fingers bordered by cell-producing valleys called crypts. But if you have undiagnosed celiac disease (an autoimmune intestinal disorder), the surface of the small intestine changes – flattening and losing the depth of these hills and valleys. What once looked like a vibrant neighborhood now looks more like a Caribbean island after a hurricane has blown through.
Healthy villi (left) and damaged villi (right).
Images courtesy of Dr. Mohsin Rashid.
In this new landscape, cell damage and reduced surface area mean the small intestine has trouble doing its job. One consequence is the failure to absorb adequate amounts of many nutrients such as calcium, vitamin D, folate, and especially IRON. In this post, I’d like to focus on iron deficiency in celiac disease. In future blog posts, we’ll look at other nutrients including calcium, vitamin D and fiber.
Role of iron
This mineral is needed to produce hemoglobin and myoglobin. Hemoglobin is the component of red blood cells that carries oxygen throughout the body. Myoglobin protein stores oxygen in the muscle cells. Iron is also needed for the formation of certain enzymes and is involved in many other metabolic functions. Most of the iron is found in hemoglobin, myoglobin and enzymes, while the remaining stored in the liver, bone marrow and spleen.
Iron Deficiency and Iron-Deficiency Anemia
Iron deficiency occurs when the normal stores of iron decline gradually over time. The main reasons for iron deficiency are: 1) an inadequate dietary iron intake, 2) impaired iron absorption and 3) blood loss. If the amount of iron becomes severely depleted, the production of hemoglobin is impaired. Thus, the red blood cells deliver less oxygen throughout the entire body. This state is referred to as iron-deficiency anemia (microcytic hypochromic anemia).
Common symptoms of iron-deficiency anemia can include fatigue, weakness, shortness of breath, pale skin, headache and dizziness. In addition, individuals can present with irritability, brittle nails, sore tongue, decreased appetite plus they have an increased susceptibility to infections. In children, reduced iron levels can even contribute to problems with attention and behavior.
Iron-Deficiency Anemia in Celiac Disease
Studies in adults and children reveal that undiagnosed/untreated celiac disease often leads to iron-deficiency anemia. For many adults, this form of anemia is one of the tell-tale symptoms of celiac disease. The main cause of this iron deficiency anemia is impaired iron absorption. Consumption of gluten (found in the grains wheat, rye and barley) triggers an immune reaction that damages the intestinal villi. As a result, individuals are unable to adequately absorb enough iron from their diet and/or supplements.
Surprisingly, not all adults and children are under-weight at diagnosis, as you might suppose. The reason is that intestinal damage can be patchy — spotty enough to cause stores of critical nutrients to be used faster than they’re replaced, but intact enough to ensure that calories are still obtained from proteins, fats and carbohydrates.
Treatment of Iron-Deficiency Anemia in Celiac Disease
Treatment for celiac disease is a strict gluten-free diet for life. With time and careful adherence to the diet, the small intestine begins to heal and regain its ability to absorb iron and other nutrients.
Following a strict gluten-free diet is essential! However, it’s equally important to pay attention to the quality of gluten-free food choices. Studies show that gluten-free diets are often unbalanced. For example, they are frequently low in key nutrients (e.g., iron, B vitamins and fiber). Also, GF diets tend to be high in calories, fat, sugar and refined flours/starches. Because of the challenges of impaired absorption and following a GF diet that supplies adequate nutrients, I always recommend individuals consult with a registered dietitian with expertise in celiac disease. The dietitian can help design and assess the success of a customized gluten-free diet as well as suggest and monitor appropriate supplementation when needed.
Dietary Reference Intake for Iron
*Adequate Intake (AI)
Good Sources of Iron
Absorption of iron from dietary sources will vary depending on several factors. These include: 1) the body’s total iron stores (when iron levels are low, absorption increases), 2) the type of iron in the food and 3) other dietary factors. The two types of iron in foods are heme and non-heme:
- Is more readily absorbed by the body than is non-heme iron
- Absorption is not changed by other foods in the diet
- Is found only in meat, poultry, fish and shellfish
- Is not absorbed as well as is heme iron
- Absorption can be increased or decreased by other foods in the diet
- Is found in fruits, vegetables, pulses (dried beans, peas, lentils), grains, nuts, seeds, eggs and blackstrap molasses
- Is also found in meat, poultry, fish and shellfish
Tips for Maximizing Iron Absorption
- Choose foods high in iron
- Eat a source of heme iron with non-heme iron at the same meal, for example:
- Stir-fried beef, chicken, pork, fish or seafood with vegetables (e.g., broccoli, mushrooms, snow peas) and rice and toasted almonds or sesame seeds
- Chili made with meat and beans
- Vitamin C increases absorption of non-heme iron; therefore, combine a vitamin C-rich food (e.g., citrus fruits and juices, kiwi fruit, strawberries, cantaloupe, broccoli, peppers [green, orange, red and yellow], tomatoes, potatoes, cabbage) with non-heme iron foods at the same meal, for example:
- Poached egg and glass of orange juice
- Casserole containing rice, beans and canned tomatoes or tomato sauce
- Spinach salad with strawberries or orange segments
- Hummus with broccoli and sliced raw peppers
- Avoid drinking coffee or tea with meals as these beverages contain tannins that interfere with iron absorption.
If you’re one of the many people with celiac disease struggling with iron-deficiency anemia – take heart. Time to heal along with a strict gluten-free diet will begin to revitalize your small intestine. Combine that with a healthy diet that maximizes iron intake and iron absorption and you’ll soon be taking the stairs two at a time!
For more information about iron deficiency and detailed lists of the iron content of gluten-free foods; celiac disease and the gluten-free diet including healthy eating strategies, recipes, meal plans, labeling, safe foods/ingredients, helpful resources and more… get a copy of Shelley’s best-selling book Gluten Free: The Definitive Resource Guide!