Resist the Risk of Iron Deficiency

Food sources of iron come in two forms - heme and non-heme. Heme iron is found in animal products such as dark meat poultry and red meat. Non-heme iron is found in foods such as spinach, iron-fortified cereals, beans and raisins. Heme iron is absorbed a lot better by the body - between 10 and 30 percent is absorbed. Non-heme iron, on the other hand, is only absorbed 2 to 10 percent of the time. Natural compounds called phytates in these plant foods prevent iron-uptake. Phytates are phosphorus-containing compounds that block iron absorbance. Natural occurring polyphenols and tannins found in non-herbal teas and coffee block in a similar fashion.

Heme sources (per 3 ounce serving) - Beef liver (6mg), beef (3.5mg), pork (3.4mg), shrimp (2.6mg), dark meat turkey (2mg), chicken breast (1mg), tuna (1mg), flounder (1mg)

Non-heme sources - Iron-fortified cereal (2-18mg/ounce), kidney beans (3mg/0.5 cup), molasses (2.3mg/1 Tbsp), baked beans (2mg/0.5 cup), cooked spinach (2mg/0.5 cup), enriched bread, pasta, rice (~2mg/slice or 1 cup)

Other Sources of Iron (Heme and Non-heme)

Although non-heme iron absorbancy is compromised, these foods can still be great sources of dietary iron. Consider eating non-heme sources with heme sources for best results. For example, include beans in a lean ground beef chili, or add spinach to a shrimp pasta. Also, cooking these foods in a cast iron skillet helps. Eat all iron-rich foods with a source of vitamin C. The vitamin helps chelate the iron, making it more soluble in the intestines. Good sources of vitamin C include citrus fruits, bell peppers, tomatoes, melon, papaya, broccoli, spinach, Brussel sprouts, strawberries, kale, and cauliflower.

Proton pump inhibitors such as prilosec used for acid reflux can be detrimental to iron absorbancy. The pH of the stomach influences aborbance in the intestines. Other nutrients can compete for absorbance as well. Zinc, manganese, and calcium all naturally exist with a +2 charge (review your chemistry!), so they will all compete for the same ion channels in the body. In other words, do not eat milk, dairy, oysters (zinc) , or pineapple (manganese) with iron-rich foods.

When looking for an iron supplement, look for iron in the ferric (+2) form. Ferrous (+3) iron is not absorbed as well, and must be first oxidized to its +2 form. Look for a supplement with at least 100% of the daily value (18mg for adult females, 10mg for males) and take separate from other supplements. Consider taking with a vitamin C (ascorbic or citric acid) supplement. If iron causes constipation, which it can, include more fiber in your diet or take a fiber supplement (cellulose, flax seed, psyllium husk, pectin) but remember to take at a different time than the iron since most fiber-rich food contains phytates.

Fact: On my test to become a dietitian, they asked what the best vegetarian source of iron was. Answer according to the test: Baked beans! Double check the sugar content or make your own. Most canned baked beans have lots of added sugars.

Am I Anemic?

Anemia is defined as insufficient red blood cells (RBC) to carry oxygen to your tissues and brain. Anemia can be a result of disease or vitamin deficiency as well as blood loss. Besides needing iron to make red blood cells, the body must also have sufficient vitamin B12 and folate for RBC production. Females are more susceptible to an iron deficiency because of menstruation. Runners are at a greater risk for iron deficiency for many reasons.

Nutrient absorption in runners is impaired after long runs or intense workouts. With a strenuous effort, blood is predominantly flowing to the muscles, heart, lung, and brain. The gut is the bottom of the blood totem pole at this point. Unfortunately, this results in poor digestion and absorption of nutrients due to villus blunting. Villi in the small intestine are responsible for nutrient absorption. Blood flows to the top of each villus "mountain," but when the blood isn't flowing to the gut, the villus tip temporarily dies and cannot absorb nutrients. As blood returns to the villi, absorption is resumed, but in the meantime, malabsorption and diarrhea are common.

Runners also are at a higher risk of anemia as a result of iron lost through sweat and red blood cell destruction from mechanical trauma, ie the pounding of each foot strike. Training at altitude further puts an athlete at risk.

Mechanical trauma, also called foot strike hemolysis (hemo- meaning blood and -lysis meaning death of a cell) occurs from vascular and red blood cell trauma in the foot. Also, red blood cells are more prone to oxidative damage, naturally occurring during exercise, which will speed the destruction of the cells.

Pseudoanemia, common in athletes, is caused by an expansion in overall blood volume. This dilutes the red blood cells, causing a false representation of anemia in blood tests, but does not usually cause problems with athletic performance. Actually, the increased blood flow aids in oxygen delivery.

Symptoms of anemia or iron deficiency include fatigue, pale skin, shortness of breath, dizziness, cold hands and feet, and headache. These symptoms normally do not appear in pseudoanemia. It is important to still get a blood test (CBC or complete blood count) to confirm a deficiency because iron can be toxic and harmful to the liver if too much is stored. A blood test will look at the following markers and help determine the cause of anemia:

• Serum Ferritin - levels of stored iron, 18-270 mcg/L (m), 18-160 mcg/L (f)
  
• Total iron binding capacity - protein that carries iron in the blood, measures how much transferrin in the blood is not carrying iron, 20-50%
  
• Red blood cell (RBC) - total number of red blood cells in that sample of blood, 4.2 - 5.6 mill/mcl (m), 3.9 - 5.2 mill/mcl (f)
  
• Hemoglobin (Hb) - protein in red blood cells that carries oxygen, 14-18 g/dl (m), 12-16 g/dl (f)
  
• Mass Cell Volume (MCV) - average volume of a red blood cell, clue to the cause of the anemia because cells are small in iron deficiency anemia as compared to a B12 or folate deficiency (pernicous anemia), 80-100 fl
  
• Hematocrit (Ht) - proportion of red blood cells in overall blood, 42-54% (m), 38-46% (f)
  
• Mean corpuscular hemoglobin (MCH) - average hemoglobin in the average red cell, 27-33 pg
  
• Mean corpuscular hemoglobin concentration (MCHC) - average concentration of hemoglobin in a given volume of red cells, 32 - 36 %

Over the course of the next few days, I will further discuss iron deficiency and anemia. I will describe the red blood cell structure, ways to increase absorbency therefore preventing a deficiency, and my own personal experience with anemia. I look forward to questions and comments!