Pamela A. Popper, Ph.D., N.D.

Wellness Forum Health

 My last blood test shows that I have low iron levels and my doctor tells me it is because I am eating a plant-based diet. She says I need to eat meat in order to bring my levels up. I don’t want to do this but I don’t want to take iron supplements either.

First, not all abnormal blood tests require immediate action. If this is the first time your test has shown low iron levels, the abnormality is small, and you are not experiencing symptoms such as fatigue, it is best to wait and have another blood test to see if the abnormality persists. If the abnormality remains stable and you continue to have no symptoms, treatment may still not be warranted. Decisions about this should be made with your doctor, who should know that healthy people often have test results slightly outside reference ranges, and unhealthy people often have test results within reference ranges, which means that most blood tests should be evaluated in consideration of the patient’s overall health status. The fact that your doctor thinks that the only way to maintain healthy iron levels is to eat meat is not a good sign; you may want to consider finding another doc who is better informed.

If your iron levels are persistently low and continue to drop, the key to resolving the issue is to determine the cause. Potential causes include excessive blood loss through menstruation, bleeding someplace in the body (the GI tract is a common location), blood loss through skin (psoriasis can cause this), poor iron absorption, dietary factors that bind iron, and anemia.

Anemia is a condition cause by an insufficient number of red blood cells to carry oxygen throughout the body. Causes include insufficient production of red blood cells, bleeding which results in loss of red blood cells, and certain autoimmune diseases, which can destroy red blood cells. There are many forms, anemia can be temporary or long-term, and the severity can range from mild to life-threatening. Anemia of chronic disease can develop in response to chronic illness or systemic inflammation (diseases such as cancer or autoimmune disease). Treating with large doses of iron or infusions can worsen the condition because the body defends itself against excess iron and often will excrete even more iron in response to treatment. Iron is toxic, and when the body is inflamed, it may limit iron as a survival tactic.[1]

Symptoms of low iron or anemia include fatigue, dizziness, headache, difficulty breathing, and feeling cold.

There are two forms of dietary iron. Heme iron is found in animal foods such as red meat, fish, and poultry, and constitutes 40% of the iron in these foods. Non-heme iron is found in foods like lentils and beans and constitutes 60% of the iron in animal foods. Iron deficiency is not common in vegetarians because when measured per 100 calories, plant foods have higher iron content than many animal foods.

The RDA for iron is 8 mg per day for adult men and postmenopausal women, and 18 mg per day for premenopausal women. One cup of soybeans contains 8.8 mg of iron, and one cup of spinach contains 6.4 mg of iron. To consume the same amount of iron in one cup of spinach with animal foods instead, a person would have to eat 1700 calories of sirloin steak!

Usually the amount of iron absorbed depends on the body’s needs. When iron stores are adequate, about 5% of dietary iron is absorbed. People who are deficient can absorb as much as 20% of dietary iron. Several factors influence absorption. One is stomach acidity, which is lower in patients taking drugs to treat reflux. Another is the condition of the GI tract; patients with conditions like celiac disease and inflammatory bowel diseases like colitis and Crohn’s often do not absorb iron and other nutrients well until inflammation levels are lowered and the microbiome is restored through probiotic treatment.

Vitamin C increases absorption, another reason why vegetarians don’t usually have low iron levels. Fruits and vegetables are high in vitamin C, while animal foods are low in vitamin C. Dairy, coffee, and tannins found in tea can inhibit absorption.

Phytic acid is the storage form of phosphorous in grains, legumes, seeds, and nuts. Root vegetables and tubers also contain phytic acid, but in lower amounts. Phytic acid can bind iron and other minerals if consumed in excess, and some people are more susceptible to the iron-binding capacity of phytic acid than others. This is often cited by promoters of Paleo and other unhealthy diets as a reason to avoid grains, but phytic acid is found in so many plant foods that it cannot be avoided, and it has several protective properties including preventing iron overload.

Pregnancy increases iron needs, which are met in two ways. At the end of the first trimester absorption of iron increases, and this increase can be up to nine times the normal rate of absorption. And calorie intake normally increases with pregnancy too. Only 5 mg of additional daily dietary iron is required, which is easily met with increased calories from plant foods.

As you can see, iron deficiency is usually not due to insufficient intake, which means that taking iron supplements addresses the symptom of the problem, not the cause. The best course of action is to identify the cause, which will dictate the course of action for increasing iron levels. And no one needs to eat animal foods in order to ensure adequate iron intake.

[1] Zarychanski R, Houston D. “Anemia of chronic disease: A harmful disorder or an adaptive, beneficial response?” CMAJ 2008 August 12;179(4):333-337