As a physician who promotes a whole food plant based diet I often get questions regarding iron in the diet and anemia risks. To understand anemia first let’s define what anemia is, then the types of anemia, causes of iron deficiency anemia and what should you do.
What is anemia?
Anemia is simply a reduced number of red blood cells circulating throughout your body. The most common laboratory studies used to measure the total red blood cells are found in a complete blood count (CBC for short). They are the hemoglobin concentration, hematocrit (HCT), or red blood cell (RBC) count. The hemoglobin is the molecule that carries oxygen in the blood, the hematocrit is the volume of red blood cells in a blood sample that has been spun down and it is expressed as a percentage, and the RBC count is the number of red blood cells in a blood sample that has not been spun down. Most physicians will refer to the hemoglobin and hematocrit when defining and discussing anemia and that is what I will focus on in this article to keep things simple. I will also only be focusing on adult men and women.
Men and women have different red blood cell parameters and measurements may vary from lab to lab but typically men’s hemoglobin (g/dL) range from 14.0 to 17.5 and women range from 12.3 to 15.3. The expected hematocrit (expressed as a percentage) for men is 42-50 and for women 36-45. Also, it is important to note that our bodies will respond to stresses placed upon it and sometimes this will lead to different ranges for specific populations such as athletes, older adults, those suffering from chronic disease, smokers and those living at high altitudes. Also, there may be certain conditions that appear to be normal and individuals are truly anemic such as someone who has lost a significant amount of blood and the initial tests may show normal concentrations. Or the opposite case, such as pregnant women may appear to be anemic because the plasma (fluid that RBCs are suspended in when looking a blood as a whole and makes up 55% of the blood volume) increases more so than the total RBCs therefore giving a false indication of anemia.
What causes anemia?
There are three causes of anemia: the decreased production of RBCs, the increased destruction of RBCs, and blood loss. Individuals may have one or more of these factors at play and that is why it is very important to look at the total history of a person and their specific risk factors.
Decreased production of RBCs may be lack of nutrients such as vitamin B12 and iron. Now this can be caused due to lack of them in the diet or they are not being absorbed. Certain medications such as acid reducers for heart burn and metformin, a common medication used for type 2 diabetes, can decrease the absorption of B12. Celiac disease can also decrease the absorption of vital nutrients such as iron. The most common cause of iron deficiency anemia is blood loss, for example women who have heavy bleeding during their monthly periods. Other causes include problems with the bone marrow where RBCs are made, chronic kidney disease (kidneys make a hormone called erythropoietin which stimulates the bone marrow to make RBCs, with kidney disease they make less of it), inflammation related to infections, autoimmune disorders or cancers.
RBCs typically live 110-120 days and then they are naturally destroyed. However, there are some conditions that will destroy RBCs before they reach their expected lifespan. These include congenital disorders life sickle cell disease, autoimmune disorders or infections like malaria.
Blood loss can occur from trauma or from disorders of the uterus (heavy bleeding during periods), kidneys (dialysis patients), gastrointestinal tract (ulcers and cancers) and lungs (coughing up blood from infection or cancer). This is why a history and proper testing of bodily fluids is crucial to the proper diagnosis of the cause of anemia. One should not assume just because someone eats a plant based diet that it is the cause of anemia.
What are the different categories of anemia?
Anemias can be classified according to the size of the RBC as well. Macrocytic anemia is when the RBC is larger than normal and can be caused by low B12 and folate levels, drugs, cancers, liver disease, alcohol abuse and hypothyroidism. Normocytic anemia occurs when the RBC size is normal and can occur with acute blood loss, chronic disease, or increased plasma volume (someone who received intravenous fluids in a recent hospital stay).
Microcytic anemia is noted when the RBC size is smaller than normal. There are several mechanisms that can cause microcytic anemia and some examples include decreased iron availability (lack of iron in diet, absorption or loss; inflammation and copper deficiency); congenital disorders such as thalassemia or lead poisoning.
What should you do if you are told you are anemic?
If you are told you are anemic it is time to become a detective in partnership with your doctor. Ask your doctor the type and cause of anemia and have them explain it to until you are satisfied with the answer. Have answers to the most common questions your doctor will ask you:
Have you had any bleeding now or in the past?
Have you had any changes in your stools such as dark tarry stools or bright red blood in your stools?
Were you recently hospitalized or had a surgery?
Do you have heavy periods?
Do you supplement with B12 if you are eating a plant based diet?
What medications including supplements are you taking?
Have you been anemic in the past?
Any recent history of nights sweats, loss of appetite, pain, fevers?
What are your chronic medical conditions?
Do you have a family history of anemias, colon cancer?
Any recent foreign travel with new symptoms?
Any changes in your energy levels recently?
Once you are satisfied that you and your doctor have figured out the cause of the anemia then you can make appropriate decisions to treat it. Anemia is often multifactorial and an accurate diagnosis requires thoughtful evaluation.
What can you do to decrease your risks of anemia when eating a plant based diet?
Since a lack of dietary iron can cause anemia you should eat iron rich plant foods such as dark green leafy vegetables, beans (lentils, soybeans and chickpeas), dried prunes and apricots, sesame seeds, nuts, and quinoa are a few to choose from. When eating foods rich in iron pair them with foods rich in vitamin C and beta-carotene to increase the absorption. Also increase your folate rich foods such as soybeans, broccoli, Brussel sprouts, potatoes and avocado. If you are also eating a whole food plant based diet you should supplement with B12. Then test don’t guess your levels of iron, folate and B12 to monitor your progress. Certain foods also contain compounds that decrease absorption of iron such as spinach, tea, coffee, cocoa and others. You may want to decrease consumption of these foods and increase the others to see if this is a factor.
It is important to remember to eat optimally with a varied and colorful whole food plant based diet and supplement wisely such as B12. When in doubt, test don’t guess and continue to ask questions of your healthcare provider until you are confident in the cause and solution of your anemia.
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