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How Serious Is Macrocytic Anemia? [+ 3 Ways To Address It]

Medically Approved by Dr. Edward Salko

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It can be stressful to find out you have macrocytic anemia, especially if you do not understand what it is. But if you do have the disorder, you do not need to worry since it is treatable and not life-threatening. 

Macrocytic anemia caused by vitamin B deficiency (megaloblastic anemia) is unlikely to pose serious health risks if diagnosed and treated early. On the other hand, if it is due to an underlying condition (non-megaloblastic anemia), its severity may vary. 

Keep reading to learn more about how serious macrocytic anemia can get and the natural ways you can employ to treat it. 

What Is Macrocytic Anemia? 

Macrocytic anemia is a blood disorder characterized by the abnormal production of large red blood cells (RBCs) or erythrocytes – an occurrence referred to as macrocytosis. Consequently, these larger-than-normal RBCs cannot function properly, making it difficult to transport oxygen to cells and collect carbon dioxide. This condition can escalate to physiological issues involving other organ or tissue functions if not treated accordingly. 


It’s highly likely to cause macrocytic anemia symptoms at the onset. In most cases, the condition doesn’t show anything abnormal until you already have it for quite some time. Thus, it’s even more critical to detect the following symptoms and see your doctor for a proper diagnosis. 

  • Fatigue
  • Diarrhea
  • Brittle nails
  • Memory loss
  • Skin paleness 
  • Lack of appetite
  • Trouble breathing
  • Unexplained weight loss
  • Confusion and problem focusing

Pro Tip: Since macrocytic is hard to detect when it’s still at its early stage, it’s important to undergo an annual physical exam with a wellness checkup. This is advisable, especially for people at risk for the condition, such as pregnant women, the elderly, vegans, and those with nutritional problems.


On top of the symptoms assessed during a physical exam, macrocytic anemia can be diagnosed through the following lab tests.

Complete Blood Cell (CBC) Count 

A CBC test is taken as part of a general health checkup or to determine any abnormalities in the blood, including macrocytosis. In doing so, it checks for the following parameters, serving as macrocytic anemia lab values:

Mean Corpuscular Volume (MCV)

Testing your blood’s MCV directly indicates the likelihood of having macrocytosis. MCV refers to the size of your RBCs. When taking an MCV blood test, check if the lab values go above 100 fL, as it usually indicates macrocytosis. 

Pro Tip: An MCV blood test is crucial in a CBC that helps diagnose macrocytic anemia. Learn more about this component and what it means to have a high MCV

Hematocrit Test (HCT)

A hematocrit test measures the percentage of RBCs in the blood. Since macrocytic anemia can be due to insufficient raw materials for producing healthy RBCs, they will likely go below the normal range. In addition, those that survive to live become abnormally large, and their lifespan is relatively shorter, which also reflects in an HCT test. 

HCT lab values for people with macrocytic anemia are as follows:

  • Non-pregnant women: less than 12 g/dL
  • Pregnant women: less than 11 g/dL
  • Men: less than 13 g/dL

Peripheral Blood Smear

A peripheral blood smear has the same goal as that of CBC – to evaluate different blood cells. However, a peripheral blood smear involves getting a blood sample, smearing it on a slide, and looking at the smear under a microscope. In contrast, CBC relies on an automated machine to measure blood cells per unit volume.

In most cases, a peripheral blood smear is performed after a CBC to further confirm macrocytosis since it allows lab technicians to visually examine the size of the RBCs.

How Serious Is Macrocytic Anemia? 

Macrocytic anemia is not as life-threatening as other forms of anemias, and it can be treated easily. However, if left untreated, it can lead to complications and more severe health issues. 

Macrocytic Anemia Causes

While macrocytosis is an illness in itself, it’s also a part of an underlying condition that could worsen without medical intervention. Therefore, proper action becomes crucial – starting with detecting what’s causing the condition. To do that, you also need to understand that there are two types of macrocytic anemia: megaloblastic and non-megaloblastic. 

Simply put, megaloblastic anemia is caused by deficiencies or malabsorption of vitamin B12 or folate. Whereas, non-megaloblastic anemia is due to an underlying medical condition, ranging from chronic alcoholism and liver problems to bone marrow failure, hypothyroidism, and myelodysplastic syndrome. 

Megaloblastic Macrocytic Anemia

Vitamin B12 and B9 (folate) deficiency

During the production of RBCs (a process called erythropoiesis), vitamins B12 and B9 support the synthesis of DNA components. Hence, a shortage of these nutrients leads to abnormal production of RBCs, specifically macrocytosis.

Nutrient malabsorption 

It’s possible to consume enough foods rich in vitamin B12 and folate yet still develop macrocytosis. This could happen if you have malabsorptive disorders that bar the proper acquisition of nutrients. One notable condition associated with this abnormality is pernicious anemia. 

Pernicious anemia is an autoimmune disorder characterized by a weakened stomach lining, which prevents vitamin B12 from being absorbed. Other medical conditions that have the same effect include Imerslund-Grasbeck syndrome (IGS) and obesity. Those who have undergone gastrectomies and bariatric surgery are more likely to experience vitamin B12 malabsorption. 

Certain drugs

Some drugs can interrupt folate absorption, delivery, and processing to form red blood cells, resulting in macrocytosis. These include valproic acid, methotrexate, antiretroviral agents, phenytoin, zidovudine, hydroxyurea, and azathioprine. 

Did You Know? Different forms of anemia exist. Some are rare and autoimmune-driven, while others result from unhealthy choices, such as poor diet. Find out everything you need to know about anemia to help prevent this condition. 

Non-Megaloblastic Macrocytic Anemia


Heavy drinking impacts the maturation of red blood cells. As a result, RBCs sustain defects, including an abnormally large size. This condition is often detected when a blood test shows increased MCV. Furthermore, alcoholism leads to premature erythrocyte destruction, exacerbating anemia for chronic alcoholic drinkers.  

Liver problem

Patients with liver disease, either due to chronic alcoholism or illness, like hepatitis B virus cirrhosis, are found to have a high inclination for macrocytosis. While the exact cause of this correlation remains unknown, it is understood that the condition links to loss of liver function. Mainly, the liver contributes to iron recycling and removes worn-out RBCs


Insufficient production of thyroid hormones has ties with vitamin B deficiency. In fact, studies have shown that over 50% of patients with hypothyroidism develop macrocytosis. Unfortunately, symptoms may set in late for both conditions. If you’re at risk of hypothyroidism, consider having your thyroid function assessed.   

Bone marrow failure

The bone marrow is where blood cells, including erythrocytes, are made. Suppose the bone marrow fails due to conditions such as a viral infection, blood disorders, radiation, chemicals, and specific drugs. Consequentially, it leads to low RBC production with abnormal size and shape. 

Myelodysplastic syndrome (MDS)

People with myelodysplastic syndrome experience abnormalities in the maturation of RBCs. After all, MDS is a group of disorders affecting the early stages of RBC production in the bone marrow. Aside from macrocytosis revealed by high MCV, you may get a hint of the condition if you have a low RBC count, along with symptoms such as bruising, bleeding, fatigue, pale skin, and breathing problems. 

3 Ways To Treat Macrocytic Anemia  

Your doctor will provide a treatment plan that may include supplementation, lifestyle improvement, and the detection of underlying medical problems related to macrocytic anemia. These steps will not only stop macrocytosis from occurring but will also prevent further complications, such as extreme fatigue and permanent cognitive impairment.

  1. Adjust your Diet

The precursor for RBC production includes key nutrients, vitamins B 12 and B9, which you can only acquire from food. If it turns out that you are deficient in these vitamins, as shown in your vitamin B12 and folates blood test result, the simplest yet most effective way to address it is to correct your diet – and here’s what you can do. 

Eat foods high in Vitamins B12 and B9

You can add the following foods to your diet: dark leafy green vegetables, whole grains, peanuts, beans, eggs, organ meat (especially liver and kidneys), shellfish, dairy products, fortified cereals, and fish (tuna, salmon, trout, etc.)

Pro Tip: Your need for folate increases with pregnancy as folic acid, as a form of vitamin B9, is essential for the development of neural tubes. Find out natural food sources of folate that are best for pregnant women.  

Consider dietary supplements

Under normal circumstances, vitamin B deficiency is less likely as you get such nutrients from plenty of staple food. However, if the deficiency is due to malabsorption and the amounts of vitamins B12 and B9 are extremely low, your doctor may prescribe supplementation. 

If you’re planning to become vegan, consult with your health provider and nutritionist, as this transition can affect your consumption of vitamin B-rich foods, like fish and beef. In such cases, you may need dietary supplements. 

Pro Tip: Being a vegan entails abstaining from animal-based foods, which may impact your overall health. Before starting this lifestyle, speak with your doctor. Also, check out the six veganism health risks you need to be aware of.  

Increase your consumption of iodine and selenium-rich foods

Hypothyroidism has a close correlation with macrocytosis, and this can be traced to possible nutrient deficiencies, specifically iodine and selenium. These minerals aid in producing thyroid hormones, triiodothyronine (T3) and thyroxine (T4). Learn more about how to improve thyroid function naturally and prevent hypothyroidism. 

  1. Treat excessive alcohol addiction

If you’re a heavy drinker with macrocytic anemia, it’s high time to consider giving it up completely. As it is easier said than done, consider having a comprehensive plan that begins with outlining your motivation and preparing yourself for withdrawal syndrome. You can work with your doctor in tracking physiological changes.

In addition, you can get into a program like Alcoholics Anonymous or something similar. More importantly, be around people who support you and will help you with your goals. 

  1. Get tested for conditions causing macrocytosis 

After getting your lab results with lab values suggesting macrocytic anemia, take note of other symptoms you experience and let your doctor know. You will likely take additional tests to trace macrocytosis back to the underlying condition. These tests could range from blood tests to imaging procedures. If your doctor suspects MDS, you may need to undergo a biopsy to confirm cancer.

Frequently Asked Questions 

How long does it take to recover from macrocytic anemia?

On average, your RBCs revert to normal production within four weeks, provided that you’re following through with the treatment for macrocytic anemia. This includes increasing your vitamin B12 and folate supply. However, if your healthcare provider detects no progress as early as two weeks, you may need further testing.  

Who is at the highest risk for macrocytic anemia?

People who are at the highest risk for developing macrocytic anemia include individuals who are prone to develop vitamin B12 and folate deficiency. These include the elderly, pregnant women, vegans and vegetarians, patients with a malabsorptive disorder, and those with chronic alcoholism as well as liver disease. 

In addition, you may also want to check if you have high MCV if you’re taking certain medications like antiretrovirals and antiseizure. These, and other forms of drugs, can also trigger macrocytosis. 

Is macrocytic anemia treatable?

Macrocytic anemia is highly treatable, mainly if the exact cause is determined and if it is diagnosed before complications set in. Between megaloblastic and non-megaloblastic anemia, the former is easier to treat as it usually only involves increasing consumption of foods that are vitamin B12 and B9 dense. In comparison, non-megaloblastic anemia will require further testing to detect the underlying condition causing macrocytosis. 

The Bottom Line

Although macrocytic anemia is not as severe as other blood disorders, it still warrants immediate treatment. If you’ve developed nutrient deficiency, check with your doctor about your risk of having macrocytosis. More importantly, be more conscious of your diet and overall lifestyle to keep control of your health.

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