Understanding and Action: How to bring down high MCV?

According to one study, macrocytosis (high MCV) is often the earliest abnormality seen in complete blood counts of patients with folate or vitamin B12 deficiency. Knowing how to bring down high MCV begins with understanding and addressing these and other potential root causes under a doctor's care.

Quick Summary

This article details the causes of high mean corpuscular volume (MCV), from nutritional deficiencies to lifestyle factors. It explores effective treatment strategies, including dietary adjustments, supplementation, and addressing underlying health conditions to help normalize red blood cell size.

Key Points

• Identify the cause: High MCV is a symptom, not a disease, so a doctor must diagnose the underlying issue for proper treatment.

• Address nutrient deficiencies: The most common causes are a lack of vitamin B12 or folate, which can be corrected with supplements and diet.

• Limit alcohol consumption: Chronic alcohol abuse is a major cause of high MCV, and reducing or eliminating intake is necessary to reverse it.

• Review medications: Certain drugs can cause elevated MCV; discuss potential alternatives with your doctor if this is the cause.

• Manage underlying conditions: Treat any medical conditions like liver disease, hypothyroidism, or myelodysplastic syndromes, as these can affect MCV levels.

• Consult a professional: Never self-diagnose or attempt to treat high MCV without consulting a healthcare provider for an accurate diagnosis and treatment plan.

What is a high MCV?

Mean Corpuscular Volume (MCV) is a measurement included in a standard Complete Blood Count (CBC) that indicates the average size of your red blood cells (RBCs). A high MCV, a condition known as macrocytosis, means your red blood cells are larger than normal. The normal adult range for MCV is typically 80 to 100 fL, though this can vary slightly by lab. While a high MCV can be an incidental finding with no symptoms, it is also a key indicator of underlying health issues that need to be investigated and addressed.

Common causes of elevated MCV

Identifying the cause of a high MCV is the most critical step toward normalizing red blood cell size. The cause can range from simple dietary issues to more complex medical conditions.

Nutritional deficiencies

One of the most frequent causes of macrocytosis is a deficiency in vitamins essential for DNA synthesis during red blood cell production. When these vitamins are lacking, cell division is impaired, leading to abnormally large red blood cells.

• Vitamin B12 (Cobalamin) deficiency: This can be caused by inadequate dietary intake, especially in vegans, or by malabsorption issues like pernicious anemia or Celiac disease.
• Folate (Vitamin B9) deficiency: Poor dietary intake, malabsorption, or conditions with increased folate requirements (like pregnancy or hemolytic anemia) can lead to this issue.

Lifestyle factors

Certain lifestyle choices have a direct impact on red blood cell health and can cause an elevated MCV.

• Chronic alcohol abuse: Excessive alcohol consumption is a common cause of high MCV. Alcohol is toxic to bone marrow and can interfere with folate metabolism. The MCV may not return to normal until several months after abstinence.
• Liver disease: Up to two-thirds of patients with chronic liver disease develop macrocytosis. The liver plays a critical role in blood cell production and function, and disease can cause uniformly enlarged, round red blood cells.

Medical conditions

Several medical conditions can influence red blood cell size and lead to a high MCV.

• Hypothyroidism: An underactive thyroid can be associated with a mildly macrocytic anemia.
• Myelodysplastic syndromes (MDS): These are a group of bone marrow disorders that can present with macrocytic anemia, especially in older adults.
• Other conditions: Chronic kidney disease, some hematological disorders, and an increased presence of reticulocytes (larger, immature red blood cells) due to accelerated red cell turnover can also elevate MCV.

Medication side effects

Certain prescription medications are known to cause a rise in MCV as a side effect. These often include drugs that interfere with DNA synthesis or folate/B12 metabolism. Examples include:

• Chemotherapy drugs
• Anti-seizure medications, such as phenytoin and valproic acid
• Methotrexate
• Antiretrovirals used to treat HIV

How to bring down high MCV? Treatments and strategies

The most effective strategy is always to treat the underlying cause. This process should be guided by a healthcare provider who can accurately diagnose the issue.

Treating nutritional deficiencies

If a vitamin deficiency is the cause, replacement therapy is the standard approach.

• Vitamin B12: Depending on the severity and cause, treatment may involve oral supplements, sublingual tablets, or intramuscular injections. Injections are often necessary for pernicious anemia or other malabsorption issues.
• Folate: Folic acid supplements are used to treat folate deficiency. Dietary improvements are also crucial.
• Dietary Adjustments: Eating a balanced diet rich in B12 and folate is a foundational step. Incorporating nutrient-rich foods helps support the body's natural red blood cell production.

Lifestyle adjustments

For lifestyle-related causes, significant changes are needed.

• Reduce alcohol intake: Abstained from or significantly reducing alcohol consumption is necessary for alcohol-induced macrocytosis. It can take months for MCV levels to normalize after cessation.
• Liver health: Addressing liver disease with the help of a medical professional is essential for normalizing MCV levels in these cases.
• Healthy habits: Ensuring adequate sleep, managing stress, and regular exercise can support overall health and improve the body's metabolic functions.

Addressing underlying medical conditions

For conditions like hypothyroidism or MDS, the primary illness must be treated to see an effect on MCV.

• Hypothyroidism: Thyroid hormone replacement therapy can resolve the associated macrocytosis.
• Myelodysplastic syndromes: Treatment for MDS is complex and must be overseen by a hematologist.
• Medication Review: A doctor may need to adjust or change medications that are causing the elevated MCV.

Comparison of high MCV causes

Feature	Vitamin B12/Folate Deficiency	Chronic Alcohol Abuse	Liver Disease	Medication Side Effect
Symptom Onset	Often gradual; fatigue, neurological symptoms (B12).	Progressive; associated with heavy drinking history.	Can be slow or acute; often with other liver-related symptoms.	Follows initiation of specific drugs; may be asymptomatic.
Associated Anemia	Megaloblastic Anemia: high MCV (>110 fL) with distinct cell shapes.	Often mild or non-anemic; typically uniform macrocytes.	Can be present; frequently accompanied by round target cells.	Varies by drug type and dose; can cause megaloblastic changes.
Primary Treatment	Supplementation (oral/injection) and dietary changes.	Abstinence from alcohol and nutritional support.	Treatment of the underlying liver condition.	Discontinuation or substitution of the causative drug.
Time to Recovery	Hemoglobin and MCV improve within weeks to months with treatment.	MCV can take 2-4 months or more to normalize after abstinence.	Dependent on the course and management of the liver disease.	Depends on the drug and patient response; normalization can take time.

Conclusion: Prioritizing a holistic approach

Elevated MCV is a valuable diagnostic clue that can point to a number of underlying health issues. A mild, asymptomatic elevation may not be immediately concerning, but it should never be ignored. The most common causes are treatable, especially nutritional deficiencies and chronic alcohol use, which can often be managed with targeted interventions. For more complex causes like liver disease or myelodysplastic syndromes, addressing the primary condition is key. The path to normalizing your MCV involves a careful medical evaluation, often including dietary and lifestyle changes, and potentially medication adjustments. Always consult your healthcare provider to understand the root cause and determine the best course of action for your specific situation. Following medical guidance not only helps bring your MCV back to a healthy range but also addresses the broader health concerns indicated by the lab result.

For more information on blood tests, see the guide on the Cleveland Clinic website.

Frequently Asked Questions

What is the fastest way to bring down high MCV?

The speed at which high MCV can be reduced depends entirely on the cause. For a simple vitamin deficiency, supplements can show improvement in blood work within a couple of months. If alcohol is the cause, it may take 2-4 months of abstinence for levels to normalize.

Can high MCV be caused by a poor diet?

Yes, a poor diet is a very common cause of high MCV. Deficiencies in vitamin B12 and folate, often due to inadequate intake, lead to macrocytosis and can be corrected with dietary improvements or supplementation.

What foods are good for high MCV?

Foods rich in vitamin B12 and folate are essential. Good sources of B12 include meat, fish, eggs, and dairy, while folate can be found in leafy green vegetables, legumes, and fortified cereals.

How long does it take for MCV to lower after quitting alcohol?

It may take more than 4 months of complete abstinence from alcohol for MCV levels to normalize. This is because red blood cells have a long lifespan, and it takes time for the bone marrow to produce new, healthy-sized cells.

Does exercise help lower high MCV?

While exercise does not directly lower MCV, regular physical activity can support overall cardiovascular health and aid in better blood circulation and nutrient absorption, which can contribute to normalizing MCV over time.

What if my high MCV is caused by medication?

If a medication is identified as the cause, your doctor may suggest an alternative drug or adjust the dosage. It is crucial not to stop any prescribed medication without first consulting your healthcare provider.

Is mild macrocytosis always a cause for concern?

Mild macrocytosis may not cause symptoms, but it should still be investigated to find the underlying cause. While it may not be serious, it could be an early sign of an issue that needs addressing.