RDW is a standard measurement reported as part of a complete blood count (CBC) that reflects the variation in size of your red blood cells. Normally, these cells are nearly uniform in size, but a high RDW indicates a greater-than-normal variation, known as anisocytosis. While an elevated RDW is not a diagnosis, it signals disruption in the body’s process for producing healthy, uniformly-sized red blood cells. Addressing a high RDW focuses on correcting the underlying health condition through targeted nutritional, lifestyle, and sometimes medical interventions.
Understanding Elevated Red Cell Distribution Width
An elevated RDW signifies that two or more populations of red blood cells are circulating, indicating a high degree of variation in volume and size. This variation occurs when the bone marrow releases new cells that are much smaller or much larger than the average red blood cell. The causes of this size discrepancy are grouped into two categories: nutritional deficiencies and systemic health issues.
Nutritional deficiencies are a common cause because iron, Vitamin B12, and folate are necessary for proper red blood cell maturation. Iron deficiency can lead to the production of small, immature cells mixed with existing normal-sized cells, resulting in a high RDW. Conversely, a lack of Vitamin B12 or folate causes the bone marrow to produce abnormally large cells, which also contributes to the cell size variation.
A high RDW can also be a marker for chronic inflammation stemming from underlying conditions such as kidney disease, liver disease, or cardiovascular disorders. Chronic disease states interfere with the body’s ability to use or transport iron effectively, disrupting the bone marrow’s ability to create uniform red blood cells. Thus, a high RDW serves as an early indicator of a persistent disturbance in foundational cellular processes.
Targeted Nutritional Strategies for Correction
Addressing an elevated RDW begins by ensuring an adequate intake of the micronutrients necessary for healthy red blood cell formation. Replenishing deficient stores of iron, Vitamin B12, and folate allows the bone marrow to stabilize production, leading to a more homogeneous population of red blood cells. This stabilization is the mechanism that lowers the RDW score over time.
For iron, focus on high-bioavailability sources, such as heme iron found in red meat, poultry, and fish. Non-heme iron, found in plant sources like lentils, beans, and spinach, requires an absorption strategy. Combining non-heme iron sources with foods rich in Vitamin C, such as citrus fruits or bell peppers, significantly enhances uptake. Vitamin C acts by reducing the less absorbable ferric iron to the more readily absorbed ferrous iron in the gut.
Restoring Vitamin B12 and folate levels is important, particularly for those with macrocytic anemia, characterized by oversized red cells. Vitamin B12 is found almost exclusively in animal products like meat, eggs, and dairy. Folate (Vitamin B9) is abundant in dark leafy greens, legumes, and fortified grains. Older adults and individuals with gastrointestinal issues often struggle with B12 absorption, making supplementation or medical intervention necessary.
It is beneficial to avoid substances that interfere with nutrient absorption. For example, consuming coffee or tea with iron-rich meals should be avoided, as the tannins can inhibit uptake. Phytic acid found in whole grains can also limit the absorption of non-heme iron. Planning meals to separate inhibitors from key nutrients ensures the body maximizes the benefit from dietary changes.
Managing Systemic Inflammation and Lifestyle Contributors
Beyond nutritional replenishment, addressing chronic inflammation is a significant strategy for lowering RDW. Inflammation can disrupt communication between the body’s iron stores and the bone marrow, leading to ineffective red blood cell production. Lifestyle modifications are effective tools for managing this systemic inflammation.
Incorporating an anti-inflammatory diet is effective. Prioritize foods rich in omega-3 fatty acids, such as fatty fish, and polyphenols found in brightly colored fruits and vegetables. Limiting the intake of refined sugars, trans fats, and highly processed foods helps reduce the inflammatory burden. These dietary adjustments help reduce circulating inflammatory markers that negatively influence red blood cell health.
Maintaining adequate hydration is an effective measure, as dehydration can temporarily increase blood viscosity and affect the apparent size distribution of blood cells. Aiming for at least eight glasses of water daily supports overall blood health and circulation. Engaging in regular moderate exercise (150 minutes per week) and prioritizing restorative sleep also helps lower inflammatory compounds like C-reactive protein (CRP).
Chronic stress can also fuel inflammation, making stress management techniques a component of a comprehensive approach. Practices like mindfulness, meditation, or yoga can help regulate the body’s inflammatory response. For individuals with a diagnosed chronic condition like diabetes or kidney disease, managing the underlying disease is paramount, as this control directly mitigates the inflammatory effect on red blood cell production.
Monitoring Progress and Necessity of Medical Intervention
The red blood cell life cycle is approximately 120 days, meaning changes in RDW levels occur slowly and cannot be seen overnight. After starting nutritional or lifestyle changes, it typically takes several weeks to months for the RDW to show a measurable reduction. Follow-up blood work, often including a repeat CBC and specific nutrient level checks, is necessary to confirm the interventions are having the desired effect.
While many cases of elevated RDW respond well to dietary and lifestyle adjustments, some underlying causes require direct medical treatment. Conditions like pernicious anemia, where B12 absorption is impaired, may necessitate injectable Vitamin B12 therapy rather than oral supplements. For severe iron deficiency, prescription-strength iron supplements may be required to achieve a therapeutic dose and accelerate normalization.
Seek immediate medical advice if you experience severe symptoms like extreme fatigue, persistent shortness of breath, dizziness, or an abnormally rapid heartbeat. These symptoms may suggest a more advanced stage of anemia or a serious underlying condition requiring prompt professional diagnosis and a supervised treatment plan. The RDW serves as a guide, but a physician is necessary to interpret the full picture of your blood work and guide treatment.