The mean corpuscular hemoglobin concentration (MCHC) is a metric frequently reported as part of a routine complete blood count. It represents the average concentration of hemoglobin packed within a given volume of red blood cells. Hemoglobin is the iron-rich protein responsible for transporting oxygen from the lungs to every tissue in the body. When a blood test reveals a low MCHC value, it indicates that the oxygen-carrying protein is not concentrated enough within these cells. This result is a common finding and often points toward a nutritional issue that is treatable.
Decoding a Low MCHC Result
A low MCHC value reflects a state known as hypochromia, describing red blood cells that are noticeably paler than normal under a microscope. This paleness results from insufficient hemoglobin density within the cell structure, as a lower concentration dilutes the pigment that gives red blood cells their characteristic color.
The physiological importance of this low concentration relates directly to the cell’s function. Hemoglobin’s primary role is to bind to oxygen in the lungs and release it throughout the body. When the concentration of this protein is reduced, the cell’s overall oxygen transport capacity is diminished. Consequently, a low MCHC can lead to reduced oxygen delivery, which may present as fatigue or shortness of breath.
Primary Underlying Causes
The most frequent cause behind a diminished MCHC is a deficiency in the body’s iron supply, leading to Iron Deficiency Anemia (IDA). Iron is required to synthesize the hemoglobin molecule. If iron stores are depleted, the body cannot manufacture hemoglobin efficiently, resulting in red blood cells with a low internal concentration of the protein.
Iron depletion often occurs due to chronic, low-grade blood loss over time, slowly draining the body’s iron reserves. Common sources of this gradual loss include heavy or prolonged menstrual periods or internal bleeding from the gastrointestinal tract, such as from ulcers or inflammation.
While iron is the main component influencing MCHC, some genetic conditions can also present with a low MCHC. Thalassemia, an inherited blood disorder, affects the body’s ability to produce adequate amounts of hemoglobin, resulting in a reduced concentration within the cells. Because treatment depends on the specific origin, a healthcare provider must perform additional blood work to determine the exact cause before any corrective steps are taken.
Targeted Dietary Adjustments
Dietary intervention is an effective way to address a low MCHC when the cause is nutritional iron deficiency. Iron in food exists in two main forms: heme iron, found exclusively in animal sources (red meat, poultry, and fish), and non-heme iron, found predominantly in plant-based foods. Heme iron is significantly more bioavailable, meaning the body absorbs it more readily.
Non-heme iron sources, including lentils, beans, spinach, and fortified cereals, require strategic pairings for maximum absorption. The absorption of non-heme iron can be tripled when consumed alongside foods rich in Vitamin C. For instance, pairing a lentil soup with bell peppers or adding citrus juice to a spinach salad converts the iron into a form that is more easily processed.
Conversely, certain substances inhibit iron absorption and should be avoided during iron-rich meals. Calcium, found in dairy products, inhibits the absorption of both heme and non-heme iron. Other inhibitors include polyphenols and tannins, which are concentrated in black tea, coffee, and cocoa.
Phytates (in whole grains, nuts, and legumes) and oxalates (in spinach and kale) also bind to iron and reduce its uptake. To minimize this interference, it is recommended to wait two hours after consuming an iron-rich meal before drinking coffee, tea, or consuming high-calcium foods. Adjusting the timing of these common inhibitors can enhance the efficacy of dietary efforts to raise MCHC levels.
Medical Interventions and Supplementation
When dietary changes alone are insufficient to correct a low MCHC, a medical professional will recommend iron supplementation. The most common oral supplements are ferrous salts, such as ferrous sulfate, ferrous gluconate, or ferrous fumarate. These compounds are taken daily for several months, even after hemoglobin levels normalize, to ensure the body’s iron reserves are fully restored.
Iron supplements are associated with gastrointestinal side effects, including nausea, stomach pain, constipation, or diarrhea. Taking the supplement with a small amount of food can help mitigate stomach upset, although large amounts of food reduce absorption. Stools may also become dark or discolored, which is an expected effect of the iron.
It is important to follow the prescribed dosage, as iron supplements are toxic if taken in excess. An iron overdose is particularly dangerous for children and can lead to severe vomiting, liver damage, and even be fatal. Supplements must be stored securely out of the reach of children. If the low MCHC is the result of chronic blood loss, medical investigation is necessary to treat the underlying source rather than merely supplementing the iron depletion.