Raising your red blood cell (RBC) count comes down to giving your body the raw materials it needs to build new cells, removing habits that destroy them, and staying active enough to signal your bone marrow to keep producing. Normal RBC counts range from 4.7 to 6.1 million cells per microliter in men and 4.2 to 5.4 million in women. If your levels fall below that range, the cause is almost always a nutrient deficiency, a chronic condition, or something suppressing your bone marrow. Here’s how to address each one.
Iron: The Most Common Missing Piece
Iron is the central atom in hemoglobin, the protein inside every red blood cell that carries oxygen. When iron is low, your bone marrow can’t build enough functional RBCs, and the ones it does produce are often smaller and paler than normal. This is iron deficiency anemia, the most common type worldwide.
Not all dietary iron is created equal. The iron in animal foods (called heme iron) is absorbed at roughly 25%, while the iron in plant foods (non-heme iron) is absorbed at 17% or less. Overall, people who eat meat absorb about 14% to 18% of the iron in their diet, while people eating exclusively plant-based diets absorb closer to 5% to 12%. That gap matters if you’re trying to rebuild depleted stores.
The richest heme iron sources are red meat, darker cuts of poultry like thighs and drumsticks, fish, and shellfish. For non-heme iron, focus on legumes, dark leafy greens, nuts, seeds, whole grains, and dried fruits. Eggs are an animal product but contain only non-heme iron. Many breads, cereals, and nutritional drinks are also fortified with iron.
To get more from plant-based iron, pair it with vitamin C at the same meal. Adding citrus fruits, bell peppers, or tomatoes to iron-rich meals helps convert non-heme iron into a form your gut absorbs more readily. On the flip side, calcium, tannins in tea and coffee, and phytates in whole grains can reduce absorption when consumed at the same time as iron-rich foods. Spacing these out can make a noticeable difference over weeks.
B12 and Folate Keep Cells Dividing
Red blood cells are produced through rapid cell division in your bone marrow. That process requires both vitamin B12 and folate to build DNA correctly. When either nutrient is deficient, the precursor cells can’t divide properly. Instead of producing normal-sized RBCs, the marrow generates oversized, immature cells called megaloblasts that don’t function well and die prematurely. The result is a type of anemia where your RBC count drops even though your body is trying to make new cells.
B12 is found almost exclusively in animal products: meat, fish, dairy, and eggs. Vegans and older adults (who often absorb B12 less efficiently) are at the highest risk of deficiency. Folate is abundant in dark leafy greens, beans, lentils, and fortified grains. If blood work shows your RBCs are abnormally large alongside a low count, a B12 or folate deficiency is one of the first things to investigate.
Copper’s Supporting Role
Copper is an essential trace mineral that works alongside iron in red blood cell production. It helps with iron transport and metabolism, and it’s required for the maturation of both red and white blood cells. A protein called ceruloplasmin carries copper through the blood and also participates in mobilizing iron so it can be used for hemoglobin synthesis. Without adequate copper, iron can accumulate in tissues without ever reaching the bone marrow where it’s needed.
Good sources include shellfish (especially oysters), organ meats, nuts, seeds, dark chocolate, and whole grains. Copper deficiency is uncommon in people eating a varied diet, but it can occur with long-term zinc supplementation, since zinc and copper compete for absorption.
Exercise Signals Your Body to Make More
Regular aerobic exercise increases total red blood cell mass over time, though the exact signaling pathways are still being studied. The leading theory involves your kidneys. During exercise, blood flow shifts away from the kidney cortex toward working muscles, which may create a temporary drop in oxygen levels around the kidney cells that produce erythropoietin (EPO), the hormone that tells bone marrow to ramp up RBC production.
Exercise also triggers a cascade of other hormones that support red blood cell production. Endurance and resistance training cause temporary increases in testosterone in both men and women, and testosterone directly stimulates EPO release and bone marrow activity. Stress hormones released during exercise promote the release of young red blood cells from the marrow into circulation. Growth hormone and insulin-like growth factors, both of which rise during exercise, also stimulate the process.
You don’t need extreme training to benefit. Consistent moderate aerobic activity, like brisk walking, cycling, or swimming several times a week, is enough to nudge your body toward producing more RBCs over a period of weeks.
How Alcohol Damages Red Blood Cells
Heavy alcohol consumption attacks red blood cell production from multiple angles. Chronic drinking reduces the number of blood cell precursors in the bone marrow and causes structural abnormalities in the cells that remain. Within five to seven days of sustained heavy drinking, large vacuoles (essentially holes) appear inside early RBC precursor cells, a visible sign of toxic damage.
Alcohol also interferes with a key enzyme involved in hemoglobin synthesis, which can lead to a specific type of anemia where iron gets trapped inside developing red blood cells instead of being incorporated into hemoglobin. On top of that, heavy drinking depletes folate, which spirals into the megaloblastic anemia described above.
Even the red blood cells that do make it into circulation can be deformed. Alcohol-related changes produce cells with abnormal membranes: some take on a mouth-like shape that gets them trapped and destroyed in the spleen, while others develop spike-like protrusions from excess cholesterol in their membranes. Heavy drinking can also deplete phosphate levels so severely that RBCs become rigid, fragile, and prone to premature destruction. Reducing or eliminating alcohol is one of the most impactful single changes you can make if your RBC count is low.
The Kidney Connection
Your kidneys are the control center for red blood cell production. Specialized cells in the kidney cortex produce the vast majority of erythropoietin in adults. When these cells sense low oxygen levels in the blood, they release EPO, which travels to the bone marrow and triggers the division and maturation of stem cells into new red blood cells.
This is why chronic kidney disease so frequently causes anemia. Damaged kidneys produce less EPO, and without that hormonal signal, the bone marrow slows production regardless of how much iron or B12 you’re consuming. People with kidney disease often need synthetic versions of EPO to maintain adequate RBC levels. If your RBC count is persistently low despite good nutrition and no obvious bleeding, kidney function is worth evaluating.
Altitude and Oxygen Exposure
Living at or visiting high altitude naturally raises your red blood cell count. The lower oxygen pressure at elevation triggers a sustained increase in EPO production, and your hematocrit (the proportion of blood volume occupied by red blood cells) typically reaches a moderately elevated steady state after a few weeks of exposure. It stays stable for as long as you remain at altitude. This is the same mechanism that endurance athletes exploit with altitude training camps.
What Counts as Anemia
The World Health Organization defines anemia as hemoglobin below 13 g/dL in men and postmenopausal women, and below 12 g/dL in premenopausal women. Some researchers have proposed slightly higher thresholds, particularly for younger men, where hemoglobin below 13.7 g/dL may already reflect a deficit. If your RBC count is low but your hemoglobin is borderline, you may be in the early stages of a deficiency that hasn’t yet crossed the clinical threshold. Tracking both numbers over time gives a clearer picture than a single blood draw.
The type of anemia matters for treatment. Small, pale red blood cells point toward iron deficiency. Large, immature cells suggest B12 or folate problems. A low count with normal-looking cells may indicate kidney issues, chronic disease, or bone marrow suppression. Knowing which pattern your blood work shows helps you target the right intervention rather than guessing.