Both red and white blood cells are produced in your bone marrow, and the raw materials they need come largely from your diet. Red blood cells carry oxygen throughout your body, while white blood cells form the backbone of your immune system. When counts drop below normal, the cause is often a nutritional deficiency, though chronic illness, medications, and bone marrow problems can also play a role. The good news: for many people, targeted dietary changes and lifestyle shifts can meaningfully move the needle.
Normal red blood cell counts range from 4.0 to 5.4 million cells per microliter for women and 4.5 to 6.1 million for men. White blood cells normally fall between 4,000 and 10,000 cells per microliter. If your numbers are outside those ranges, the strategies below can help, but the first step is understanding why they’re low.
Why Blood Cell Counts Drop
Iron deficiency is the most common cause of anemia worldwide, and vitamin B12 deficiency is the most common cause of a specific type called megaloblastic anemia, where red blood cells grow abnormally large and can’t function properly. Folate deficiency causes a similar problem, though it’s become less common since many countries began fortifying flour, bread, pasta, and cereal with folic acid.
Less obvious deficiencies matter too. Low copper levels can cause both anemia and a drop in a key type of white blood cell called neutrophils. Vitamin E deficiency can trigger a form of anemia where red blood cells break down too quickly. And zinc deficiency reduces the activity of natural killer cells and other immune cells that destroy viruses, bacteria, and tumor cells. People most at risk for these deficiencies include those with gut malabsorption conditions, those on highly restrictive diets (including vegan diets without proper supplementation), people with food allergies that limit dietary variety, and those with chronic alcohol use.
Key Nutrients for Red Blood Cells
Iron
Iron is the central building block of hemoglobin, the protein inside red blood cells that carries oxygen. Without enough iron, your body produces smaller, less effective red blood cells. The richest dietary sources are red meat, organ meats, shellfish, and dark poultry meat. Plant sources include lentils, beans, spinach, and fortified cereals, though your body absorbs iron from plant foods less efficiently. Pairing plant-based iron with vitamin C (a squeeze of lemon on your lentils, for example) significantly improves absorption.
Vitamin B12
B12 is essential for your bone marrow to produce red blood cells at the correct size and rate. It’s found almost exclusively in animal products: red meat, fish, poultry, eggs, milk, and other dairy. If you eat little or no animal food, fortified options like certain breakfast cereals, nutritional yeast, and plant milks can fill the gap. People over 50 and those with absorption issues often need supplements, typically in the range of 500 to 2,000 micrograms daily by mouth for a dietary deficiency.
Folate
Folate works alongside B12 in red blood cell production. Dark green leafy vegetables, peas, beans, legumes, and citrus fruits are the best natural sources. Many breads, flours, pastas, and cereals are also fortified with folic acid. For people with a confirmed deficiency, treatment doses typically range from 1 to 5 milligrams daily for one to four months.
Red blood cells live about 120 days in circulation before being replaced, so don’t expect overnight results. After correcting a deficiency, it generally takes several weeks to a few months before blood tests show meaningful improvement.
Key Nutrients for White Blood Cells
Vitamin C
Vitamin C does more than support iron absorption. High doses enhance the activity of natural killer cells, a critical part of your innate immune defense. Citrus fruits, bell peppers, strawberries, broccoli, and kiwi are all rich sources. Most people can get adequate amounts from a varied diet that includes several servings of fruits and vegetables daily.
Vitamin D
Vitamin D plays a direct regulatory role in immune function. It modulates how T cells, B cells, and other immune cells behave, and it promotes the activity of regulatory T cells that help keep inflammation in check. Sunlight exposure triggers vitamin D production in your skin, but dietary sources include fatty fish, egg yolks, fortified milk, and fortified cereals. Many people, particularly those in northern latitudes or with darker skin, are deficient without knowing it.
Zinc
Zinc has regulatory effects on T cell growth and activity. When zinc levels are low, both natural killer cells and the immune cells that directly destroy infected or abnormal cells become less effective. Oysters are the single richest source, but red meat, poultry, beans, nuts, and whole grains all contribute. One important caution: excessive zinc supplementation can actually cause copper deficiency, which itself leads to low white blood cell counts. More is not better here.
The Role of Protein
Your bone marrow needs a steady supply of amino acids to manufacture both red and white blood cells. Protein is the raw material. Malnutrition, and specifically inadequate protein intake, is associated with delays in blood cell production and recovery. Research on patients undergoing bone marrow transplants has found that those with lower protein intake had significantly worse outcomes in rebuilding their blood cell counts. While most healthy adults eating a balanced diet get sufficient protein, people recovering from illness, surgery, or chemotherapy may benefit from aiming for around 1.5 grams of protein per kilogram of body weight daily. Good sources include lean meats, fish, eggs, dairy, beans, lentils, and tofu.
Exercise and Blood Cell Production
Aerobic exercise stimulates your body to produce more red blood cells over time. The mechanism works through oxygen demand: when your muscles consume more oxygen during sustained activity, your kidneys respond by releasing a hormone called erythropoietin, which signals your bone marrow to ramp up red blood cell production. Regular cardio exercise like running, cycling, or swimming, maintained over weeks and months, gradually increases your total red blood cell volume.
This effect is amplified at higher altitudes. When you’re above roughly 1,600 meters (about 5,200 feet), the lower oxygen pressure in the air triggers a stronger erythropoietin response. Athletes have long used altitude training for this reason. During the first phase of acclimatization, the hormone surges. During the second phase, after several weeks of continuous exposure, red blood cell volume measurably increases. You don’t need to move to the mountains, but if you live at or visit higher elevations, the effect is real and well-documented.
For white blood cells, moderate exercise supports healthy immune function. Intense, prolonged exercise can temporarily suppress immune activity, so consistency at a moderate level tends to be more beneficial than occasional extreme efforts.
Sleep, Stress, and Recovery
Chronic sleep deprivation and sustained psychological stress both suppress bone marrow activity. Stress hormones, particularly cortisol, can reduce white blood cell production and alter how immune cells function when they are produced. Getting seven to nine hours of sleep per night and managing chronic stress through whatever works for you (physical activity, social connection, relaxation techniques) creates the baseline conditions your bone marrow needs to work efficiently. These aren’t minor lifestyle add-ons. For someone with borderline counts, poor sleep and high stress can be the difference between normal and low.
When Diet Alone Isn’t Enough
If your counts remain low despite eating a nutrient-rich diet, the issue may not be intake but absorption. Conditions like celiac disease, Crohn’s disease, short gut syndrome, and even chronic use of certain medications (particularly acid-reducing drugs) can prevent your gut from absorbing B12, iron, or folate effectively. In these cases, higher-dose supplements or injections may be necessary. For B12, people with impaired absorption often need 1,000 to 2,000 micrograms daily by mouth, or monthly injections of 1,000 micrograms.
Persistently low white blood cell counts that don’t respond to nutritional changes can signal bone marrow disorders, autoimmune conditions, or medication side effects. Similarly, anemia that doesn’t improve with iron or B12 supplementation after two to three months warrants further investigation. Blood cell production is a complex process, and while nutrition and lifestyle form the foundation, some causes require targeted medical treatment.