Anaemia is a condition where your body doesn’t have enough healthy red blood cells to carry oxygen to all the tissues and organs that need it, leaving you feeling tired, weak, and short of breath in ways that can affect your everyday life.

Understanding Anaemia: A Common Blood Disorder

Anaemia happens when your blood cannot carry enough oxygen throughout your body. This occurs because you either don’t have enough red blood cells (the cells that transport oxygen) or because these cells don’t contain enough hemoglobin, which is the iron-rich protein that actually carries oxygen from your lungs to the rest of your body. When your tissues and organs don’t get the oxygen they need, your body struggles to function normally, and you begin to feel the effects in many different ways.^[1][2]

Think of red blood cells as delivery trucks carrying oxygen packages to every part of your body. When you have anaemia, you either have fewer trucks on the road, or the trucks you have aren’t carrying full loads. Either way, your body’s organs and tissues don’t receive the oxygen supply they need to work properly. This shortage of oxygen is what creates the symptoms people with anaemia experience every day.^[3]

Anaemia is not a single disease but rather a sign that something else is going on in your body. It can develop suddenly or gradually over time, and it can range from mild cases that barely cause symptoms to severe forms that require immediate medical attention. Some types of anaemia last only a short time and can be easily treated, while others are long-term conditions that need ongoing management throughout a person’s life.^[1][3]

How Common Is Anaemia?

Anaemia is the most common blood disorder worldwide, affecting millions of people across all age groups and backgrounds. In the United States alone, approximately three million people live with some form of anaemia. When we look at the global picture, the numbers become even more striking: experts estimate that about one in three people worldwide are affected by this condition.^[2][4]

The condition does not affect everyone equally. According to the World Health Organization, anaemia is a major public health concern that primarily impacts young children, pregnant women, women who have recently given birth, and adolescent girls and menstruating women. Globally, about 40 percent of children aged six months to five years, 37 percent of pregnant women, and 30 percent of women between 15 and 49 years of age are affected by anaemia.^[5]

The burden of anaemia falls most heavily on low- and lower-middle income countries, particularly affecting people living in rural areas, those in poorer households, and individuals who have received no formal education. The WHO Regions of Africa and South-East Asia face the greatest challenges, with an estimated 106 million women and 103 million children affected in Africa, and 244 million women and 83 million children affected in South-East Asia.^[5]

What Causes Anaemia?

Anaemia develops for many different reasons, but all causes fall into three main categories: your body loses too much blood, your body doesn’t produce enough red blood cells, or your body destroys red blood cells faster than it can replace them. Understanding which of these problems is causing your anaemia helps doctors determine the right treatment approach.^[1][8]

Blood loss is one of the most common causes of anaemia. This loss can happen suddenly, such as from a serious injury or during surgery, or it can occur slowly over time. Women who experience heavy menstrual periods often develop anaemia because of the ongoing blood loss each month. Internal bleeding from conditions like stomach ulcers, inflammatory bowel disease, or cancer can also lead to anaemia, sometimes without a person even knowing they are losing blood. Regular use of certain medications, such as aspirin or ibuprofen, can irritate the stomach lining and cause small amounts of bleeding that add up over time.^[1][4]

Poor nutrition is another major cause of anaemia worldwide. Your body needs iron, vitamin B12, and folate to produce healthy red blood cells. When your diet doesn’t provide enough of these nutrients, your body cannot make the red blood cells it needs. Iron deficiency is the most common nutritional cause of anaemia globally. People who follow restrictive diets, have had weight loss surgery, or have conditions that affect nutrient absorption in the intestines are particularly at risk for nutritional anaemia.^[5][7]

Chronic diseases can interfere with red blood cell production in various ways. Kidney disease is a common culprit because healthy kidneys produce a hormone called erythropoietin that signals your bone marrow to make red blood cells. When kidneys are damaged, they produce less of this hormone, leading to anaemia. Inflammatory conditions such as rheumatoid arthritis, inflammatory bowel disease, and cancer can trigger anemia of chronic disease, where inflammation makes it harder for your body to use the iron it has stored. Autoimmune diseases can cause your immune system to mistakenly attack your own red blood cells, destroying them faster than your body can replace them.^[2][4]

Some people inherit genetic conditions that affect their red blood cells from birth. Sickle cell anemia causes red blood cells to become rigid and crescent-shaped rather than round and flexible, leading to blocked blood vessels and destroyed cells. Thalassemia results in the body producing less hemoglobin than normal, creating small red blood cells and anaemia. Other inherited conditions like Fanconi anemia and Diamond-Blackfan anemia affect the bone marrow’s ability to produce red blood cells at all.^[2][4]

Who Is at Higher Risk for Developing Anaemia?

Certain groups of people face a higher likelihood of developing anaemia based on their age, biological sex, health status, and life circumstances. Understanding these risk factors can help people recognize when they need to be especially watchful for symptoms and seek medical attention earlier.

Women of childbearing age face significantly higher risk than men because of menstrual blood loss each month. Those who experience particularly heavy periods lose more blood and therefore more iron, making iron-deficiency anaemia more likely. Pregnancy increases risk even further because a growing baby requires substantial amounts of iron and other nutrients, and the mother’s blood volume expands dramatically. Women who are pregnant or have recently given birth need much more iron than usual, and if they don’t get enough through diet or supplements, anaemia can develop.^[3][5]

Young children, particularly infants and toddlers under two years old, are vulnerable to anaemia during periods of rapid growth when their bodies need extra iron to produce new red blood cells quickly. If their diet doesn’t provide sufficient iron-rich foods, they can easily become anaemic. Adolescents going through growth spurts also need more iron, and teenage girls face the added risk of menstruation beginning.^[5]

Older adults increasingly face anaemia risk as they age. This happens partly because chronic health conditions that can cause anaemia become more common with advancing years, and partly because of changes in diet, medication use, and the body’s ability to absorb nutrients. People with chronic conditions such as kidney disease, cancer, liver disease, thyroid disease, or autoimmune disorders have higher anaemia risk because these illnesses can interfere with red blood cell production or survival.^[2][4]

People who have undergone gastric bypass surgery for weight loss may develop anaemia because the surgical changes to their digestive system can make it difficult to absorb iron and vitamin B12 properly. Those who donate blood frequently, athletes who engage in intense endurance training, and individuals with intestinal disorders like Crohn’s disease or celiac disease that affect nutrient absorption all face elevated risk as well.^[4][7]

Recognizing the Symptoms of Anaemia

The symptoms of anaemia can be subtle at first, especially if the condition develops slowly. Many people with mild anaemia don’t realize anything is wrong because their bodies gradually adjust to having less oxygen available. However, as anaemia worsens, symptoms typically become more noticeable and begin to interfere with daily activities.^[1][2]

Fatigue is the hallmark symptom of anaemia and often the first one people notice. This isn’t ordinary tiredness that improves after a good night’s sleep—it’s a profound exhaustion that makes even simple tasks feel overwhelming. People with anaemia often describe feeling too tired to manage their normal activities, struggling to get through the workday, or needing to rest frequently. This happens because without enough oxygen reaching your muscles and organs, your body has to work much harder to accomplish basic functions.^[2][4]

Weakness accompanies the fatigue, making physical activities more difficult than usual. You might notice that climbing stairs leaves you breathless, carrying groceries feels harder, or you need to sit down more often. Shortness of breath occurs because your body tries to compensate for low oxygen levels by making you breathe faster and deeper. This can happen even during light activity or sometimes while resting.^[1][3]

Your skin may appear paler than normal, or if you have darker skin, the inside of your lower eyelids, gums, or nail beds might look paler or have a yellowish tinge. This paleness occurs because there are fewer red blood cells circulating near the skin’s surface. Some people also notice their hands and feet feel cold because blood flow to the extremities decreases when oxygen is in short supply.^[1][5]

Changes in heart rhythm and function can develop as your heart works harder to pump oxygen-depleted blood throughout your body. You might feel your heart racing, pounding, or beating irregularly (called heart palpitations). Some people experience chest pain, particularly during physical activity. Dizziness, lightheadedness, or feeling like you might faint can occur when your brain doesn’t receive enough oxygen.^[1][2]

Headaches become more frequent for many people with anaemia, again related to insufficient oxygen reaching the brain. You might find it harder to concentrate or remember things. Some people develop a ringing or whooshing sound in their ears called pulsatile tinnitus.^[2][4]

Less common symptoms can include a sore or swollen tongue, cracks at the corners of your mouth, frequent infections because your immune system isn’t working as well, and unusual cravings for non-food items like ice, dirt, or starch (called pica). Your nails might become brittle or develop a spoon-shaped appearance. Hair loss can increase, with more hair coming out when brushing or washing. Some people experience restless legs syndrome, an uncomfortable sensation in the legs accompanied by an irresistible urge to move them.^[1][6]

How Can Anaemia Be Prevented?

While not all forms of anaemia can be prevented—particularly inherited types—many cases can be avoided through attention to diet and lifestyle, along with proper management of underlying health conditions. Prevention strategies focus primarily on ensuring your body has the nutrients it needs to produce healthy red blood cells.

Eating a diet rich in iron is one of the most important prevention steps. Iron comes in two forms in food: heme iron from animal sources and non-heme iron from plant sources. Your body absorbs heme iron more easily, which is found in red meat, poultry, and fish. Plant-based iron sources include beans, lentils, tofu, dark leafy green vegetables like spinach and kale, fortified cereals and breads, and dried fruits such as raisins and apricots. If you eat primarily plant-based foods, you’ll need to consume more of them to get adequate iron since this type is less efficiently absorbed.^[3][9]

Vitamin C significantly improves iron absorption, so pairing iron-rich foods with vitamin C sources makes your meals more effective at preventing anaemia. This means eating foods like citrus fruits, strawberries, tomatoes, bell peppers, or broccoli alongside your iron sources, or drinking orange juice with meals. Some people find that taking iron supplements with vitamin C-rich foods helps their bodies absorb the iron better.^[7]

Getting enough vitamin B12 and folate is equally important for preventing certain types of anaemia. Vitamin B12 is found naturally in animal products including meat, eggs, milk, and cheese. People who follow strict vegetarian or vegan diets may need B12 supplements or fortified foods to meet their needs. Folate is abundant in leafy green vegetables, citrus fruits, beans, and fortified grain products.^[9]

For people at high risk, such as pregnant women, young children, or those with heavy menstrual periods, healthcare providers often recommend iron supplements to prevent anaemia from developing. Pregnant women typically need prenatal vitamins containing iron and folate throughout pregnancy and sometimes for several months after delivery. Women with heavy periods should discuss with their doctor whether iron supplements might be appropriate, or whether investigating the cause of heavy bleeding is needed.^[3]

Managing chronic conditions that can lead to anaemia is another key prevention strategy. If you have kidney disease, inflammatory bowel disease, or other chronic illnesses, working closely with your healthcare team to treat these conditions can help prevent anaemia from developing as a complication. Regular health check-ups and blood tests can catch anaemia early, before symptoms become severe.^[4]

Avoiding excessive use of medications that can cause stomach bleeding, such as aspirin and ibuprofen, helps prevent blood-loss anaemia. If you need these medications regularly, talk to your doctor about ways to protect your stomach lining or alternative pain relief options.^[1]

How the Body Changes with Anaemia: Understanding Pathophysiology

To understand what happens in anaemia, it helps to know how healthy blood normally works. Your bone marrow—the soft, spongy tissue inside your bones—constantly produces new red blood cells to replace old ones that wear out. These red blood cells are filled with hemoglobin, the protein that gives blood its red color and carries oxygen. Each hemoglobin molecule needs iron at its center to bind oxygen. When red blood cells flow through your lungs, the hemoglobin picks up oxygen and then releases it to tissues and organs throughout your body as blood circulates.^[4]

In anaemia, this oxygen delivery system breaks down in one or more ways. When you don’t have enough iron, your bone marrow cannot produce normal amounts of hemoglobin. The red blood cells that do form are smaller than usual and paler because they contain less hemoglobin. These undersized cells cannot carry as much oxygen, so even though you may have a reasonable number of red blood cells, they’re not doing their job effectively. This is what happens in iron-deficiency anaemia, the most common type worldwide.^[3][4]

When vitamin B12 or folate levels are too low, your bone marrow produces red blood cells that are abnormally large and don’t function properly. The cells are also produced in smaller numbers than normal. These oversized cells, called macrocytic red blood cells, have trouble moving through small blood vessels and don’t live as long as normal cells. Without enough B12 or folate, the DNA inside developing red blood cells cannot form correctly, disrupting the entire production process.^[2][7]

In chronic disease, inflammation in the body interferes with iron metabolism. Even when iron stores are adequate, the body cannot access and use the iron properly to make hemoglobin. Inflammatory proteins trap iron in storage sites rather than making it available for red blood cell production. Additionally, inflammatory conditions can suppress the bone marrow’s ability to produce red blood cells and may shorten the lifespan of existing cells.^[2]

Damaged kidneys cannot produce enough erythropoietin, the hormone that signals bone marrow to make red blood cells. Without this chemical messenger, production slows dramatically. This is why people with kidney disease commonly develop anaemia that worsens as kidney function declines.^[4]

In hemolytic anaemias, something causes red blood cells to be destroyed faster than the bone marrow can replace them. This might happen because the cells themselves are defective (as in sickle cell disease or thalassemia), or because the immune system mistakenly identifies healthy red blood cells as foreign and attacks them. As cells break apart, hemoglobin is released into the bloodstream and can cause jaundice (yellowing of skin and eyes) as the body struggles to process the breakdown products.^[2][4]

When anaemia develops, your body tries to compensate in several ways. Your heart beats faster and more forcefully to circulate oxygen-poor blood more quickly. Your breathing rate increases to bring more oxygen into your lungs. Blood flow is redirected away from less critical areas like the skin and extremities toward vital organs like the brain and heart. These compensatory mechanisms are what create many of the symptoms people experience: the rapid heartbeat, shortness of breath, pale skin, and cold hands and feet.^[1]

Over time, if anaemia is severe or long-lasting, these compensatory changes can damage the cardiovascular system. The heart becomes overworked from constantly pumping harder and faster, potentially leading to heart enlargement, heart failure, or irregular heart rhythms. This is why treating anaemia is important even when symptoms seem manageable—the long-term stress on the heart can have serious consequences.^[1]