Which Deficiency Disease Causes Tiredness and Shortness of Breath?

January 10, 2026 •

4 min read

According to the World Health Organization (WHO), anemia affects approximately 2 billion people globally, often causing widespread but frequently overlooked symptoms like persistent tiredness and shortness of breath. This article delves into the primary deficiency diseases responsible for these common symptoms and how they impact your body's ability to transport oxygen.

Quick Summary

The primary deficiency disease causing tiredness and shortness of breath is anemia, most commonly from iron, vitamin B12, or folate deficiency, which impairs the blood's capacity to carry oxygen throughout the body.

Key Points

Anemia is the primary deficiency cause: Conditions like iron, vitamin B12, or folate deficiency can lead to anemia, which is the root cause of tiredness and shortness of breath.
Hemoglobin is affected: These deficiencies interfere with the production or function of hemoglobin, the protein responsible for carrying oxygen in the blood.
Iron deficiency is most common: Iron deficiency is the most widespread nutritional cause of anemia, affecting oxygen transport and leading to fatigue.
B12 deficiency can cause nerve damage: A vitamin B12 deficiency can result in megaloblastic anemia and may also cause neurological issues like numbness or memory loss.
Folate deficiency has a rapid onset: Because the body doesn't store folate for long, a deficiency can occur relatively quickly, causing anemia symptoms.
Diagnosis requires a blood test: A complete blood count (CBC) is typically used to diagnose anemia and identify the specific deficiency.
Treatment depends on the cause: Treatment ranges from dietary changes and oral supplements to injections for issues like pernicious anemia.

Understanding the Link Between Anemia and Nutrient Deficiencies

Anemia is not a single disease but a condition characterized by a lower-than-normal number of red blood cells or a reduced hemoglobin concentration. Hemoglobin is an iron-rich protein that enables red blood cells to carry oxygen from the lungs to the rest of the body. When there isn't enough hemoglobin, or if the red blood cells are abnormal, the body's tissues don't receive adequate oxygen, leading to the hallmark symptoms of fatigue and shortness of breath. Several nutritional deficiencies are major culprits behind anemia, primarily involving a lack of iron, vitamin B12, or folate.

Iron Deficiency Anemia: The Most Common Culprit

Iron deficiency is the most widespread nutritional cause of anemia worldwide. The body uses iron to produce hemoglobin, and a shortage of iron directly reduces the amount of oxygen your blood can transport. The resulting lack of oxygen to muscles and tissues is what makes you feel tired and weak, and prompts your body to breathe faster to compensate, causing shortness of breath.

Common causes of iron deficiency include:

Dietary insufficiency: Not consuming enough iron-rich foods, especially common in vegetarians and vegans.
Blood loss: This is a major factor, particularly for women with heavy menstrual periods or individuals with internal bleeding from issues like peptic ulcers or gastrointestinal polyps.
Impaired absorption: Conditions like celiac disease or surgeries involving the intestines can prevent the body from absorbing iron properly.
Pregnancy: Increased blood volume and demand for iron from the developing fetus can lead to iron deficiency.

Vitamin B12 Deficiency: Neurological and Physical Symptoms

Vitamin B12 is essential for the formation of healthy red blood cells and for proper nerve function. A deficiency can lead to megaloblastic anemia, where the red blood cells become abnormally large and are unable to function correctly. In addition to tiredness and shortness of breath, a B12 deficiency can cause neurological problems, such as tingling in the hands and feet, memory issues, and balance problems.

Key factors contributing to B12 deficiency:

Pernicious anemia: An autoimmune condition where the body's immune system attacks cells in the stomach that produce intrinsic factor, a protein necessary for B12 absorption.
Diet: Vegans and strict vegetarians are at risk, as B12 is primarily found in animal products like meat, eggs, and dairy.
Digestive conditions and surgery: Crohn's disease, celiac disease, or gastric bypass surgery can impair B12 absorption.
Aging: Older adults often have lower stomach acid, making B12 absorption more difficult.

Folate Deficiency: Often Overlooked

Folate, or vitamin B9, works with vitamin B12 to produce red blood cells and synthesize DNA. A deficiency also causes megaloblastic anemia, with symptoms including fatigue, weakness, and shortness of breath. Unlike B12, the body's folate stores are depleted much faster.

Causes of folate deficiency include:

Poor diet: Not eating enough folate-rich foods like leafy greens, citrus fruits, and legumes.
Alcohol consumption: Excessive alcohol use interferes with folate absorption and metabolism.
Increased requirements: Pregnancy, certain blood disorders, and some cancers increase the body's demand for folate.

Comparison of Deficiency Anemias


Feature	Iron Deficiency Anemia	Vitamin B12 Deficiency Anemia	Folate Deficiency Anemia
Primary Cause	Low iron intake, blood loss, poor absorption	Lack of intrinsic factor (pernicious anemia), vegan diet, poor absorption	Poor diet, alcoholism, increased physiological needs
Associated Red Blood Cell Size	Smaller than normal (microcytic)	Abnormally large (megaloblastic)	Abnormally large (megaloblastic)
Key Symptoms	Fatigue, shortness of breath, pale skin, cold hands/feet, brittle nails	Fatigue, shortness of breath, pale/yellowish skin, tingling/numbness, memory problems	Fatigue, shortness of breath, pale skin, irritability, diarrhea
Neurological Symptoms	Rare	Common; pins and needles, memory loss, balance issues	Rare; can include irritability, confusion
Treatment	Iron supplements, dietary changes, addressing blood loss	B12 injections or high-dose supplements	Folic acid supplements, dietary adjustments

Diagnosis and Management

If you experience persistent tiredness and shortness of breath, it is crucial to consult a healthcare professional. A simple blood test, such as a complete blood count (CBC), can determine if you have anemia and what might be causing it. Based on the results, your doctor can recommend the appropriate course of action, which may include dietary changes, supplements, or further investigation to address an underlying condition. For example, chronic untreated anemia can lead to severe health issues, including heart problems, so early diagnosis and treatment are vital.

The Path to Recovery

For many, addressing the underlying nutritional deficiency is the key to recovery. Supplementation, when necessary and supervised by a doctor, can quickly restore levels of missing nutrients. However, long-term success often relies on sustainable dietary habits and managing any underlying health issues. For instance, incorporating a variety of iron-rich foods, like lean meat, lentils, and spinach, alongside vitamin C sources, can enhance iron absorption. Similarly, for those with B12 deficiency due to dietary choices, fortified foods or consistent supplementation are necessary. Awareness and proactivity are the best tools for managing these conditions and reclaiming your energy.

This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Frequently Asked Questions

When iron levels are low, the body cannot produce enough hemoglobin, the protein in red blood cells that carries oxygen. With less oxygen being delivered to the body's tissues and muscles, your breathing rate increases as your body tries to compensate, leading to shortness of breath.

Yes, a vitamin B12 deficiency can lead to megaloblastic anemia, a condition where red blood cells are abnormally large and dysfunctional. This reduces the blood's ability to carry oxygen, causing symptoms like extreme fatigue and shortness of breath.

The fastest treatment for severe vitamin B12 deficiency is often vitamin B12 injections, as they bypass any absorption issues in the gut. For less severe cases, high-dose oral supplements can also be effective.

For iron deficiency, consume iron-rich foods like lean red meat, lentils, and leafy greens, along with vitamin C sources to enhance absorption. For B12, incorporate animal products or fortified cereals. For folate, eat leafy greens, legumes, and citrus fruits.

Yes, a folate deficiency can lead to megaloblastic anemia, where the body produces fewer, oversized red blood cells. This impairs oxygen delivery and can cause symptoms like shortness of breath.

Pernicious anemia can cause irreversible nerve damage and neurological problems if left untreated. Early diagnosis and treatment with B12 supplementation can prevent these serious, long-term complications.

Iron deficiency is a lack of the mineral iron in the body. Anemia is a condition caused by a lack of healthy red blood cells or hemoglobin. While iron deficiency is a common cause of anemia, a person can have iron deficiency without being anemic, especially in the early stages.