Anemia, a condition where the number of red blood cells or hemoglobin is lower than normal, is a major global health concern. Hemoglobin plays a vital role in transporting oxygen throughout the body. When hemoglobin levels drop, the body struggles to deliver oxygen to vital organs, leading to symptoms like fatigue, weakness, dizziness, and shortness of breath.

Anemia affects millions worldwide, especially vulnerable groups like young children, menstruating girls, and pregnant women. In India, the situation is alarming. The National Family Health Survey (NFHS-5) reports that 67% of children aged 6–59 months and 57% of women aged 15–49 years are anemic. Pregnant women and adolescent girls are at higher risk, with anemia affecting 52.2% and 59.1%, respectively.

Anemia has multiple causes, including nutrient deficiencies, infections, chronic diseases, and inherited disorders. Iron deficiency is the most common cause, but deficiencies in folate, vitamin B12, and vitamin A also contribute. These deficiencies can severely affect cognitive function, particularly in older adults. Here are some key types of anemia linked to cognitive decline:

• Iron Deficiency Anemia
  
  This is the most common form of anemia and occurs when the body lacks enough iron to produce hemoglobin. Iron is essential for brain health. Studies show that people with iron deficiency are at a higher risk of developing mild cognitive impairment (MCI) and dementia, including Alzheimer's disease

• Vitamin B12 Deficiency Anemia
  
  Vitamin B12 supports nerve and red blood cell health. A deficiency can lead to neurological problems and cognitive decline. Symptoms like memory loss and confusion may worsen without proper treatment.

• Folate Deficiency Anemia
  
  Folate is important for DNA synthesis and red blood cell production. A lack of folate can lead to anemia and has been linked to cognitive decline and dementia. Like vitamin B12 deficiency, folate deficiency can cause neurological symptoms that affect cognitive function.

Impact of Anemia on Cognitive Function

To understand how anemia affects cognitive function, it's important to first define what cognitive function is. Cognitive function refers to mental processes such as memory, attention, learning, reasoning, and problem-solving. These abilities are essential for daily tasks and overall well-being. When anemia becomes severe, it can significantly impact these cognitive abilities.

Anemia increases the risk of cognitive impairments, including mild cognitive impairment (MCI) and dementia. Studies have shown that individuals with anemia are almost 40% more likely to experience cognitive decline compared to those without the condition. This is mainly due to chronic brain hypoxia, which occurs when low hemoglobin levels reduce oxygen delivery to the brain. Over time, this oxygen deficiency can lead to structural changes in the brain, further affecting cognitive function.

Here's How Anemia Affects Cognitive Functions

Decline in Cognitive Performance:

Individuals with hemoglobin levels below 10 g/dL often show a significant decline in cognitive performance, scoring much lower than their peers with milder anemia. This drop in performance indicates a clear impact on brain function.

Increased Risk of Mild Cognitive Impairment (MCI):

Anemia is closely linked to an increased risk of developing MCI, a condition where noticeable memory and thinking skills decline before the onset of dementia. Those with anemia are almost twice as likely to develop MCI compared to non-anemic individuals.

Accelerated Cognitive Decline:

Anemia has been found to accelerate cognitive decline. A study indicated that anemia could bring forward the onset of dementia by about 1.53 years. This highlights how persistent anemia can significantly contribute to cognitive deterioration.

Mechanisms Behind Cognitive Impairment:

The primary mechanism through which anemia affects cognitive function is chronic hypoxia, where the brain does not receive enough oxygen due to low hemoglobin levels. This oxygen deficiency can cause ischemia (insufficient blood flow) and neurovascular damage, leading to cognitive dysfunction. As anemia worsens, the brain’s compensatory mechanisms fail, further exacerbating cognitive decline.

Impact on Cognitive Domains:

Anemia predominantly affects cognitive functions such as processing speed and accuracy in tasks. Severe anemia, due to the lack of oxygen, can lead to significant cognitive dysfunction, while milder forms may only cause minimal impairment due to the body's compensatory efforts.

Expert Opinion:

Dr. Arindam Biswas, an Internal Medicine Specialist, explains, "Anemia weakens the body by reducing hemoglobin levels, responsible for carrying oxygen. This lack of oxygen leads to cognitive decline, causing symptoms such as sleep disturbances, forgetfulness, and confusion, especially in cases of severe anemia."

He further adds, "In rural areas, iron deficiency anemia is prevalent, often caused by malnutrition, poverty, and worm infestations. Women are especially vulnerable due to menstrual blood loss. In contrast, urban areas tend to experience anemia due to blood disorders like thalassemia, autoimmune conditions such as lupus (SLE), or bone marrow issues like cancers. These factors also contribute to cognitive impairment."

Populations Most Vulnerable to Anemia's Cognitive Effects

Older Adults: Anemia becomes more common with age. Older adults with anemia are at a higher risk of cognitive decline and dementia.

Children and Adolescents: Young people, particularly those with iron deficiency, may face difficulties in learning and development due to impaired cognitive function.

Pregnant Women: Pregnancy increases nutritional needs. Iron deficiency anemia (IDA) during pregnancy can impact both maternal health and foetal development.

Potential for Intervention

The good news is that anemia is treatable. Many causes, such as iron deficiency, can be addressed effectively. Here are some key interventions:

Iron Supplementation: Studies show that iron supplementation can improve cognitive function in individuals with iron deficiency anemia. Early treatment is vital to prevent long-term effects on brain health.

Awareness and Screening: Raising awareness about anemia's signs and promoting regular screening can help identify individuals at risk. Early detection allows for timely intervention and better outcomes.

Even Anemia Can Affect Mental Health

Anemia can have a significant impact on mental health also, especially in relation to conditions like depression and anxiety. According to renowned psychiatrist Dr. Rudraprosad Chakraborty, "Anemia affects a person's overall well-being. When someone is anemic, they are not just physically unwell but also at risk for mental health issues. Iron is a vital component of the body, and in cases of iron deficiency anemia, individuals often experience sleep problems, poor oxygen transport, low energy, and a weakened immune system. While anemia may not directly cause mental health disorders, it plays a critical indirect role in influencing mental well-being."

Conclusion

Anemia is more than just a physical condition. It can significantly impact cognitive function and mental health. The lack of adequate oxygen delivery to the brain can lead to cognitive decline and behavioural changes. Early detection and treatment of anemia are crucial for preventing these effects. With proper intervention, such as iron supplementation and awareness, the risks can be managed, improving overall health and well-being. By addressing anemia early, we can not only protect physical health but also support mental clarity and emotional stability, leading to a better quality of life for affected individuals.