What does lack of DHA do? Understanding the Health Consequences

December 10, 2025 •

4 min read

DHA is a critical omega-3 fatty acid, and a low intake can significantly impact various bodily functions, from cellular communication to brain health. Understanding what does lack of DHA do is crucial for maintaining overall well-being, especially since your body cannot produce it in sufficient amounts.

Quick Summary

DHA deficiency can lead to impaired brain function, poor vision, skin problems, and mood swings. It negatively impacts all life stages, from fetal development to cognitive aging.

Key Points

Brain Function: DHA deficiency can impair cognitive performance, leading to memory issues, slower reaction times, and increased risk of cognitive decline with age.
Mental Health: Low DHA is associated with a higher risk of mood disorders, including depression, anxiety, and behavioral problems like ADHD in children.
Visual Impairment: As a key component of the retina, a lack of DHA can cause vision problems, such as impaired visual acuity and dry eye syndrome.
Developmental Issues: In pregnant women, DHA deficiency increases the risk of premature birth and postpartum depression, and negatively impacts the fetal brain and eye development.
Physical Symptoms: Signs of a systemic DHA shortage can include dry, flaky skin, brittle hair, joint pain due to increased inflammation, and a weakened immune system.
Dietary Dependency: Since the body cannot produce adequate DHA, regular intake from sources like fatty fish, algae, or fortified foods is essential to maintain optimal levels.

The Critical Role of DHA in the Body

DHA, or docosahexaenoic acid, is a long-chain polyunsaturated omega-3 fatty acid vital for cell membrane structure, especially in the brain and retina. It aids efficient nerve cell communication. Since the body doesn't produce enough, dietary intake from sources like fatty fish or supplements is essential. Deficiency affects cell function, particularly in the nervous system.

How DHA Deficiency Impacts Brain Function

Insufficient DHA affects brain health across all ages, potentially causing cognitive decline in adults.

Cognitive Decline and Memory Problems

Low DHA is linked to cognitive issues, including memory complaints. Supplementation can improve memory and learning in those with mild cognitive impairment and young adults with low intake. Lower DHA levels in older adults are associated with an increased risk of dementia and Alzheimer's disease.

Neurotransmitter Dysregulation

DHA deficiency affects neurotransmitters crucial for mood and mental function, impacting serotonin and dopamine signaling. This contributes to mood and behavioral changes linked to low DHA.

Effects of DHA Deficiency on Mental Health

Low DHA significantly impacts mental health, playing a role in mood and behavioral disorders.

Mood Swings, Anxiety, and Depression

Low omega-3 levels are associated with increased risk of depression and anxiety. Higher fish consumption correlates with lower depression rates. Depressed individuals often have lower EPA and DHA levels, and supplementation may improve symptoms.

ADHD and Other Behavioral Issues

In children, DHA deficiency is linked to behavioral and learning difficulties, with children with ADHD often having lower DHA levels. Supplementation may improve attention and reduce aggression. Deficiency during brain maturation can increase anxiety risk in adulthood.

The Impact of DHA Deficiency During Pregnancy and Infancy

Critical for Fetal and Infant Development

DHA is crucial for fetal brain and retina development, especially in the third trimester. Fetal DHA depends entirely on maternal intake. Low maternal DHA is linked to poor visual and neural development and learning issues in the child. Infant DHA comes through breast milk, and supplementation can improve vision and problem-solving. Premature infants are particularly vulnerable.

Maternal Health Concerns

Low DHA in pregnant women is associated with increased risk of premature birth and postpartum depression. Adequate intake benefits both mother and child.

Visual Problems Linked to Low DHA Levels

As a major retinal component, DHA deficiency affects eye health.

Poor Eyesight and Retinal Dysfunction

Low DHA can impair visual acuity and retinal function. The retina uses DHA to activate rhodopsin, essential for receiving images. Deficiency can slow this process, causing visual problems, particularly in children.

Dry Eye Syndrome

DHA helps maintain eye moisture. Low omega-3 intake is linked to dry eye syndrome, and supplementation can improve symptoms.

Systemic Consequences of DHA Depletion

DHA deficiency impacts beyond the brain and eyes, affecting other body systems.

Skin and Hair Issues

Omega-3s maintain skin health, reducing inflammation and promoting hydration. Deficiency symptoms include dry, flaky skin, dermatitis, eczema, and brittle hair. EPA may protect against skin aging and acne.

Cardiovascular and Inflammatory Conditions

DHA and other omega-3s have anti-inflammatory properties. Chronic inflammation contributes to heart disease and arthritis. Low DHA is linked to increased heart disease risk, higher triglycerides, and blood pressure. It can also worsen inflammatory conditions like arthritis.

DHA vs. Other Omega-3s: A Comparison

Comparing DHA with other omega-3s like EPA and ALA clarifies the impact of DHA deficiency.


Feature	DHA (Docosahexaenoic Acid)	EPA (Eicosapentaenoic Acid)	ALA (Alpha-Linolenic Acid)
Primary Role	Major structural component of brain and retina	Reduces inflammation, supports cardiovascular health	Essential fatty acid, converted to EPA/DHA
Best Food Sources	Fatty fish (salmon, mackerel), algae	Fatty fish, algae	Flaxseed, walnuts, chia seeds
Conversion Rate	Very limited from ALA	Limited from ALA	Not converted from others
Deficiency Impact	Impaired brain function, visual problems	Increased inflammation, mood issues	Broader omega-3 deficiency

Addressing a DHA Deficiency

Preventing or correcting DHA deficiency involves diet and potential supplementation. Most adults need 250-500 mg of EPA and DHA daily.

Dietary Sources of DHA

Fatty Fish: Excellent sources include salmon, mackerel, sardines, herring, and tuna.
Algae: Algae-based supplements provide a vegan source of DHA.
Fortified Foods: Some products are fortified with DHA.

Considerations for High-Risk Groups

Pregnancy and Breastfeeding: At least 200 mg of DHA daily is often recommended.
Vegetarians and Vegans: Algae oil supplementation is often necessary due to low ALA conversion.
Memory or Cognitive Issues: Higher doses (500-1,700 mg DHA daily) may help mild memory complaints.

Conclusion: The Importance of Sufficient DHA

In conclusion, a lack of DHA can cause widespread issues affecting brain function, mental health, vision, and physical well-being. From developmental problems in infants to cognitive decline in adults, the consequences highlight the importance of this nutrient. Adequate intake through diet (fatty fish) or supplements (algae oil) is crucial for preventing these effects and supporting health throughout life. Prioritizing DHA protects vital organ systems. For more on omega-3s, see the National Institutes of Health's fact sheet.

Frequently Asked Questions

Symptoms can include cognitive issues such as poor memory and concentration, mood swings, dry and flaky skin, brittle nails, dry eyes, and fatigue. Some people may also experience increased joint pain and inflammation.

A lack of DHA, particularly during the third trimester and first year of life, can lead to impaired neural and visual development. It is crucial for building the structural components of the brain and retina.

Yes, low DHA levels are associated with a higher risk of depression and anxiety. Sufficient DHA is important for maintaining membrane fluidity in the brain, which affects neurotransmitter function, including serotonin and dopamine signaling.

Absolutely. DHA is a major structural component of the retina, and insufficient levels can lead to poor visual acuity, retinal dysfunction, and dry eyes.

The best sources are fatty fish like salmon, mackerel, and sardines. For vegetarians and vegans, algae oil or algae-based supplements are an excellent alternative.

For pregnant women, a DHA deficiency can increase the risk of premature birth and postpartum depression. It can also negatively affect the unborn baby's brain and eye development.

Yes. While plant-based omega-3 (ALA) can be converted to DHA, the conversion rate is very low. Vegetarians and vegans should consider algae-based DHA supplements to ensure adequate intake.

DHA deficiency can contribute to heart disease risk factors by increasing blood triglycerides and potentially raising blood pressure. Its anti-inflammatory properties are also reduced, which can affect heart health.