Nutrition - DHA for brain function

Mar 2014   DHA and brain
DHA (docosahexaenoic acid) is critical for the health of the brain. It is now well established by research studies that the development, growth and function of human brain is positively influenced by the sufficient dietary availability of DHA. It helps in neurogenesis, neurotransmission,
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anti-inflammatory responses and protection against free radicals.

There are many general health benefits of long chain omega-3 fats, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However the  neurological benefits of omega-3 fats are derived from the DHA rather than the EPA. Apart from genetic predispositions, nutritional deficiencies of omega-3 fats have been found to be the cause of emotional, mental and psychiatric disorders like depression, bipolar disorder and schizophrenia.

DHA and brain

Docosahexaenoic acid is the structural fat and the basic building blocks of our brain cells. It is found in high concentration in the gray matter and constitutes nearly 97% of the omega-3 fats in the brain.

In the brain cell membranes, it is incorporated into the membrane phospholipid components. Here it helps in the maintenance of a highly fluid microenvironment in the cell membranes of the nervous system which is conducive for electrical signaling. Docosahexaenoic acid is important for the transmission of brain signals and sustained enhancement of communication between the cells. For memory and learning, formation of the synaptic connections and sustained cell signaling and communication within the grey matter are vital.

Role of DHA in brain development

The proper development of the fetal brain and the nervous system will support the intelligence, cognitive abilities and mental function of the children and adults throughout life.

In the last trimester of pregnancy there is threefold increase in the size of the fetal brain. The mother's blood levels of DHA decline as they meet the fatty acid need of the fetus. The placenta extracts the docosahexaenoic acid from the mother's blood and concentrates them in the fetal blood. There is preferential DHA transfer to the fetus. As a result of this, the fetal levels of DHA may be twice that of the mother. If the mother's DHA levels are low, it is sourced from the brain of the mother. The depletion of mother's DHA can cause Postpartum depression or postnatal depression.

Research studies have shown that the mother's intake of dietary DHA has a direct effect on the development of the brain and retina of the fetus. The lack of DHA in food can affect the fetal mental development which will significantly impact the intelligence and memory of the individual.

Docosahexaenoic acid continue to be vital for the brain development even after birth. Research studies have also shown that breast milk contains higher amounts of docosahexaenoic acid when compared to dairy milk or the earlier formula feeds which were not fortified with DHA.
Breastfed children have been found to have higher Intelligence quotient (IQ) when compared to the formula feed fed children. In another study from UK, children fed with DHA fortified formula feed had higher scores in problem solving than those children fed with plain formula feed.

Many emotional, mental and psychiatric disorders in childhood like learning difficulties, disturbed mood, lack of concentration, poor memory, behavioral problems, attention deficit hyperactivity disorder and autism have been linked to low levels of docosahexaenoic acid. Considering the beneficial effects of docosahexaenoic acid many formula feeds are being fortified with this fatty acid.

Role of DHA in adult brain function

Just like young children, it is very important to the elderly. In elderly people, nutritional deficiency of this omega-3 fat is one of the contributing factors of degenerative changes in the nervous system and mental decline. Dietary deficiency can initiate and also speed up the age-related deterioration of intellectual faculties leading to memory loss, learning difficulties, lack of concentration, poor judgment, mood swings, depression, dementia and Alzheimer's disease.

Fish is a great source of DHA. Elderly people who ate fish regularly had better working memory. Apart from supporting the metabolism of the brain, docosahexaenoic acid helps in controlling the proinflammatory pathways and processes involved in the degeneration of the nervous system.

Research studies have demonstrated that dietary deficiency of DHA is an important risk factor for Alzheimer's disease and dementia. In patients affected by multiple sclerosis, it is found that the blood levels of this fatty acid are low. In a research study it was found that when schizophrenic patients are treated with omega-3 fatty acids, they were relieved of the symptoms such as social withdrawal, lack of emotions, delusions, suicidal behavior, anger, and hostility and hallucinations.

Adequate nutritional DHA supply ensures that the cells in the brain and other parts of the nervous system develop and function properly from the fetus stage to old age.
Related topics in nutritional deficiency diseases:
Side effects of DHA.
DHA supplements.
Fat deficiency.
Fish oil - DHA - EPA.
DHA from algae.
Arachidonic acid Foods.
Two essential fatty acids.
Polyunsaturated fatty acids structure.
Examples of monounsaturated fats.
Trans fats definition.

Reference:
1.Sheila M. Innis. Dietary (n-3) Fatty Acids and Brain Development. 2007 American Society for Nutrition.
2.Kidd PM. Omega-3 DHA and EPA for cognition, behavior, and mood: clinical findings and structural-functional synergies with cell membrane phospholipids. Altern Med Rev. 2007 Sep;12(3):207-27.

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DHA in brain

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