Brain Nutrients: DHA is a Hero

Optimal nutrition intake is necessary for normal brain development.1 According to the UNICEF, the years from conception through birth till the age of eight years is a critical period for complete and healthy cognitive, emotional and physical growth of children.2 With age the brain weight increases and attains adult weight between the ages 6 to 14 years. Also, since the brain is metabolically very active, it accounts for a large percentage of total metabolic rates of the body. By the time the child is 2 years, the brain is about 80 percent of the adult weight. It continues to develop through adolescence and even in adulthood by adapting to changing environments.3

Cognitive Development

Cognition is a process by which a person registers, encodes, selects, maintains, transforms, stores and retrieves information. In the first year of life, infant learns to construct mental structures, which is dependent on observations and body movements. The child develops attention skills by exploring and concentrating on the environment and starts focusing on testing and organizing the information through the pre-school years. Activity and motor skills form an integral part of developing the attention system by increasing the responsiveness to the environment. Early childhood is a period when the environment has an important impact on determining how the brain and central nervous system grows and develops.2 Cognitive development continues through school years with development of skills like thought, memory and language. Complete adult intelligence and hypothetical thinking develop during adolescence.4

During periods of fast growth, the demand for brain nutrients is high. Inadequate nutrition at this time will cause a compromise in the normal structure of the brain.3 Improper nutrition in the first years of life of the child interferes with brain development, leading to neurological and behavioral disorders such as learning disabilities and mental retardation. In fact, babies who are given good nutrition and healthy psychosocial stimulation had better brain function at age 12 years than those raised in a less stimulating environment.2    

Effect of Nutrition on Cognitive Development

Right nutrition can change gene structure and effect the gene expression by enabling them to exert their effects on brain growth and development. Brain is a specialized tissue and its functions depend on the generation of electric potentials and their conduction through nerves. To perform these special functions, the brain has a higher requirements for nutrients such as choline, folic acid, iron, zinc and docosahexaenoic acid (DHA).5

Nutrient deficiencies have an effect on five early developmental processes of the brain1:

1) Neuron proliferation,

2) Axon and dendrite growth

3) Synapse formation, pruning, and function

4) Myelination

5) Neuron apoptosis

Brain Nutrients

All nutrients are important for brain growth and function, but few have a particularly important effect on early brain development. If the main nutrients for brain development are deficient during sensitive or critical periods of brain development, it can result in long-term brain dysfunction.6 [

Protein- Protein plays a role in cell growth and replication, production of brain neurotransmitters, myelination, and development of dendritic arborisation of the developing brain. Protein deficiency results in growth failure in children that in turn has a negative impact on neurodevelopment. Restricted protein intake in childhood has been found to result in smaller brains with reduced RNA and DNA content, fewer neurons, simpler dendritic and synaptic head architecture, along with lesser neurotransmitters and growth factors.6

The recommended dietary allowance for children aged 1 to 3 years is 15.7 gram of protein per day. For children in 4-6 years age group, the allowance is 20.3 gram per day. The requirements of children from 7 to 9 years are 29.6 grams per day. Boys in the age group 10-12 years need 39.3 grams per day and girls in the same age group need 40.4 grams per day.7

Iron– Iron helps in brain myelination, and the development and function of the dopamine, serotonin, and norepinephrine systems.6 Iron deficiency leads to poor memory and cognition, myelin defects, and slower nerve signal transmission in auditory and visual systems. Studies have demonstrated that iron deficiency anemia is associated with impaired development of mental and physical coordination skills in children. It weakens the child’s learning ability, slows down mental and motor development, and reduces work performance.4

Recommended dietary allowance for iron in children 1 to 3 years is 9mg per day, for 4 to 6 years is 13mg per day, and 7 to 9 years is 16 mg per day. Boys aged 10-12 years need 21 mg and girls aged 10-12 years need 27 mg per day of iron.7

Children above the age of 2 years who have iron deficiency anemia demonstrate better cognition when given iron supplementation. Studies have also shown that children over the age of 7 years with iron deficiency when given iron supplements exhibited better scores on intelligence tests.8

Zinc- Zinc has a role in cell growth and division, DNA and RNA synthesis, and normal metabolism. Zinc deficiency has been associated with reduced brain volume, compromised cognitive development and attention in children.4 Children in the age group 1 to 3 years need 5 mg of zinc per day, age group 4 to 6 years need 7 mg per day and age group 7 to 9 years need 8 mg of zinc per day. Children in the age group 10-12 years need 9 mg zinc every day.7

Iodine- Iodine helps in brain development by supporting thyroid hormone synthesis. Iodine deficiency during early childhood is associated with cognitive impairment. Randomized clinical trials in school age children indicate that cognitive performance can be improved by iodine supfplementation.9

Severe iodine deficiency can result in speech, hearing, IQ, and gait defects in the child. Children in the age group 3 to 8 years need 90 mcg of iodine per day and in the age group 9 to 13 years need 120 mcg per day.10

Vitamin B12: Vitamin B12 has a role in axon myelination that is essential for impulse conduction and it protects neurons from degeneration. It may also alter the synthesis of different cytokines, growth factors and oxidative energy metabolites such as lactic acid. All these are a part of cognitive functions. In children, vitamin B12 is associated is associated with apathy, cerebral atrophy, and demyelination of nerve cells. Studies have found that teenagers who consumed a macrobiotic diet till the age of 6 years had lower levels of fluid intelligence, spatial ability, and short term memory compared to teenagers who consumed an omnivorous diet till the age of 6 years.11 For children in the age group 1 to 6 years the daily requirement is 0.6 mcg per day, 7 to 9 years is 0.8 mcg per day and 10-12 years is 0.8 mcg per day.7

Folic acid: Folic acid is another important brain nutrient. Folic acid has a role in neural stem cell proliferation and differentiation, reduced cell death, and altered DNA synthesis.11 Children in the ages 1 to 6 years need 80-100 mcg of folic acid per day and in the age group 7 to 12 years need 120-140 mcg per day of folic acid.7

Thiamine: Long term thiamine deficiency can result in permanent brain damage. In children, deficiency can result in lesions in the basal ganglia and the frontal lobes.12 Children in the age group of 4 to 6 years need 0.7 mg of thiamine per day and in the age group need 0.8 mg per day. Boys in the age group 10-12 years need 1.1 mg per day and girls in the same age need 1 mg per day.7

Pyridoxine: Pyridoxine (vitamin B6) is essential for the synthesis of adrenaline (epinephrine), serotonin, dopamine, gamma amino butyric acid (GABA), tyramine and other neurotransmitters. The nutrient is closely associated with cognitive functions such as concentration, learning, memory, and reasoning. Deficiency of pyridoxine leads to changes in receptor binding of many neurotransmitters such as glutamate and glycine.13 Children aged 4-6 years require 1.1 mg of pyridoxine per day and in the age group 7 to 9 years need 1.4 mg per day. Boys aged 10-12 years need 1.8 mg per day and girls in the same age group need 1.6 mg per day.7

Vitamin D: Vitamin D deficiency is associated with impaired neurodevelopment in young children. It is associated with neuroprotective effects by neuromodulation, anti-inflammatory, anti-ischemic and anti-oxidant properties. Vitamin D affects the proteins directly involved in learning, memory, motor control, and social behavior. Deficiency of vitamin D has been associated with autism. Adequate vitamin D intake during early stages of life ensures normal receptor transcriptional activity important for brain development and mental functioning. An RDA of 600 IU has been set as an upper limit for children.14

Choline: Choline has a role in closure of fetal neural tube, memory and learning. It is major component of phospholipids in cell membranes and a precursor for the neurotransmitter acetylcholine.11

DHA – Main nutrient for brain/cognition development

Brain development is fastest in the early years of life compared to the rest of the body.15 DHA is a fundamental nutrient for cognition development in children. DHA not only contributes to the structure of brain cell membrane but it is also involved in neurogenesis, neurotransmission, and cell survival within the Central Nervous System (CNS). DHA alters gene expression in mammalian brain tissue that contributes to neurite outgrowth and learning and memory. It also enhances the process of neurite outgrowth in hippocampal neurons, which in turn promotes learning abilities. DHA promotes neuronal growth and also improves learning and memory by facilitating the formation of pre- and postsynaptic proteins that enable synaptic transmission and long-term potentiation. Under oxidative stress, DHA can also promote repair and growth of neurons.16 According to the WHO, the requirement for DHA plus EPA (Eicosapentaenoic acid) for children in the age group 2 to 4 years is 100-150 mg per day, for 4 to 6 years is 150-200 mg per day and for 6 to 10 years is 200-250 mg per day.17

DHA and Cognition in children– DHA affects brain function well beyond early development in healthy children. Higher plasma and red blood cell DHA and EPA levels are correlated with superior verbal learning, spelling and reading abilities in children. Supplementation with DHA offers a safe and effective way to improve reading and behavior in healthy, school-aged children.16 The usual intake of DHA among toddlers and children is generally low and supplementation with polyunsaturated fatty acids including DHA brings significant improvements in their cognition, behavior and school performance.18

Conclusion

Early childhood is a period in development where the environment including adequate nutrition has an important impact on determining how the brain and central nervous system grows and develops. Inappropriate stimulation during early childhood makes it difficult for the brain to rewire itself at a later time. Nutrition in early childhood has a profound effect children’s ability to learn, think analytically, socialize with others, and their ability to adapt to change.2

References

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  2. UNICEF. Early Childhood Development: The key to a full and productive life; 2001. Available from: https://www.unicef.org/dprk/ecd.pdf.
  3. David B. The influence of children’s diet on their cognition and behavior. Eur J Nutr. 2008; 47(Suppl 3):25–37.
  4. Md. Abdullah Al Mamun, Ghani RBA. The role of iron and zinc in cognitive development of children. Asian J Med Biol Res. 2017; 3(2): 145-151.
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  6. Cusick SE, Georgieff MK. The role of nutrition in brain development: the golden opportunity of the “first 1000 days”. J Pediatr. 2016 August; 175:16–21.
  7. Narasinga Rao BS. Nutrient requirement and safe dietary intake for Indians. NFI Bull. 2010 January; 31(1): 1–5.
  8. Arcanjo FPN, Arcanjo CPC, Santos PR. Schoolchildren with learning difficulties have low iron status and high anemia prevalence. J Nutr Metab. 2016 Sep 15; 2016. doi: 10.1155/2016/7357136.
  9. Melse-Boonstra A, Jaiswal N. Iodine deficiency in pregnancy, infancy and childhood and its consequences for brain development. Clin Endocrinol Metab. 2010 February; 24(1): 29-38.
  10. National Institutes of Health. Iodine: Fact Sheet for Health Professionals. Available from: https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/
  11. Nyaradi A, Li J, Hickling S, Foster J, Oddy WH. The role of nutrition in children’s neurocognitive development, from pregnancy through childhood. Front Hum Neurosci. March 2013; 7:1–16.
  12. Whitfield KC, Bourassa MW, Adamolekun B, Bergeron G, Bettendorff L, Brown KH, et al. Thiamine deficiency disorders: diagnosis, prevalence, and a roadmap for global control programs. Ann N Y Acad Sci. 2018; 1430: 3–43.
  13. Huskisson E, Maggini S, Ruf M. The influence of micronutrients on cognitive function and performance. J Int Med Res. 2007; 35: 1–19.
  14. Weydert JA. Vitamin D in children’s health. Children 2014; 1:208-226.
  15. Garg P, Kumar Pejaver R, Sukhija M, Ahuja A. Role of DHA, ARA, & phospholipids in brain development: an Indian perspective. Clin Epidemiol Global Health. 2017 December; 5(4): 155–162.
  16. Weiser MJ, Butt CM, Mohajeri MH. Docosahexaenoic acid and cognition throughout the lifespan. Nutrients. 2016 February; 8(2): 99. doi:10.3390/nu8020099.
  17. WHO. Interim Summary of Conclusions and Dietary Recommendations on Total Fat & Fatty Acids. From the Joint FAO/WHO Expert Consultation on Fats and Fatty Acids in Human Nutrition, 10-14 November, 2008, WHO, Geneva.
  18. Kuratko CN, Barrett EC, Nelson EB, Salem N Jr. The relationship of docosahexaenoic acid (DHA) with learning and behavior in healthy children: a review. Nutrients. 2013 Jul 19;5(7):2777-2810.

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