03:07am Monday 25 September 2017

Conditionally essential long chain fatty acids in early life

Breast milk

Breast milk is considered the ‘nutritional gold standard’ for infant feeding in early life and is relatively high in fat. Fat provides around half of the energy in breast milk.1 ‘Conditionally essential’ nutrients can become essential under some developmental or disease conditions. The main ones present in breast milk are docosahexaenoic acid (DHA) and arachidonic acid (AA), both essential structural components in the human body.1 The concentrations of DHA and AA in breast milk are around 0.3% and 0.5% (of total fats), respectively.2 While the level of DHA in breast milk can vary, depending on the mother’s diet (e.g. the amount of fish consumed), the level of AA is less influenced by diet.3 Human breast milk also includes important long chain fatty acids that are also found in the milk of ruminants, such as vaccenic acid (0.4%) and nervonic acid (0.05%).4,5

Their role in growth and development
The scientific evidence shows that dietary DHA plays a role for development of the central nervous system due to the body’s limited ability to produce it. DHA is incorporated at high levels in the grey and white matter of the brain and in the rods and cones of the retina in the eye during growth, in particular during late pregnancy and the first two years of life, and is therefore essential for normal brain development.1,3,6,7 A number of health claims relating to DHA, including infant brain and eye development, were recently permitted in Europe.8 Evidence of long-lasting effects (beyond infancy) of DHA on cognition remains inconclusive.1 This may be due to a lack of long-term follow-up studies on specific aspects of cognitive and behavioural function, and the complexity and difficulty of assessing neurodevelopment in children.1,9

The European Food Safety Authority (EFSA) advise pregnant and breastfeeding women to consume an extra 100-200 mg DHA per day in addition to 3-4 servings of seafood (fish and shell fish) per week.10,11 Foods (e.g. bread, dressings, meat products, eggs) or supplements may be enriched with these omega-3 fatty acids.10 The recommendation for infants aged 6-24 months is 100 mg DHA daily and for children aged 2-18 years 250 mg DHA daily.12

AA is also an important structural component of the brain, nervous tissue, lining of the blood vessels, heart, liver, kidneys, placenta and indeed, most important organs.1,3 AA builds up in an infant’s brain especially in early pregnancy.1,6 The metabolic derivatives of AA control blood flow, platelet adhesion (when platelets in blood stick to a damaged blood vessel), immune function and reproduction. Indeed, the Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO) have stated “There can be little doubt about the essentiality of DHA and AA for the brain”.13 Whereas a recent EFSA opinion suggests it is still unclear whether dietary intake of AA plays a critical role relative to intake of DHA.1,3

Vaccenic acid, a naturally occurring trans fatty acid present in human breast milk, has been shown to be important, together with other long chain fatty acids such as DHA in the prevention of the development of allergies in small children.4 Similarly, nervonic acid, present at levels of around 0.05% (of total fats) is incorporated into the developing central nervous system, mainly from mid-gestation, until the end of the second postnatal year.5

Infant and follow-on formulae
Over the years, a lot of effort has gone into making infant formula more similar to breast milk. While exclusive breastfeeding is the preferred choice for infants in the first 6 months of life, this is not always an option and some have to rely on formula feeding. Therefore, a recent EFSA opinion suggests that DHA should be added to infant formulae, and follow-on formulae (which may be used during complementary feeding), and that formula-fed infants should be given similar amounts of DHA as breast-fed infants.1 This EFSA opinion considered that there is no necessity to add AA to infant formulae.1 This is in contrast to Codex recommendations (internationally recognised standards), which outline that if DHA is added to infant formula, AA content should reach at least the same concentration as DHA.14 The FAO/WHO requirement for AA and DHA for brain development and health is (0.2-0.3% of the energy or 0.4-0.6% of the fatty acids for formula milks for 0-6 months).13 There are calls for more research in this area to test formula milk without added AA to confirm its suitability and safety.15

While further research is needed to elucidate the link between dietary intakes of conditionally essential fatty acids and neurological development, it is clear that in the human body these fatty acids play a key role.

References

  1. European Food Safety Authority (2014). Scientific Opinion on the essential composition of infant and follow-on formulae. EFSA Journal 12(7):3760.
  2. Brenna JT et al. (2007). Docosahexaenoic and arachidonic acid concentrations in human breast milk worldwide. American Journal of Clinical Nutrition 85:1457-1464.
  3. Lauritzen L et al. (2014). Dietary arachidonic acid in perinatal nutrition: a commentary. Pediatric Research. doi: 10.1038/pr.2014.166.
  4. Thijs C1 et al. (2011). Fatty acids in breast milk and development of atopic eczema and allergic sensitisation in infancy. Allergy 66(1):58-67.
  5. Sala-Vila A et al. (2004). The source of long-chain PUFA in formula supplements does not affect the fatty acid composition of plasma lipids in full-term infants. Journal of Nutrition 134(4):868-873.
  6. Kuipers RS et al. (2011). Intrauterine, postpartum and adult relationships between arachidonic acid (AA) and docosahexaenoic acid (DHA). Prostaglandins, Leukotrienes and Essential Fatty Acids 85:245-252.
  7. Ryan AS et al. (2013). Role of Fatty Acids in the Neurological Development of Children (Chapter 26). In Watson RR et al. (ed.) Nutrition in Infancy: Volume 2 Nutrition and Health. New York, US: Springer Science.
  8. European Commission website, EU Register of nutrition and health claims made of foods.
  9. Hoffman DR et al. (2009). Toward optimizing of vision and cognition in term infants by dietary docosahexaenoic acid ad arachidonic acid supplementation: a review of roandomized controlled trials. Prostaglandins Leukot Essent Fatty Acids 81:151-158.
  10. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) (2012). Scientific Opinion on the Tolerable Upper Intake Level of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA). EFSA Journal 10(7):2815.
  11. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) (2014). Scientific Opinion on health benefits of seafood (fish and shellfish) consumption in relation to health risks associated with exposure to methylmercury. EFSA Journal 12(7):3761.
  12. European Food Safety Authority (2014). Scientific Opinion on the substantiation of a health claim related to DHA and contribution to normal brain development pursuant to Article 14 of Regulation (EC) No 1924/2006. EFSA Journal 12(10):3840.
  13. FAO/WHO (2010). Fats and Fatty Acids in Human Nutrition, Report of an expert consultation. Food and Nutrition Paper no 91. Rome: FAO. ISSN 0254-4725. http://www.who.int/nutrition/publications/nutrientrequirements/fatsandfattyacids_humannutrition/en/
  14. CODEX Alimentarius (2011). Standard for infant formula and formulas for special medical purposes intended for infants. Codex Stan 72 – 1981.
  15. Koletzko B et al. (2015).Should Infant Formula Provide Both Omega-3 DHA and Omega-6 Arachidonic Acid? Annals of Nutrition and Metabolism 66(2-3):137-138. 
ABOUT EUFIC

The European Food Information Council (EUFIC) is a non-profit organisation which communicates science-based information on nutrition and health, food safety and quality, to help consumers to be better informed when choosing a well-balanced, safe and healthful diet.


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