|
Role of docosahexaenoic acid (DHA) in children: DHA is an omega-3 polyunsaturated essential fatty acid. The development of visual and
neurological functions in infants has been demonstrated in various DHA studies. (1) In a
randomized controlled trial in USA, it has been found that toddler formula supplemented with
DHA improved RBC DHA status and lowered incidence of respiratory illness (p=0.024) compared
to formula without DHA in children less than 3 years of age. (2) Thus role of DHA in infants and
toddlers seems to be defined and adequate intake needs to be ensured.
Intake of DHA in children: Eicosapentaenoic acid (EPA) and DHA intake is often low in 2-12 years old children relative
to intake in breast fed infants and adult intake. It has been found that large proportions of children
have low levels of intake of n-3 omega fatty acids with > 97% of all groups consuming less than
1% energy from this fats due to poor intake of EPA & DHA. (3)
Consumption of healthy diets that contribute with adequate amounts of fat and fatty acids
is needed to children. (3) Dietary intakes in childhood should support future adult health such as
prevention of metabolic disorders & cardiovascular disease, support immune function and
maintain healthy reproductive system (4).
DHA is predominant in fish and seafood and consumption of these foods in Indian
children is virtually lacking. In vegetarians the predominant polyunsaturated fatty acid is linolenic
acid (LA) - an omega 6 fatty acid. Alpha linolenic acid (ALA) which is an omega 3 fatty acid is not
so abundant in vegetarian diets. (5) ALA is a precursor of EPA and DHA. The ideal ratio of LA to
ALA should be 3:1 in the diet, however most diets have a ratio of 10:1 or 15:1. (5) Under these
circumstances, omega 6 fatty acids inhibit the conversion pathway of omega 3 fatty acids. Thus
decreasing LA content has been found to increase the ALA conversion to EPA and DHA.
Sources of DHA: Foods with rich ALA content are rape seed oil, walnut and flaxseed oil. (5) Milk and
cheese are good sources of omega - 3. Half a pint of milk provides 10% of recommended daily
intake (RDI) of ALA. Although fish oils are rich sources of DHA, most commercially available fish
oils contain higher amount of EPA than DHA. Most DHA found in extracted fish oil preparation is
derived from microalgae consumed by the fish. Pure DHA from fish oil is not readily available in
the commercial market due to difficulties in extraction and purification processes. Currently, the
best commercial source of DHA is derived from microalgae by fermentation which is the
vegetarian source of DHA. (6) This vegetarian source of commercial microalgae DHA may have
to be supplemented in children to achieve adequate DHA content.
The DHA content in various foods is depicted in Table 1.
Table 1: Dietary sources of DHA (7)
Source |
Grams of omega - 3 fatty acid |
Fish |
(per 3 oz serving) |
» Tuna |
0.21 - 1.1 |
» Pollock |
0.45 |
» Salmon |
1.1 - 1.9 |
» Cod |
0.15 - 0.24 |
» Catfish |
0.22 - 0.3 |
» Flounder |
0.48 |
» Grouper |
0.23 |
» Halibut |
0.60 - 1.12 |
» Mahi mahi |
0.13 |
» Orange Roughy |
0.028 |
» Red snapper |
0.29 |
» Shark |
0.83 |
» Sword fish |
0.97 |
» Tile fish |
0.90 |
» King mackerel |
0.36 |
Botanical sources |
Percentage of omega - 3 in seed oil |
Chia |
64 |
Kiwifruit |
62 |
Perilla |
58 |
Flaxseed |
55(18% of omega-3 in the whole food |
Cow berry |
49 |
Camelina |
36 |
Purslane |
35 |
Black raspberry |
33 |
Hemp seed |
19 (8.7% of omega 3 in the whole food) |
Daily requirement of DHA (8): While exact dose of DHA to be consumed is not known, the following are recommended
amounts:
| » |
Pregnant and Nursing women - A workshop sponsored by the National Institutes of
Health and International Society for the study of fatty acids and lipids (NIH/ISSFAL) recommended an intake of 300mg/day of DHA |
| » |
Children and Healthy Adults - NIH/ISSFAL have recommended an intake of 220 mg/day of DHA. |
Conclusion: Adequate amount of DHA is required in children for cognitive, visual, immunological effects.
Intake of DHA from diet is often poor and thus supplementation of DHA may be required.
References:
1. |
Gil-Campos M, Dalmau Serra J; Comite de Nutricion de la Asociacion Espanola de
Pediatrķa. Importance of docosahexaenoic acid (DHA): Functions and recommendations for
its ingestion in infants. An Pediatr (Barc). 2010 Jun 4. [Epub ahead of print] Spanish |
2. |
Minns LM, Kerling EH, Neely MR, Sullivan DK, Wampler JL, Harris CL,et al. Toddler formula
supplemented with docosahexaenoic acid (DHA) improves DHA status and respiratory health in a randomized, double-blind, controlled trial of US children less than 3 years of age.
Prostaglandins Leukot Essent Fatty Acids. 2010; 82: 287-293 |
3. |
Bermudez OI, Toher C, Montenegro-Bethancourt G, Vossenaar M, Mathias P, Doak C,
Solomons NW. Dietary intakes and food sources of fat and fatty acids in Guatemalan schoolchildren: a cross-sectional study. Nutr J. 2010; 9: 20 |
4. |
Koletzko B, Uauy R, Palou A, Kok F, Hornstra G, Eilander A, et al. Dietary intake of
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in children - a workshop report. Br J Nutr. 2010; 103: 923-928. |
5. |
|
6. |
|
7. |
|
8. |
|
|
|
|
|
