In patients who were given total intravenous (‘parenteral’) nutrition containing fat-free glucose-amino acid mixtures, biochemical signs of essential fatty acid deficiency developed in as little as seven to ten days (207). In these cases, the continuous glucose infusion resulted in high circulating insulin levels, which inhibited the release of essential fatty acids stored in fat (‘adipose’) tissue.
Essential fatty acid deficiency has also been found to occur in patients with chronic poor absorption of fat from food (208) and in patients with cystic fibrosis (209).
Blood docosahexaenoic acid (DHA) concentrations decrease when omega-3 fatty acid intake is insufficient but no cutoff values have been established.
Because the last three months of pregnancy are a critical period for the accumulation of the omega-3 fatty acid docosahexaenoic acid (DHA) in the brain and retina, preterm infants are thought to be particularly vulnerable to adverse effects of insufficient DHA on visual and neurological development (15). Supplementing mothers with DHA in the last half of gestation results in a reduction of preterm births and shorter length of hospital stays (309, 311).
Supplementing mothers with DHA in the last half of gestation results in a reduction of preterm births and shorter length of hospital stays (309, 311).
Human milk contains DHA in addition to the omega-3 fatty acids alpha-linolenic acid (ALA) and eicosapentaenoic acid (EPA). Although preterm infants can synthesize DHA from ALA, they generally cannot synthesize enough to prevent declines in blood and cellular DHA concentrations without additional dietary intake. Therefore, it was proposed that preterm infant formulas be supplemented with enough DHA to bring blood and cellular DHA levels of formula-fed infants up to those of breast-fed infants (210).In developing countries, deficiencies in intakes of DHA and ARA from complementary foods introduced in 6-36 month old children exist (339). Such deficiencies are associated with higher percentages of stunting, infections, infant mortality and impairments in cognitive performance.
Clinical signs of essential fatty acid deficiency include a dry scaly rash, decreased growth in infants and children, increased susceptibility to infection, and poor wound healing (211).
Symptoms of an omega-3 fatty acid deficiency include visual problems and sensory nerve disorders (‘neuropathy’) (212).
Studies in animals have revealed significant impairment of omega-3 fatty acids deficiency on learning and memory (213, 214). These studies have prompted clinical trials in humans to assess the impact of omega-3 PUFA on cognitive development and cognitive decline.DHA is essential for normal brain development and visual function. Adequate DHA composition allows for optimal function in areas of visual acuity and attention span, IQ and visuospatial learning during early infant development (312, 314, 316). Some studies in older adults with mild memory complaints have also shown a cognitive benefit with DHA supplementation (277, 278, 334, 337), suggesting that adequate DHA levels may optimize brain function in later life also.
Authored by Dr Peter Engel in 2010, reviewed and revised by Karin Yurko-Mauro on 30.06.2017.
