Iron and omega-3 fatty acid deficiencies impacts children’s brains
It is well known that nutritional deficiencies can impact a child’s development. According to the World Health Organization, iron deficiency is the most common nutritional deficiency worldwide, affecting approximately 2 billion people. A number of children throughout the globe have an insufficient intake of omega-3 fatty acids.
Iron deficiency commonly results in anemia. Omega-3 fatty acids derived from fish or fish oils, which consist of docosahexaenoic acid (DHA) plus eicosapentaenoic acid (EPA). DHA is required in high levels in the brain and retina as a physiologically-essential nutrient to provide for optimal neuronal functioning (learning ability, mental development) and visual acuity, in young and old alike. A team of international researchers noted that little is known about the combined effects of iron and omega-3 fatty acid supplementation on cognitive performance. They explained that either DHA/EPA or iron alone in rats with combined iron and omega-3 fatty acid deficiency has been reported to exacerbate (worsen) cognitive deficits associated with deficiency. Therefore, they conducted a study that evaluated the effects of iron and DHA/EPA supplementation, alone and in combination, in children with poor iron and omega-3 fatty acid status. They published their results on line on October 24 in the American Journal of Clinical Nutrition.
Although nutritional deficiency in children has a worldwide presence, poor children in developing nations are at particular risk for deficiencies in iron, as well as other nutrients, including the omega-3 fatty acids. The researchers evaluated the effects of giving 321 schoolchildren, aged six to 11 years, in South Africa either supplements containing iron, omega-3 fatty acids or both. All of the children had low levels of both nutrients. They were allocated to receive: (1) iron (50 mg) plus DHA/EPA (420/80 mg); (2) iron plus placebo; (3) placebo plus a mixture of DHA and EPA (DHA/EPA); or (4) placebo plus placebo as oral supplements. They received the supplements or placebos f times per week for 8.5 months. Cognition was assessed at baseline and endpoint by using the Hopkins Verbal Learning Test (HVLT) and subscales of the Kaufman Assessment Battery for Children.
The researchers found that both iron and DHA/EPA significantly increased weight-for-age z scores. A z score measures how much a value deviates from an average score. In this case, the higher z scores indicated better cognitive performance. Iron increased the number of words recalled at HVLT recall 2; in anemic children, iron increased scores in the Atlantis Delayed test and HVLT recall 2. In addition, DHA/EPA was found to have no benefit in any of the cognitive tests but decreased Atlantis test scores in children who were anemic at baseline and decreased Atlantis delayed scores in girls with iron deficiency; however, boys tended to perform better.
The authors concluded that in children with poor iron and omega-3 fatty acid status, iron supplementation improved verbal and nonverbal learning and memory, particularly in children with anemia. In contrast, DHA/EPA supplementation had no benefits on cognition and impaired working memory in anemic children and long-term memory and retrieval in girls with ID.
Take home message:
Although this study was conducted on poor children in a developing nation, a number of children in the US suffer from nutritional deficiencies as a result of poor diet and or poverty. Oily fish are a good source of omega-3 fatty acids. Green leafy vegetables, such as spinach, as well as red meats, are high in iron. Inexpensive supplements of these nutrients are also widely available.
Reference: American Journal of Clinical Nutrition