The results could have important implications for children's education and national development in low income countries, say the researchers.

At least 250 million children worldwide younger than 5 fail to reach their cognitive developmental potential.

While undernutrition is not the only factor, it is associated with long term brain impairment. Previous research, however, has suggested that traditional supplementary foods for young children might lack key nutrients that could support regenerative changes in the brain.

So a team of US researchers set out to assess the effects of food supplementation on improving working memory (a key element of long term academic attainment) and blood flow to the brain (cerebral blood flow, a measure of brain health) in children at risk of undernutrition.

Their findings are based on 1,059 children aged 15 months to 7 years living in 10 villages in Guinea-Bissau, West Africa, who were randomized to receive one of three meals, served five mornings each week for 23 weeks.

The first was a new food supplement (NEWSUP) high in antioxidants, other vitamins and minerals, polyphenols from cocoa, omega 3 fatty acids and protein. The second was a fortified blended food (FBF) used in nutrition programs, and the third was a control meal (a traditional rice breakfast).

The main outcome measure was working memory, but the researchers also measured red blood cell (hemoglobin) levels, growth, body composition, and cerebral blood flow at the start of the study and shortly before the end of supplementation.

Among children younger than 4, randomization to NEWSUP had a substantial beneficial effect on working memory, especially in those who consumed at least 75% of their supplement, compared with a traditional rice breakfast.

NEWSUP also increased cerebral blood flow, improved body composition (more lean tissue with less fat), and had a beneficial effect on hemoglobin concentration in children younger than 4 with anemia.

Among children aged 4 and older, NEWSUP had no significant effect on working memory or anemia, but increased lean tissue compared with fortified blended food.

The researchers point to some study limitations, such as being limited to one cognitive measure, and the need for longer study durations in older children to see if effects could be detected after 4 years. However, strengths included being able to directly observe the children eating the meals provided and blinded assessment and analysis of data by people who were not involved in the study's design and delivery.

As such, they say nutritional supplementation for 23 weeks "could improve cognitive function in vulnerable young children living in low income countries, with additional benefits for brain health and nutritional status."

They acknowledge that further research is needed, but add these results could also be very relevant for children living in affluent countries, since many children consume an unhealthy diet, and for other vulnerable groups such as older adults with inadequate nutrition and vulnerability to cognitive impairment.

For more details click on the link: https://www.bmj.com/content/370/bmj.m2397