Undernourished children showed improvement in brain function after taking nutritional supplements for six months, researchers said Thursday.

The findings have important implications for children’s education and national development in low-income countries, they reported in BMJ, a medical journal.

At least 250 million children worldwide under five fail to reach their cognitive-developmental potential, according to the World Health Organization (WHO).

Undernutrition is not the only factor but has been associated with long term brain impairment.

To see whether targeted supplements could make a difference, a team of US researchers conducted trials in Guinea-Bissau that measured working memory (key for studying) and blood flow to the brain (a measure of brain health) in more than 1,000 children at risk of undernutrition.

The children, aged 15 months to seven years, were divided into three groups that received different meals five mornings a week for 23 weeks.

The first group’s daily meal contained a new food supplement — called NEWSUP — high in antioxidants, other vitamins and minerals, polyphenols from cocoa, omega 3 fatty acids and protein.

The second group had so-called fortified blended food (FBF), long used in nutrition programmes, and the third was a traditional rice breakfast with no supplements.

Besides working memory, the researchers measured red blood cell (haemoglobin) levels, growth, body composition, and cerebral blood flow at the start and shortly before the end of trial.

Among children younger than four, the NEWSUP diet provided a substantial boost to working memory compared with a traditional rice breakfast, the researchers found.

It also increased cerebral blood flow, improved the ratio of lean tissue to fat in the body, and helped haemoglobin concentration in children under four with anaemia.

Among children four and older, however, NEWSUP had no significant effect on working memory or anaemia.

Including only one cognitive measure was a limitation to the study, the researchers acknowledged, as was the short duration.

A trial over four years rather than four months might show similar benefits in older children, they speculated.