cognition

Junk food limits intelligence of teenagers

From a study on the dietary patterns and cognitive performance in 602 adolescents performed at The University of Western Australia, researchers found a “higher dietary intake of the ‘Western’ dietary pattern at age 14" was "associated with diminished cognitive performance 3 years later, at 17 years."

Using a food frequency questionnaire administered when the children were 14 years old (2003–2006), ‘Healthy’ and ‘Western’ dietary patterns were identified by factor analysis. Associations between dietary patterns at 14 years of age and cognitive performance at 17 years of age were assessed prospectively using multivariate regression models.

Epoch Times reports:

It was observed that children with higher consumption of takeout foods, processed meats, soft drinks and other refined and sugar-laden fare had decreased psychomotor function, impaired reaction time and problems focusing visually. Junk food eaters also had trouble learning and remembering things compared to those who ate more fruits and leafy green vegetables.

Elevated blood glucose impairs memory

A study published online in Neurology on October 23, 2013 sheds light on the possible mechanisms of dementia in persons with elevated blood glucose but without diabetes as discussed in the previous post. The hippocampus, located in the inner aspect of both temporal lobes, is the key brain structure for memory consolidation and storage.

The researchers “aimed to elucidate whether higher glycosylated hemoglobin (HbA1c) and glucose levels exert a negative impact on memory performance and hippocampal volume and microstructure in a cohort of healthy, older, nondiabetic individuals without dementia.”

Learning tests, blood levels of HbA1c, glucose, and insulin, and advanced (3-tesla) MRI scans were performed on 141 persons  (72 women & 69 men) with an average age of 63. Those with lower glucose and HbA1c levels had better learning and memory and a healthier hippocampi:

“Lower HbA1c and glucose levels were significantly associated with better scores in delayed recall, learning ability, and memory consolidation. …Moreover, mediation analyses indicated that beneficial effects of lower HbA1c on memory are in part mediated by hippocampal volume and microstructure.”

The authors concluded:

“Our results indicate that even in the absence of manifest type 2 diabetes mellitus or impaired glucose tolerance, chronically higher blood glucose levels exert a negative influence on cognition, possibly mediated by structural changes in learning-relevant brain areas. Therefore, strategies aimed at lowering glucose levels even in the normal range may beneficially influence cognition in the older population, a hypothesis to be examined in future interventional trials.

Source:  Higher glucose levels associated with lower memory and reduced hippocampal microstructure 

Related Post:  Even mild elevations in blood sugar increase risk of dementia