DIETARY BORON, BRAIN-FUNCTION, AND COGNITIVE PERFORMANCE

Although the trace element boron has yet to be recognized as an essent ial nutrient for humans, recent data from animal and human studies sug gest that boron may be important for mineral metabolism and membrane f unction. To investigate further the functional role of boron, brain el ectrophysiology and cognitive performance were assessed in response to dietary manipulation of boron (approximate to 0.25 versus approximate to 3.25 mg boron/2000 kcal/day) in three studies with healthy older m en and women. Within-subject designs were used to assess functional re sponses in all studies. Spectral analysis of electroencephalographic d ata showed effects of dietary boron in two of the three studies. When the low boron intake was compared to the high intake, there was a sign ificant (p<0.05) increase in the proportion of low-frequency activity, and a decrease in the proportion of higher-frequency activity. an eff ect often observed in response to general malnutrition and heavy metal toxicity. Performance (e.g., response time) on various cognitive and psychomotor tasks also showed an effect of dietary boron. When contras ted with the high boron intake, low dietary boron resulted in signific antly poorer performance (p<0.05) on tasks emphasizing manual dexterit y (studies II and III); eye-band coordination (study II); attention (a ll studies); perception (study III); encoding and short-term memory (a ll studies); and long-term memory (study I). Collectively, the data fr om these three studies indicate that boron may play a role in human br ain function and cognitive performance, and provide additional evidenc e that boron is an essential nutrient for humans.