Coffee, but not caffeine, has positive effects on cognition and psychomotor behavior in aging

Abstract

The complex mixture of phytochemicals in fruits and vegetables provides protective health benefits, mainly through additive and/or synergistic effects. The presence of several bioactive compounds, such as polyphenols and caffeine, implicates coffee as a potential nutritional therapeutic in aging. Moderate (three to five cups a day) coffee consumption in humans is associated with a significant decrease in the risk of developing certain chronic diseases. However, the ability of coffee supplementation to improve cognitive function in aged individuals and the effect of the individual components in coffee, such as caffeine, have not been fully evaluated. We fed aged rats (19 months) one of five coffee-supplemented diets (0, 0.165, 0.275, 0.55, and 0.825% of the diet) for 8 weeks prior to motor and cognitive behavior assessment. Aged rats supplemented with a 0.55% coffee diet, equivalent to ten cups of coffee, performed better in psychomotor testing (rotarod) and in a working memory task (Morris water maze) compared to aged rats fed a control diet. A diet with 0.55% coffee appeared to be optimal. The 0.165% coffee-supplemented group (three cups) showed some improvement in reference memory performance in the Morris water maze. In a subsequent study, the effects of caffeine alone did not account for the performance improvements, showing that the neuroprotective benefits of coffee are not due to caffeine alone, but rather to other bioactive compounds in coffee. Therefore, coffee, in achievable amounts, may reduce both motor and cognitive deficits in aging.

Figures

Fig. 1

Latency to fall (mean ± SEM, seconds) in the rotarod test for the control and coffee groups. Means with different letters are significantly different from each other (p < 0.05; Fisher’s LSD)

Fig. 2

Morris water maze performance assessed as latency in seconds (a; mean ± SEM) and distance in meters (b) to find the hidden platform on days 3 and 4 of testing animals in the control and coffee groups. The asterisks indicate a difference (i.e., an improvement) between Trial 1 and Trial 2 performances (one asterisk indicates p < 0.05, two asterisks p < 0.01), indicating improved working memory. Number sign indicates p < 0.05, compared to control

Fig. 3

Latency to fall (mean ± SEM, seconds) in the inclined screen test for the control, coffee, and caffeine groups. Means with different letters are significantly different from each other (p < 0.05; Fisher’s LSD)

Fig. 4

Morris water maze performance assessed as latency in seconds (a; mean ± SEM) and distance in meters (b) to find the hidden platform on days 3 and 4 of testing animals in the control, coffee, and caffeine groups. The asterisks indicate a difference (i.e., an improvement) between Trial 1 and Trial 2 performances (one asterisk indicates p < 0.05, two asterisks p < 0.01), indicating improved working memory. Commercial at indicates p < 0.05 compared to the ten-cup group