Carbohydrates consist of sugars, oligosaccharides, and polysaccharides. These components are found in a large range of foods in the diet and have variable effects on digestion, blood sugar levels, and impacts on health. Despite the evidence accumulated from biological and epidemiological studies and non-randomised clinical trials, there are still no randomised, controlled trials for analysing the efficacy and safety of carbohydrates in improving cognitive performance in this review. Thus, we need more studies on different types of carbohydrates, particularly those from fruit, vegetable and whole grain sources, for older adults with normal cognition and mild cognitive impairment in order to understand the role of this nutrient in the prevention or reduction of cognitive decline.
Mild cognitive impairment (MCI) is an intermediate state between normal cognition and dementia in which daily function is largely intact. This condition may present an opportunity for research into the prevention of dementia. Carbohydrate is an essential and easily accessible macronutrient which influences cognitive performance. A better understanding of carbohydrate-driven cognitive changes in normal cognition and mild cognitive impairment may suggest ways to prevent or reduce cognitive decline.
To assess the effectiveness of carbohydrates in improving cognitive function in older adults.
We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialized Register on 22 June 2010 using the terms: carbohydrates OR carbohydrate OR monosaccharides OR disaccharides OR oligosaccharides OR polysaccharides OR CARBS. ALOIS contains records from all major healthcare databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many trial databases and grey literature sources.
All randomised controlled trials (RCT) that have examined the efficacy of any form of carbohydrates in normal cognition and MCI.
One review author selected and retrieved relevant articles for further assessment. The remaining authors independently assessed whether any of the retrieved trials should be included. Disagreements were resolved by discussion.
There is no suitable RCT of any form of carbohydrates involving independent-living older adults with normal cognition or mild cognitive impairment.
There are no suitable RCTs on which to base any recommendations about the use of any form of carbohydrate for enhancing cognitive performance in older adults with normal cognition or mild cognitive impairment. More studies of many different carbohydrates are needed to tease out complex nutritional issues and further evaluate memory improvement.