Table 4.
Summary of studies examining the effects of manipulating glycemic response on cognitive performance domains.
| Authors | Sample Size (Age) | Intervention | Design (Within or Between Subjects) |
Cognitive Outcomes | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Verbal Episodic Memory | Executive Function | Working Memory | Attention | Processing Speed/RT | Problem Solving | Moderating Effect of Postprandial Glycemic Response | ||||
| Benton et al. 2003 [137] | 71 (M = 21) |
High-SAG biscuit, 50 g: 34 g CHO (8 g SAG + 20 g RAG, GI = 42) vs. Low-SAG cereal bar, 50 g: 31 g CHO (0.05 g SAG + 21 g RAG, GI = 66) | Between (overnight fast) | O | Enhanced after low GI at 150 & 210 min | |||||
| Benton & Nabb 2004 [136] | 323 (M = 21) |
No breakfast vs. High-SAG biscuit, 50 g: 34 g CHO (7.9 g SAG, 18.8 g RAG, GI = 42) vs. Low-SAG cereal bar, 49 g: 34 g CHO (0.4 g SAG + 21.6 g RAG, GI = 66) or (0.05 g SAG + 21.10 g RAG) |
Between (overnight fast) | O | − | Enhanced after low GI at 210 min | ||||
| Nabb & Benton, 2006b [139] | 189 (M = 20) |
8 breakfast conditions differing in energy (114–407 kcal), & contained either low or high levels of CHO (24 or 59 g), fat (1 or 16 g) or proteins (2 or 10 g) |
Between (overnight fast) | O | O | O | Episodic: better glucose tolerance, low caloric intake & lower levels of blood glucose = enhanced performance. RT & vigilance: better glucose tolerance, higher levels of blood glucose = faster RT and better vigilance | |||
| Nabb & Benton, 2006a [138] | 168 (M = 20) |
8 breakfast conditions differing in contents of available CHO and dietary fiber: Low carb (15 g) with low or medium DF [100 mL milk vs. Medium CHO (30 g) with low, medium or high DF [200 mL milk] vs. High CHO (50 g) with low, medium or high DF [200 mL milk] |
Between | O | Episodic: high carb meal + better glucose tolerance = forgot less words vs. poor glucose tolerance ppts. Poor glucose tolerance + low carb meal = forgot less words vs. high carb meal & poorer word recall after low vs. high fiber. Attention: better glucose tolerance + medium and high carb meals = faster RT (90 min) | |||||
| Smith & Foster, 2008 [6] | 36 (M = 15.6) |
30 g All-Bran (GI = 30) vs. 30 g Cornflakes (GI = 77). Served with 125 mL of milk |
Between (overnight fast) | − a O a | Episodic: no effect on verbal learning. High GI = fewer items forgotten in long delay recall vs. short delay (vs. low GI) | |||||
| Micha et al. 2010 [135] | 60 (M = 13) |
Classification of habitual breakfast intake into 4 groups: HIGH GL:low or high GI and LOW GL:low or high GI | Between (overnight fast) | O a,1 − b | − | O 2 | O 2 | O 3 | Fractionation of effects on specific cognitive tests by GL and GI breakfast forms. Enhancing effects in High GL forms which were associated with higher BG levels ~120 min post ingestion | |
O Significant effect;—No effect; X Impairment GL—glycemic load; GI—glycemic index; SAG—slowly available glucose; RAG—rapidly available glucose; CHO—carbohydrate; DF—dietary fiber; ᵃ Effects under dual task paradigm; b Immediate word recall; 1 High GI breakfast only; 2 Low-GI, high-GL breakfast only; 3 High-GL breakfast only.