Table 3.
Summary of articles on the role of IF in dementia management in humans
| Study name (year) | Population | Methodology | Outcomes and conclusion | |
|---|---|---|---|---|
| Prehn et al. [22] | 37 postmenopausal women aged 40–80 years old with a BMI >27 kg/m2 | Participants were randomized into • CR group (n = 19) • Control group (n = 18) and assessed at baseline, after 12 weeks, and after 16 weeks. CR group had 8 weeks of 800 kcal/day, following 4 weeks of weight maintenance phase |
• After 12 weeks, CR group found to have a better memory performance, learning, delayed recall compared to the control group • No significant improvement in recognition and memory performance found after 16 weeks • A significant increase in gray matter density in bilateral inferior frontal gyrus in the CR compared to the control group after 12 weeks (p < 0.05) but not at 16 weeks |
|
| Trevizol [19] | 220 subjects, ages 21–50 with an initial BMI of 22–28 | Participants were randomized for 2 years to • 25% CR (n = 145) • Ad libitum diet (n = 75) Possible moderator effects of sleep problems, mood disturbances, perceived stress, and physical activity on longitudinal changes of IL-6 levels in the sample, as well as the effects of CR. |
• Both groups displayed a decrease in IL-6 peripheral levels in 12 and 24 months • A reduction in IL-6 level was associated with improvements in working memory tests, and to a greater degree working memory tasks |
|
| Horie et al. [20] | 80 participants with MCI, ages 60 and above | Participants were randomized into 2 groups • Conventional medical care and brief lifestyle change counseling (n = 40) • Conventional medical care and CR counseling with nutritionist (n = 40) Subjects were followed up for 12 months |
• A decrease in BMI through CR in obese subjects with MCI was safe and correlated with improvements in memory, executive function, global cognition, and language; this association was strongest in younger seniors and in APOE4 carriers | |
| Kim et al. [17] | 45 healthy, non-smoking subjects aged 35–75 years with a waist circumference of greater than 102 cm in men and 88 cm in women | Subjects were randomized into • Continuous CR (n = 22); with a daily deficit of 500 kcals • Intermittent CR (n = 23); 600 kcal for two consecutive days each week All endpoint measurements were taken in duplicate after four to 5 weeks of the dietary intervention |
• No significant difference in cognitive changes between the two diets • A significant decrease in recognition memory performance in the intermittent CR group compared to the continuous CR group |
|
| Martin et al. [18] | 48 overweight (BMI 25–30 kg/m2) adults ages 25–50 years |
Participants were randomized for 6 months to • Control (weight maintenance diet) (n = 12) • 25% CR (n = 12) • CR plus structured exercise (12.5% CR plus 12.5% increase in energy expenditure via structured exercise) (n = 12) • Low-calorie diet (890 kcal/d liquid formula diet until 15% of body weight was lost, followed by weight maintenance) (n = 12) |
• CR trial did not indicate a significant change in short-term verbal memory at 3- or 6-month follow-up • Performance on the Auditory Consonant Trigram for 9- and 18-second delay conditions trials improved significantly at months 3 and 6 months • Visual perception and memory were not negatively affected during the trial |
|
| Cheatham et al. [23] | 46 healthy, overweight (BMI 25–29.9 kg/m2) adults ages 20–42 years | Subjects were randomized to receive a high-glycemic or low-glycemic diet and one of two levels of CR (10% or 30% relative to baseline energy requirements). 34 subjects randomized to the 30% CR groups and 12 subjects to the 10% CR groups | • No effect on changes in cognition in either high- or low-glycemic weight loss at 6 months follow-up • High-glycemic diet was associated with increase signs of subclinical depression |
|
| Peven et al. [16] | 125 subjects aged 18–55 with BMI ranging from 25.0 to 39.9 kg/m2 | Subject were randomized for a 12-month follow-up into • Diet only (n = 50); 1,200–1,800 kilocalories per day (kcal/day) based on baseline body weight • Diet + moderate exercise (n = 30) prescribed exercise regimen progressed from 100 to 150 min per week by week 9 of the intervention • Diet + high exercise (n = 45), prescribed exercise that progressed from 100 to 250 min per week by week 25 |
• Weight loss alone was not sufficient to induce improvements in executive functions and reward processing, and supported studies that did not show intervention effects on cognition • Engaging in exercise yielded greater cognitive gains over a 12-month follow-up than weight loss through diet alone |
|
| Smith et al. [21] | 124 overweight (BMI from 25 to 40 kg/m2) | Participants were randomized into • DASH diet alone (n = 38) • DASH + weight management (n = 43) • Usual care control (n = 43) Following assessment of executive function, memory, learning, and psychomotor speed before and after a 4-month treatment program |
DASH diet associated with CR and aerobic exercise improved neurocognitive performance among individuals with high blood pressure, especially among individuals with poorer vascular health | |
| Espeland et al. [15] | 5,145 subjects aged 45–76 years, with BMI >25 kg/m2 overweight or obese with type 2 diabetes, and with no major cognitive deficits | Participants randomly assigned for a 10-year follow-up to • Intensive lifestyle intervention (n = 2,540), daily calorie goal (1,200–1,800 based on initial weight), and ≥175 min/week physical activity • Control diabetes support and education (n = 2,544) Participants were queried about difficulties with three cognitive abilities at baseline and repeated over time. Memory, thinking and problem-solving, decision-making, and depression |
• Intensive lifestyle intervention was associated with fewer complaints about difficulties in decision-making and problem-solving ability, especially in nonobese, but not memory deficit It was found that intensive lifestyle intervention may have worsened the severity of complaints about problem-solving ability among individuals with cardiovascular disease history |
APOE, apolipoprotein E; BMI, body mass index; CR, caloric restriction; DASH, Dietary Approaches to Stop Hypertension; IF, intermittent fasting; IL-6, interleukin-6; MCI, mild cognitive impairment.