Longer-term soy nut consumption improves cerebral blood flow and psychomotor speed: results of a randomized, controlled crossover trial in older men and women

BACKGROUND: Effects of soy foods on cerebral blood flow (CBF)—a marker of cerebrovascular function—may contribute to the beneficial effects of plant-based diets on cognitive performance. OBJECTIVES: We aimed to investigate longer-term effects of soy nut consumption on CBF in older adults. Changes in 3 different domains of cognitive performance were also studied. METHODS: Twenty-three healthy participants (age: 60–70 y; BMI: 20–30 kg/m(2)) participated in a randomized, controlled, single-blinded crossover trial with an intervention (67 g/d of soy nuts providing ∼25.5 g protein and 174 mg isoflavones) and control period (no nuts) of 16 wk, separated by an 8-wk washout period. Adults followed the Dutch food-based dietary guidelines. At the end of each period, CBF was assessed with arterial spin labeling MRI. Psychomotor speed, executive function, and memory were assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB). RESULTS: No serious adverse events were reported, and soy nut intake was well tolerated. Body weights remained stable during the study. Serum isoflavone concentrations increased (daidzein mean difference ± SD: 128 ± 113 ng/mL, P < 0.001; genistein: 454 ± 256 ng/mL, P < 0.001), indicating excellent compliance. Regional CBF increased in 4 brain clusters located in the left occipital and temporal lobes (mean ± SD increase: 11.1 ± 12.4 mL · 100 g(−1) · min(−1), volume: 11,296 mm(3), P < 0.001), bilateral occipital lobe (12.1 ± 15.0 mL · 100 g(−1) · min(−1), volume: 2632 mm(3), P = 0.002), right occipital and parietal lobes (12.7 ± 14.3 mL · 100 g(−1) · min(−1), volume: 2280 mm(3), P = 0.005), and left frontal lobe (12.4 ± 14.5 mL · 100 g(−1) · min(−1), volume: 2120 mm(3), P = 0.009) which is part of the ventral network. These 4 regions are involved in psychomotor speed performance, which improved as the movement time reduced by (mean ± SD) 20 ± 37 ms (P = 0.005). Executive function and memory did not change. CONCLUSIONS: Longer-term soy nut consumption may improve cerebrovascular function of older adults, because regional CBF increased. Effects may underlie observed improvements in psychomotor speed. This trial was registered at clinicaltrials.gov as NCT03627637

Circadian rhythm parameters and physical activity associated with cardiometabolic risk factors in the PREVIEW lifestyle study

ObjectiveThe aim of this study was an assessment of post hoc associations among circadian rhythm parameters, physical activity (PA), and cardiometabolic risk factors in adults with obesity and prediabetes after 3 years of weight loss maintenance. MethodsCircadian rhythm parameters (continuous wrist-temperature measurements), PA, systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), plasma high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, remnant cholesterol, triacylglycerol, and C-reactive protein (CRP) concentrations were determined in 91 free-living participants (mean [SD], age = 56.6 [10] years; BMI = 28.2 [4.0]; homeostatic model assessment of insulin resistance [HOMA-IR] = 3.2 [3.1]) and in 38 participants in sedentary respiration chamber conditions (age = 56.6 [10] years; BMI = 28.5 [4.0]; HOMA-IR = 3.3 [1.4]). Associations of circadian rhythm parameters and PA with cardiometabolic risk factors were determined using factor analyses followed by Pearson correlations. ResultsValues of cardiometabolic risk factors were similar, whereas circadian rhythm parameters and PA differed significantly (p &lt; 0.05) between conditions. In both conditions, parameters indicating a robust circadian rhythm associated inversely with CRP and positively with plasma HDL-C concentrations. In free-living conditions, PA associated inversely with SBP and HR and positively with HDL-C and robust circadian rhythm parameters. In sedentary conditions, PA associated positively with HR and inversely with robust circadian rhythm parameters. PA mediated the inverse association of parameters indicating a robust circadian rhythm with SBP in free-living conditions. ConclusionsIn adults with obesity and prediabetes, parameters indicating a robust circadian rhythm were, independently of PA, associated with lower cardiometabolic risk and CRP. Only in free-living conditions, PA mediated the association of higher circadian stability with lower SBP