Lactotripeptide ingestion increases cerebral blood flow velocity in middle-aged and older adults

Long-term effects of an egg-protein hydrolysate on cognitive performance and brain vascular function: a double-blind randomized controlled trial in adults with elevated subjective cognitive failures

PURPOSE

Short-term intake of the egg-protein hydrolysate Newtricious (NWT)-03 improved executive function, but underlying mechanisms and long-term effects, including other cognitive domains, are unknown.

METHODS

A 36-week randomized controlled trial involving 44 overweight/obese individuals experiencing elevated Subjective Cognitive Failures (SCF; aged 60-75 years) assessed the impact of daily consumption of 5.7 g of NWT-03 or placebo powders on cognitive performance (psychomotor speed, executive function, memory) and Cerebral Blood Flow (CBF), a marker of brain vascular function. Cognitive performance was evaluated using a neurophysiological test battery (CANTAB) and CBF was measured using magnetic resonance imaging perfusion method Arterial Spin Labeling (ASL). Serum samples were collected to determine brain-derived neurotrophic factor (BDNF) concentrations.

RESULTS

Anthropometrics, and energy and nutrient intakes remained stable throughout the trial. NWT-03 was well tolerated, and compliance was excellent (median: 99%; range: 87-103%). No overall intervention effects were observed on cognitive performance or CBF, but post-hoc analyses revealed significant improvements on executive function in women, but not men. Specifically, a reduction of 74 ms in reaction latency on the multitasking task (95% CI: -134 to -15; p = 0.02), a reduction of 9 between errors (95%CI: -14 to -3; p < 0.001), and a reduction of 9 total errors (95%CI: -15 to -3; p < 0.001) on the spatial working memory task were found in women. No intervention effects were observed on serum BDNF concentrations (p = 0.31).

CONCLUSION

Long-term consumption of NWT-03 improved multitasking abilities and working memory in women with elevated SCF. Brain vascular function remained unaffected. Sex differences in executive function require additional clarification.

Effects of lactotripeptide ingestion and physical activity intervention on the fatigue status of middle-aged and older adults: a randomized controlled trial

This randomized controlled trial aimed to investigate the effects of eight weeks of lactotripeptide (LTP) ingestion, physical activity (PA) intervention, and combined intervention on the fatigue status of middle-aged and older adults. A total of 78 middle-aged and older adults (63 ± 8 years of age) were randomly assigned to four groups: placebo, LTP, placebo with PA intervention (placebo + PA), and LTP with PA intervention (LTP + PA). All participants ingested the placebo or LTP tablets daily (three tablets/day). The placebo + PA and LTP + PA groups participated in a weekly supervised exercise class and were instructed to increase their moderate- to vigorous-intensity PA at home. The visual analog scale, Brief Fatigue Inventory, Profile of Mood States second edition (POMS2), and Beck Depression Inventory second edition (BDI-II) were administered before and after the intervention. No significant interactions or main effects were observed between LTP ingestion and PA intervention on any of the fatigue scales. The main-effect analyses revealed that the PA intervention improved the total mood disturbance score of the POMS2 (F = 5.22, P = 0.03) and BDI-II score (F = 4.81, P = 0.03). After the post hoc paired comparisons, the total mood disturbance and BDI-II scores improved more with the combined intervention than with the PA intervention alone (percentage difference between the effect of combined intervention and PA intervention alone was 3.7% for total mood disturbance score and 13.7% for BDI-II score). The present study suggests that eight weeks of LTP ingestion and PA intervention did not have a significant effect on fatigue status. However, the PA intervention improved mood status and depressive symptoms, and these effects were enhanced by LTP ingestion.

The biological role of prolyl oligopeptidase and the procognitive potential of its peptidic inhibitors from food proteins

Prolyl oligopeptidase (POP) is a conserved serine protease belonging to proline-specific peptidases. It has both enzymatic and non-enzymatic activity and is involved in numerous biological processes in the human body, playing a role in e.g., cellular growth and differentiation, inflammation, as well as the development of some neurodegenerative and neuropsychiatric disorders. This article describes the physiological and pathological aspects of POP activity and the state-of-art of its peptidic inhibitors originating from food proteins, with a particular focus on their potential as cognition-enhancing agents. Although some milk, meat, fish, and plant protein-derived peptides have the potential to be applied as natural, procognitive nutraceuticals, their effectiveness requires further evaluation, especially in clinical trials. We demonstrated that the important features of the most promising POP-inhibiting peptides are very short sequence, high content of hydrophobic amino acids, and usually the presence of proline residue.

Effect of Casein Hydrolysate on Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Casein hydrolysate has various biological functional activities, especially prominent are angiotensin I-converting enzyme inhibitory activities. Increasing evidence has reported the prominent hypotensive effect of casein hydrolysate. However, the effects of casein hydrolysate on cardiovascular risk factors remain unclear and require more comprehensive and detailed studies. Here, we conducted a systematic review and meta-analysis on eligible randomized controlled trials (RCTs) to summarize the effects of casein hydrolysate supplementation on blood pressure, blood lipids, and blood glucose. In the pooled analyses, casein hydrolysate significantly reduced systolic blood pressure by 3.20 mmHg (-4.53 to -1.87 mmHg) and diastolic blood pressure by 1.50 mmHg (-2.31 to -0.69 mmHg). Supplementation of casein hydrolysate displayed no effect on total cholesterol (-0.07 mmol/L; -0.17 to 0.03 mmol/L), low-density lipoprotein cholesterol (-0.04 mmol/L; -0.15 to 0.08 mmol/L), high-density lipoprotein cholesterol (-0.01 mmol/L; -0.06 to 0.03 mmol/L), triglycerides (-0.05 mmol/L, -0.14 to 0.05 mmol/L), or fasting blood glucose (-0.01 mmol/L; -0.10 to 0.09 mmol/L) compared with the placebo diets. Collectively, this study indicated that supplementation of casein hydrolysate displayed decreasing effect on blood pressure without affecting blood lipids or glycemic status.

Conventional and in silico approaches to select promising food-derived bioactive peptides: A review

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Seaweed and edible insects are considered new sources of bioactive peptides.

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Conventional approaches are necessary to validate the bioactivity of peptides.

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Bioinformatics tools accelerate the obtaining of bioactive peptides.

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The integrated approach is a promising strategy to obtain bioactive peptides.

The interest for food-derived bioactive peptides, either from common or unconventional sources, has increased due to their potential therapeutic effect against a wide range of diseases. The study of such bioactive peptides using conventional methods is a long journey, expensive and time-consuming. Hence, bioinformatic approaches, which can not only help to predict the formation of bioactive peptides from any known protein source, but also to analyze the protein structure/function relationship, have gained a new meaning in this scientific field. Therefore, this review aims to provides an overview of conventional characterization methods and the most recent advances in the field of in silico approaches for predicting and screening promising food-derived bioactive peptides.

Release of Leu-Pro-Pro from corn gluten meal by fermentation with a Lactobacillus helveticus strain

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitory peptides are potential alternatives to the synthetic ACE inhibitory drugs, but the in vivo antihypertensive effects of most of them have not been confirmed. The tripeptide Leu-Pro-Pro (LPP) is one of the few peptides that have been proved clinically effective in reducing the blood pressure of hypertensive patients and casein is currently its major source. LPP is contained in multiple fractions of zein, and corn gluten meal (CGM) is hence a potential new source of LPP. For this purpose, CGM was fermented with a Lactobacillus helveticus strain and the medium composition was optimized; the decoloration of the resultant hydrolysate was investigated as well.

RESULTS

LPP could be successfully released from CGM by fermentation with the strain Lactobacillus helveticus CICC 22536. The highest LPP content and protein recovery of 561 mg kg^-1 and 14.92% occurred in the medium containing 20 g L^-1 glucose, 15 g L^-1 beef extract, 60 g L^-1 CGM, 10 g L^-1 CaCO₃ , 0.5 g L^-1 NaCl, and inoculation amount 6%. The supplementation of Flavourzyme® further improved the two parameters to 662 mg kg^-1 and 36.94%, respectively. The permeate of the hydrolysate after ultrafiltration through a 5 kDa membrane could be effectively decolored by the macroporous resin XAD-16 without notable protein loss, and its LPP content was further boosted to 743 mg kg^-1 .

CONCLUSION

CGM is a potential new source of LPP and its ultrafiltered and decolored hydrolysate could be used to develop new antihypertensive functional foods. © 2021 Society of Chemical Industry.

Effects of Dietary Food Components on Cognitive Functions in Older Adults

Population aging has recently been an important issue as the number of elderly people is growing worldwide every year, and the extension of social security costs is financially costly. The increase in the number of elderly people with cognitive decline is a serious problem related to the aging of populations. Therefore, it is necessary to consider not only physical care but also cognitive patterns in the future care of older adults. Since food contains a variety of bioactive substances, dietary patterns may help improve age-related cognitive decline. However, the relationship between cognitive function and individual food components remains ambiguous as no clear efficacy or mechanism has been confirmed. Against this background, this review summarizes previous reports on the biological process of cognitive decline in the elderly and the relationship between individual compounds in foods and cognitive function, as well as the role of individual components of food in cognitive function, in the following order: lipids, carotenoids, vitamins, phenolic compounds, amino acids, peptides, and proteins. Based on the research presented in this review, a proper diet that preserves cognitive function has the potential to improve age-related cognitive decline, Alzheimer's disease, and Parkinson's disease. Hopefully, this review will help to trigger the development of new foods and technologies that improve aging and cognitive functions and extend the healthy life span.

The Effects of Cow-Milk Protein Supplementation in Elderly Population: Systematic Review and Narrative Synthesis

BACKGROUND

To review currently available evidence on the effect of cow-milk proteins supplementation (CPS) on health in the elderly.

METHODS

Five electronic databases (Pubmed, Web of Science, Embase, Cochrane Library, ClinicalTrials.gov) were searched for studies about CPS among older people. All types of publications were included, with the exception of systematic reviews, meta-analyses, opinion letters, editorials, case reports, conference abstracts and comments. An additional search in Google Scholar and a manual review of the reference lists were performed.

RESULTS

Overall, 103 studies were included. Several studies explored the role of CPS in the preservation or improvement of muscle mass among healthy subjects (40 studies) and pre-frail, frail or sarcopenic patients (14), with evidence of beneficial effects. Other studies assessed the effect of CPS on bones (12), cardiovascular disease (8), inflamm-aging (7), chronic pulmonary disease (4), neurocognitive function (4), and vaccines (2), with weak evidence of positive effects. Seven studies in the field of protein metabolism investigated the role of CPS as an important contributor to nutritional needs. Other investigational areas are considered in the last five studies.

CONCLUSIONS

The beneficial effects of CPS in achieving aged-related nutritional goals, in preserving muscle mass and in recovering after hospitalization may be particularly relevant in the elderly.

Effect of sleep efficiency on salivary metabolite profile and cognitive function during exercise in volleyball athletes

PURPOSE

Sleep duration is known to affect physiological and circadian metabolites and human homeostasis. However, little is known about the relationship between sleep quality and metabolite and cognitive function during exercise. Therefore, the aim of the present study was to investigate the impact of sleep quality on metabolite level and cognitive function in female volleyball athletes.

METHODS

Twelve female volleyball athletes participated in this study. Sleep efficiency was measured for 1 week using NemuriSCAN (Paramount Bed Co. Ltd., Japan) as an index of sleep quality. The subjects were divided into better (n = 6) and lesser (n = 6) sleep quality groups by the median value of sleep efficiency. Saliva samples were collected using a Salimetric oral swab cotton and salivary metabolites were analysed using capillary electrophoresis and time-of-flight mass spectrometry. The subjects performed Stroop tasks (simple and difficult tasks) at rest and during aerobic exercise in recumbent cycle ergometer at light and heavy intensity.

RESULTS

Increased sleep efficiency was found in the better sleep quality group, whereas total sleep time was similar. There were differences in urea cycle and Krebs cycle metabolites between the two groups; their levels were correlated with sleep efficiency. The difficult-task response time during heavy exercise was faster in the better sleep quality group.

CONCLUSION

We demonstrated that sleep efficiency was associated with urea cycle and Krebs cycle metabolite levels and response time during heavy exercise in volleyball athletes. These results suggested that sleep quality may affect amino acid and energy metabolism and cognitive function during heavy exercise.

Combined effects of lactotripeptide and aerobic exercise on cognitive function and cerebral oxygenation in middle-aged and older adults

Background

Age-related declines in cognitive function and cerebral perfusion increase the risk of dementia. Although nutrition and exercise may be effective in reducing cognitive decline, the effect of lactotripeptide (LTP) on cerebral oxygenation and hemodynamics remains unclear.

Objectives

The aim of this study was to investigate the effects of LTP ingestion on cerebral oxygenation, cognitive function, and vascular function in middle-aged and older adults with or without an exercise intervention.

Methods

We recruited 2 separate groups of participants, one with and one without an exercise intervention. Each group was then randomly assigned into a placebo group and an LTP group. The participants ingested a placebo or LTP every day. The exercise group performed aerobic exercises 4-6 d/wk. Before and after the 8-wk intervention, we measured oxygenated hemoglobin (oxy-Hb) concentration (oxy-Hb change) in the prefrontal cortex during the Stroop task (primary outcome), Stroop interference time, and carotid artery β-stiffness (both secondary outcomes).

Results

Sixty-four participants completed the study. Changes in oxy-Hb signal in the prefrontal cortex were greater in the LTP group than in the placebo group under both the exercise and nonexercise conditions (P < 0.05). In addition, the magnitude of improvement in the oxy-Hb change in the left prefrontal cortex was correlated with Stroop interference (r = -0.39, P < 0.05) and carotid β-stiffness (r = -0.41, P < 0.05).

Conclusions

An 8-wk intake of LTP increased cerebral oxygenation in the prefrontal cortex region in middle-aged and older adults, with and without exercise. The intervention-induced improvements in brain neural activation were associated with cognitive and vascular function. This trial was registered at www.umin.ac.jp as UMIN000022313.

Central artery stiffness is related to cerebral oxygenation hemodynamics during executive function tasks in healthy middle-aged and older adults

Age-related decreases in cognitive function, cerebral perfusion, and vascular function increase the risk of dementia. However, the effects of central artery stiffness on cerebral oxygenation hemodynamics during executive function tasks and executive function remain unclear. The aim of this cross-sectional study was to investigate the relationships among central artery stiffness, cerebral oxygenation hemodynamics during executive function tasks, and executive function in middle-aged and older adults. Sixty-two middle-aged and older adults (age range: 51-79 years) were recruited for this study. For each participant, we measured the carotid artery β-stiffness, oxygenated hemoglobin (oxy-Hb) signal change in the prefrontal cortex during the Stroop task, and Stroop interference time. Correlation analyses revealed that the carotid artery β-stiffness was significantly correlated with the Stroop interference time (r = 0.43, P < 0.001) and with the oxy-Hb signal change in the left (r = -0.38, P = 0.002), but not the right, prefrontal cortex. In addition, the Stroop interference time was significantly correlated with the oxy-Hb signal change in the left (r = -0.42, P = 0.001), but not the right, prefrontal cortex. The participants were divided into the low and high arterial stiffness groups according to the median value. We found that the Stroop interference time was significantly shorter (P = 0.006) and the oxy-Hb signal change in the left prefrontal cortex was significantly larger in the low arterial stiffness group than in the high arterial stiffness group (P = 0.011). In the low, but not the high, arterial stiffness group, the oxy-Hb signal change of the left prefrontal cortex during executive function tasks was significantly larger than the oxy-Hb signal change of the right prefrontal cortex (P = 0.014). These results suggest that increases in central artery stiffness are associated with decreases in oxygenation hemodynamics in the left prefrontal cortex during executive function tasks and reductions in executive function.