The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial

BACKGROUND & AIMS

Sleep quality is a pivotal part of health and there is growing evidence on the association between gut microbiota composition and sleep quality. 5-Hydroxytryptophan (5-HTP) is known as a precursor of the sleep regulating neurotransmitter and hormone. However, efficacy of 5-HTP supplementation for improving sleep quality in older adults is unclear. Hence, the aim of this study is to assess the impact of 5-HTP supplementation on sleep quality and gut microbiota composition in older adults.

METHODS

This is a single-blinded, 12-week parallel randomized controlled trial. Thirty older adults (66 ± 3 years) in Singapore were randomly assigned to either consume or not consume 100 mg 5-HTP daily. Every 4 weeks, sleep quality was assessed via both subjective (Pittsburg Sleep Quality Index) and objective (actigraphy watch) measures. A global sleep score (GSS) was obtained from the PSQI, where a GSS>5 defines as poor sleeper while a GSS≤5 defines as good sleeper. Blood serotonin level, urine melatonin concentration, gut microbiota composition and stool short chain fatty acids (SCFA) content were assessed at week 0 and 12. This study was registered in clinicaltrials.gov as NCT04078724 (https://clinicaltrials.gov/ct2/show/NCT04078724).

RESULTS

5-HTP supplementation showed an overall favorable effect on certain sleep quality components and an increase in serum serotonin concentration. In particular, at week 12, not good sleepers but poor sleepers with 5-HTP supplementation were able to significantly improve subjective GSS (ΔSL5-HTP: -2.80 ± 1.10 min, p-value = 0.005). In addition, they showed an increase in microbiota diversity (Simpson5-HTP vs. SimpsonControl: 0.037 ± 0.032 a.u. vs. -0.007 ± 0.022 a.u.; pinteraction: 0.013) and relative abundance of SCFA producing bacteria in the gut.

CONCLUSIONS

5-HTP supplementation can improve certain sleep quality components in older adults and this benefit was more prominently observed in poor sleepers. 5-HTP was also able to improve the gut microbiota composition in poor sleepers.

Regular Consumption of Biovalorized Okara-Containing Biscuit Improves Circulating Short-Chain Fatty Acids and Fecal Bile Acids Concentrations by Modulating the Gut Microbiome: A Randomized Controlled Crossover Trial

SCOPE

Okara is a fiber-rich food by-product whereby biovalorization with Rhizopus oligosporus can improve its nutritional quality, generating fermentable substrates for improved gut health maintenance. This study evaluates the impact of okara- and biovalorized okara-containing biscuits consumption on gut health in Singapore adults.

METHODS AND RESULTS

Participants consumed control (C), 20% flour-substituted okara- (AOK) and biovalorized okara- (RO) biscuits for 3 weeks, with assessment of gut metabolites, microbiome, and dietary intake. Fecal valeric acid was significantly higher with RO compared to AOK (P = 0.005). RO and AOK had significantly higher total serum short-chain fatty acids (P = 0.002&0.018 respectively) and acetic acid (P = 0.007&0.030 respectively) compared to C. Higher serum propionic acid (P = 0.004) and lower fecal lithocholic acid (P = 0.009) were observed with RO. Although serum zonulin showed no significant difference, AOK reduced Clostridiales while RO increased Bifidobacterium.

CONCLUSION

Okara consumption improved serum SCFA regardless of fermentation while biovalorised okara further enhanced gut metabolites by modulating gut microbiome. This article is protected by copyright. All rights reserved.

Postprandial glycemic and circulating SCFA concentrations following okara- and biovalorized okara-containing biscuit consumption in middle-aged and older adults: a crossover randomized controlled trial

Okara is a high-fiber food by-product that can be biotransformed with Rhizopus oligosporus to improve its nutritional value and palatability. This research aims to assess postprandial changes in glycemic-related and lipid-related outcomes in middle-aged and older Singaporeans following okara- and biovalorized okara-containing biscuit consumption. Fifteen participants (58 ± 6 years old, mean ± SD) completed the randomized crossover study. Participants were provided control (C), okara (AOK)-, and biovalorized okara (RO)-containing biscuits in separate 4 h mixed meal tolerance tests. Serum glucose and insulin, insulin indices, serum short-chain fatty acids (SCFA) and lipid-lipoprotein panels, and sensory analysis were assessed. Glucose-stimulated insulin secretion was significantly lower for RO than for C (p: 0.035) while log insulin incremental area under the curve (AUC) was significantly lower for AOK compared to that for C (p: 0.023). The estimated insulin sensitivity index and estimated metabolic clearance rate were significantly higher for AOK compared to that for C (p: 0.025 and 0.016 respectively). Normalized AUC for total SCFA was significantly higher for RO compared to that for C (p: 0.038). Normalized AUC for LDL-cholesterol was significantly higher for AOK than for C (p: 0.010). No significant difference was noted for glucose, total cholesterol, HDL-cholesterol, and triglyceride concentrations. RO had greater flavor and overall liking than AOK (p: 0.007 and 0.017 respectively). Biscuits incorporated with okara or biovalorized okara can attenuate postprandial insulin responses. RO offered a greater SCFA response than C, indicating improved SCFA concentrations upon consumption of okara improved with fermentation. The trial was registered under https://www.clinicaltrials.gov (NCT03978104, 25 May 2019).

Biovalorized Okara Consumption Improves Gut Metabolites by Modulating Gut Microbiome: A Randomized Controlled Crossover Trial

Objectives

Okara is a major food by-product of soymilk or tofu production, particularly rich in dietary fiber. Biovalorization with Rhizopus oligosporus can improve its nutritional quality with greater soluble fiber, bioavailable isoflavones, and antioxidants. These nutrients are fermented by the gut microbiota to generate gut metabolites involved in gut health maintenance. This study evaluates the impact of okara and biovalorized okara- containing biscuits consumption on gut health in middle-aged and older Singaporeans.

Methods

Healthy participants (n = 15) of the crossover trial were randomly allocated to 3-week interventions of 100 g of control (C), 20% flour substituted autoclaved okara- (AOK), and 20% four substituted R. oligosporus biovalorized okara- (RO) containing biscuits, with 3-week washout periods. Pre- and post- intervention serum short-chain fatty acids (SCFA), fecal SCFA, fecal bile acids, serum zonulin, gastrointestinal symptoms, and dietary intakes were assessed. Pre- and post- intervention fecal 16S ribosomal RNA V3-V4 sequencing was also investigated for gut microbiome analysis. Results are presented as change value mean (95% confidence interval).

Results

Amongst fecal SCFA, only valeric acid (µmol/g) observed a significant difference, higher with RO compared to AOK (0.16 (0.01, 0.30) vs −0.20 (−0.34, −0.05), P = 0.005). RO and AOK had significantly higher total serum SCFA (P = 0.002 & 0.018 respectively) and serum acetic acid (P = 0.007 & 0.030 respectively) compared to C. RO had significant improvements with higher serum propionic acid (µmol/L) (RO: 3.04 (0.80, 5.27) vs C: −2.65 (−4.97, −0.33), P = 0.004) and lower fecal lithocholic acid (mg/g) (a secondary bile acid) (RO: −0.11 (−0.20, −0.02) vs C: 0.10 (0.01, 0.19), P = 0.009) contrasted to C. Although serum zonulin showed no significant difference, AOK induced a reduction in Clostridiales while RO increased Bifidobacterium. Okara consumption increased dietary fiber intake, with greater soluble fiber intake from RO compared to AOK and C (P = 0.018 & 0.019 respectively), aligning with the greater flatulence felt by participants on RO.

Conclusions

Okara consumption improved serum SCFA rather than fecal SCFA, regardless of fermentation. Biovalorized okara consumption further improved SCFA and bile acid profiles by modulating gut microbiome.

Funding Sources

Singapore Ministry of Education.

Effect of Okara and Biovalorized Okara Biscuits Consumption on Postprandial Circulating Amino Acid Concentrations: A Crossover Randomized Controlled Trial

Objectives

Soymilk or tofu production results in considerable okara (soybean pulp) generation. Although okara has a high protein content and contains all essential amino acids, its low water solubility and anti-nutrient presence reduces its protein digestibility. Okara fermented with Rhizopus oligosporus can increase its digestibility by lowering anti-nutrient content and liberating free amino acids. However, neither okara nor biovalorized okara has been evaluated for its effect on postprandial blood amino acids. This study hence explored this gap in knowledge with okara- and biovalorized okara- containing biscuits consumption.

Methods

The randomized controlled crossover trial involved 15 middle-aged and older Singaporean adults. Each participant undertook 3 separate 2-hour meal tolerance test with 100 g of control biscuits (C), biovalorized okara biscuits (RO), and autoclaved okara biscuits (AOK). RO and AOK were developed with the same recipe as C, utilizing a 20% wheat flour substitution with R. oligosporus fermented okara or autoclaved okara respectively. Biscuit total and free amino acids contents were analyzed by cation-exchange chromatography. Circulating free amino acids concentrations were assessed at timepoints 0, 15, 30, 45, 60, 90, and 120 min. Incremental area under curve (iAUC) and peak concentration were assessed, with results presented as mean (95% confidence interval).

Results

Biscuit total amino acid content (mean ± standard deviation, g/100 g) was significantly greater for RO (7.51 ± 0.22) and AOK (6.78 ± 0.39) compared to C (5.93 ± 0.33), with RO having notably greater alanine, cysteine, and proline content over AOK. Free amino acid content in biscuit (nmol/g) in ascending order was C (485 ± 11), AOK (698 ± 13), and RO (3414 ± 97). Amino acid iAUC had no significant difference, as demonstrated with total amino acids iAUC (μmol/L·min) (P = 0.568, C: 23 649 (13 738, 33 560), RO: 23 284 (13 374, 33 195) & AOK: 17 257 (7 346, 27 168)). Peak iAUC concentration also showed no significant difference across all amino acids, with total amino acids peak iAUC concentration (μmol/L) as P = 0.560, C: 387 (233,540), RO: 456 (303,610) & AOK: 343 (189,497).

Conclusions

Consumption of okara- or biovalorized okara- containing biscuits does not alter postprandial amino acid responses in middle-aged and older Singaporeans.

Funding Sources

Singapore Ministry of Education.

Impact of fiber-fortified food consumption on anthropometric measurements and cardiometabolic outcomes: A systematic review, meta-analyses, and meta-regressions of randomized controlled trials

The consumption of processed and refined food lacking in fiber has led to global prevalence of obesity and cardiometabolic diseases. Fiber-fortification into these foods can yield potential health improvements to reduce disease risk. This meta-analyses aimed to evaluate how fiber-fortified food consumption changes body composition, blood pressure, blood lipid-lipoprotein panel, and glycemic-related markers. Searches were performed from 5 databases, with 31 randomized controlled trial eventually analyzed. Hedges' g values (95% confidence interval [CI]) attained from outcome change values were calculated using random-effects model. Fiber-fortified food significantly reduced body weight (-0.31 [-0.59, -0.03]), fat mass (-0.49 [-0.72, -0.26]), total cholesterol (-0.54 [-0.71, -0.36]), low-density lipoprotein cholesterol (-0.49 [-0.65, -0.33]), triglycerides (-0.24 [-0.36, -0.12]), fasting glucose (-0.30 [-0.49, -0.12]), and HbA1c (-0.44 [-0.74, -0.13]). Subgroup analysis differentiated soluble fiber as significantly reducing triglycerides and insulin while insoluble fiber significantly reduced body weight, BMI, and HbA1c. Greater outcome improvements were observed with solid/semi-solid food state than liquid state. Additionally, fiber fortification of <15 g/day induced more health outcome benefits compared to ≥15 g/day, although meta-regression found a dose-dependent improvement to waist circumference (p-value = 0.036). Findings from this study suggest that consuming food fortified with dietary fiber can improve anthropometric and cardiometabolic outcomes.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2053658.

Association Between Dietary Protein Intake and Sleep Quality in Middle-Aged and Older Adults in Singapore

Poor sleep has been associated with the increased risk of developing detrimental health conditions. Diet and certain nutrients, such as dietary protein (PRO) may improve sleep. This cross-sectional study aimed to investigate the relationship between PRO intake, their amino acid components, and sources with sleep quality in middle-aged and older adults residing in Singapore. A dataset of 104 healthy subjects between the age of 50 and 75 years old were used. Collected data included 3-day food record and sleep quality [sleep duration, global sleep score (GSS), sleep latency (SL), and sleep efficiency (SE)]. The collected 3-day food records were extracted for PRO, tryptophan (Trp), and large neutral amino acid (LNAA) intake. PRO intake was further categorized into plant and animal PRO. A multivariate multiple linear regression (MLR) was performed to assess the association between PRO intake and sleep quality. Dietary Trp:LNAA ratio was positively associated with sleep duration (β_total: 108.234 h; p: 0.005) after multiple covariates adjustment. Similarly, plant Trp (β_plant: 2.653 h/g; p: 0.020) and plant Trp:LNAA (β_plant: 54.006 h; p: 0.008) was positively associated with sleep duration. No significant associations were observed for both SL and SE. Sleep duration in middle-aged and older Singaporean adults was positively associated with dietary Trp and Trp:LNAA, especially when obtained from plant sources.

Association of Gut Microbiome Dysbiosis with Neurodegeneration: Can Gut Microbe-Modifying Diet Prevent or Alleviate the Symptoms of Neurodegenerative Diseases?

The central nervous system was classically perceived as anatomically and functionally independent from the other visceral organs. But in recent decades, compelling evidence has led the scientific community to place a greater emphasis on the role of gut microbes on the brain. Pathological observations and early gastrointestinal symptoms highlighted that gut dysbiosis likely precedes the onset of cognitive deficits in Alzheimer's disease (AD) and Parkinson's disease (PD) patients. The delicate balance in the number and functions of pathogenic microbes and alternative probiotic populations is critical in the modulation of systemic inflammation and neuronal health. However, there is limited success in restoring healthy microbial biodiversity in AD and PD patients with general probiotics interventions and fecal microbial therapies. Fortunately, the gut microflora is susceptible to long-term extrinsic influences such as lifestyle and dietary choices, providing opportunities for treatment through comparatively individual-specific control of human behavior. In this review, we examine the impact of restrictive diets on the gut microbiome populations associated with AD and PD. The overall evidence presented supports that gut dysbiosis is a plausible prelude to disease onset, and early dietary interventions are likely beneficial for the prevention and treatment of progressive neurodegenerative diseases.

Wolfberry Consumption with a Healthy Dietary Pattern Lowers Oxidative Stress and Improves Carotenoids Status in Middle-Aged and Older Adults: A Randomized Controlled Trial

Objectives

The incorporation of zeaxanthin rich wolfberry (Lycium barbarum) into a healthy dietary pattern may augment its antioxidant effects although evidence evaluating whole fruits is lacking. The objectives of this study are to (1) investigate the impact of dietary counselling, either with or without whole dried wolfberry on oxidative stress status in middle-aged and older Singaporean adults and (2) delineate underlying mechanisms by examining associations with the corresponding changes in carotenoids status.

Methods

In this 16-week, parallel design randomized controlled trial, 40 subjects (29 F, 11 M; aged 50 to 64 y) received dietary counselling to follow a healthy dietary pattern. Compared to the control group (CG, n = 18), the wolfberry group (WG, n = 22) additionally cooked and consumed 15 g/d whole dried wolfberry with their main meals. Biomarkers of oxidative stress (plasma malondialdehyde (MDA)

by thiobarbituric acid reactive substance assay and 8-isoprostanes by ELISA) were measured at baseline and week 16. Plasma and dietary carotenoids analyzed by HPLC and 3-day food records respectively were measured at baseline, week 8 and week 16 while skin carotenoids status (SCS) by resonance Raman spectroscopy was assayed every 4 weeks.

Results

Plasma 8-isoprostanes showed a time effect (P &lt; 0.05), attributed to the marked decline in the WG only (WG: −19.0 ± 43.6 ng/L; CG: −7.7 ± 38.7 ng/L, mean ± SD) though no effect was observed for MDA. A significant interaction effect (P &lt; 0.001), driven by higher plasma zeaxanthin (WG: +0.08 ± 0.13 nmol/L; CG: −0.03 ± 0.05 nmol/L) and SCS (WG: +4242 ± 4938 a.u.; CG: +1713 ± 5921 a.u.) was observed in the WG with a marked increase evident from week 8 onwards although concentrations of the other plasma carotenoids were maintained. Moreover, the change value for plasma zeaxanthin in the WG was inversely associated with the corresponding changes in plasma 8-isoprostanes (−0.21 (−0.43, 0.00) ng/µmol, regression coefficient (95% CI); P = 0.05). This same association was absent in the CG.

Conclusions

Consuming wolfberry with a healthy dietary pattern attenuates oxidative stress in middle-aged and older adults and this may be attributed to the rich zeaxanthin content in wolfberry.

Funding Sources

National University of Singapore Ministry of Education, Singapore Agency for Science, Technology and Research.

Postprandial Glycemic, Insulinemic, and Short-Chain Fatty Acids Responses Following the Consumption of Okara and Biovalorized Okara Incorporated Biscuits

Objectives

Okara is a fiber-rich food processing by-product. However, it is underutilized as food due to its rapid putrefaction and poor sensorial properties. Valorization via fermentation (biovalorization) can alleviate its undesirable qualities while augmenting its soluble fiber content. The increase in soluble fiber may improve postprandial glycemic and insulinemic responses, potentially via generation of short-chain fatty acids (SCFAs) from colonic bacteria fermentation. This study aimed to assess the effect of consuming okara and biovalorized okara-containing biscuits on postprandial glucose, insulin and SCFAs responses in older Singaporeans.

Methods

Fifteen healthy middle-aged and older Singaporeans participated in a randomized controlled crossover trial. Subjects underwent a 4-hour mixed meal tolerance test with 100 g ingestion of 3 types of biscuits – control (C, no okara), biovalorised okara (RO) and autoclaved okara (AOK). RO and AOK biscuits were produced by 20%

substitution of wheat flour with okara powder that was fermented with Rhizopus oligosporus (7% w/w) or autoclaved. The 4-hour incremental area under the curve (iAUC) of glucose, insulin and SCFAs (acetate, propionate and butyrate) were assessed. β-cell function was evaluated based on glucose stimulated insulin secretion, using a ratio of 4-hour AUC of insulin to glucose. Estimated insulin sensitivity (ISI) and metabolic clearance rate (MCR) were assessed with Stumvoll Index.

Results

Although no difference in glucose response was noted, RO showed significantly lower insulin iAUC (RO: 8931 ± 1058 mU/L × min, mean ± SE; C: 10271 ± 866 mU/L × min, p = 0.021) and improved β-cell function (p = 0.028) compared to C. AOK yielded significantly greater ISI and MCR compared to C (pISI = 0.016, pMCR = 0.009) while RO showed no difference against AOK or C. Significantly higher acetate and total SCFAs iAUC were evident for both RO and AOK relative to C (C vs RO: pacetate = 0.012, ptotal SCFA = 0.001; C vs AOK: pacetate = 0.015, ptotal SCFA = 0.001). AOK also had significantly greater propionate and butyrate iAUC compared to C (C vs AOK: pacetate = 0.002, pbutyrate = 0.001).

Conclusions

Consumption of okara and biovalorized okara-containing biscuits offers the benefit of attenuating postprandial insulinemic response possibly via SCFAs modulation.

Funding Sources

Singapore Ministry of Education

Wolfberry (Lycium barbarum) Consumption with a Healthy Dietary Pattern Lowers Oxidative Stress in Middle-Aged and Older Adults: A Randomized Controlled Trial

Incorporating zeaxanthin-rich wolfberry (Lycium barbarum) into a healthy dietary pattern may augment its antioxidant potential. The present 16-week, parallel design randomized controlled trial aimed to investigate the impact of adhering to a healthy dietary pattern, either with or without whole dried wolfberry (15 g/d) on oxidative stress status (plasma malondialdehyde and 8-iso-prostaglandin F2α) in middle-aged and older adults. Changes to carotenoids status (plasma and skin carotenoids) and body composition were further evaluated to explore potential mechanisms which underlie the antioxidant properties of wolfberry. Plasma 8-iso-prostaglandin F2α, plasma zeaxanthin and skin carotenoids status were significantly raised in the wolfberry consuming group (n = 22; p < 0.05) compared to the control group which showed no changes (n = 18). Likewise in the wolfberry group only, inverse association was observed between the change values of plasma zeaxanthin and plasma 8-iso-prostaglandin F2α (−0.21 (−0.43, 0.00) ng/µmol, regression coefficient (95% CI); p = 0.05). Wolfberry consumption with a healthy dietary pattern may serve as a dietary strategy to attenuate lipid peroxidation among middle-aged and older adults who are at a heightened risk of oxidative stress induced age-related disorders. The antioxidant properties of wolfberry may be attributed to its rich zeaxanthin content.

The Influence of Different Foods and Food Ingredients on Acute Postprandial Triglyceride Response: A Systematic Literature Review and Meta-Analysis of Randomized Controlled Trials

The use of postprandial triglyceride (ppTG) as a cardiovascular disease risk indicator has gained recent popularity. However, the influence of different foods or food ingredients on the ppTG response has not been comprehensively characterized. A systematic literature review and meta-analysis was conducted to assess the effects of foods or food ingredients on the ppTG response. PubMed, MEDLINE, Cochrane, and CINAHL databases were searched for relevant acute (<24-h) randomized controlled trials published up to September 2018. Based on our selection criteria, 179 relevant trials (366 comparisons) were identified and systematically compiled into distinct food or food ingredient categories. A ppTG-lowering effect was noted for soluble fiber (Hedges' giAUC = -0.72; 95% CI: -1.33, -0.11), sodium bicarbonate mineral water (Hedges' gAUC = -0.42; 95% CI: -0.79, -0.04), diacylglycerol oil (Hedges' giAUC = -0.38; 95% CI: -0.75, -0.00), and whey protein when it was contrasted with other proteins. The fats group showed significant but opposite effects depending on the outcome measure used (Hedges' giAUC = -0.32; 95% CI: -0.61, -0.03; and Hedges' gAUC = 0.16; 95% CI: 0.06, 0.26). Data for other important food groups (nuts, vegetables, and polyphenols) were also assessed but of limited availability. Assessing for oral fat tolerance test (OFTT) recommendation compliance, most trials were ≥4 h long but lacked a sufficiently high fat challenge. iAUC and AUC were more common measures of ppTG. Overall, our analyses indicate that the effects on ppTG by different food groups are diverse, largely influenced by the type of food or food ingredient within the same group. The type of ppTG measurement can also influence the response.