Recent advances in dietary proteins and lipid metabolism

Unveiling the microbiota-mediated impact of different dietary proteins on post-digestive processes: A simulated in vitro approach

Protein digestion and microbial metabolism play crucial roles in overall health. However, the mechanisms that differentiate the digestion and metabolism of dietary proteins from different sources in the organism remain poorly understood. This study investigated the digestive properties and microbial fermentation of various animal proteins (chicken, pork, beef, and casein) and plant proteins (soy bean, mung bean, kidney bean, rice, and wheat) in an in vitro simulation. The results indicated that animal-derived proteins had higher essential amino acid content (33.97-37.12 g/100 g) and digestibility levels (49.15-60.94 %), and provided more small molecule peptides upon digestion. Nevertheless, soy bean and wheat proteins also exhibited higher digestibility (54.70 % and 60.94 %), probably due to the extraction process. The fermentation results showed that distinct metabolic profiles that emerged for different protein sources. Plant-derived proteins (especially kidney bean, rice and wheat) promoted the proliferation of beneficial bacteria and microbial diversification and stimulated short-chain fatty acids (SCFA) production. Conversely, meat proteins (pork, chicken, beef) had significantly lower microbial diversity and SCFA than these plant proteins. These findings provide valuable insights into the effects of dietary protein sources on digestion and gut microbiome, and offer scientific guidance for optimizing dietary choices to improve health.

Impact of increased protein intake in older adults: a 12-week double-blind randomised controlled trial

BACKGROUND

Emerging evidence suggests health-promoting properties of increased protein intake. There is increased interest in plant protein but a dearth of information in relation to its impact on muscle function. The objective of the present work was to examine the impact of intake of different types of proteins on muscle functional parameters including handgrip strength, biomarkers of metabolic health, sleep quality and quality of life in a group of older adults.

METHODS

Healthy men and women aged 50 years and older entered a double-blinded, randomised, controlled nutritional intervention study with three parallel arms: high plant protein, high dairy protein and low protein. Participants consumed once daily a ready-to-mix shake (containing 20 g of protein in high protein groups) for 12 weeks. Changes in handgrip and leg strength, body composition, metabolic health, quality of life and sleep quality were analysed by linear mixed models in an intention-to-treat approach.

RESULTS

Eligible participants (n = 171) were randomly assigned to the groups (plant: n = 60, dairy: n = 56, low protein: n = 55) and 141 completed the study. Handgrip strength increased after the intervention (Ptime = 0.038), with no significant difference between the groups. There was no significant difference between groups for any other health outcomes.

CONCLUSIONS

In a population of older adults, increasing protein intake by 20 g daily for 12 weeks (whether plant-based or dairy-based) did not result in significant differences in muscle function, body composition, metabolic health, sleep quality or quality of life, compared with the low protein group.

Adherence to the Mediterranean Diet Is Inversely Associated with the Prevalence of Metabolic Syndrome in Older People from the North of Spain

Background: The aim of this study was to relate adherence to the Mediterranean diet (MedDiet) to the prevalence of metabolic syndrome (MetS) in an elderly population from the north of Spain. Methods: We carried out an observational, descriptive, cross-sectional, and correlational study involving 556 non-institutionalised individuals aged 65 to 79 years. The MEDAS-14 questionnaire score was used to define the degree of adherence to the Mediterranean diet. The diagnosis of MetS was conducted using the International Diabetes Federation (IDF) criteria. Results: In 264 subjects with an average age of 71.9 (SD: ±4.2), 39% of whom were men, 36.4% had good adherence (score ≥ 9 in MEDAS-14), with no differences by gender or age. The prevalence of MetS was 40.2%, with 47.6% in men and 35.4% in women (p < 0.05). The prevalence of MetS was 2.4 times more frequent among individuals who consumed less than two servings (200 g) of vegetables daily compared with those who consumed two or more servings of vegetables daily (OR: 2.368, 95%CI: 1.141−4.916, p = 0.021). Low adherence to the MedDiet (MEDAS-14 score ≤ 8) was associated with an 82% higher prevalence of MetS (OR: 1.817, 95%CI: 1.072−3.081, p = 0.027). Conclusion: An inverse relationship was established between adherence to the MedDiet and the prevalence of MetS.

Bioactive peptides of whey: obtaining, activity, mechanism of action, and further applications

Bioactive peptides derived from diverse food proteins have been part of diverse investigations. Whey is a rich source of proteins and components related to biological activity. It is known that proteins have effects that promote health benefits. Peptides derived from whey proteins are currently widely studied. These bioactive peptides are amino acid sequences that are encrypted within the first structure of proteins, which required hydrolysis for their release. The hydrolysis could be through in vitro or in vivo enzymatic digestion and using microorganisms in fermented systems. The biological activities associated with bio-peptides include immunomodulatory properties, antibacterial, antihypertensive, antioxidant and opioid, etc. These functions are related to general conditions of health or reduced risk of certain chronic illnesses. To determine the suitability of these peptides/ingredients for applications in food technology, clinical studies are required to evaluate their bioavailability, health claims, and safety of them. This review aimed to describe the biological importance of whey proteins according to the incidence in human health, their role as bioactive peptides source, describing methods, and obtaining technics. In addition, the paper exposes biochemical mechanisms during the activity exerted by biopeptides of whey, and their application trends.

DO-SRS imaging of diet regulated metabolic activities in Drosophila during aging processes

Lipid metabolism plays crucial roles during aging processes, but how it is regulated by diets and how it interplays with aging still remain unclear. We proposed a new optical imaging platform by integrating heavy water (D2 O) probing with stimulated Raman scattering (DO-SRS) microscopy, for the first time, to directly visualize and quantify lipid metabolism regulated by different diets and insulin signaling pathway in Drosophila fat body during aging. We found that calorie restriction, low protein diet, and (moderately) high protein and high sucrose diets enhanced lipid turnover in flies at all ages, while (moderately) high fructose and glucose diets only promoted lipid turnover in aged flies. The measured lipid turnover enhancements under diverse diets were due to different mechanisms. High protein diet shortened the lifespan while all other diets extended the lifespan. Downregulating the insulin signaling pathway enhanced lipid turnover, which is likely related to lifespan increase, while upregulating insulin signaling pathway decreased lipid turnover that would shorten the lifespan. Our study offers the first approach to directly visualize spatiotemporal alterations of lipid turnover in aging Drosophila in situ, for a better understanding of the interconnections between lipid metabolism, diets, and aging.

The Effect of Dietary Interventions on Hypertriglyceridemia: From Public Health to Molecular Nutrition Evidence

Approximately 25–50% of the population worldwide exhibits serum triglycerides (TG) (≥150 mg/dL) which are associated with an increased level of highly atherogenic remnant-like particles, non-alcoholic fatty liver disease, and pancreatitis risk. High serum TG levels could be related to cardiovascular disease, which is the most prevalent cause of mortality in Western countries. The etiology of hypertriglyceridemia (HTG) is multifactorial and can be classified as primary and secondary causes. Among the primary causes are genetic disorders. On the other hand, secondary causes of HTG comprise lifestyle factors, medical conditions, and drugs. Among lifestyle changes, adequate diets and nutrition are the initial steps to treat and prevent serum lipid alterations. Dietary intervention for HTG is recommended in order to modify the amount of macronutrients. Macronutrient distribution changes such as fat or protein, low-carbohydrate diets, and caloric restriction seem to be effective strategies in reducing TG levels. Particularly, the Mediterranean diet is the dietary pattern with the most consistent evidence for efficacy in HTG while the use of omega-3 supplements consumption is the dietary component with the highest number of randomized clinical trials (RCT) carried out with effective results on reducing TG. The aim of this review was to provide a better comprehension between human nutrition and lipid metabolism.

Dietary Protein From Different Sources Exerted a Great Impact on Lipid Metabolism and Mitochondrial Oxidative Phosphorylation in Rat Liver

Associations between meat diets and human health have been widely considered. In this study, we focused on long-term effects of different sources of meat protein on liver metabolic enzymes. For 90 days, rats were fed with semisynthetic diets that differed only with protein source. Casein was used as a reference and isolated soybean, fish, chicken, pork, and beef proteins were compared. Changes in liver proteome were determined by isobaric tag for relative and absolute quantitation (iTRAQ) labeling and liquid chromatography electrospray ionization tandem mass spectrometry/mass spectrometry (LC–ESI–MS/MS). Fish and pork protein diets upregulated the gene expression involved in cholesterol synthesis and esterification, and pork protein diet also upregulated the gene expression of high-density lipoprotein receptor and low-density lipoprotein receptor. Chicken, pork, and beef protein diets upregulated the gene expression involved in cholesterol reverse transport and bile acid production, which increased the total cholesterol level in the fish protein diet group. Total cholesterol levels in liver were lower in the pork and beef protein diet groups. Triglyceride levels in liver were lower in chicken, pork, and beef protein diet groups. Peroxisomal proliferator-activated receptor-gamma coactivator-1 was upregulated by chicken, pork and beef protein diets, and promoted the degradation and metabolism of triglyceride, resulting in lower triglyceride in the three diet groups. Meat proteins at a recommended level could be more conducive to cholesterol degradation, triglyceride decomposition, and energy balance maintenance at a healthy level. The findings give a new insight into the associations between meat diet intake and human health.

Urinary Medium-Chained Acyl-Carnitines Sign High Caloric Intake whereas Short-Chained Acyl-Carnitines Sign High -Protein Diet within a High-Fat, Hypercaloric Diet in a Randomized Crossover Design Dietary Trial

The western dietary pattern is known for its frequent meals rich in saturated fat and protein, resulting in a postprandial state for a large part of the day. Therefore, our aim was to investigate the postprandial glucose and lipid metabolism in response to high (HP) or normal (NP) protein, high-fat hypercaloric diet and to identify early biomarkers of protein intake and hepatic lipid accumulation. In a crossover design, 17 healthy subjects were randomly assigned to consume a HP or NP hypercaloric diet for two weeks. In parallel, a control group (CD; n = 10) consumed a weight-maintaining control diet. Biomarkers of postprandial lipid and glucose metabolism were measured in 24 h urine and in plasma before and following a meal challenge. The metabolic profile of urine but not plasma, showed increased excretion of ¹³C, carnitine and short chain acyl-carnitines after adaptation to the HP diet. Urinary excretion of decatrienoylcarnitine and octenoylcarnitine increased after adaptation to the NP diet. Our results suggest that the higher excretion of short-chain urinary acyl-carnitines could facilitate the elimination of excess fat of the HP diet and thereby reduce hepatic fat accumulation previously reported, whereas the higher excretion medium-chains acyl-carnitine could be early biomarkers of hepatic lipid accumulation.

Effects of whey protein on glycemic control and serum lipoproteins in patients with metabolic syndrome and related conditions: a systematic review and meta-analysis of randomized controlled clinical trials

Background

This systematic review and meta-analysis aimed to assess the effects of whey protein on serum lipoproteins and glycemic status in patients with metabolic syndrome (MetS) and related disorders.

Methods

Online databases, such as Web of Science, Cochrane Library, PubMed and Scopus were systematically searched by two independent authors from inception until 30th April 2020 for English randomized clinical trials investigating the efficacy of whey protein administration in subjects with Mets or related conditions on the parameters of glycemic and lipid control compared to certain control. In order to evaluate the included studies’ methodological quality, Cochrane Collaboration risk of bias tool was applied. Using Cochrane’s Q test and I-square (I²) statistic, the included trials’ heterogeneity was also examined. Using a random-effects model, data were pooled, and weighted mean difference (WMD) was considered as the overall effect size.

Results

Twenty-two studies were selected to be included in this meta-analysis. Consumption of whey protein resulted in significant reduction of HbA1c (WMD: -0.15; 95% CI: − 0.29, − 0.01) insulin (WMD: -0.94; 95% CI: − 1.68, − 0.21) and homeostasis model assessment-estimated insulin resistance (HOMA-IR) (WMD: -0.20; 95% CI: − 0.36, − 0.05). A significant reduction in triglycerides levels (WMD: -17.12; 95% CI: − 26.52, − 7.72), total cholesterol (WMD: -10.88; 95% CI -18.60, − 3.17), LDL-cholesterol levels (WMD: -8.47 95% CI: − 16.59, − 0.36) and total cholesterol/HDL-cholesterol ratio (WMD: -0.26; 95% CI: − 0.41, − 0.10) was found as well.

Conclusions

This meta-analysis suggests that supplementation with whey protein had beneficial effect on several indicators of glycemic control and lipid parameters in patients with MetS and related conditions.

Supplementation with Low Doses of a Cod Protein Hydrolysate on Glucose Regulation and Lipid Metabolism in Adults with Metabolic Syndrome: A Randomized, Double-Blind Study

The risk of cardiovascular diseases and type 2 diabetes mellitus are increased in subjects with metabolic syndrome (MetS), and hydrolyzed fish protein may have favorable effects on metabolic health. Here, we investigated the effect of 8 weeks supplementation with 4 g of cod protein hydrolysate (CPH) on glucose metabolism, lipid profile and body composition in individuals with MetS in a double-blind, randomized intervention study with a parallel-group design. Subjects received a daily supplement of CPH (n = 15) or placebo (n = 15). Primary outcomes were serum fasting and postprandial glucose levels. Secondary outcomes were fasting and postprandial insulin and glucagon-like peptide 1 (GLP-1), fasting lipid concentrations and body composition. No difference was observed between CPH and placebo for insulin, glucose or GLP-1 after 8 weeks intervention. Fasting triacylglycerol decreased in both the CPH group and placebo group, with no change between groups. Fasting total cholesterol and low-density lipoprotein cholesterol decreased significantly within both groups from baseline to study end, but no difference was observed between the two groups. In conclusion, supplementing with a low dose of CPH in subjects with MetS for 8 weeks had no effect on fasting or postprandial levels of insulin, glucose or GLP-1, lipid profile or body composition.

Dietary taurine stimulates the hepatic biosynthesis of both bile acids and cholesterol in the marine teleost, tiger puffer (Takifugu rubripes)

Taurine (TAU) plays important roles in the metabolism of bile acids, cholesterol and lipids. However, little relevant information has been available in fish where TAU has been identified as a conditionally essential nutrient. The present study aimed to investigate the effects of dietary TAU on the metabolism of bile acids, cholesterol and lipids in tiger puffer, which is both an important aquaculture species and a good research model, having a unique lipid storage pattern. An 8-week feeding trial was conducted in a flow-through seawater system. Three experimental diets differed only in TAU level, that is, 1·7, 8·2 and 14·0 mg/kg. TAU supplementation increased the total bile acid content in liver but decreased the content in serum. TAU supplementation also increased the contents of total cholesterol and HDL-cholesterol in both liver and serum. The hepatic bile acid profile mainly includes taurocholic acid (94·48 %), taurochenodeoxycholic acid (4·17 %) and taurodeoxycholic acid (1·35 %), and the contents of all these conjugated bile acids were increased by dietary TAU. The hepatic lipidomics analysis showed that TAU tended to decrease the abundance of individual phospholipids and increase those of some individual TAG and ceramides. The hepatic mRNA expression study showed that TAU stimulated the biosynthesis of both bile acids and cholesterol, possibly via regulation of farnesoid X receptor and HDL metabolism. TAU also stimulated the hepatic expression of lipogenic genes. In conclusion, dietary TAU stimulated the hepatic biosynthesis of both bile acids and cholesterol and tended to regulate lipid metabolism in multiple ways.

Differential effects of protein intake versus intake of a defined oligopeptide on FGF-21 in obese human subjects in vivo

BACKGROUND

FGF-21 is described as a powerful metabolic regulator with beneficial effects including glucose-lowering and improvement of insulin sensitivity without hypoglycaemia. On the other hand, FGF-21 is activated when muscle and other tissues are stressed by external effects or internal cellular pathogens that lead to shortcomings in metabolic balance. Previous results suggested that FGF-21 could be a promising target to develop future metabolic therapeutics.

PURPOSE

The present study was performed to gain deeper insight into the regulation of FGF-21 by protein metabolism in obese human subjects.

METHODS

FGF-21 serum concentrations were measured in a cohort of n = 246 obese humans ± type 2 diabetes mellitus (T2DM) (median age 53.0 [46.0; 60.0] years and BMI 40.43 [35.11; 47.24] kg/m²) and related to the nutritional protein intake. In addition, the effect of a novel oligopeptide purified from a β-casein hydrolysate on FGF-21 was examined in vitro in liver cells and in vivo in a human intervention study with the main focus on metabolic inflammation including 40 mainly obese subjects (mean age 41.08 ± 9.76 years, mean BMI 38.29 ± 9.4 kg/m²) in a randomized 20 weeks double-blind cross-over design.

MAIN FINDINGS

In the cohort analysis, FGF-21 serum concentrations were significant lower with higher protein intake in obese subjects without T2DM but not in obese subjects with T2DM. Furthermore, relative methionine intake was inversely related to FGF-21. While global protein intake in obesity was inversely associated with FGF-21, incubation of HepG2 cells with a β-casein oligopeptide increased FGF-21 expression in vitro. This stimulatory effect was also present in vivo, since in the clinical intervention study treatment of obese subjects with the β-casein oligopeptide for 8 weeks significantly increased FGF-21 serum levels from W0 = 23.86 pg/mL to W8 = 30.54 pg/mL (p < 0.001), while no increase was found for placebo.

CONCLUSION

While the total nutritional protein intake is inversely associated with FGF-21 serum levels, a purified and well characterised oligopeptide is able to induce FGF-21 serum levels in humans. These findings suggest a differential role of various components of protein metabolism on FGF-21, rather than this factor being solely a sensor of total nutritional protein intake.

A systematic review and meta-analysis of the association between fish consumption and risk of metabolic syndrome

AIMS

Results regarding the association between fish intake and risk of metabolic syndrome (MetS) are ambiguous. Therefore, this study aims to evaluate whether there is an association between fish consumption and risk of MetS.

DATA SYNTHESIS

A comprehensive literature search was conducted of PubMed, Embase, ScienceDirect and Google Scholar up to August 2019. A random-effects model was used to pool the risk of MetS in the highest category of fish consumption compared with the lowest one. Subgroup analysis was conducted based on country of region, gender, dietary tool, MetS definition, energy adjustment and sample size. A dose-response of analysis of fish intake and risk of MetS was also conducted. Twelve studies with a total of 16 effect sizes (10 cross-sectional and six cohort) were included. An inverse association was observed between fish intake and risk of MetS in cohort (OR = 0.80, 95% CI: 0.66, 0.96; P = 0.017, I² = 62.9%) but not cross-sectional studies (OR = 0.80, 95% CI: 0.70, 1.02; P = 0.085, I² = 50.1%). Subgroup analysis suggested that the results were influenced by all the included variables but sample size. A significant non-linear association was observed between fish intake levels and risk of MetS (P-value for non-linearity = 0.010).

CONCLUSION

An inverse association existed between fish intake and risk of MetS when combining data from prospective cohort studies. Further studies are needed to confirm such an effect.

Are dietary amino acids prospectively predicts changes in serum lipid profile?

BACKGROUND

Besides of dietary fat and carbohydrate, amino acids(AAs), as constituent components of dietary protein have been related with serum lipid levels. This study aims to examine the association between dietary AAs and prospective changes in serum lipid profile in adults.

METHODS

Analyses were conducted on 3881 participants aged, 18-75 years of Tehran lipid and Glucose study, at baseline (2008-2011) and were followed for 3 years (2011-2014) to ascertain serum lipid profile changes. Dietary intakes of AAs were collected at baseline using food frequency questionnaire. Multiple linear regression adjusted for age, sex, body mass index, physical activity, smoking and daily intakes of energy, total fat, and fiber were used.

RESULTS

The median(IQR) changes in triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C) were 6.0(-19.0, -35.5), 9.0(7.0, -24.0), 1.0(-3.0, -6.0), and 5.2(-8.0, -18.6) mg/dl, respectively. Higher intakes of isoleucine, lysine, tyrosine, alanine, threonine, methionine, valine, histidine, aspartic acid, and branched chain, alkaline, and alcoholic AAs were positively associated with TGs-changes in the final adjusted model, whereas tryptophan, glutamic acid, and acidic AAs were negatively related to TG-changes. Alanine and tryptophan were associated with higher and lower LDL-C-changes, respectively. Lysine, alanine, methionine, aspartic acid, and alkaline AAs showed positive association with changes in TC, whereas tryptophan and glutamic acid had a negative association with TC-changes.

CONCLUSION

Our findings showed that some dietary amino acids have the potential to increase or decrease serum lipid profile.

Prevalence of Metabolic Syndrome and Its Components in Bamboutos Division's Adults, West Region of Cameroon

The prevalence of metabolic syndrome (MetS) and its associated risks remain unappreciated in Bamboutos Division, west region of Cameroon. This study aimed to evaluate the prevalence of MetS, its individual components, and associated risk factors among Bamboutos Division's adults population using a Joint Interim Statement of the International Diabetes Federation (IDF) Task Force on Epidemiology and Prevention definitions parameters. A cross-sectional study was conducted from May 2016 to May 2018 in Mbouda ADLUCEM Hospital and Mbouda District Hospital, two reference hospitals in Bamboutos Division, west region of Cameroon. Interview, physical and clinical examinations, and lipid and fasting blood glucose measurements were conducted for 604 adults. The definition of MetS proposed by IDF was used. The prevalence of MetS was 32.45% with highly significant female predominance (46.11% for females and 14.01 % for males). In the entire participants, the most common abnormalities were low-HDL (82.78%) and hypertriglyceridemia (53.97%) [p<0.001]. Participants with obesity (OR: 16.34; 95% CI: 9.21-28.96), overweight (OR: 7.45; 95% CI: 4.17-13.30), and highest hs-CRP (hs-CRP >11 mg/l) had a higher risk of developing MetS. The most common MetS component was abdominal obesity (OR: 353.13; 95% CI: 136.16-915.81). MetS is prevalent among Bamboutos Division's adults in west region of Cameroon and abdominal obesity is the most common MetS component. This study highlights the need for evidence-based prevention, diagnosis, and management of MetS and its associated factors among Bamboutos Division's adults in Cameroon.

Acute Effects of Single Doses of Bonito Fish Peptides and Vitamin D on Whole Blood Gene Expression Levels: A Randomized Controlled Trial

Fish contains high quality proteins and essential nutrients including 25-hydroxyvitamin D (25(OH)D). Fish peptide consumption can lower cardiovascular disease (CVD) risk factors, and studies have shown an association between 25(OH)D deficiency, CVD and CVD risk factors, such as diabetes. This study investigated acute effects of a single dose of cholecalciferol (VitD₃), bonito fish peptide hydrolysate (BPH), or a combination of both on CVD risk factors and whole blood gene expression levels. A randomized, crossover, placebo controlled trial was conducted in 22 adults. They ingested, in random order and at 7-day intervals, 1000 IU of VitD₃, 3 g of BPH, a combination of both, or a placebo. A 180 min oral glucose tolerance test was performed. Differences in whole-genome expression levels after versus before each supplementation were computed for 18 subjects. We observed that 16, 1 and 5 transcripts were differentially expressed post- vs. pre-ingestion for VitD₃, BPH or VitD₃ + BPH treatments, respectively. VitD₃-containing treatments affected the expression of the solute carrier family 25 member 20 (SLC25A20) gene involved in fatty acid oxidation, various transcription factors and genes related to glucose metabolism. These results suggest that VitD₃ rapidly modulates genes related to CVD risk factors in blood while BPH seems to moderately modulate gene expression levels.

Nutrients in Fish and Possible Associations with Cardiovascular Disease Risk Factors in Metabolic Syndrome

Non-communicable diseases (NSDs) are responsible for two-thirds of all deaths globally, whereas cardiovascular disease (CVD) alone counts for nearly half of them. To reduce the impact of CVD, targeting modifiable risk factors comprised in metabolic syndrome (e.g., waist circumference, lipid profile, blood pressure, and blood glucose) is of great importance. Beneficial effects of fish consumption on CVD has been revealed over the past decades, and some studies suggest that fish consumption may have a protective role in preventing metabolic syndrome. Fish contains a variety of nutrients that may contribute to health benefits. This review examines current recommendations for fish intake as a source of various nutrients (proteins, n-3 fatty acids, vitamin D, iodine, selenium, and taurine), and their effects on metabolic syndrome and the CVD risk factors. Fatty fish is recommended due to its high levels of n-3 fatty acids, however lean fish also contains nutrients that may be beneficial in the prevention of CVD.

Lean Fish Consumption Is Associated with Beneficial Changes in the Metabolic Syndrome Components: A 13-Year Follow-Up Study from the Norwegian Tromsø Study

BACKGROUND

Fish consumption may have beneficial effects on metabolic syndrome (MetS); however, limited information of such associations exists. This study investigated possible associations between fish consumption and changes in MetS components during a 13-year follow-up period.

METHODS

The sample included participants (26-69 years) from the Tromsø Study 4 (1994-1995, n = 23,907) and Tromsø Study 6 (2007-2008, n = 12,981). Data were collected using questionnaires including food frequency questions, non-fasting blood samples, and physical examinations. MetS was defined using the Joint Interim Societies (JIS) definition, in which one point was given for each MetS criteria fulfilled (metabolic score). Longitudinal analyses were performed using Linear mixed models.

RESULTS

For both genders, lean fish consumption once a week or more was significantly associated with decreased future metabolic score, decreased triglycerides, and increased high-density lipoprotein (HDL)-cholesterol, whereas decreased waist circumference and blood pressure was identified only for men (age adjusted models). Fatty fish consumption was significantly associated with increased waist circumference for both genders and increased HDL-cholesterol levels in men. Conclusion: The results suggest that fatty and lean fish consumption may influence MetS differently and that lean fish consumption in particular seems to be associated with beneficial changes in the MetS components.

Effect of meal composition on postprandial lipid concentrations and lipoprotein particle numbers: A randomized cross-over study

Background

It is unclear how high-protein (HP) and high-monounsaturated fat (HMF) meals affect postprandial blood lipids and lipoprotein particle numbers (LPN).

Purpose

To compare a HP versus a HMF meal on postprandial lipid and LPN responses.

Methods

Twenty-four participants (age: 36.3±15.0 years; body mass index: 23.6±2.0 kg/m²; 45.8% female) were fed a HP (31.9% energy from protein) and a HMF (35.2% fat and 20.7% monounsaturated fat) meal in a randomized cross-over trial design. Energy and carbohydrate content were the same across meals. Blood samples were drawn in the fasting state and 3 hour postprandial state, and assessed for lipids and LPN.

Results

Repeated measures analysis showed a significant (p<0.05) treatment by time interaction effect for triglycerides (TG), the primary variable, total high-density lipoprotein particles (T-HDLP) and T-HDLP minus large-buoyant high-density lipoprotein 2b (T-HDLP—LB-HDL2b). HP versus HMF condition led to significantly lower TG at 120 (geometric mean: 90.1 (95% confidence interval (CI): 76.4–106.3) vs. 146.5 (124.2–172.9) mg/dL) and 180 (101.4 (83.1–123.8) vs. 148.7 (121.9–181.4) mg/dL) min and higher T-HDLP at 120 (mean difference: 297.3 (95% CI: 48.6–545.9) nmol/L) and 180 (291.6 (15.8–567.5) nmol/L) min. The difference in T-HDLP by condition was due to the significantly higher small-dense HDLP (T-HDLP—LB-HDL2b) during HP versus HMF condition at 120 (mean difference: 452.6 (95% CI: 177.4–727.9) nmol/L) and 180 (496.8 (263.1–730.6) nmol/L) min. Area under the curve analysis showed that HP versus HMF condition led to significantly lower TG, non-HDLP, and very-low-density lipoprotein particles (VLDLP) responses but significantly less favorable responses in LB-HDL2b particles, T-HDLP—LB-HDL2b, and LB-HDL2b/T-HDLP ratio.

Conclusion

The HP meal led to lower TG, non-HDLP, and VLDLP but less favorable LB-HDL2b, small-dense HDLP, and LB-HDL2b/T-HDLP ratio responses versus a HMF meal. Further studies are needed to confirm these findings over multiple meals.

Nutraceuticals and Bioactive Components from Fish for Dyslipidemia and Cardiovascular Risk Reduction

Cardiovascular disease remains the most common health problem in developed countries, and residual risk after implementing all current therapies is still high. Permanent changes in lifestyle may be hard to achieve and people may not always be motivated enough to make the recommended modifications. Emerging research has explored the application of natural food-based strategies in disease management. In recent years, much focus has been placed on the beneficial effects of fish consumption. Many of the positive effects of fish consumption on dyslipidemia and heart diseases have been attributed to n-3 polyunsaturated fatty acids (n-3 PUFAs, i.e., EPA and DHA); however, fish is also an excellent source of protein and, recently, fish protein hydrolysates containing bioactive peptides have shown promising activities for the prevention/management of cardiovascular disease and associated health complications. The present review will focus on n-3 PUFAs and bioactive peptides effects on cardiovascular disease risk factors. Moreover, since considerable controversy exists regarding the association between n-3 PUFAs and major cardiovascular endpoints, we have also reviewed the main clinical trials supporting or not this association.

Lean fish consumption is associated with lower risk of metabolic syndrome: a Norwegian cross sectional study

Background

Fish consumption may have a role in reducing the prevalence of metabolic syndrome (MetS). The aim of this study was to identify associations between fish consumption and MetS and its components, especially regarding differences concerning consumption of fatty and lean fish.

Methods

This cross sectional study uses data from the Tromsø 6 survey (2007–08), where a sample of 12 981 adults, aged 30–87 years (47 % men) from the Norwegian general population was included. Fish consumption was assessed using food frequency questionnaires (FFQ). Blood sample assessments, anthropometric and blood pressure measurements were carried out according to standard protocols. MetS was defined using the Joint Interim Societies (JIS) definition. All tests were two-sided. Analyses were performed using IBM SPSS Statistics 22 (Pearson’s correlation, Chi-Square tests, analysis of variance (ANOVA), linear and logistic regression models).

Results

Mean age was 57.5, and the prevalence of MetS was 22.6 %. Fish consumption once a week or more was associated with lower risk of having MetS among men (OR 0.85, CI 95 % 0.74 to 0.98, P = 0.03). In the adjusted models, lean fish consumption was associated with a decreased risk of having MetS, whereas fatty fish consumption was not associated with a decreased risk of having MetS. Both an increased fatty and lean fish consumption (0–1 times per month, 2–3 times per month, 1–3 times per week, 4–6 times per week, 1–2 times per day) were associated with decreased serum triglyceride (TG), and increased high-density lipoprotein cholesterol (HDL-C).

Conclusions

Fish consumption may be associated with a lower risk of having MetS and consumption of lean fish seems to be driving the association. Further investigation is warranted to establish associations between fish consumption and MetS.

Dietary soy and meat proteins induce distinct physiological and gene expression changes in rats

This study reports on a comprehensive comparison of the effects of soy and meat proteins given at the recommended level on physiological markers of metabolic syndrome and the hepatic transcriptome. Male rats were fed semi-synthetic diets for 1 wk that differed only regarding protein source, with casein serving as reference. Body weight gain and adipose tissue mass were significantly reduced by soy but not meat proteins. The insulin resistance index was improved by soy, and to a lesser extent by meat proteins. Liver triacylglycerol contents were reduced by both protein sources, which coincided with increased plasma triacylglycerol concentrations. Both soy and meat proteins changed plasma amino acid patterns. The expression of 1571 and 1369 genes were altered by soy and meat proteins respectively. Functional classification revealed that lipid, energy and amino acid metabolic pathways, as well as insulin signaling pathways were regulated differently by soy and meat proteins. Several transcriptional regulators, including NFE2L2, ATF4, Srebf1 and Rictor were identified as potential key upstream regulators. These results suggest that soy and meat proteins induce distinct physiological and gene expression responses in rats and provide novel evidence and suggestions for the health effects of different protein sources in human diets.

Associations between fish consumption and metabolic syndrome. A large cross-sectional study from the Norwegian Tromsø Study: Tromsø 4

BACKGROUND

Fish consumption may prevent or improve metabolic health. The aim of this study was to identify associations between fish consumption, both fatty and lean, and metabolic syndrome and its components.

METHODS

Associations between fish consumption and metabolic syndrome and its components were studied in a large sample from a Norwegian population (N = 23,907), using cross-sectional data from the Tromsø 4 survey (1994-1995). Metabolic syndrome was defined using the JIS definition, and dietary data was collected using food frequency questionnaires (FFQ). Blood samples were taken for biochemical assessments, and anthropometric and blood pressure measurements were carried out according to standard protocols.

RESULTS

In this sample from an adult population (aged 26-70 years, mean age 44 years, SD 11.69, 48 % men), a higher fish consumption (≥1/week) was associated with a healthier lipid profile with increased HDL-C and decreased TG. Participants aged 60-70 years consuming fish once a week or more had significantly lower risk of having MetS, compared to those consuming fish less than once a week (OR 0.64, CI 0.45-0.91). When investigating fatty and lean fish separately, only lean fish consumption was associated with a reduced the risk of having MetS. Participants aged 60-70 years consuming lean fish once a week or more, had lower risk of having MetS compared to those consuming lean fish less than once a week (OR 0.65, CI 0.48-0.87). No association was found for consumption of fatty fish, or for lean fish in the age groups <45 or 45-59 years.

CONCLUSIONS

These results indicates that fatty and lean fish consumption influences MetS risk differently, possibly also related to age. However, further investigation is needed to establish how various fish consumption may influence MetS and its components, particularly when stratified by fatty and lean fish.

Interactions between adipose tissue and the immune system in health and malnutrition

Adipose tissue provides the body with a storage depot of nutrients that is drained during times of starvation and replenished when food sources are abundant. As such, it is the primary sensor for nutrient availability in the milieu of an organism, which it communicates to the body through the excretion of hormones. Adipose tissue regulates a multitude of body functions associated with metabolism, such as gluconeogenesis, feeding and nutrient uptake. The immune system forms a vital layer of protection against micro-organisms that try to gain access to the nutrients contained in the body. Because infections need to be resolved as quickly as possible, speed is favored over energy-efficiency in an immune response. Especially when immune cells are activated, they switch to fast, but energy-inefficient anaerobic respiration to fulfill their energetic needs. Despite the necessity for an effective immune system, it is not given free rein in its energy expenditure. Signals derived from adipose tissue limit immune cell numbers and activity under conditions of nutrient shortage, whereas they allow proper immune cell activity when food sources are sufficiently available. When excessive fat accumulation occurs, such as in diet-induced obesity, adipose tissue becomes the site of pathological immune cell activation, causing chronic low-grade systemic inflammation. Obesity is therefore associated with a number of disorders in which the immune system plays a central role, such as atherosclerosis and non-alcoholic steatohepatitis. In this review, we will discuss the way in which adipose tissue regulates activity of the immune system under healthy and pathological conditions.

Plant protein and animal proteins: do they differentially affect cardiovascular disease risk?

Proteins from plant-based compared with animal-based food sources may have different effects on cardiovascular disease (CVD) risk factors. Numerous epidemiologic and intervention studies have evaluated their respective health benefits; however, it is difficult to isolate the role of plant or animal protein on CVD risk. This review evaluates the current evidence from observational and intervention studies, focusing on the specific protein-providing foods and populations studied. Dietary protein is derived from many food sources, and each provides a different composite of nonprotein compounds that can also affect CVD risk factors. Increasing the consumption of protein-rich foods also typically results in lower intakes of other nutrients, which may simultaneously influence outcomes. Given these complexities, blanket statements about plant or animal protein may be too general, and greater consideration of the specific protein food sources and the background diet is required. The potential mechanisms responsible for any specific effects of plant and animal protein are similarly multifaceted and include the amino acid content of particular foods, contributions from other nonprotein compounds provided concomitantly by the whole food, and interactions with the gut microbiome. Evidence to date is inconclusive, and additional studies are needed to further advance our understanding of the complexity of plant protein vs. animal protein comparisons. Nonetheless, current evidence supports the idea that CVD risk can be reduced by a dietary pattern that provides more plant sources of protein compared with the typical American diet and also includes animal-based protein foods that are unprocessed and low in saturated fat.

The impact of a pure protein load on the glucose levels in type 1 diabetes patients treated with insulin pumps

We aimed to estimate the impact of ingestion of a pure protein load on the glucose levels in T1DM patients treated with insulin pumps. We examined 10 T1DM patients (6 females, mean age-32.3 years, mean HbA1c-6.8%) treated with insulin pumps equipped with a continuous glucose monitoring system (CGMS). In Phase I, baseline insulin infusion was optimized to minimize the differences in fasting glucose levels to less than 30 mg/dL between any two time points between 9 a.m. and 3 p.m. In Phase II, the patients were exposed to single pure protein load. CGMS record was performed and the glucose pattern was defined for 6 hours of each phase. The maximal glucose level increment was similar for the entire duration of the fasting and the protein load test (26.6 versus 27.6 mg/dL, resp., P < 0.78). There was only a borderline difference in change between baseline versus 6th hour glucose (12.5 and 19.0 mg/dL, P = 0.04). Glucose variability, assessed by standard deviation of mean glucose levels, was 36.4 and 37.9 mg/dL, respectively (P = 0.01). The administration of a pure protein load does not seem to have a clinically significant impact on glucose levels in T1DM patients treated with insulin pumps.

Rapid determination of oligopeptides and amino acids in soybean protein hydrolysates using high-resolution mass spectrometry

INTRODUCTION

Soybean protein hydrolysates (SPHs), especially oligopeptides, have shown a variety of functional properties, including immunomodulatory and anti-oxidant effects. Soybean protein hydrolysate products have been used as functional ingredients in food, sports nutrition or clinical nutrition. However, the mixture is mostly undefined due to its complex nature, containing peptides and minor amino acids as well as small proteins.

OBJECTIVES

To develop a specific and efficient method for the identification and structural characterisation of oligopeptides in SPHs, and to determine free amino acids in SPHs in the same analytical run, for evaluation of the chemical profile of SPH products.

METHODS

Accurate mass spectrometry (MS) datasets of SPH samples were recorded on a high-performance liquid chromatography (HPLC) tandem high-resolution (HR) MS system. Potential oligopeptides were tentatively characterised based on their elemental compositions and ring double bond equivalent (RDBE) values, as well as HRMS/MS data. The analytical method to determine amino acids was evaluated in terms of linearity, precision, apparent recovery and limits of detection and quantitation.

RESULTS

In total, 186 oligopeptides spanning the mass range of m/z 200-1500 and three major free amino acids could be determined in SPH samples in a single sample injection. Ninety-nine oligopeptides were tentatively characterised. The sensitive and specific instrumental performances also permitted the determination of 19 amino acids with a limit of quantitation of ≤ 0.1 μg/mL.

CONCLUSION

The HPLC-HRMS technique has proven to be an advantageous tool for the rapid characterisation of oligopeptides and determination of amino acids in soybean protein hydrolysates.

Flavonoids promoting HaCaT migration: II. Molecular mechanism of 4',6,7-trimethoxyisoflavone via NOX2 activation

Flavonoids are major active ingredients in plants and are considered components of food that provide medical or health benefits. They have diversified structures and have effects on human health, including wound healing induction. More than a hundred flavonoids were screened for HaCaT keratinocytes cellular migration measurements and the relationships between their structural properties and the effects promoting cellular migration were examined. Here, among flavonoids used in the previous structure-activity relationship calculations, 4',6,7-trimethoxyisoflavone (TMF) was one of the compounds showing the best activity, so that its molecular mechanism of the wound healing effect on HaCaT keratinocytes was investigated in more detail. Our data revealed that TMF increased the wound healing rate, but not the proliferation rate, in a dose-dependent manner. Treatment of keratinocytes with TMF influenced signaling pathways, affecting the phosphorylation of AKT and ERK in a time-dependent manner. TMF also induced the cell-cell adhesion protein E-cadherin, which is essential for promoting collective cell migration. Furthermore, the TMF treatment group also showed higher ROS and NOX2 transcriptional and protein levels. Correlating with matrix metalloproteinase induction by TMF, levels of extracellular matrix proteins such as collagens I and III were significantly lower in the treatment group. To confirm that the effects of TMF occur through the NOX2 pathway, we co-treated cells with TMF plus an NADPH inhibitor (DPI) or a ROS scavenger (NAC). Western blotting revealed that DPI and NAC attenuated the effect of TMF, suggesting that TMF induces ROS through the NOX2 pathway and regulates keratinocyte migration. In summary, TMF promotes wound healing through NOX2 induction, which leads to collective migration and MMP activation.

Fish consumption and its possible preventive role on the development and prevalence of metabolic syndrome - a systematic review

Metabolic syndrome (MetS) has a huge impact on public health, and today lifestyle interventions remain the primary mode for MetS therapy. It is therefore important to elucidate the possible preventive effects of diet and foods, and their MetS-related health implications. To examine how fish consumption affects the development and prevalence of MetS, we systematically reviewed cross-sectional, prospective cohort, and intervention studies conducted among adults (humans) and, reporting consumption of fish or seafood as being related to MetS (prevalence or incidence), where MetS was defined via an established definition. The literature search in PubMed identified 502 citations, and after screening, 49 full-text articles were retrieved and assessed for eligibility. After excluding duplicates and those not meeting the inclusion criteria, seven studies from Croatia, Finland, France, Iceland, Iran, Korea, and US were included. Four studies (one follow-up and three cross-sectional) found associations between fish consumption and MetS (three among men, and one among women), suggesting that fish consumption may prevent or improve metabolic health and have a protective role in MetS prevention. This protective role might be related to gender, and men may benefit more from the consumption of fish. However, lack of controlling for potential confounders may also inflict the results. Additional research is required to further explore fish consumption and its potential role in improving or reversing MetS and its components.