Thylakoids reduce body fat and fat cell size by binding to dietary fat making it less available for absorption in high-fat fed mice

Thylakoid supplementation and hunger and fullness perception: a systematic review and dose-response meta-analysis of randomized controlled trials

CONTEXT

It has been suggested that thylakoid supplementation could be associated with favorable changes in appetite. However, the present trials are inconsistent.

OBJECTIVE

This systematic review and meta-analysis aimed to investigate whether thylakoid supplementation is effective in hunger/fullness changes.

DATA SOURCES

A comprehensive literature search was performed before conducting a systematic search in PubMed, Scopus, and ISI Web of Sciences databases up to May 2023.

DATA EXTRACTION

Of the 262 articles found, 5 articles that measured hunger fullness expressed as ratings on the visual analog scale (VAS) for appetite analyses were selected and thoroughly examined. Relevant information, such as the authors' names, year of publication, country of origin, study design, number and status of participants, intervention dosage and type, study duration, assay used, and key findings, was extracted from these articles. The Jadad scale was used to evaluate the quality of studies.

DATA ANALYSIS

The data were obtained using STATA version 13 (StataCorp). Effect sizes were reported as weighted mean differences (WMDs) and 95% confidence intervals (CIs). Subgroup analyses were performed to estimate whether the effects of thylakoid supplementation on hunger and fullness varied according to dose, intervention duration, baseline population age and body mass index, baseline hunger and fullness, total sample size, and study quality. Fractional polynomial modeling was carried out to estimate time- and dose-response meta-analysis of the association between thylakoid and satiety and fullness. The meta-analysis also suggests a significant association between the combination of thylakoids with meals and reduced hunger (WMD: -2.415 mm; 95% CI: -3.544, -1.287; P < 0.001) and increased fullness (WMD: +4.602 mm; 95% CI: 2.356, 6.848; P < 0.001). Further analysis showed that thylakoid supplementation with 2 doses of 5 g/day (P = 0.002) and 7.4 g/day (P = 0.021) is more effective in reducing the feeling of hunger during an intervention of less than 56 days (P < 0.001) and with a lower level of hunger (VAS <45 mm, P < 0.001). Furthermore, a significant increase in the perception of fullness was found at a duration of less than 84 days (P < 0.001) and baseline fullness of more than 45 mm (P < 0.001).

CONCLUSIONS

Supplementation with thylakoid shows favorable effects on reducing hunger and increasing fullness during a shorter intervention duration. Further trials are required to shed light on this relationship.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023432429.

NRF2 is essential for adaptative browning of white adipocytes

White adipose tissue browning, defined by accelerated mitochondrial metabolism and biogenesis, is considered a promising mean to treat or prevent obesity-associated metabolic disturbances. We hypothesize that redox stress acutely leads to increased production of reactive oxygen species (ROS), which activate electrophile sensor nuclear factor erythroid 2-Related Factor 2 (NRF2) that over time results in an adaptive adipose tissue browning process. To test this, we have exploited adipocyte-specific NRF2 knockout mice and cultured adipocytes and analyzed time- and dose-dependent effect of NAC and lactate treatment on antioxidant expression and browning-like processes. We found that short-term antioxidant treatment with N-acetylcysteine (NAC) induced reductive stress as evident from increased intracellular NADH levels, increased ROS-production, reduced oxygen consumption rate (OCR), and increased NRF2 levels in white adipocytes. In contrast, and in line with our hypothesis, longer-term NAC treatment led to a NRF2-dependent browning response. Lactate treatment elicited similar effects as NAC, and mechanistically, these NRF2-dependent adipocyte browning responses in vitro were mediated by increased heme oxygenase-1 (HMOX1) activity. Moreover, this NRF2-HMOX1 axis was also important for β3-adrenergic receptor activation-induced adipose tissue browning in vivo. In conclusion, our findings show that administration of exogenous antioxidants can affect biological function not solely through ROS neutralization, but also through reductive stress. We also demonstrate that NRF2 is essential for white adipose tissue browning processes.

Dietary Bamboo Charcoal Decreased Visceral Adipose Tissue Weight by Enhancing Fecal Lipid Excretions in Mice with High-Fat Diet-Induced Obesity

Bamboo charcoal (BC) powder is prepared from thick bamboo stems via dry distillation and is often used for food coloring. Due to the unique structure of the micropores in bamboo stems, BC powder also serves as an indigestible carrier to prevent the absorption of toxic substances and nutrients from the digestive tract. This study evaluated the health-promoting function of BC, particularly its effects in decreasing visceral adipose tissue in a mouse model with high-fat diet (HFD)-induced obesity. Four-week-old male C57BL/6J mice were divided into three groups and fed either a low-fat (LF) diet (7% fat), HF diet (25% fat), or HF diet with 0.5% BC (HF-BC). After 80 days, the HF-BC diet was found to have decreased epididymal and mesenteric white adipose tissue weights compared to HFD. The inhibition of visceral fat accumulation by BC intake was partly due to enhanced fecal fatty acid excretion induced by its bile acid-binding and pancreatic lipase inhibition. Contrarily, the gut microbiota, known to influence systemic energy metabolism, did not change significantly between the HF and HF-BC groups. These results indicate that dietary BC inhibits visceral fat accumulation, which could reduce obesity development.

Digestibility and oxidative stability of plant lipid assemblies: An underexplored source of potentially bioactive surfactants?

Most lipids in our diet come under the form of triacylglycerols that are often redispersed and stabilized by surfactants in processed foods. In plant however, lipid assemblies constitute interesting sources of natural bioactive and functional ingredients. In most photosynthetic sources, polar lipids rich in ω3 fatty acids are concentrated. The objective of this review is to summarize all the knowledge about the physico-chemical composition, digestive behavior and oxidative stability of plant polar lipid assemblies to emphasize their potential as functional ingredients in human diet and their potentialities to substitute artificial surfactants/antioxidants. The specific composition of plant membrane assemblies is detailed, including plasma membranes, oil bodies, and chloroplast; emphasizing its concentration in phospholipids, galactolipids, peculiar proteins, and phenolic compounds. These molecular species are hydrolyzed by specific digestive enzymes in the human gastrointestinal tract and reduced the hydrolysis of triacylglycerols and their subsequent absorption. Galactolipids specifically can activate ileal break and intrinsically present an antioxidant (AO) activity and metal chelating activity. In addition, their natural association with phenolic compounds and their physical state (Lα state of digalactosyldiacylglycerols) in membrane assemblies can enhance their stability to oxidation. All these elements make plant membrane molecules and assemblies very promising components with a wide range of potential applications to vectorize ω3 polyunsaturated fatty acids, and equilibrate human diet.

Administration of hydro-alcoholic extract of spinach improves oxidative stress and inflammation in high-fat diet-induced NAFLD rats

Background

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. The aim of this study was to evaluate the effects of hydro-alcoholic extract of spinach (HES) on hepatic and serum measurements of NAFLD in a rat model.

Methods

In the prevention phase, 18 Sprague–Dawley rats were fed a high-fat diet, a high-fat diet plus 400 mg/kg HES, or a chow diet for seven weeks. For the treatment phase, after the induction of NAFLD, they were fed a high-fat diet, a high-fat diet plus 400 mg/kg HES, a chow diet, or a chow diet plus 400 mg/kg HES for four weeks (n = 6).

Results

Administration of HES combined with high-fat diet in rats was associated with decreased food intake (P < 0.01), weight loss (P = 0.01), and increased superoxide dismutase (SOD) (P = 0.02) enzyme activity in the liver, at the end of the prevention phase. hs-CRP (P < 0.05), PTX-3 (P < 0.05), and TNF-α (P < 0.05) gene expression in the liver were decreased and PPAR-γ (P < 0.05) gene expression in the liver was increased by spinach intake, both in the prevention and treatment phases. Furthermore, administration of spinach in the treatment phase increased serum TAC (P = 0.03) and hepatic GPX (P = 0.01) enzyme activity.

Conclusion

Taking into account the potential beneficial effects of HES on prevention and treatment of NAFLD in the present study, to confirm these findings, we propose that further clinical trials be conducted on human subjects with NAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03396-x.

Changes of body composition and circulating neopterin, omentin-1, and chemerin in response to thylakoid-rich spinach extract with a hypocaloric diet in obese women with polycystic ovary syndrome: A randomized controlled trial

This trial evaluated the effects of thylakoid-rich spinach extract supplementation combined with a hypocaloric diet on body composition and serum levels of neopterin, chemerin, and omentin-1 in obese women with polycystic ovary syndrome (PCOS). In this randomized controlled trial, 48 obese women with PCOS, aged 20-45 years old, were recruited and randomly divided into thylakoid (n = 24) and placebo (n = 24) groups. They received a low-calorie diet with 5 g/day thylakoid-rich spinach extract or a low-calorie diet with 5 g/day placebo for 12 weeks. The mean age of the participants of the thylakoid group was 31.86 years, and the placebo group was 32.04 years. Thylakoid-rich spinach extract supplementation with a low-calorie diet increased serum levels of omentin-1 (10.90 vs. 3.87 ng/L; p < .001) and decreased fat mass (-5.19 vs. -1.35 kg; p < .001) and serum levels of neopterin (-0.66 vs. -0.38 nmol/L; p = .003) and chemerin (-41.24 vs. -11.26 ng/L; p < .001) in the thylakoid group compared to the placebo group. A significant improvement in omentin-1, chemerin, and neopterin by thylakoid-rich spinach extract supplementation was under the influence of weight change and insulin resistance status throughout the study. A significant decrease in the other anthropometric indices and insulin resistance was also observed in the thylakoid group, compared to the placebo group (p < .001, for all parameters). Thylakoid-rich spinach extract combined with a low-calorie diet increased circulating omentin-1 and decreased fat mass, abdominal obesity, as well as circulating chemerin, neopterin, and insulin in obese women with PCOS.

Effects of thylakoid intake on appetite and weight loss: a systematic review

Background

Previous studies have shown thylakoids, the membrane proteins which are extracted from green leaves like spinach, can induce satiety through homeostatic and non-homeostatic pathways. In this study, we reviewed the current human literature on thylakoids' characteristics and their relationship to satiety regulation and weight loss.

Methods

A systematic search of literature published between January 1990 and May 2019 was conducted on the electronic databases; including WEB OF SCIENCE, Cochrane Library, MEDLINE, Scopus, and EMBASE databases. We included all clinical trials that addressed the effects of thylakoids or chloroplast intake on satiety and weight loss.

Results

After excluding non-human studies, non-RCTs, duplications, studies with irrelevant data and interventions, eight studies were included in the qualitative synthesis. All studies supported this hypothesis that thylakoids reduce the feeling of hunger by increasing postprandial cholecystokinin and leptin and decreasing serum ghrelin, but the consequences of thylakoid intake on anthropometric characteristics were controversial.

Conclusion

In conclusion, our results may approve this postulation that receiving a thylakoid-enriched meal can decrease appetite and probably food intake in short term; however, more studies are needed to explore the effects of long term supplementation with thylakoids on weight loss in human subjects.

The effects of hydroalcoholic extract of spinach on prevention and treatment of some metabolic and histologic features in a rat model of nonalcoholic fatty liver disease

BACKGROUND

This study evaluated the effects of hydroalcoholic extract of spinach (HES) on nonalcoholic fatty liver disease (NAFLD). In the prevention phase, 18 Sprague-Dawley rats were fed a high-fat diet, a high-fat diet plus 400 mg kg^-1 HES, or a chow diet for 7 weeks. For the treatment phase, after the induction of NAFLD, they were fed a high-fat diet, a high-fat diet plus 400 mg kg^-1 HES, a chow diet, or chow diet plus 400 mg kg^-1 HES for 4 weeks (n = 6).

RESULTS

Weight gain (P = 0.01), food intake (P < 0.01), serum glucose (P = 0.01), triglyceride (TG) (P = 0.02), low-density lipoprotein cholesterol (LDL-c) (P = 0.01), aspartate aminotransferase (AST) (P = 0.02), liver steatosis, and the nonalcoholic fatty liver disease (NAFLD) activity score (NAS) (P < 0.01) in the high-fat group were statistically higher than in the other groups at the end of the prevention phase. Feeding spinach extract to rats on a high-fat diet decreased serum glucose (P = 0.01), total cholesterol (TCh) (P < 0.01), AST (P = 0.01), alkaline phosphatase (ALP) (P < 0.01), and liver steatosis (P < 0.01) in the treatment phase.

CONCLUSION

Overall, spinach extract showed beneficial effects in the prevention and treatment of NAFLD. © 2019 Society of Chemical Industry.

Thylakoids: A Novel Food-Derived Supplement for Obesity - A Mini-Review

Nowadays, overweight and obesity are major epidemic health problems that can bring about some other health issues such as cardiovascular disease which is the first cause of mortality worldwide. Thylakoids are disc-like membranes responsible for photosynthetic light reactions in chloroplasts of green plants. Although only a few animal and human studies have been conducted regarding the impact of thylakoids on overweight- and obesity-related factors, all of them have resulted in positive outcomes. These outcomes are as follows: increment of satiety response; suppression of hunger sensations, particularly hedonic hunger; reduction of body weight and fat; promotion of glucose homeostasis; decrease in serum lipids; attenuation of oxidative stress and inflammation; and modulation of gut microbiota, notably by increasing some helpful bacteria such as Lactobacillus reuteri. It seems that some of these useful effects are related to retarded absorption of dietary fat and carbohydrate caused by thylakoids. There is still a need for more well-designed studies.

Adipose cell size: importance in health and disease

Adipose tissue is necessary to harbor energy. To handle excess energy, adipose tissue expands by increasing adipocyte size (hypertrophy) and number (hyperplasia). Here, we have summarized the different experimental techniques used to study adipocyte cell size and describe adipocyte size in relation to insulin resistance, type 2 diabetes, and diet interventions. Hypertrophic adipocytes have an impaired cellular function, and inherent mechanisms restrict their expansion to protect against cell breakage and subsequent inflammation. Reduction of large fat cells by diet restriction, physical activity, or bariatric surgery therefore is necessary to improve cellular function and health. Small fat cells may also be dysfunctional and unable to expand. The distribution and function of the entire cell size range of fat cells, from small to very large fat cells, are an important but understudied aspect of adipose tissue biology. To prevent dysmetabolism, therapeutic strategies to expand small fat cells, recruit new fat cells, and reduce large fat cells are needed.