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Vegan diet in young children remodels metabolism and challenges the statuses of essential nutrients.
Hovinen, T, Korkalo, L, Freese, R, Skaffari, E, Isohanni, P, Niemi, M, Nevalainen, J, Gylling, H, Zamboni, N, Erkkola, M, et al
EMBO molecular medicine. 2021;13(2):e13492
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As vegan diets gain popularity amongst families, there is little known about the impact of strict plant-based diets on metabolism and micronutrient status in children, apart from reduced average growth within the norm. This small study looked at 40 Finnish children from one day centre, and compared children following an omnivore or vegetarian diet to those raised on a vegan diet. The diets were analysed, and biomarkers and metabolites were measured. The metabolic profile and nutrient status of children who followed a vegan diet from birth were distinctively different to other diet patterns, including vegetarians. The authors suggest that little animal source foods are enough to shift the metabolism of children. Dietary analysis showed that vegan children had higher folate consumption and lower protein and saturated fats intake. Despite intake appearing adequate, serum markers for fat-soluble vitamins A and D were low. While the fatty acid ALA was higher compared to omnivores, DHA and overall cholesterol were decreased. The authors concluded that the bodies own cholesterol production does not seem to compensate for a lack of dietary cholesterol in this case and it remains to be established whether lower cholesterol in vegan children are negative to health. Furthermore, the circulating amino acids pool was decreased in vegan children, particularly branch chained amino acids. The most distinct difference, however, was seen in the variance of bile acid patterns. The physiological functions of bile acids go beyond digestion, yet the consequences of diverging bile acid profiles in children’s health are unknown. In conclusion, the data shows that a strict vegan diet affects the metabolism of healthy children, but much of the long-term impact on health is currently still unclear. This article highlights some of the differences, risks and uncertainties that come with raising young children on a strictly vegan diet.
Abstract
Vegan diets are gaining popularity, also in families with young children. However, the effects of strict plant-based diets on metabolism and micronutrient status of children are unknown. We recruited 40 Finnish children with a median age 3.5 years-vegans, vegetarians, or omnivores from same daycare centers-for a cross-sectional study. They enjoyed nutritionist-planned vegan or omnivore meals in daycare, and the full diets were analyzed with questionnaires and food records. Detailed analysis of serum metabolomics and biomarkers indicated vitamin A insufficiency and border-line sufficient vitamin D in all vegan participants. Their serum total, HDL and LDL cholesterol, essential amino acid, and docosahexaenoic n-3 fatty acid (DHA) levels were markedly low and primary bile acid biosynthesis, and phospholipid balance was distinct from omnivores. Possible combination of low vitamin A and DHA status raise concern for their visual health. Our evidence indicates that (i) vitamin A and D status of vegan children requires special attention; (ii) dietary recommendations for children cannot be extrapolated from adult vegan studies; and (iii) longitudinal studies on infant-onset vegan diets are warranted.
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Effects of Probiotic NVP-1704 on Mental Health and Sleep in Healthy Adults: An 8-Week Randomized, Double-Blind, Placebo-Controlled Trial.
Lee, HJ, Hong, JK, Kim, JK, Kim, DH, Jang, SW, Han, SW, Yoon, IY
Nutrients. 2021;13(8)
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Dietary changes directly alter the gut microbiome composition. A diversified gut microbiome may have therapeutic implications for mental health, and specific strains of probiotics have shown the potential to treat depression and anxiety. Several preclinical trials have found the probiotic mixture NVP-1704 to alleviate depression and anxiety in mice through modulating the gut-brain-microbiome axis. The aim of this randomised, double-blind, placebo-controlled, parallel study was to examine the efficacy and safety of NVP-1704 for the management of depression, anxiety and insomnia in healthy adults. A total of 156 healthy adults with subclinical depression, anxiety and insomnia were randomised to receive either NVP-1704 or placebo for eight weeks. Participants completed various questionnaires and biomarkers of stress and inflammation were assessed. After eight weeks, this study found that NVP-1704 to be a safe and well-tolerated probiotic with beneficial effects on depression, sleep quality, inflammation and gut microbiome composition in healthy adults. Based on this study, the authors conclude the therapeutic effects of NVP-1704 previously found in preclinical mice trials may now be translated to clinical trials. The authors suggest large, highly controlled, longitudinal human studies be conducted in the future to further confirm the benefits of probiotics on mental health and sleep.
Abstract
The human gut microbiome is closely linked to mental health and sleep. We aimed to verify the efficacy and safety of probiotic NVP-1704, a mixture of Lactobacillus reuteri NK33 and Bifidobacterium adolescentis NK98, in improving stress, depression, anxiety, and sleep disturbances, along with the measurement of some blood biomarkers. A total of 156 healthy adults with subclinical symptoms of depression, anxiety, and insomnia were retrospectively registered and randomly assigned to receive either NVP-1704 (n = 78) or a placebo (n = 78) for eight weeks. Participants completed the Stress Response Inventory, Beck's Depression and Anxiety Inventory, Pittsburg Sleep Quality Index, and Insomnia Severity Index at baseline, at four and eight weeks of treatment. Pre- and post-treatment blood tests for biomarkers were conducted. After intervention, gut microbiota composition was quantified by pyrosequencing the bacterial 16S rRNA gene. The NVP-1704 group had a more significant reduction in depressive symptoms at four and eight weeks of treatment, and anxiety symptoms at four weeks compared to the placebo group. Those receiving NVP-1704 also experienced an improvement in sleep quality. NVP-1704 treatment led to a decrease in serum interleukin-6 levels. Furthermore, NVP-1704 increased Bifidobacteriaceae and Lactobacillacea, whereas it decreased Enterobacteriaceae in the gut microbiota composition. Our findings suggest that probiotic NVP-1704 could be beneficial for mental health and sleep.
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Moderate Consumption of Beer (with and without Ethanol) and Menopausal Symptoms: Results from a Parallel Clinical Trial in Postmenopausal Women.
Trius-Soler, M, Marhuenda-Muñoz, M, Laveriano-Santos, EP, Martínez-Huélamo, M, Sasot, G, Storniolo, CE, Estruch, R, Lamuela-Raventós, RM, Tresserra-Rimbau, A
Nutrients. 2021;13(7)
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During the menopause, hormonal changes can trigger uncomfortable symptoms such as hot flashes, night sweats, sleep disturbances, and vaginal dryness. Hormone replacement therapy does reduce some of the symptoms, however there has been an increased interest in alternative therapies such as phytoestrogens to relieve these symptoms. Phytoestrogens are compounds with oestrogen-like properties naturally found in plants. Beer is the main food source of the strongest phytoestrogen identified to date. The aim of this six-month parallel, controlled clinical intervention trial was to evaluate if a moderate daily intake of beer, with or without alcohol, could reduce menopausal symptoms in women. Female sex hormone profile and cardiovascular risk factors (CVRF) were also monitored. 34 postmenopausal women took part. One group included alcoholic beer (AB), and a second group added non-alcoholic beer (NAB) for 6 months. The control group took no alcohol in this time. After a 6-month follow-up both groups (AB and NAB) significantly reduced the severity of the menopause-related symptoms. These results must be considered as preliminary and will require confirmation with larger sample sizes.
Abstract
The menopausal transition can be a challenging period for women's health and a trigger of uncomfortable symptoms. Beer is the main food source of isoxanthohumol, a precursor of 8-prenylnaringenin, the strongest phytoestrogen identified to date. As phytoestrogens are reported to reduce perimenopausal symptoms, we evaluated if a daily moderate consumption of beer with (AB) and without alcohol (NAB) could improve menopausal symptoms and modify cardiovascular risk factors. A total of 37 postmenopausal women were enrolled in a parallel controlled intervention trial and assigned to three study groups: 16 were administered AB (330 mL/day), 7 NAB (660 mL/day), and 14 were in the control group. After a 6-month follow-up of the 34 participants who finished the trial, both interventions (AB and NAB) significantly reduced the severity of the menopause-related symptoms (p-value AB vs. Control: 0.009; p-value NAB vs. Control: 0.033). Moreover, AB had a beneficial net effect on psychological menopausal discomforts compared to the control group. As the sex hormone profile did not differ significantly between the study groups, the effects of both types of beers (AB and NAB) are attributed to the non-alcoholic fraction of beer. Furthermore, moderate NAB consumption improved the lipid profile and decreased blood pressure in postmenopausal women.
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Vegans, Vegetarians and Pescatarians Are at Risk of Iodine Deficiency in Norway.
Groufh-Jacobsen, S, Hess, SY, Aakre, I, Folven Gjengedal, EL, Blandhoel Pettersen, K, Henjum, S
Nutrients. 2020;12(11)
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Plant based diets, especially veganism have become increasingly popular all over the world. Changing from an omnivorous to a vegan or vegetarian diet has been associated with various health benefits; however, these dietary patterns are also linked to an increased risk of micronutrient deficiency. Iodine is a trace element which is needed to produce thyroid hormones and therefore maintain normal physiological functions of the body. In Norway, the main dietary sources of iodine are milk, seafood and eggs. The aim of this study was to evaluate iodine status, dietary intake of iodine, supplement use, macroalgae use and iodine knowledge of Norwegian vegans, vegetarians and pescatarian. Vegans, vegetarians and pescatarians in Norway are at risk of iodine deficiency and have limited knowledge of iodine. They were unable to reach recommended iodine intake from food sources alone. Data is needed on thyroid function in vegans, vegetarians and pescatarians to fully understand the consequences of iodine supplement use or macro algae use when adhering to a vegan, vegetarian or pescatarian diet in Norway.
Abstract
Low iodine intakes have been documented in different population groups in Norway. We aimed to assess iodine status, dietary intake, supplement and macroalgae use, and iodine knowledge in vegans, vegetarians and pescatarians. In this study, 115 vegans, 55 vegetarians and 35 pescatarians from the Oslo region of Norway, aged 18-60 years, participated. A spot urine sample was collected along with a dietary assessment of iodine intake, supplement and macroalgae use. The median urinary iodine concentration (MUIC) in vegans was 43 µg/L (moderate iodine deficiency), in vegetarians 67 µg/L and in pescatarians 96 µg/L (mild iodine deficiency). In multiple linear regression analysis, use of iodine supplements was one of the strongest predictors of UIC. About half of the participants had median 24-h iodine intakes below estimated average requirement (EAR) of 100 µg/day. Fifty percent had low knowledge score, while 27% had very low knowledge score. Vegans, vegetarians and possibly pescatarians in Norway, are unable to reach the recommended iodine intake merely from food and are dependent on iodine supplements. There is an urgent need for dietary guidance targeting vegans, vegetarians and pescatarians to avoid inadequate iodine intake in non-supplement users, as well as avoiding excess iodine intake in macroalgae users.
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Efficacy of a 2-Month Very Low-Calorie Ketogenic Diet (VLCKD) Compared to a Standard Low-Calorie Diet in Reducing Visceral and Liver Fat Accumulation in Patients With Obesity.
Cunha, GM, Guzman, G, Correa De Mello, LL, Trein, B, Spina, L, Bussade, I, Marques Prata, J, Sajoux, I, Countinho, W
Frontiers in endocrinology. 2020;11:607
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Excess fat in the liver, known as non-alcoholic fatty liver disease (NAFLD), has been shown to increase the risk of chronic diseases such as type 2 diabetes. Standard treatment regimens consist of low-calorie (LC) diets and exercise, however these may be ineffective at reversing fat accumulation in the liver. A very low-calorie ketogenic diet (VLCKD) has been proposed as an alternative treatment for NAFLD. This randomised control pilot study of 39 individuals with obesity aimed to compare LC diet and VLCKD on fat accumulation and indicators for NAFLD for two months. The results showed greater weight loss, abdominal fat reduction, liver fat reduction and improvements in liver function with VLCKD compared to the LC diet. Cholesterol was significantly reduced by both diets. However liver stiffness remained unchanged. The authors concluded that VLCKD was more successful at reducing liver fat and abdominal fat accumulation than current standard therapy and has the potential to improve NAFLD. Health care professionals could use this study to improve liver and abdominal fat loss in patients with obesity to improve NAFLD, when standard therapy has been inadequate.
Abstract
Background: Currently the treatment of non-alcoholic fatty liver disease (NAFLD) is based on weight loss through lifestyle changes, such as exercise combined with calorie-restricted dieting. Objectives: To assess the effects of a commercially available weight loss program based on a very low-calorie ketogenic diet (VLCKD) on visceral adipose tissue (VAT) and liver fat content compared to a standard low-calorie (LC) diet. As a secondary aim, we evaluated the effect on liver stiffness measurements. Methods: Open, randomized controlled, prospective pilot study. Patients were randomized and treated either with an LC or a VLCKD and received orientation and encouragement to physical activity equally for both groups. VAT, liver fat fraction, and liver stiffness were measured at baseline and after 2 months of treatment using magnetic resonance imaging. Paired t-tests were used for comparison of continuous variables between visits and unpaired test between groups. Categorical variables were compared using the χ2-test. Pearson correlation was used to assess the association between VAT, anthropometric measures, and hepatic fat fraction. A significance level of the results was established at p < 0.05. Results: Thirty-nine patients (20 with VLCKD and 19 with LC) were evaluated at baseline and 2 months of intervention. Relative weight loss at 2 months was -9.59 ± 2.87% in the VLCKD group and -1.87 ± 2.4% in the LC group (p < 0.001). Mean reductions in VAT were -32.0 cm2 for VLCKD group and -12.58 cm2 for LC group (p < 0.05). Reductions in liver fat fraction were significantly more pronounced in the VLCKD group than in the LC group (4.77 vs. 0.79%; p < 0.005). Conclusion: Patients undergoing a VLCKD achieved superior weight loss, with significant VAT and liver fat fraction reductions when compared to the standard LC diet. The weight loss and rapid mobilization of liver fat demonstrated with VLCKD could serve as an effective alternative for the treatment of NAFLD. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT04322110.
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Two apples a day lower serum cholesterol and improve cardiometabolic biomarkers in mildly hypercholesterolemic adults: a randomized, controlled, crossover trial.
Koutsos, A, Riccadonna, S, Ulaszewska, MM, Franceschi, P, Trošt, K, Galvin, A, Braune, T, Fava, F, Perenzoni, D, Mattivi, F, et al
The American journal of clinical nutrition. 2020;111(2):307-318
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Apples contain naturally occurring substances, called polyphenols, which in combination with fibre may be beneficial in preventing heart disease in a number of different ways. However, high quality research on this is lacking. This randomised control crossover trial of 40 individuals with slightly elevated cholesterol, aimed to assess the effects of consuming two apples a day for 20 weeks, on indicators for heart disease and in particular cholesterol levels. The results showed that consuming two apples per day resulted in decreased cholesterol and improved indicators for heart disease. It was concluded that the consumption of 2 apples per day decreased heart disease risk, attributed to the polyphenols and fibre they contain. Health professionals could use this study to recommend 2 apples per day in patients with slightly raised cholesterol in order to decrease their risk of heart disease.
Abstract
BACKGROUND Apples are rich in bioactive polyphenols and fiber. Evidence suggests that consumption of apples or their bioactive components is associated with beneficial effects on lipid metabolism and other markers of cardiovascular disease (CVD). However, adequately powered randomized controlled trials are necessary to confirm these data and explore the mechanisms. OBJECTIVE We aimed to determine the effects of apple consumption on circulating lipids, vascular function, and other CVD risk markers. METHODS The trial was a randomized, controlled, crossover, intervention study. Healthy mildly hypercholesterolemic volunteers (23 women, 17 men), with a mean ± SD BMI 25.3 ± 3.7 kg/m2 and age 51 ± 11 y, consumed 2 apples/d [Renetta Canada, rich in proanthocyanidins (PAs)] or a sugar- and energy-matched apple control beverage (CB) for 8 wk each, separated by a 4-wk washout period. Fasted blood was collected before and after each treatment. Serum lipids, glucose, insulin, bile acids, and endothelial and inflammation biomarkers were measured, in addition to microvascular reactivity, using laser Doppler imaging with iontophoresis, and arterial stiffness, using pulse wave analysis. RESULTS Whole apple (WA) consumption decreased serum total (WA: 5.89 mmol/L; CB: 6.11 mmol/L; P = 0.006) and LDL cholesterol (WA: 3.72 mmol/L; CB: 3.86 mmol/L; P = 0.031), triacylglycerol (WA: 1.17 mmol/L; CB: 1.30 mmol/L; P = 0.021), and intercellular cell adhesion molecule-1 (WA: 153.9 ng/mL; CB: 159.4 ng/mL; P = 0.028), and increased serum uric acid (WA: 341.4 μmol/L; CB: 330 μmol/L; P = 0.020) compared with the CB. The response to endothelium-dependent microvascular vasodilation was greater after the apples [WA: 853 perfusion units (PU), CB: 760 PU; P = 0.037] than after the CB. Apples had no effect on blood pressure or other CVD markers. CONCLUSIONS These data support beneficial hypocholesterolemic and vascular effects of the daily consumption of PA-rich apples by mildly hypercholesterolemic individuals.This trial was registered at clinicaltrials.gov as NCT01988389.
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Mediterranean diet intervention in overweight and obese subjects lowers plasma cholesterol and causes changes in the gut microbiome and metabolome independently of energy intake.
Meslier, V, Laiola, M, Roager, HM, De Filippis, F, Roume, H, Quinquis, B, Giacco, R, Mennella, I, Ferracane, R, Pons, N, et al
Gut. 2020;69(7):1258-1268
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Evidence suggests that the Mediterranean diet (MD) may help prevent cardiovascular disease (CVD). However, this could be influenced by an individual’s gut microbiome, highlighting a need for personalised nutrition practices. This randomised crossover control trial aimed to evaluate an 8-week personalised MD intervention in 82 overweight and obese subjects, who were at high risk of cardiovascular disease. The results showed that a personalised MD lowered cholesterol, regardless of the amount of energy consumed and the amount of exercise performed and relied upon adherence to the MD. Gut microbiome composition was altered by a MD and although markers for diabetes were not improved overall, there was an improvement in prediabetes in individuals with higher levels of Bacteroides species and lower levels of Prevotella species. It was concluded that a MD may reduce cholesterol and alter the gut microbiome to benefit cardiovascular health. Health professionals could use this study to switch patients to a MD whilst maintaining their energy intake to reduce cardiovascular risk. In order to see maximum benefit, it would be recommended to take a personalised approach and analyse an individual’s gut microbiome in order to tailor recommendations.
Abstract
OBJECTIVES This study aimed to explore the effects of an isocaloric Mediterranean diet (MD) intervention on metabolic health, gut microbiome and systemic metabolome in subjects with lifestyle risk factors for metabolic disease. DESIGN Eighty-two healthy overweight and obese subjects with a habitually low intake of fruit and vegetables and a sedentary lifestyle participated in a parallel 8-week randomised controlled trial. Forty-three participants consumed an MD tailored to their habitual energy intakes (MedD), and 39 maintained their regular diets (ConD). Dietary adherence, metabolic parameters, gut microbiome and systemic metabolome were monitored over the study period. RESULTS Increased MD adherence in the MedD group successfully reprogrammed subjects' intake of fibre and animal proteins. Compliance was confirmed by lowered levels of carnitine in plasma and urine. Significant reductions in plasma cholesterol (primary outcome) and faecal bile acids occurred in the MedD compared with the ConD group. Shotgun metagenomics showed gut microbiome changes that reflected individual MD adherence and increase in gene richness in participants who reduced systemic inflammation over the intervention. The MD intervention led to increased levels of the fibre-degrading Faecalibacterium prausnitzii and of genes for microbial carbohydrate degradation linked to butyrate metabolism. The dietary changes in the MedD group led to increased urinary urolithins, faecal bile acid degradation and insulin sensitivity that co-varied with specific microbial taxa. CONCLUSION Switching subjects to an MD while maintaining their energy intake reduced their blood cholesterol and caused multiple changes in their microbiome and metabolome that are relevant in future strategies for the improvement of metabolic health.
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Increased Colonic Permeability and Lifestyles as Contributing Factors to Obesity and Liver Steatosis.
Di Palo, DM, Garruti, G, Di Ciaula, A, Molina-Molina, E, Shanmugam, H, De Angelis, M, Portincasa, P
Nutrients. 2020;12(2)
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Intestinal permeability (IP) is dependent on the structure and function of the intestinal barrier. The gut barrier integrity is the result of ongoing equilibrium and crosstalk involving the microbiome, the mucus, the enterocytes [intestinal absorptive cells], the gut immune system, and the gut–vascular barrier. The main aim of this study was to explore the pan-enteric IP (stomach, small intestine, and colon) with respect to size and fat distribution, as well as the presence of liver steatosis. The study is a cohort study that examined 120 subjects (obese n = 45, overweight n=30, normal weight n = 45). Groups were gender-matched except for the prevalence of males in the overweight group. Results highlight the existence of an association between colonic (but not stomach and small intestinal) permeability, obesity, and liver steatosis. Findings show that: - liver steatosis was detected in 69 (57.5%) subjects, of which 36 (52%) were males. The prevalence of liver steatosis increased from 4% in normal weight subjects to 77%, and to 98% in overweight and obese subjects, respectively. - gastrointestinal permeability changed between age groups at every tract, whereas stomach and small intestine IP decreased with age. Furthermore, this finding also occurred in subjects aged over or equal to 65 years, with respect to colonic permeability. Authors conclude that further studies must evaluate the possibility of modulating colonic permeability to allow both primary prevention measures and new therapeutic strategies in metabolic and liver diseases.
Abstract
Intestinal permeability (IP) is essential in maintaining gut-metabolic functions in health. An unequivocal evaluation of IP, as marker of intestinal barrier integrity, however, is missing in health and in several diseases. We aimed to assess IP in the whole gastrointestinal tract according to body mass index (BMI) and liver steatosis. In 120 patients (61F:59M; mean age 45 ± SEM 1.2 years, range: 18-75), IP was distinctively studied by urine recovery of orally administered sucrose (SO, stomach), lactulose/mannitol ratio (LA/MA, small intestine), and sucralose (SA, colon). By triple quadrupole mass-spectrometry and high-performance liquid chromatography, we measured urinary recovery of saccharide probes. Subjects were stratified according to BMI as normal weight, overweight, and obesity, and answered questionnaires regarding dietary habits and adherence to the Mediterranean Diet. Liver steatosis was assessed by ultrasonography. IP at every gastrointestinal tract was similar in both sexes and decreased with age. Stomach and small intestinal permeability did not differ according to BMI. Colonic permeability increased with BMI, waist, neck, and hip circumferences and was significantly higher in obese than in lean subjects. As determined by logistic regression, the odds ratio (OR) of BMI increment was significantly higher in subjects in the highest tertile of sucralose excretion, also after adjusting for age and consumption of junk food. The presence of liver steatosis was associated with increased colonic permeability. Patients with lower score of adherence to Mediterranean diet had a higher score of 'junk food'. Intestinal permeability tended to increase in subjects with a lower adherence to Mediterranean diet. In conclusion, colonic (but not stomach and small intestinal) permeability seems to be linked to obesity and liver steatosis independently from dietary habits, age, and physical activity. The exact role of these last factors, however, requires specific studies focusing on intestinal permeability. Results should pave the way to both primary prevention measures and new therapeutic strategies in metabolic and liver diseases.
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Diet-induced weight loss alters hepatic glucocorticoid metabolism in type 2 diabetes mellitus.
Stomby, A, Otten, J, Ryberg, M, Andrew, R, Walker, BR, Olsson, T
European journal of endocrinology. 2020;182(4):447-457
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Cushing syndrome is caused by an overexposure to cortisol and associated with abdominal adiposity, hypertension, dyslipidaemia, insulin resistance and type 2 diabetes mellitus (T2DM), and therefore bears similarities with metabolic syndrome and obesity. Whilst circulating cortisol levels are normal or slightly decreased in obese individuals, they tend to be increased in T2DM. The aim of this study was to investigate associations between obesity and T2DM measures and glucocorticoid metabolism, and any possible effects of a palaeolithic diet (PD) with or without exercise. In this single-blind study (investigators examining patients were blind to intervention), 28 patients with overweight or obesity and T2DM were randomised to either a PD alone or combined with a structured resistance and aerobic exercise programme for 12 weeks. The PD was based on a high intake of vegetables, fruit, lean meat, nuts, egg, fish and seafood, whilst grains, sugar, salt, dairy products and refined fats were reduced. Body mass index, waist circumference, glycaemic control, liver and systemic insulin sensitivity improved in both groups with no statistically significant difference between groups. There was no association between insulin sensitivity and indices of tissue specific glucocorticoid metabolism. PD with and without exercise was associated with increased conversion of the inactive cortisone to the active cortisol through increased activity of the conversion enzyme in the liver, but not with increased urinary excretion of glucocorticoid metabolites. The authors concluded that the results suggests that dysregulation of liver glucocorticoid metabolism in these patients is a consequence rather than a cause of metabolic dysfunction.
Abstract
CONTEXT Altered tissue-specific glucocorticoid metabolism has been described in uncomplicated obesity and type 2 diabetes. We hypothesized that weight loss induced by diet and exercise, which has previously been shown to reverse abnormal cortisol metabolism in uncomplicated obesity, also normalizes cortisol metabolism in patients with type 2 diabetes. OBJECTIVE Test the effects of a diet intervention with added exercise on glucocorticoid metabolism. DESIGN Two groups followed a Paleolithic diet (PD) for 12 weeks with added 180 min of structured aerobic and resistance exercise per week in one randomized group (PDEX). SETTING Umeå University Hospital. PARTICIPANTS Men and women with type 2 diabetes treated with lifestyle modification ± metformin were included. Twenty-eight participants (PD, n = 15; PDEX, n = 13) completed measurements of glucocorticoid metabolism. MAIN OUTCOME MEASURES Changes in glucocorticoid metabolite levels in 24-h urine samples, expression of HSD11B1 mRNA in s.c. adipose tissue and conversion of orally administered cortisone to cortisol measured in plasma. Body composition and insulin sensitivity were measured using a hyperinsulinemic-euglycemic clamp, and liver fat was measured by magnetic resonance spectroscopy. RESULTS Both groups lost weight and improved insulin sensitivity. Conversion of orally taken cortisone to plasma cortisol and the ratio of 5α-THF + 5β-THF/THE in urine increased in both groups. CONCLUSIONS These interventions caused weight loss and improved insulin sensitivity with concomitant increases in the conversion of cortisone to cortisol, which is an estimate of hepatic HSD11B1 activity. This suggests that dysregulation of liver glucocorticoid metabolism in these patients is a consequence rather than a cause of metabolic dysfunction.
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Broccoli consumption affects the human gastrointestinal microbiota.
Kaczmarek, JL, Liu, X, Charron, CS, Novotny, JA, Jeffery, EH, Seifried, HE, Ross, SA, Miller, MJ, Swanson, KS, Holscher, HD
The Journal of nutritional biochemistry. 2019;63:27-34
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Diet affects metabolic and gastrointestinal diseases, with the microbiome considered to be a mediating factor. Broccoli is a good source of fibre and phytochemicals including glucosinolates. The aim of this investigator-blinded, controlled feeding, randomised, crossover study was to evaluate the effects of broccoli on the composition and function of the microbiome. 18 healthy adults received 200 g cooked broccoli and 20 g raw daikon radish per day for 18 days in addition to a controlled, brassica-free diet or the same diet without the broccoli and daikon radish, with a 24-day washout period. A statistically significant increase in the ratio of Bacteroidetes to Firmicutes was observed following the broccoli intervention. When stratified by BMI above or below 25, this increase was only seen in those with a lower BMI whilst those with a higher BMI displayed a decrease in the ratio, although the latter was not statistically significant. In those with the lower BMI, there was also a correlation between the changes in the microbiota composition and glucosinolate metabolites. It was predicted that the involved changes would affect the functions of the endocrine system, transport and catabolism and energy metabolism. The authors concluded that eating broccoli may affect both the composition and the function of the microbiome.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Broccoli consumption at dosages of 200g per day were shown to change the composition of gastrointestinal microbiota, increasing Bacteroidetes and decreasing Firmicutes, and impact their function
- The observed results were strongest in those with a BMI of less than 26
- While interesting, the study only included 18 participants and therefore the results should be further confirmed.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
There is growing evidence linking dysbiosis of the gastrointestinal microbiota and diet-induced gastrointestinal and metabolic diseases. Both long-term and acute dietary changes, fasting, eating frequency, and consumption of specific fibres and food phytochemicals play a role in shaping the composition and function of the microbiota, although evidence is lacking for specific foods. This study aimed to determine the impact of broccoli intake on the number of bacterial strains and their functional capacity.
Methods
This was a single-blind, randomised, crossover, complete feeding intervention. Study participants were healthy adults (n=18, females =10). Participants were requested to not eat Brassica vegetables for 3 weeks before the start of the study.
Subjects participated in two 18-day diet periods separated by a 24-hour washout, during which breakfast and dinner were consumed on site to observe compliance. The control diet was prepared using traditional American foods, excluding all Brassica vegetables. During the broccoli intervention period, participants consumed the same base diet with the addition of 200g of broccoli.
Faecal samples were collected on day 1, and day 16. Quantitative polymerase chain reaction was performed on bacterial strains. On day 17, time series plasma sampling and 24-hour urine collection was done.
Results
There was no difference in alpha diversity (a measure of microbiome diversity within a sample) between the two treatment periods. This indicates that no bacterial species were extinguished by broccoli treatment. Beta diversity analysis (a measure of the (dis)similarity between samples) indicated that bacterial communities were impacted by treatment (P=0.03).
After broccoli consumption, Bacteroidetes increased by 10% (P =0.03), while Firmicutes decreased by 8% (P=0.05). Overall the ratio of Bacteroidetes to Firmicutes increased by 37% (P=0.01) versus a 5% decrease in the control period. The Bacteroides genus increased by 6% (P=0.02) versus a 2% decrease in the control period.
Interestingly, the effects were most strong in those with a lower BMI (< 26 kg/m2) who had an increase in metabolites after broccoli consumption. Algorithms to predict the function of the microbiota showed that broccoli increased endocrine (P=0.05), energy metabolism (P=0.01), transport and catabolism (P=0.04) pathways.
Conclusion
Broccoli intake, at 200g daily, changes the composition and potentially impacts the function of the gut microbiota.
Clinical practice applications:
- Studies like this allow practitioners to focus on specific foods in specific quantities to positively alter the microbiota and their function
- Cruciferous vegetables, like broccoli, kale, cauliflower, cabbage, Brussel sprouts, are an important group as they contain fibre and phytonutrients such as glucosinolates. These compounds can be metabolised by the microbiota into active compounds with health benefits. This study has shown the bidirectional benefit of broccoli consumption in that it can positively impact the function and composition of the microbiota
- Interestingly, the results in this small study were driven by participants with a BMI of less than 26. Sub-group analysis found no statistically significant relationships in participants with BMI >26
- It is worth noting that it is possible that the addition of 5g of fibre from the broccoli is also contributing to the changes observed.
Considerations for future research:
- Larger, controlled feeding studies that isolate specific foods to identify their effects on the microbiota are needed
- Genetic sequencing for only a few bacterial myrosinases has been completed and therefore future studies should aim to assess the metabolic capabilities in faecal samples such as myrosinase activity
- While this study and others have shown changes in the types of bacteria after cruciferous vegetable consumption the consistency of results has been mixed potentially due to differing study designs and treatment dosages. Further studies to clarify and confirm these results would be beneficial
- To assess the function of the microbiota a predictive algorithm was used. This requires experimental confirmation by such methods as metabolite profiling and whole genome shotgun sequencing.
Abstract
The human gastrointestinal microbiota is increasingly linked to health outcomes; however, our understanding of how specific foods alter the microbiota is limited. Cruciferous vegetables such as broccoli are a good source of dietary fiber and phytonutrients, including glucosinolates, which can be metabolized by gastrointestinal microbes. This study aimed to determine the impact of broccoli consumption on the gastrointestinal microbiota of healthy adults. A controlled feeding, randomized, crossover study consisting of two 18-day treatment periods separated by a 24-day washout was conducted in healthy adults (n=18). Participants were fed at weight maintenance with the intervention period diet including 200 g of cooked broccoli and 20 g of raw daikon radish per day. Fecal samples were collected at baseline and at the end of each treatment period for microbial analysis. Beta diversity analysis indicated that bacterial communities were impacted by treatment (P=.03). Broccoli consumption decreased the relative abundance of Firmicutes by 9% compared to control (P=.05), increased the relative abundance of Bacteroidetes by 10% compared to control (P=.03) and increased Bacteroides by 8% relative to control (P=.02). Furthermore, the effects were strongest among participants with body mass index <26 kg/m2, and within this group, there were associations between bacterial relative abundance and glucosinolate metabolites. Functional prediction revealed that broccoli consumption increased the pathways involved in the functions of the endocrine system (P=.05), transport and catabolism (P=.04), and energy metabolism (P=.01). These results reveal that broccoli consumption affects the composition and function of the human gastrointestinal microbiota.