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Gut microbiota plasticity is correlated with sustained weight loss on a low-carb or low-fat dietary intervention.
Grembi, JA, Nguyen, LH, Haggerty, TD, Gardner, CD, Holmes, SP, Parsonnet, J
Scientific reports. 2020;10(1):1405
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Obesity is responsible for a substantial number of deaths and is associated with considerable economic costs. Dietary intervention can help with weight loss; however, success varies between individuals. Gut microbiota could influence weight loss as they have been shown in previous studies to affect feelings of hunger. This cohort study taken from an RCT of 161 obese adults aimed to determine if differing gut microbiota communities could be involved in determining weight loss success when on a low-carbohydrate or a low-fat diet over 12 months. The results showed that specific gut microbiota did not predict weight loss success. However, having a diverse gut microbiota prior to starting a low-fat diet, predicted higher weight loss. This was only observed in those on a low-carbohydrate diet after 10 weeks of dieting. Interestingly individuals that reported better dietary adherence weren’t necessarily more successful with weight loss. It was concluded that gut microbiota diversity is important in sustained weight loss, especially if on a low-fat diet. This study could be used by healthcare professionals to understand that microbial diversity may determine the success of a diet regime and the importance of personalising recommendations.
Abstract
While low-carbohydrate and low-fat diets can both lead to weight-loss, a substantial variability in achieved long-term outcomes exists among obese but otherwise healthy adults. We examined the hypothesis that structural differences in the gut microbiota explain a portion of variability in weight-loss using two cohorts of obese adults enrolled in the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) study. A total of 161 pre-diet fecal samples were sequenced from a discovery cohort (n = 66) and 106 from a validation cohort (n = 56). An additional 157 fecal samples were sequenced from the discovery cohort after 10 weeks of dietary intervention. We found no specific bacterial signatures associated with weight loss that were consistent across both cohorts. However, the gut microbiota plasticity (i.e. variability), was correlated with long-term (12-month) weight loss in a diet-dependent manner; on the low-fat diet subjects with higher pre-diet daily plasticity had higher sustained weight loss, whereas on the low-carbohydrate diet those with higher plasticity over 10 weeks of dieting had higher 12-month weight loss. Our findings suggest the potential importance of gut microbiota plasticity for sustained weight-loss. We highlight the advantages of evaluating kinetic trends and assessing reproducibility in studies of the gut microbiota.
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An Almond-Based Low Carbohydrate Diet Improves Depression and Glycometabolism in Patients with Type 2 Diabetes through Modulating Gut Microbiota and GLP-1: A Randomized Controlled Trial.
Ren, M, Zhang, H, Qi, J, Hu, A, Jiang, Q, Hou, Y, Feng, Q, Ojo, O, Wang, X
Nutrients. 2020;12(10)
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Associations between type 2 diabetes (T2D) and depression may exist, with depression increasing the risk of T2D and T2D increasing risk of depression. Nutritional changes such as a low carbohydrate diet (LCD) are a large part of T2D management, however the effects on depression remain controversial. Almonds as part of a LCD may have additional benefits to individuals with T2D and those with depression, potentially through its ability to modify gut microbiota. This three-month randomised control trial of 50 individuals with T2D aimed to determine if an almond based LCD (a-LCD) would affect depression and T2D through modulation of gut microbiota and associated gut-brain signalling molecules compared to a low-fat diet (LFD). The results showed that although measures of blood glucose control improved in both groups, those on the a-LCD had better blood glucose control. Symptoms of depression were reduced in participants on the a-LCD compared to the LFD. Gut-brain signalling molecules were maintained in the a-LCD but decreased in the LFD after three months. Several species of gut bacteria were changed by a-LCD. It was concluded that an a-LCD diet may improve symptoms of depression in individuals with T2D through the modulation of gut bacteria and maintenance of gut-brain signalling molecules. This study could be used by healthcare professionals to recommend a low carbohydrate diet rich in almonds for the improvement of symptoms of depression and blood glucose control in individuals with T2D. Low fat diets may also be of benefit to blood glucose control individuals with T2D.
Abstract
BACKGROUND Alow carbohydrate diet (LCD) is more beneficial for the glycometabolism in type 2 diabetes (T2DM) and may be effective in reducing depression. Almond, which is a common nut, has been shown to effectively improve hyperglycemia and depression symptoms. This study aimed to determine the effect of an almond-based LCD (a-LCD) on depression and glycometabolism, as well as gut microbiota and fasting glucagon-like peptide 1 (GLP-1) in patients with T2DM. METHODS This was a randomized controlled trial which compared an a-LCD with a low-fat diet (LFD). Forty-five participants with T2DM at a diabetes club and the Endocrine Division of the First and Second Affiliated Hospital of Soochow University between December 2018 to December 2019 completed each dietary intervention for 3 months, including 22 in the a-LCD group and 23 in the LFD group. The indicators for depression and biochemical indicators including glycosylated hemoglobin (HbA1c), gut microbiota, and GLP-1 concentration were assessed at the baseline and third month and compared between the two groups. RESULTS A-LCD significantly improved depression and HbA1c (p <0.01). Meanwhile, a-LCD significantly increased the short chain fatty acid (SCFAs)-producing bacteria Roseburia, Ruminococcus and Eubacterium. The GLP-1 concentration in the a-LCD group was higher than that in the LFD group (p <0.05). CONCLUSIONS A-LCD could exert a beneficial effect on depression and glycometabolism in patients with T2DM. We speculate that the role of a-LCD in improving depression in patients with T2DM may be associated with it stimulating the growth of SCFAs-producing bacteria, increasing SCFAs production and GPR43 activation, and further maintaining GLP-1 secretion. In future studies, the SCFAs and GPR43 activation should be further examined.