{"id":22456,"date":"2016-12-23T01:38:46","date_gmt":"2016-12-23T09:38:46","guid":{"rendered":"http:\/\/www.jewishindependent.ca\/?p=22456"},"modified":"2016-12-21T12:15:41","modified_gmt":"2016-12-21T20:15:41","slug":"keeping-the-weight-off","status":"publish","type":"post","link":"https:\/\/www.jewishindependent.ca\/index.php\/2016\/12\/23\/keeping-the-weight-off\/","title":{"rendered":"Keeping the weight off"},"content":{"rendered":"

(image from wis-wander.weizmann.ac.il<\/a>)<\/em><\/strong><\/span><\/p>\n

Following a successful diet, many people are dismayed to find their weight rebounding \u2013 an all-too-common phenomenon termed \u201crecurrent\u201d or \u201cyo-yo\u201d obesity. Worse still, the vast majority of recurrently obese individuals not only rebound to their pre-dieting weight but also gain more weight with each dieting cycle. During each round of dieting-and-weight-regain, their proportion of body fat increases, and so does the risk of developing the manifestations of metabolic syndrome, including adult-onset diabetes, fatty liver and other obesity-related diseases.<\/p>\n

As recently reported in Nature<\/em>, researchers at the Weizmann Institute of Science have shown in mice that intestinal microbes \u2013 collectively termed the gut microbiome \u2013 play an unexpectedly important role in exacerbated post-dieting weight gain, and that this common phenomenon may in the future be prevented or treated by altering the composition or function of the microbiome.<\/p>\n

The study was performed by research teams headed by Dr. Eran Elinav of the immunology department and Prof. Eran Segal of the computer science and applied mathematics department. The researchers found that, after a cycle of gaining and losing weight, all the mice\u2019s body systems fully reverted to normal \u2013 except the microbiome. For about six months after losing weight, post-obese mice retained an abnormal \u201cobese\u201d microbiome.<\/p>\n

\u201cWe\u2019ve shown in obese mice that, following successful dieting and weight loss, the microbiome retains a \u2018memory\u2019 of previous obesity,\u201d said Elinav. \u201cThis persistent microbiome accelerated the regaining of weight when the mice were put back on a high-calorie diet or ate regular food in excessive amounts.\u201d<\/p>\n

Segal elaborated: \u201cBy conducting a detailed functional analysis of the microbiome, we\u2019ve developed potential therapeutic approaches to alleviating its impact on weight regain.\u201d<\/p>\n

The study was led by Christoph Thaiss, a PhD student in Elinav\u2019s lab. Thaiss collaborated with master\u2019s student Shlomik Itav of Elinav\u2019s lab, Daphna Rothschild, a PhD student of Segal\u2019s lab, as well as with other scientists from Weizmann and elsewhere.<\/p>\n

In a series of experiments, the scientists demonstrated that the makeup of the \u201cobese\u201d microbiome was a major driver of accelerated post-dieting weight gain. For example, when the researchers depleted the intestinal microbes in mice by giving them broad-spectrum antibiotics, the exaggerated post-diet weight gain was eliminated. In another experiment, when intestinal microbes from mice with a history of obesity were introduced into germ-free mice \u2013 which, by definition, carry no microbiome of their own \u2013 their weight gain was accelerated upon feeding with a high-calorie diet, compared to germ-free mice that had received an implant of intestinal microbes from mice with no history of weight gain.<\/p>\n

Next, the scientists developed a machine-learning algorithm, based on hundreds of individualized microbiome parameters, which successfully and accurately predicted the rate of weight regain in each mouse, based on the characteristics of its microbiome after weight gain and successful dieting. Furthermore, by combining genomic and metabolic approaches, they then identified two molecules driving the impact of the microbiome on regaining weight. These molecules \u2013 belonging to the class of organic chemicals called flavonoids that are obtained through eating certain vegetables \u2013 are rapidly degraded by the \u201cpost-dieting\u201d microbiome, so that the levels of these molecules in post-dieting mice are significantly lower than those in mice with no history of obesity. The researchers found that under normal circumstances, these two flavonoids promote energy expenditure during fat metabolism. Low levels of these flavonoids in weight cycling prevented this fat-derived energy release, causing the post-dieting mice to accumulate extra fat when they were returned to a high-calorie diet.<\/p>\n

Finally, the researchers used these insights to develop new proof-of-concept treatments for recurrent obesity. First, they implanted formerly obese mice with gut microbes from mice that had never been obese. This fecal microbiome transplantation erased the \u201cmemory\u201d of obesity in these mice when they were re-exposed to a high-calorie diet, preventing excessive recurrent obesity.<\/p>\n

Next, the scientists used an approach that is likely to be more unobjectionable to humans: they supplemented post-dieting mice with flavonoids added to their drinking water. This brought their flavonoid levels, and thus their energy expenditure, back to normal levels. As a result, even on return to a high-calorie diet, the mice did not experience accelerated weight gain.<\/p>\n

\u201cWe call this approach \u2018post-biotic\u2019 intervention,\u201d Segal said. \u201cIn contrast to probiotics, which introduce helpful microbes into the intestines, we are not introducing the microbes themselves but substances affected by the microbiome, which might prove to be more safe and effective.\u201d<\/p>\n

Recurrent obesity is an epidemic. \u201cObesity affects nearly half of the world\u2019s adult population, and predisposes people to common life-risking complications such as adult-onset diabetes and heart disease,\u201d said Elinav. \u201cIf the results of our mouse studies are found to be applicable to humans, they may help diagnose and treat recurrent obesity and this, in turn, may help alleviate the obesity epidemic.\u201d<\/p>\n

Also taking part in the study were Mariska Meijer, Maayan Levy, Claudia Moresi, Lenka Dohnalova, Sofia Braverman, Shachar Rozin, Dr. Mally Dori-Bachash and staff scientist Hagit Shapiro of the immunology department, staff scientists Drs. Yael Kuperman and Inbal Biton, and Prof. Alon Harmelin of the veterinary resources department, and Dr. Sergey Malitsky and Prof. Asaph Aharoni of the plant and environmental sciences department \u2013 all of the Weizmann Institute \u2013 as well as Prof. Arieh Gertler of the Hebrew University of Jerusalem and Prof. Zamir Halpern of the Tel-Aviv Sourasky Medical Centre.<\/p>\n","protected":false},"excerpt":{"rendered":"

(image from wis-wander.weizmann.ac.il) Following a successful diet, many people are dismayed to find their weight rebounding \u2013 an all-too-common phenomenon termed \u201crecurrent\u201d or \u201cyo-yo\u201d obesity. Worse still, the vast majority of recurrently obese individuals not only rebound to their pre-dieting weight but also gain more weight with each dieting cycle. During each round of dieting-and-weight-regain, […]<\/p>\n","protected":false},"author":2,"featured_media":22438,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4329],"tags":[2864,5684,2225],"class_list":["post-22456","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-israel","tag-health","tag-obesity","tag-science"],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":8}},"_links":{"self":[{"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/posts\/22456","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/comments?post=22456"}],"version-history":[{"count":0,"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/posts\/22456\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/media\/22438"}],"wp:attachment":[{"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/media?parent=22456"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/categories?post=22456"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jewishindependent.ca\/index.php\/wp-json\/wp\/v2\/tags?post=22456"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}