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The prevalence of excessive weight gain (obesity) has steadily increased since about 1980. Excessive weight gain is associated with many comorbidities; thus, a successful treatment is needed. The most common form of non-surgical treatment for excessive weight gain is caloric restriction with the intent to reduce body weight by 10%.

The prevalence of excessive weight gain (obesity) has steadily increased since about 1980. Excessive weight gain is associated with many comorbidities; thus, a successful treatment is needed. The most common form of non-surgical treatment for excessive weight gain is caloric restriction with the intent to reduce body weight by 10%. Though this treatment is successful at reducing body weight, it often fails at maintaining the weight loss. Dietary menthol has been suggested as a possible treatment for excessive weight gain and has produced promising results as a preventative method for excessive weight gain. Our studies aimed at reducing weight regain and maintaining caloric restriction by feeding male Sprague-Dawley rats 0.5% dietary menthol during a period of caloric restriction, aimed at reducing their body weight by 10%, following an experimental period where the rats were fed a high-fat diet (HFD) or low-fat diet (LFD). The effects of the dietary menthol were observed during the weight regain period following the caloric restriction period. Two studies were conducted, and both were unable to achieve a maintenance of weight loss following caloric restriction, although our first study was able to produce a delay in weight regain and did not show any evidence of increased thermogenesis in menthol-treated rats. Our findings differ from the findings of previous studies on dietary menthol which could possibly be due to species effects, differences in procedures, age effects, or effects of different fatty acid compositions. The contrasting results in our studies could be due to genetic differences between litters used or a difference in manufacturing of the menthol diet between studies. Given the partial response to menthol in the first study, it can be suggested that the concentration of 0.5% may be below the threshold of menthol sensitivity for some rats. Future research should focus on increasing the concentration of dietary menthol from 0.5% to 1%, since the current concentration did not yield a reduction in weight regain or maintenance of caloric restriction.
ContributorsRascon, Kasandra (Author) / Herman, Richard (Thesis director) / Sweazea, Karen (Committee member) / Kim, Minjoo (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
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Description
This study was conducted to observe the effects of varying diets on weight regain after caloric restriction. Touted as a potentially effective non-invasive treatment to obesity, caloric restriction uses the gradual decrease in caloric intake to aid in weight loss. However, once a patient is taken off caloric restriction, a

This study was conducted to observe the effects of varying diets on weight regain after caloric restriction. Touted as a potentially effective non-invasive treatment to obesity, caloric restriction uses the gradual decrease in caloric intake to aid in weight loss. However, once a patient is taken off caloric restriction, a marked regain of weight regain occurs, nullifying the weight loss from caloric restriction. To find ways to suppress this weight regain, this study observed the effects of four different diets: low-fat diet (chow), high-fat diet (HFD), 0.5% concentration menthol infused chow, and 1% concentration menthol infused chow. Over a span of 3 years, 43 male Sprague-Dawley rats were placed through a strict feeding protocol: 3 weeks of chow food (3.1 kcal/gram), 8 or 12 weeks of HFD (5.42 kcal/gram), and caloric restriction for 4 weeks. Separate data analysis was conducted for the year 2017-2018, due to a slightly different protocol when compared to 2018-2019 and 2019-2020.

In 2017-2018, the results showed that 0.5% menthol (n=4) suppressed weight gain more effectively than both the baseline chow diet (n=4, p=0.022) and the HFD (n=4, p=0.027). Again in 2018-2020, the 0.5% menthol (n=6) showed promising results, showing significant suppression of weight gain when compared to chow (n=13, p=0.022). Unfortunately, the difference in weight gain in 1% menthol (n=6) was inconclusive when comparing to both chow and HFD. Although 1% menthol was inconclusive in its efficacy in suppressing weight regain, the promising results on 0.5% menthol show that menthol has the potential to be an effective treatment to both prevent rapid weight gain and maintain weight loss from caloric restriction.
ContributorsLee, Justin (Author) / Van Horn, Wade (Thesis director) / Baluch, Debra (Committee member) / Herman, Richard (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
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Description
Long chain ω-3PUFA fatty acid supplementation in animal models of diet-induced-obesity has consistently shown to improve insulin sensitivity. The same is not always reported in studies with obese, insulin resistant (IR) subjects. We studied whether high-dose ω-3PUFA supplementation for 3 months improves insulin sensitivity and adipose tissue (AT) inflammation

Long chain ω-3PUFA fatty acid supplementation in animal models of diet-induced-obesity has consistently shown to improve insulin sensitivity. The same is not always reported in studies with obese, insulin resistant (IR) subjects. We studied whether high-dose ω-3PUFA supplementation for 3 months improves insulin sensitivity and adipose tissue (AT) inflammation in severely obese, IR subjects. Thirteen obese, IR subjects underwent 80 mU/m 2· min euglycemic-hyperinsulinemic clamp with subcutaneous (Sc) AT biopsy before and after three months of ω-3PUFA (DHA & EPA, 4g/daily) supplementation. Cytoadipokine plasma profiles were assessed before and after ω-3PUFA. AT-specific inflammatory gene expression was evaluated on Sc fat biopsies. Microarray analysis was performed on the fat biopsies collected during the program. Palmitic and stearic acid plasma levels were significantly reduced (P<0.05) after ω-3PUFA. Gene expression of pro-inflammatory markers and adipokines were improved after ω-3PUFA (P<0.05). Systemic inflammation was decreased after ω-3PUFA, as shown by cytokine assessment (P<0.05). These changes were associated with a 25% increase in insulin-stimulated glucose disposal (4.67±0.62mg/kg ffm•min vs 5.87±0.79mg/kg ffm•min) despite no change in
body weight. Microarray analysis identified 53 probe sets significantly altered post- ω-3PUFA, with APOE being one of the most upregulated genes. High dose of long chain ω-3PUFA supplementation modulates significant changes in plasma fatty acid profile, AT and systemic inflammation. These findings associate with significant improvement of insulin-stimulated glucose disposal. Unbiased microarray analysis of Sc fat biopsy identified APOE as the most differentially regulated gene after ω-3PUFA 22 supplementation. We speculate that ω-3PUFA increases macrophage-derived APOE mRNA levels with anti-inflammatory properties.
ContributorsRau, Cassandra (Author) / Kastanos, Christos (Thesis director) / De Filippis, Eleanna (Committee member) / School of Life Sciences (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
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Description

According to the CDC, obesity has increased from 30.5% to 42.4% over the past 18 years. Western diets (WDs) consist of large portions in high fats, high carbohydrates, excess sugar and high-glycemic foods that can cause metabolic complications and mitochondrial dysfunction. Diet-induced obesity can lead to changes in muscle metabolism

According to the CDC, obesity has increased from 30.5% to 42.4% over the past 18 years. Western diets (WDs) consist of large portions in high fats, high carbohydrates, excess sugar and high-glycemic foods that can cause metabolic complications and mitochondrial dysfunction. Diet-induced obesity can lead to changes in muscle metabolism and muscle fiber phenotypes, which in turn lead to metabolic complications. Muscle fiber phenotype is determined protein isoform-content of myosin heavy chain (MHC). Regular exercise alters mitochondrial content and fat oxidation and shifts MHC proportions under healthy circumstances. However, diet and exercise-driven fiber type shifts in diet-induced obesity are less understood. We designed our experiment to better understand the impact of diet and/ or exercise on fiber type content of gastrocnemius muscle in diet-induced obese mice. Exercise and genistein may be used as a treatment strategy to restore the MHC proportions in obese subjects to that of the lean subjects. We hypothesized that genistein and exercise would have the greatest MHC I change in muscle fiber phenotype of mouse gastrocnemius muscles. Further, we also hypothesized that a standard diet would reverse the expected increase in fast fiber phenotype (MHC IIb). Lastly, we also hypothesized that exercise would also reduce the abundance of MHC IIb. Gastrocnemius muscles were collected from mice, homogenized, run through gel electrophoresis and stained to give muscle fiber proportions. Paired sample t-tests were conducted for differences between the MHC isoforms compared to the lean (LN) and high-fat diet (HFD) control groups. The results showed that genistein and exercise significantly increased the abundance of MHC I muscle fibers (19%, p<0.05). Additionally, diet and exercise restored the muscle fiber phenotype to that of lean control. As expected, HFD obese mice exhibited elevated fast twitch fibers compared to only 3% slow twitch fibers. These findings show the potential for exercise and supplementation of genistein as a strategy to combat diet induced obesity. Future research should aim to understand the mechanisms that genistein acts on to make these changes, and aim to replicate these data in humans with obesity.

ContributorsSodhi, Harkaran (Author) / Katsanos, Christos (Thesis director) / Wang, Shu (Committee member) / Serrano, Nathan (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2022-05