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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Dietary Prevention of Obesity-related Disease Research » Research » Research Project #427566

Research Project: Food Factors to Prevent Obesity and Related Diseases

Location: Dietary Prevention of Obesity-related Disease Research

2017 Annual Report


Objectives
Objective 1: Determine the effect of consuming dietary sources of fat with varied saturation and chain length on the physiological responses of satiety, lipid oxidation, and energy metabolism. Sub-objective 1A: Determine the acute effects of consuming dietary fats of varied saturation and chain length on satiety, thermogenesis and energy utilization in healthy individuals. Sub-objective 1B: Determine the chronic effects of consuming dietary fats of varied saturation and chain length on satiety, energy utilization, and body composition. Objective 2: Determine the role of long chain omega 3 (LCn3) fatty acids in modulating the function of bone cells and the contribution of RANKL/RANK/OPG pathway in obesity-induced changes in bone metabolism in animal and cell models. Sub-objective 2A1: Define the role of LCn3 in preventing adiposity-induced bone loss. Sub-objective 2B: Define the optimal ratio of n6/n3 in improving bone quality and quantity in an obesity animal model. Objective 3: Define the influences of dietary fatty acids and energy balance upon conversion of alpha-linolenic acid (ALA; 18:3n3) to LCn3. Sub-Objective 3A: Determine the effects of saturated fatty acids (SFA) content upon mechanisms of ALA disposition under eucaloric conditions. Sub-Objective 3B: Determine the effects of SFA content upon mechanisms of ALA disposition in rodents under hypercaloric conditions. Objective 4: Define the extent to which consuming rainbow trout bred for elevated LCn3 content reduces CVD risk markers, such as platelet reactivity and related eicosanoids, in people.


Approach
Fat is an essential part of a healthy diet. However, the fatty acid compositions of dietary fats are often overlooked in designing healthy diets. Many Americans consume diets high in saturated fatty acids (SFA) and low in unsaturated fatty acids, including long-chain omega-3 fatty acids (LCn3). This imbalance may contribute to obesity and exacerbate osteoporosis and cardiovascular disease (CVD). The aim of our work is to provide robust data that will inform evidence-based recommendations for the appropriate levels and composition of dietary fats to maintain health and prevent disease. We will accomplish this aim by completing four research objectives that will clarify how the fatty acid profile of dietary fat contributes to health, or conversely, to disease progression. These objectives will use a combination of clinical translational studies in humans and mechanistic studies in rodents and isolated cells. Objective 1 addresses the role of dietary fats in the development of obesity by studying their effects on the modulation of satiety and energy metabolism; Objective 2 addresses the roles of specific fatty acids in preventing bone structure deterioration and promoting bone health in obesity; Objective 3 addresses the impacts of dietary fatty acids and energy balance on LCn3 metabolism; Objective 4 addresses the impact of consuming LCn3-rich rainbow trout on CVD risk markers in humans. We will fulfill these objectives through a combination of clinical translational and mechanistic studies involving human volunteers and rodent models.


Progress Report
Objective 1A. In this clinical trial we are evaluating the energetic and satiety responses to dietary fat intake in humans. Specifically, in an acute study, we are evaluating the responses to saturated fat, monounsaturated fat, and polyunsaturated fat containing high linoleic acid, high alpha-linolenic acid, or long chain omega-3 fatty acids. Participants are given a test meal and their energetic responses (energy expenditure, thermic effect of food, and beta-oxidation of fat) and satiety (gut hormones and subjective responses) are determined over 4 hours. Fatty acid binding protein polymorphisms will be used as a covariate in assessing energetic responses to the treatments. The trial is currently underway. Objective 1B. In this clinical trial we are evaluating the energetic and satiety responses to dietary fat intake in humans. Specifically, in a chronic feeding trial, we are evaluating the responses to saturated fat, monounsaturated fat, and polyunsaturated fat containing high linoleic acid, high alpha-linolenic acid, or long chain omega-3 fatty acids (LCn3). Participants will be given a 4 week dietary intervention after which their energetic responses (energy expenditure, thermic effect of food, and beta-oxidation of fat) and satiety (gut hormones and subjective responses) will be determined over 4 hours. We will determine fatty acid binding protein (FABP) polymorphisms to be used as a covariate in assessing responses. The protocol is ready for initiation and IRB approval is pending. An HQ supported post-doc has been hired to work on this project with emphasis on the FABP assessment and interpretation. Ancillary Study: In an epidemiological assessment of dietary fat intake and body mass index (BMI) using the 2005-2012 National Health and Nutrition Examination Survey and What We Eat in America surveys, we demonstrated that, overall, the reported intake of carbohydrates, protein, total fat, total saturated fat, the log chain saturated fats palmitate and stearate, and monounsaturated fatty acids were positively associated with BMI while total and individual polyunsaturated fatty acids and medium chain fatty acid intake was not associated with BMI. There were some notable divergent results for specific socioeconomic groups. These findings support the experimental trials demonstrating fatty acid dependent associations between dietary fatty acid composition and body weight. Objective 2A2. An animal study was initiated to define the role of bone marrow adipocytes in high-fat induced bone loss in mice. PPAR-gamma floxed (f/f) and a breeding pair of Osx-1-Cre line mice have been obtained from the Jax Lab. Currently, PPAR-gamma floxed (f/f) or PPAR-gamma KO mice are being generated with genotyping selection through in-house breeding of PPAR-gamma floxed (f/f) and Osx-1-Cre mice. Forty-eight six-wk old PPAR-gamma floxed (f/f) or PPAR-gamma KO mice have been randomized to 4 groups and fed one of the 4 diets (n=12): a normal-fat (10%en fat) control diet (as soybean oil, SO) or a 45% high-fat diet (10% as SO + 35% as lard). It is anticipated that the feeding study will be finished before the end of October 2017. At the end of the study, mice will be sacrificed and functional change including gene expression of adipocytes, osteoblasts, and osteoclasts will be evaluated. Serum bone formation and resorption markers will be determined.Objective 2B. An animal study was initiated to define the optimal ratio of n6/n3 in improving bone quality and quantity in obesity animal model. Fifty-two 6-wk male C57BL/6 mice were assigned randomly to 4 treatment groups (n = 13) and fed one of the following diets: a normal-fat diet (10%en) or high-fat diets (45%en) with n-6, as LA, at 9% en, 6% en, and 3% en. ALA was kept constant at 1% en in all diets. For high-fat diets, the ratios of MUFA:SFA were kept similar around 0.95. Animals will be fed the experimental diets for 6 months. The animal feeding study will be completed at the end of November 2017. Body weight will be measured every other week and whole body composition will be determined at the beginning, mid- and the end of the study. At the end of the study, bone structure, serum markers and expression of genes related to bone metabolism will be measured. Ancillary Study: We analyzed samples collected from a 28-wk single-arm experimental feeding intervention human study to determine whether high fruit and vegetable intake is beneficial to bone health. Our data indicate that low intake of fruits and vegetables increased serum bone resorption marker, C-terminal telopeptide of type 1 collagen (CTX) and decreased serum bone formation marker, bone specific alkaline phosphatase (BAP). High intake of fruits and vegetables decreased bone resorption marker CTX and increased bone formation marker BAP. The results support that increased consumption of fruits and vegetables at or above federal dietary guidance improves bone health. The manuscript from this work is currently under review. Objective 3. We furthered our studies to determine whether the content of dietary saturated fatty acids (SFA), vs the monounsaturated fatty acid oleic acid, decreases the metabolism of the n-3 polyunsaturated fatty acid (PUFA) alpha-linolenic acid (ALA) to longer chain (LC) polyunsaturated fatty acids. Our data demonstrate that in adult mice, a high oleic acid diet reduced liver content and adipose content of the n-3 fatty acid ALA and that of the n-6 fatty acid linoleic acid (LA) but did not decrease the levels of their LCPUFA products docosahexaenoic acid (DHA) and arachidonic acid (ARA). Indeed, we found increases in DHA and ARA in liver. We also showed that the high oleic diet reduced the tissue content of LA and ALA-derived oxylipins. This work is published. Because the high oleic diet, but not the mixed SFA diet, increased liver triacylglycerol (TAG) content, we attempted to determine whether the high oleic diet reduced liver export of TAG. To do this we adopted a Wistar rat model in order to repeat the above study. The rat would provide more plasma for the necessary TAG export studies. However, we found that the Wistar rat, as opposed to C57 black mice, did not become obese or develop fatty liver. We intend to repeat the experiment with the obese-prone Sprague-Dawley rat which we have shown to accumulate liver TAG during obesity. We developed a novel means of characterizing and analyzing phospholipid biomarkers in human plasma. Specific types of phospholipids, a class of fats circulating in the blood, are often used as biomarkers for cardiovascular disease, diabetes, and Alzheimer’s disease. Using an instrument called a hybrid quadrupole linear ion trap mass spectrometer, we developed an analytical method to identify and quantify these phospholipids that have the same size but different structure. This method is rapid and provides more detailed information regarding bloods lipids. This work will assist clinical and basic scientists in improving biomarker analysis for human disease. This work is published. We tested the extent to which medium chain (MC) SFA vs LCSFA (palmitic acid and stearic acid) modified obesity-related disease outcomes in mice fed obesogenic diets for 16 weeks. Our data demonstrate that while all animals became obese with both types of SFA sources, the MCSFA-fed animals had better insulin sensitivity and had less fat deposition in the liver. Markers of inflammatory stress and PUFA metabolism were analyzed. We performed a lipidomic analysis of the plasma from these mice to determine lipid biomarkers of n-3 metabolism. This work is currently in preparation for manuscript submission. We are collaborating with the University of Manitoba to determine how dietary sources of omega-3 fatty acids when fed to laying hens impact the type and quantity of omega-3 fatty acids in resulting eggs. We have performed lipidomic analysis of eggs produced by feeding hens either alpha-linolenic acid or fish oil – a source of long chain omega 3 fatty acids. Results from these analyses are being prepared for manuscript submission. Objective 4. In this clinical trial, we are comparing the efficacy of fish with differing long chain n3 fatty acid contents to reduce cardiovascular disease (CVD) risk markers in obese people with elevated CVD risk. Specifically, we are comparing diploid and triploid farm-raised rainbow trout and tilapia. To date, all fish have been obtained and the fatty acid profile determined. IRB approval has been obtained and we are actively recruiting for the study. As part of this research, we determined that n-3 LCPUFA fatty acids in human plasma are incorporated into selective phospholipid and triacylglycerol lipid species following intake of n-3 LCPUFA rich marine fish. This work is currently in preparation for manuscript submission. As a subordinate project of Objective 4, we are collaborating with the National Center for Cool and Cold Water Aquaculture in Kearneysville, West Virginia, to determine the impact of fish ploidy number and age upon the fatty acid content of farmed rainbow trout, Oncorhynchus mykiss. Our data indicate that fatty acids accumulate during aging in triploid female trout unable to undergo sexual maturation vs diploid trout. This work has been published. We are currently comparing finishing strategies to optimize LCn-3 fatty acid content in triploid rainbow trout.


Accomplishments
1. Dietary fatty acid intake is related to body weight. The relationship between reported fatty acid intake and body weight was studied by evaluating National Health and Nutrition Examination Surveys, What We Eat in America data from 2005-2015. ARS researchers at Grand Forks, North Dakota, determined that increasing intakes of total saturated and monounsaturated fatty acids and long–chain saturated fatty acids is associated with increasing body weight. Overall, polyunsaturated fatty acid and medium-chain saturated fat intake is not related to body weight. These data support findings that intake of dietary fatty acids, particularly saturated and monounsaturated fatty acids, is related to excess body weight.

2. Cooking methods modify the fatty acid and oxylipin content of farmed rainbow trout. ARS scientists at Grand Forks, North Dakota in collaboration with scientists from the USDA ARS National Center for Cool and Cold Water Aquaculture and the University of North Dakota conducted a study to determine the effect of cooking method on fatty acid and oxylipin content of farmed rainbow trout. Results showed pan frying was the only method that altered the fatty acid content of the fish while modifications in the oxylipin content varied by cooking method. Our data indicate that cooking methods (baking, broiling, microwaving or pan frying) and types of oil used (corn oil, canola oil or peanut oil) can impact the levels of fatty acids and their metabolites in fish.

3. Moderate caloric restriction combined with exercise decreases fat mass and improves bone mass. Weight loss can prevent obesity-related chronic disorders but it may be bad to bone health. ARS scientists at Grand Forks, North Dakota investigated how the degree of dietary energy restriction plus different intensity of physical activity affects body fat mass, bone structure and markers of bone turnover differently. They demonstrated that energy restriction is more effective means than exercise to decrease obesity but is detrimental to bone structure. The combination of moderate exercise and caloric restriction is the best means for improving bone mass.

4. Increasing fruit and vegetable consumption is good to bone health. Does fruit and vegetable intake affect markers of bone health? ARS scientists at Grand Forks, North Dakota analyzed blood markers of bone turnover in response to changes of fruit and vegetable intake in twenty-nine human participants. They demonstrated that increased fruit and vegetable intake decreases bone resorption and increases bone formation markers. The findings support that intake of fruits and vegetables at or above federal dietary guidance is beneficial to bone health.

5. High protein intake does not impair calcium homeostasis and bone health, given adequate intake of other nutrients such as calcium and vitamin D. ARS scientists at Grand Forks, North Dakota systemically reviewed the most recent epidemiological and interventional clinical studies assessing the impact of dietary protein on calcium metabolism and bone health. Findings from the review indicate that a high protein intake has beneficial effects by increasing intestinal calcium absorption, increasing blood IGF-1, and lowering blood parathyroid hormone. These beneficial effects compensate for the negative effects of protein-induced acid load on urinary calcium excretion.

6. Improving the nutrient content of farmed trout. ARS scientists in Grand Forks, North Dakota and Kearneysville, West Virginia are collaborating to determine the breeding and feeding practices needed to improve the levels of heart healthy omega 3 fatty acids in farmed raised rainbow trout. Scientists demonstrated that the genetic breed and age of rainbow trout impacts omega 3 fatty acid content of farmed raised rainbow trout. These findings will benefit fish producers and American consumers.

7. Saturated fatty acids and oleic acid have different effects in obese mice. Emerging evidence shows that the type of fatty acids that comprise our dietary fat intake impact the development of obesity and outcomes including fatty liver and insulin resistance. ARS scientists at Grand Forks, North Dakota demonstrated that diets made with either saturated fats versus oleic acid had different impacts upon the formation of fatty liver and the metabolism of polyunsaturated fatty acids. The data indicated that some types of saturated fats may have beneficial effects.

8. Development of improved methods for determining lipid biomarkers in humans. ARS scientists at Grand Forks, North Dakota developed a novel means of characterizing and analyzing lipid biomarkers in human plasma. Specific types of phospholipids, a class of fats circulating in the blood, are often used as biomarkers for cardiovascular disease, diabetes, and Alzheimer’s disease. Using an instrument called a hybrid quadrupole linear ion trap mass spectrometer, they developed an analytical method to identify and quantify these phospholipids that have the same size but different structure. This method is rapid and provides more detailed information regarding bloods lipids. This work will assist clinical and basic scientists in improving biomarker analysis for human disease.

9. Energy restriction and mild omega-3 fatty acid loss in juvenile animals modifies gene expression in the brain. Undernutrition is a pervasive problem in several regions of the world. Dietary omega-3 fatty acids are considered essential fatty acids and can be deficient in diets that lack sufficient calories. ARS scientists at Grand Forks, North Dakota demonstrated that lack of calories and lack of n-3 polyunsaturated fatty acid modify the expression of genes in the brain that regulate inflammation and learning. These data are important for those researchers who study childhood nutrition and development particularly with respect to undernutrition in underdeveloped countries.


Review Publications
Chung, M., Wang, D., Archer, E., Higgins, J., Kim, S., Laughlin, M., Qi, L., Raatz, S.K., Siegel, R.D., Slavin, J.L., Spahn, J., Steffen, D., Warshaw, H., Tang, A.M. 2016. Research needs and prioritizations for studies linking dietary sugars and potentially related health outcomes. Biomedical Central Nutrition. doi:10.1186/s40795-016-0108-0.
Raatz, S.K., Conrad, Z.S., Johnson, L., Picklo, M.J., Jahns, L.A. 2017. Relationship of the reported intakes of fat and fatty acids to body weight in US adults. Nutrients. doi:10.3390/nu9050438.
Cleveland, B.M., Weber, G.M., Raatz, S.K., Rexroad III, C.E., Picklo, M.J. 2017. Fatty acid partitioning varies across fillet regions during sexual maturation in female rainbow trout (Oncorhynchus mykiss). Aquaculture. 475:52-60.
Arikawa, A.Y., Kaufman, B.C., Raatz, S.K., Kurzer, M.S. 2017. Effects of a parallel arm randomized controlled weight loss pilot study on biological and psychosocial parameters of overweight and obese breast cancer survivors. Pilot and Feasibility Studies. 4:17.
Zacek, P., Bukowski, M.R., Rosenberger, T., Picklo, M.J. 2016. Quantitation of isobaric phosphatidylcholine species in human plasma using a hybrid quadrupole linear ion trap mass spectrometer. Journal of Lipid Research. 57:2225-2234.
Picklo, M.J., Johnson, L., Idso, J.P. 2017. Peroxisome proliferator-activated receptor mRNA levels are modified by dietary n-3 fatty acid restriction and energy restriction in the brain and liver of growing rats. Journal of Nutrition. 147(2):161-169.
Picklo, M.J., Idso, J.P., Seeger, D., Aukema, H., Murphy, E. 2017. Comparative effects of high oleic acid vs high mixed saturated fatty acid obesogenic diets upon PUFA metabolism in mice. Prostaglandins Leukotrienes and Essential Fatty Acids. 119:25-37.
Yan, L., Sundaram, S. 2016. Monocyte chemotactic protein-1 deficiency reduces spontaneous metastasis of Lewis lung carcinoma in mice fed a high-fat diet. Oncotarget. 7(17):24792-24799.
Wu, R.T., Cao, L., Mattson, E., Witwer, K.W., Cao, J.J., Zeng, H., He, X., Combs, G.F., Cheng, W. 2017. Opposing impacts on healthspan and longevity by limiting dietary selenium in Telomere Dysfunctional mice. Aging Cell. 16(1):125-135.
Ekoue, D.N., Zaichick, S., Valyi-Nagy, K., Picklo, M.J., Lacher, C.P., Hoskins, K., Bonini, M., Diamond, A.M. 2017. Selenium levels in human breast carcinoma tissue are associated with a common polymorphism in the gene for SELENOP (Selenoprotein P). Journal of Trace Elements in Medicine and Biology. 39:227-233.
Raatz, S.K., Jahns, L.A., Johnson, L.K., Scheett, A., Carriquiry, A., Lemieux, A., Nakajima, M., Al'Absi, M. 2017. Smokers report lower intake of key nutrients than nonsmokers yet both fall short of meeting recommended intakes. Nutrition Research. 45:30-37.