Weight loss maintenance and emotional and physical problems were investigated in subjects on a protein-sparing modified fast. Four months following a weight reduction program using the protein-sparing modified fast, twenty of the forty-two subjects were contacted. Each was asked to complete a questionnaire related to emotional and physical effects of the diet and a diet history checksheet. Each subject was weighed to determine if weight loss had been maintained. Results of the questionnaire, diet history, and blood chemistry analysis indicate that for these subjects, the modified fast may be safe and effective in reducing and maintaining weight loss over a short time period under close supervision by a physician.

Quality protein maize (QPM), high protein corn (HPC) and food grade maize (FGM) were processed into tortillas and direct expanded extruded snacks. QPM had similar test weight, density and kernel size with 45% more lysine and 38% more tryptophan compared to FGM. HPC had the largest kernel with density and test weight similar to FGM. During alkaline cooking, HPC absorbed water faster than QPM and FGM. White QPM required shorter cooking time and had less dry matter losses compared to FGM. All corn varieties had excellent pericarp removal at the optimum cooking time. Tortillas from QPM had better pliability and rollability after storage compared to FGM and HPC. HPC tortillas had lower rupture force after storage. The use of QPM for tortilla production may reduce energy and sewage cost, and could produce a tortilla with longer shelf stability with improved nutritional value. Decorticated and non-decorticated QPM, FGM and HPC grain were processed into corn meal and direct expanded snacks. A modified short scale dry milling system was used to produce the corn meal. QPM produced more coarse meal with greater fat content compared to FGM. Decortication decreased fiber content and coarse meal yield. Non-decorticated meal had greater protein, fiber and fat content compared to decorticated meal. The modified short flow milling system provides reduced lost fractions for extrusion into nutritionally improved products. Extrusion was performed in a low cost friction extruder. QPM extruded faster than FGM and HPC. FGM required greater specific mechanical energy than QPM. Extrudates from FGM were the most expanded followed by QPM and HPC. Extrudates from the three corn varieties were acceptable to the panelists and decortication did not affect acceptability. The improved nutritional value of QPM, was retained during dry milling and extrusion. Current QPM varieties can be processed into tortillas with longer shelf stability and meal for extrusion into a wide variety of snacks and other foods. These may have application in specialty health foods and in developing countries where maize is a staple food.

In setting the AMDR for protein at 10-35% of daily energy, the Institute of Medicine acknowledged a lack of data regarding the safety of long-term intakes. The current study assessed the impact of chronic (17 months) protein consumption at the upper end of the AMDR on renal function, histology, and inflammation. Using plant and animal whole protein sources, female Sprague-Dawley rats (70 days old; n=8-11 at 4, 8, 12, or 17 mo.) were randomized to either a normal (NP; 15% of energy) or high protein (HP; 35% of energy) diet. Egg albumen and skim milk replaced carbohydrates in the HP diet. Diets were balanced for energy, fat, vitamins and minerals, and offered ad libitum. Renal function was analyzed by creatinine clearance and urinary protein levels. Glomerular hypertrophy, glomerulosclerosis and tubulointerstitial fibrosis were assessed on kidney sections. Kidney disease progression was determined by the measurement of transforming growth factor beta-1 (TGF-β1) and renal inflammation by the measurement of chemokines monocyte chemoattractant protein-1 (MCP-1) and regulated upon activation normal T-cell expressed and secreted (RANTES). Rats consuming the HP compared to NP diet had ~17% higher kidney weights (P<0.0001) and ~4.8 times higher proteinuria (P<0.0001). There was a trend towards higher creatinine clearance with HP (P=0.055). Consistent with this, HP compared to NP rats had ~22% larger glomeruli (P<0.0001) and ~33% more glomerulosclerosis (P=0.0003). The HP diet had no significant effect on tubulointerstitial fibrosis and renal TGF-β1 levels and did not result in higher renal levels of MCP-1 and RANTES. In fact, per mg renal protein, HP rats had ~16% lower MCP-1 (P<0.0001) and ~34% lower levels of RANTES (P<0.0001) than NP. The absence of an increase in cytokine levels may be a reflection of the moderate changes in renal pathology observed in rats offered HP diets. These data in normal female rats suggest that protein intakes at the upper end of the AMDR are detrimental to kidney health in the long-term. While modest, this may have implications for individuals whose kidney function is compromised, especially given the prevalence of those unaware of their kidney disease within North America. / October 2007

Thesis (Ph.D.)--Ohio University, August, 2009. / Release of full electronic text on OhioLINK has been delayed until September 1, 2012. Includes bibliographical references (leaves 157-195)

Thesis (Ph.D.)--Ohio University, August, 2009. / Title from PDF t.p. Release of full electronic text on OhioLINK has been delayed until September 1, 2012. Includes bibliographical references (leaves 157-195)

Quality protein maize (QPM), high protein corn (HPC) and food grade maize (FGM) were processed into tortillas and direct expanded extruded snacks. QPM had similar test weight, density and kernel size with 45% more lysine and 38% more tryptophan compared to FGM. HPC had the largest kernel with density and test weight similar to FGM. During alkaline cooking, HPC absorbed water faster than QPM and FGM. White QPM required shorter cooking time and had less dry matter losses compared to FGM. All corn varieties had excellent pericarp removal at the optimum cooking time. Tortillas from QPM had better pliability and rollability after storage compared to FGM and HPC. HPC tortillas had lower rupture force after storage. The use of QPM for tortilla production may reduce energy and sewage cost, and could produce a tortilla with longer shelf stability with improved nutritional value. Decorticated and non-decorticated QPM, FGM and HPC grain were processed into corn meal and direct expanded snacks. A modified short scale dry milling system was used to produce the corn meal. QPM produced more coarse meal with greater fat content compared to FGM. Decortication decreased fiber content and coarse meal yield. Non-decorticated meal had greater protein, fiber and fat content compared to decorticated meal. The modified short flow milling system provides reduced lost fractions for extrusion into nutritionally improved products. Extrusion was performed in a low cost friction extruder. QPM extruded faster than FGM and HPC. FGM required greater specific mechanical energy than QPM. Extrudates from FGM were the most expanded followed by QPM and HPC. Extrudates from the three corn varieties were acceptable to the panelists and decortication did not affect acceptability. The improved nutritional value of QPM, was retained during dry milling and extrusion. Current QPM varieties can be processed into tortillas with longer shelf stability and meal for extrusion into a wide variety of snacks and other foods. These may have application in specialty health foods and in developing countries where maize is a staple food.

In setting the AMDR for protein at 10-35% of daily energy, the Institute of Medicine acknowledged a lack of data regarding the safety of long-term intakes. The current study assessed the impact of chronic (17 months) protein consumption at the upper end of the AMDR on renal function, histology, and inflammation. Using plant and animal whole protein sources, female Sprague-Dawley rats (70 days old; n=8-11 at 4, 8, 12, or 17 mo.) were randomized to either a normal (NP; 15% of energy) or high protein (HP; 35% of energy) diet. Egg albumen and skim milk replaced carbohydrates in the HP diet. Diets were balanced for energy, fat, vitamins and minerals, and offered ad libitum. Renal function was analyzed by creatinine clearance and urinary protein levels. Glomerular hypertrophy, glomerulosclerosis and tubulointerstitial fibrosis were assessed on kidney sections. Kidney disease progression was determined by the measurement of transforming growth factor beta-1 (TGF-β1) and renal inflammation by the measurement of chemokines monocyte chemoattractant protein-1 (MCP-1) and regulated upon activation normal T-cell expressed and secreted (RANTES). Rats consuming the HP compared to NP diet had ~17% higher kidney weights (P<0.0001) and ~4.8 times higher proteinuria (P<0.0001). There was a trend towards higher creatinine clearance with HP (P=0.055). Consistent with this, HP compared to NP rats had ~22% larger glomeruli (P<0.0001) and ~33% more glomerulosclerosis (P=0.0003). The HP diet had no significant effect on tubulointerstitial fibrosis and renal TGF-β1 levels and did not result in higher renal levels of MCP-1 and RANTES. In fact, per mg renal protein, HP rats had ~16% lower MCP-1 (P<0.0001) and ~34% lower levels of RANTES (P<0.0001) than NP. The absence of an increase in cytokine levels may be a reflection of the moderate changes in renal pathology observed in rats offered HP diets. These data in normal female rats suggest that protein intakes at the upper end of the AMDR are detrimental to kidney health in the long-term. While modest, this may have implications for individuals whose kidney function is compromised, especially given the prevalence of those unaware of their kidney disease within North America.

Despite inconsistent results in the literature, high protein diets are being promoted for the management of metabolic syndrome parameters primarily due to their proposed favorable effects on weight loss. Therefore, lean and fa/fa Zucker rats were given normal and high protein diets with varying protein sources for 12 weeks. A high protein diet with a mixture of animal and plant protein sources was the most effective for improving metabolic syndrome parameters, specifically insulin resistance and hepatic steatosis. A high protein soy diet was the second most effective diet, while a high protein casein diet demonstrated no benefits compared to the other two high protein diets and minimal benefits compared to a normal protein casein diet. Interestingly, high protein diets did not affect body weight regardless of protein source. These findings suggest that the source of protein within a high protein diet is critical for improving metabolic syndrome parameters and that improvements can be observed independent of weight loss.

In setting the AMDR for protein at 10-35% of daily energy, the Institute of Medicine acknowledged a lack of data regarding the safety of long-term intakes. The current study assessed the impact of chronic (17 months) protein consumption at the upper end of the AMDR on renal function, histology, and inflammation. Using plant and animal whole protein sources, female Sprague-Dawley rats (70 days old; n=8-11 at 4, 8, 12, or 17 mo.) were randomized to either a normal (NP; 15% of energy) or high protein (HP; 35% of energy) diet. Egg albumen and skim milk replaced carbohydrates in the HP diet. Diets were balanced for energy, fat, vitamins and minerals, and offered ad libitum. Renal function was analyzed by creatinine clearance and urinary protein levels. Glomerular hypertrophy, glomerulosclerosis and tubulointerstitial fibrosis were assessed on kidney sections. Kidney disease progression was determined by the measurement of transforming growth factor beta-1 (TGF-β1) and renal inflammation by the measurement of chemokines monocyte chemoattractant protein-1 (MCP-1) and regulated upon activation normal T-cell expressed and secreted (RANTES). Rats consuming the HP compared to NP diet had ~17% higher kidney weights (P<0.0001) and ~4.8 times higher proteinuria (P<0.0001). There was a trend towards higher creatinine clearance with HP (P=0.055). Consistent with this, HP compared to NP rats had ~22% larger glomeruli (P<0.0001) and ~33% more glomerulosclerosis (P=0.0003). The HP diet had no significant effect on tubulointerstitial fibrosis and renal TGF-β1 levels and did not result in higher renal levels of MCP-1 and RANTES. In fact, per mg renal protein, HP rats had ~16% lower MCP-1 (P<0.0001) and ~34% lower levels of RANTES (P<0.0001) than NP. The absence of an increase in cytokine levels may be a reflection of the moderate changes in renal pathology observed in rats offered HP diets. These data in normal female rats suggest that protein intakes at the upper end of the AMDR are detrimental to kidney health in the long-term. While modest, this may have implications for individuals whose kidney function is compromised, especially given the prevalence of those unaware of their kidney disease within North America.

The development of lean body mass (LBM) is closely linked to protein feeding. Along with resistance exercise protein feeding, or amino acid provision, stimulate muscle protein synthesis (MPS). Repeated stimulation of MPS above protein breakdown results in lean mass accretion. Many athletes aim to build or maintain LBM. The aim of this thesis was to better understand the relationship between LBM and protein feeding in trained individuals. This aim was studied in the applied setting and at whole body, muscle and molecular level. Chapter 2 revealed differences in total body mass and LBM between young rugby union players competing at different playing standards. Protein consumption was higher in players that played at a higher standard. The protein consumption of players at both playing standards was higher than current protein recommendations for athletes. The Under 20 (U20) rugby union players in Chapter 3 also consumed more protein than current recommendations state. Their dietary habits changed depending on their environment and they consumed more protein while in Six Nations (6N) camp compared with out of camp. Also, there were changes in dietary habits for individuals, however, those changes did not occur at the group level. Using the camp as an education tool for good nutrition habits could be advantageous. As a group, rugby union players’ body composition did not change from pre to post a 6N tournament. However, there was individual variation, which could be meaningful for the individual players. We provide evidence suggesting that in elite sport, athletes should be considered as individuals as well as part of a group if appropriate. The protein ribosomal protein S6 kinase 1 (p70S6K1) is part of the mammalian target of rapamycin complex 1 (mTORC1) pathway, which regulates MPS. The response of p70S6K1 activity was 62% greater following resistance exercise coupled with protein feeding compared with protein feeding alone in Chapter 3. P70S6K1 activity explained a small amount of the variation in previously published MPS data. The activity of the signalling protein p70S6K1 was unchanged in response to different doses of whey protein in Chapter 4 and 5. These data suggest that resistance exercise is a larger stimulus of p70S6K1 activity and when manipulating aspects of protein feeding p70S6K1 activation may be a limited measure. Consumption of 40 g of whey protein stimulated myofibrillar MPS to a greater extent than 20 g after a bout of whole body resistance exercise. The amount of LBM that the trained individual possessed did not influence this observed response. These data suggest that the amount of muscle mass exercised may influence the amount of protein required to increase MPS stimulation. For those engaging in whole body resistance exercise 20 g of protein is not sufficient to maximally stimulate MPS. The athletes in Chapters 2 and 3 of this thesis consumed more protein than current recommendations that do not take into account whole body exercise. Current post-exercise protein recommendations may no longer be optimal given this new information. Future work should directly investigate the MPS response to protein ingestion following resistance exercise engaging different amounts of muscle mass in well trained and elite populations. Identifying the protein dose required for maximal stimulation of MPS following whole body exercise would be an informative area of future research.