Restriction Of Essential Amino Acids Research Articles

Restriction of essential amino acids dictates the systemic metabolic response to dietary protein dilution

Dietary protein dilution (DPD) promotes metabolic-remodelling and -health but the precise nutritional components driving this response remain elusive. Here, by mimicking amino acid (AA) supply from a casein-based diet, we demonstrate that restriction of dietary essential AA (EAA), but not non-EAA, drives the systemic metabolic response to total AA deprivation; independent from dietary carbohydrate supply. Furthermore, systemic deprivation of threonine and tryptophan, independent of total AA supply, are both adequate and necessary to confer the systemic metabolic response to both diet, and genetic AA-transport loss, driven AA restriction. Dietary threonine restriction (DTR) retards the development of obesity-associated metabolic dysfunction. Liver-derived fibroblast growth factor 21 is required for the metabolic remodelling with DTR. Strikingly, hepatocyte-selective establishment of threonine biosynthetic capacity reverses the systemic metabolic response to DTR. Taken together, our studies of mice demonstrate that the restriction of EAA are sufficient and necessary to confer the systemic metabolic effects of DPD.

Essential amino acid restriction dictates the systemic metabolic response to dietary protein dilution

Essential amino acid restriction dictates the systemic metabolic response to dietary protein dilution

Assessment of the relative contribution of dietary nitrogen from fish meal and biofloc meal to the growth of Pacific white shrimp (Litopenaeus vannamei )

The relative contribution of the dietary nitrogen supplied by fish meal and a biofloc meal to the growth of Pacific white shrimp was evaluated using stable isotope analysis. Biofloculated material was obtained from an experimental tilapia culture system. Five formulated diets were supplied. Two of them consisted in isotopic controls having only fish meal or biofloc meal as protein source. Three mixed diets were formulated with varying proportions of these ingredients on a dietary nitrogen basis (75:25, 50:50 and 25:75). At the end of the trial, survival rates were similar (92–100%) but significant differences in mean final weight were observed and a negative correlation between the inclusion of biofloc meal and weight gain was evidenced. Mean final weight in shrimp fed on diet containing only fish meal was 2.8 g, while mean final weight of animals fed on diet containing 50% biofloc was 1.9 g. Isotopic mixing models indicated that all diets contributed higher proportions of dietary nitrogen from fish meal than from biofloc meal. Dietary nitrogen available in diets containing 25%, 50% and 75% of biofloc meal was incorporated in muscle tissue as 5%, 41% and 64% respectively. Diet supplying 25% of nitrogen from biofloc was the only mixed diet eliciting growth comparable to diet containing only fish meal. Lower growth and nitrogen deposition in shrimp fed on diets containing high proportions of biofloc meal were possibly associated to the use of only two protein sources and a restriction of essential amino acids.

Remodeling of Lipid Metabolism by Dietary Restriction of Essential Amino Acids

All forms of life share the ability to sense environmental change and respond in real time by engaging adaptive homeostatic programs. In higher organisms, the composition of consumed meals presents a complex, constantly changing nutritional environment, and we are only beginning to understand the sensing and signaling systems that detect and coordinate the transcriptional, physiological, and behavioral responses to meal components. Although it has long been axiomatic that dietary composition plays a deterministic role in overall health, the growing prevalence of obesity and metabolic syndrome has prompted a refocus of attention on the significance of dietary macronutrients to health outcomes. Findings from earlier investigations of potential roles for dietary carbohydrates and fat in disease progression or remediation (1–4) are now being reframed by experimental evidence linking dilution of dietary protein to compensatory increases in ingestive behavior (5,6). Recent studies also illustrate that modifying dietary essential amino acid (EAA) composition has profound effects on lipid metabolism and energy balance (7–10). A consensus is emerging to support the view that protein intake is monitored through nutrient-sensing mechanisms that detect changes in EAAs and provide regulatory input to both energy balance and the integration of carbohydrate and lipid metabolism (5,6,11,12). We will examine the transcriptional and metabolic responses to EAA deprivation or restriction to make the broader case that EAA sensing and signaling play an essential role in coordinating metabolic responses to dietary composition, particularly the content and composition of dietary protein. ### Protein leverage hypothesis. Simpson and Raubenheimer (11) used an integrative modeling approach to develop a geometric framework for evaluating the impact of dietary macronutrients on response variables such as nutrient selection, body composition, longevity, and reproduction. The geometric framework model of nutrition was originally developed and tested in experiments in which life …

Management of Leukemia with Limiting Amino Acid Diet, Especially Low Phenylalanine and Tyrosine Diet (the 2nd Report)

It has been already reported by us that the growth of the implanted tumor is remarkablly affected by the restriction of essential amino acids. From our amino acid imbalance studies, it has been found that the restriction of phenylalanine causes the returdation of tumor without any undesireble side effect against the host. Such effect of phenylalanine deficient diet has also been found to be accelerated by the restriction of tyrosine. The phenylalanine hydroxylase activity of liver decreased remarkablly in the tumor bearing animal. Foretheremore, it has also been confirmed that the restriction of an essential amino acid causes the elongation of the doubling time of tumor cell.From the experimental facts mentioned above, the effectiveness of amino acid imbalance diet has been clinically investigated in all types of leukemia and other malignant diseases. The patients have been treated initially with low phenylalanine diet and then recently with low phenylalanine-tyrosine diet. The combined restriction therapy of phenylalanine and tyrosine seemed to be more effective than the single restriction of phenylalanine. Phenylalanine-tyrosine limiting milk according to our prescription has been used as the main nitrogen source of the diet. The dosis of phenylalanine and of tyrosine supplied daily were 1.8g. respectively for adult and were 1.1g. for infant. Such phenylalanine dosis as mentioned above exceeds slightly the lowest essential dosis of it.Up to now, 22 patients were treated with this amino acid imbalance diet for one month to tow and half years, without any side effect. The patients treated with this diet were as follows; 11 cases of acute leukemia including 5 infants, 6 cases of chronic leukemia and 5 cases having solid malignant tumor. Single application of this diet not so effective except few successful cases. The clinical responce against chemotherapy, however, was remarkably improved with this diet therapy and long term remission was obtained. One case of malignant lymphoma has been well controled for long time with this diet therapy only.