Effects of Different Protein Sources on Amino Acid Absorption and Plasma Appearance of Tryptophan, Large Neutral Amino Acids, and Tryptophan Metabolites in Pigs.

Background: Absorption of tryptophan (TRP) across the gut epithelium is potentially modulated by competing large neutral amino acids (LNAAs), which could affect the appearance of TRP and its metabolites in the bloodstream.

Objectives: This study aimed to determine, in a growing pig model of an adult human, the absorption of TRP and other LNAAs from the gastrointestinal tract, and plasma appearance of TRP, LNAAs, and TRP metabolites, in response to dietary proteins varying in TRP content.

Methods: Pigs were adapted for 7 d to each of 4 diets that differed in their protein source and TRP content: 1) alpha-lactalbumin (AL; 9.

Perspective: Measuring Sweetness in Foods, Beverages, and Diets: Toward Understanding the Role of Sweetness in Health.

Various global public health agencies recommend minimizing exposure to sweet-tasting foods or beverages. The underlying rationale is that reducing exposure to the perception of sweet tastes, without regard to the source of sweetness, may reduce preferences for sweetness, added sugar intake, caloric intake, and body weight. However, the veracity of this sequence of outcomes has yet to be documented, as revealed by findings from recent systematic reviews on the topic.

Monosodium Glutamate in the Diet Does Not Raise Brain Glutamate Concentrations or Disrupt Brain Functions.

The non-essential amino acid glutamate participates in numerous metabolic pathways in the body. It also performs important physiologic functions, which include a sensory role as one of the basic tastes (as monosodium glutamate [MSG]), and a role in neuronal function as the dominant excitatory neurotransmitter in the central nervous system. Its pleasant taste (as MSG) has led to its inclusion as a flavoring agent in foods for centuries.

Introduction and Summary of the 2018 Dietary Glutamate Workshop.

The 2018 Dietary Glutamate Workshop was organized and sponsored by the International Glutamate Technical Committee to provide a platform for a broad expert discussion on all relevant aspects of glutamate metabolism and safety in human nutrition. The participants reached a consensus with previous safety evaluations conducted by the global expert bodies, but contradicted the 2017 re-evaluation of dietary glutamates by the European Food Safety Authority, which proposed a group acceptable daily intake (ADI) of 30 mg/kg body weight per day. The participants of the Workshop concluded that the present knowledge on metabolism, kinetics, developmental and general toxicity of dietary glutamates did not warrant a change in the previous ADI of "not specified.

Applications for α-lactalbumin in human nutrition.

α-Lactalbumin is a whey protein that constitutes approximately 22% of the proteins in human milk and approximately 3.5% of those in bovine milk. Within the mammary gland, α-lactalbumin plays a central role in milk production as part of the lactose synthase complex required for lactose formation, which drives milk volume.

A Perspective on the Safety of Supplemental Tryptophan Based on Its Metabolic Fates.

Over the past 50 y, tryptophan has been ingested in amounts well in excess of its dietary requirement. This use is based on extensive findings that ingesting tryptophan increases brain tryptophan concentrations, which stimulates the synthesis and release of the neurotransmitter serotonin, from which it is derived. Such increases in serotonin function may improve mood and sleep.

Saliency-aware food image segmentation for personal dietary assessment using a wearable computer.

Image-based dietary assessment has recently received much attention in the community of obesity research. In this assessment, foods in digital pictures are specified, and their portion sizes (volumes) are estimated. Although manual processing is currently the most utilized method, image processing holds much promise since it may eventually lead to automatic dietary assessment.

An exploratory study on a chest-worn computer for evaluation of diet, physical activity and lifestyle.

Recently, wearable computers have become new members in the family of mobile electronic devices, adding new functions to those provided by smart-phones and tablets. As "always-on" miniature computers in the personal space, they will play increasing roles in the field of healthcare. In this work, we present our development of eButton, a wearable computer designed as a personalized, attractive, and convenient chest pin in a circular shape.

Non-nutritive sweeteners and obesity.

Non-nutritive sweeteners (NNSs) provide sweetness to foods and beverages without adding calories. They have thus been found useful in minimizing the dietary sugar content of diabetics and the dietary energy content of individuals attempting to lose or maintain body weight. Their usefulness in weight reduction has recently been questioned, however, based on the notion that they can actually increase hunger and food intake and thereby promote weight gain.

Accuracy of food portion size estimation from digital pictures acquired by a chest-worn camera.

Objective: Accurate estimation of food portion size is of paramount importance in dietary studies. We have developed a small, chest-worn electronic device called eButton which automatically takes pictures of consumed foods for objective dietary assessment. From the acquired pictures, the food portion size can be calculated semi-automatically with the help of computer software.

Model-based measurement of food portion size for image-based dietary assessment using 3D/2D registration.

Dietary assessment is important in health maintenance and intervention in many chronic conditions, such as obesity, diabetes, and cardiovascular disease. However, there is currently a lack of convenient methods for measuring the volume of food (portion size) in real-life settings. We present a computational method to estimate food volume from a single photographical image of food contained in a typical dining plate.

Oral branched-chain amino acid supplements that reduce brain serotonin during exercise in rats also lower brain catecholamines.

Exercise raises brain serotonin release and is postulated to cause fatigue in athletes; ingestion of branched-chain amino acids (BCAA), by competitively inhibiting tryptophan transport into brain, lowers brain tryptophan uptake and serotonin synthesis and release in rats, and reputedly in humans prevents exercise-induced increases in serotonin and fatigue. This latter effect in humans is disputed. But BCAA also competitively inhibit tyrosine uptake into brain, and thus catecholamine synthesis and release.

The ingestion of different dietary proteins by humans induces large changes in the plasma tryptophan ratio, a predictor of brain tryptophan uptake and serotonin synthesis.

Background & Aims: The ingestion by rats of different proteins causes large differences in the plasma ratio of tryptophan to other large neutral amino acids, which predicts brain tryptophan uptake and serotonin synthesis. We evaluated in humans whether ingesting these proteins also produces large excursions in the tryptophan ratio.

Methods: Fasting males (n = 6) ingested V-8 Juice containing 40 g of α-lactalbumin, gluten, zein or starch.

3D localization of circular feature in 2D image and application to food volume estimation.

A novel method to estimate the 3D location of a circular feature from a 2D image is presented and applied to the problem of objective dietary assessment from images taken by a wearable device. Instead of using a common reference (e.g.

Effects and side effects associated with the non-nutritional use of tryptophan by humans.

The daily nutritional requirement for L-tryptophan (Trp) is modest (5 mg/kg). However, many adults choose to consume much more, up to 4-5 g/d (60-70 mg/kg), typically to improve mood or sleep. Ingesting L-Trp raises brain tryptophan levels and stimulates its conversion to serotonin in neurons, which is thought to mediate its actions.

Large neutral amino acids: dietary effects on brain neurochemistry and function.

The ingestion of large neutral amino acids (LNAA), notably tryptophan, tyrosine and the branched-chain amino acids (BCAA), modifies tryptophan and tyrosine uptake into brain and their conversion to serotonin and catecholamines, respectively. The particular effect reflects the competitive nature of the transporter for LNAA at the blood-brain barrier. For example, raising blood tryptophan or tyrosine levels raises their uptake into brain, while raising blood BCAA levels lowers tryptophan and tyrosine uptake; serotonin and catecholamine synthesis in brain parallel the tryptophan and tyrosine changes.

Mechanisms for sweetness.

A remarkable amount of information has emerged in the past decade regarding sweet taste physiology. This article reviews these data, with a particular focus on the elucidation of the sweet taste receptor, its location and actions in taste transduction in the mouth, its nontaste functions in the gastrointestinal tract (e.g.

Imaged based estimation of food volume using circular referents in dietary assessment.

Measuring food volume (portion size) is a critical component in both clinical and research dietary studies. With the wide availability of cell phones and other camera-ready mobile devices, food pictures can be taken, stored or transmitted easily to form an image based dietary record. Although this record enables a more accurate dietary recall, a digital image of food usually cannot be used to estimate portion size directly due to the lack of information about the scale and orientation of the food within the image.

Effect of chronic protein ingestion on tyrosine and tryptophan levels and catecholamine and serotonin synthesis in rat brain.

Objectives: Previous studies have shown that brain tyrosine (TYR) levels and catecholamine synthesis rate increase in rats as chronic dietary protein content increases from 2 to 10% (% weight). A single protein, casein, was examined. The present study explores how TYR levels and catecholamine synthesis (and tryptophan (TRP) levels and serotonin synthesis) change when different proteins are ingested chronically over the same range of dietary protein contents.

Physical Activity Recognition Based on Motion in Images Acquired by a Wearable Camera.

A new technique to extract and evaluate physical activity patterns from image sequences captured by a wearable camera is presented in this paper. Unlike standard activity recognition schemes, the video data captured by our device do not include the wearer him/herself. The physical activity of the wearer, such as walking or exercising, is analyzed indirectly through the camera motion extracted from the acquired video frames.

The chronic ingestion of diets containing different proteins produces marked variations in brain tryptophan levels and serotonin synthesis in the rat.

Serotonin (5HT) synthesis in brain is influenced by precursor (tryptophan (TRP)) concentrations, which are modified by food ingestion. Hence, in rats, a carbohydrate meal raises brain TRP and 5HT; a protein-containing meal does not, but little attention has focused on differences among dietary proteins. Recently, single meals containing different proteins have been shown to produce marked changes in TRP and 5HT.