The use of amino acids to aid in weight loss

Psychology

The use of Amino Acids to Aid in Weight Loss

The amino acids that may aid in weight loss include carnitine, phenylalanine, and tryptophan. Tryptophan helps one to feel full and satisfied. Carnitine plays a more significant role in amino acid weight loss. This amino acid is vital to the production of energy for the heart and other muscles and for the transfer of fatty acids into the cell for burning. There have been many studies that have been done that have shown that these as well as many others all play some part in the process of weight loss. For those who are trying to loose weight it is important to make sure that amino acids are included in their diet plan.

Amino acids are the building blocks of protein. There are approximately 28 known amino acids that are needed in order to build the proteins that the body needs for growth, repair, and maintenance of body tissues. The body can make eleven amino acids on its own. These include arginine, alanine, asparagines, aspartic acid, cystine, glutamine, glutamic acid, glycine, praline, serine, and tyrosine. The others must come from the diet. These amino acids, also referred to as essential amino acids, are isopeucine, methionine, leucine, lysine, phenylalanine, threonine, tryptophan, and valine. Other amino acids, such as carnitine and histidine are not used for protein building, but they are still important to bodily functions (Group, 2009).

Amino acids that may aid in weight loss include carnitine, phenylalanine, and tryptophan. Tryptophan is found in excess in lean turkey meat, and it helps one to feel full and satisfied. Carnitine, on the other hand, plays a more significant role in amino acid weight loss. This amino acid is vital to the production of energy for the heart and other muscles and for the transfer of fatty acids into the cell for burning. This boosts the body's metabolism and provides energy for both the brain and the muscles. Many professional athletes supplement their diet with carnitine in order to increase energy levels and stamina, and to lower blood levels of fat. Even though the body can manufacture some carnitine on its own from the essential amino acids lysine and methionine, many people are deficient in this nutrient. L-carnitine fumarate is a popular weight loss supplement available in most pharmacies and health food stores (Group, 2009).

There have been many studies done that have looked at the affects that amino acids have on weight loss. One of these studies was done by Koren, Purnell, Breen, Matthys, Callahan, Meeuws, Burden and Weigle, (2007). Serotonin mediates satiety in the central nervous system. Brain serotonin content is dependant on the plasma ratio of tryptophan (Trp) to large neutral amino acids (LNAA) and may be affected by diet make up. The researchers looked at whether high-carbohydrate or high-protein diets induce satiety and weight loss by altering plasma concentrations of these amino acids. The results showed that Ad libitum caloric intake fell by 222-8-81 kcal/day with a 3.7-8-0.6 kg weight loss at 12 weeks in study 1. Ad libitum caloric intake fell by 441-8-63 kcal / day with a 4.9-8-0.5 kg weight loss at 12 weeks in study 2. They came to the conclusion that an increase in either carbohydrate or protein intake increases satiety and leads to significant weight loss, however, these effects are not mediated by an increase in plasma concentration of Trp or the Trp: LNAA ratio.

The nutrition and sports medicine literature have long implicated branched-chain amino acids in the enhancement of body composition and biophysical profiles. In combination with moderate caloric restriction, BCAA supplementation results in significant reductions of adipose mass, while maintaining muscle mass and metabolic rate, both normally compromised during caloric restriction. BCAA supplementation also appears to have a role in improving glucose tolerance and homeostasis. While topiramate's contribution to the patient's weight loss cannot be excluded, most of its effect would have likely occurred within the first 18 months of treatment. In a study done by Gordon-Elliott and Margolese, (2006) they observed a patient, whose appetite suppression and significant weight loss began after the initiation of BCAA, and after having received 18 months of topiramate. It is their feeling that further study of prolonged treatment with adjunctive BCAA for antipsychotic induced weight gain and TD is necessary.

Outside of the need for amino acids that are required for synthesis of new proteins, amino acids participate in numerous other metabolic roles. In many cases the importance of these pathways is proportional to dietary intake, such as dietary intake of tryptophan or phenylalanine as precursors to neurotransmitters with dietary intake potentially impacting appetite regulation, or intake of arginine altering epithelial production of nitrous oxide and cell signaling pathways. Another case of an amino acid with metabolic roles proportional to dietary intake is the BCAA leucine with potential regulatory roles on skeletal muscle protein synthesis and glycemic control (Layman and Baum, 2004).

Leucine displays an array of metabolic roles. Like all amino acids, leucine is necessary for protein synthesis. Based on nitrogen-balance measurements, there is a requirement for leucine to maintain short-term stability of body protein. Leucine contributes in numerous other metabolic processes including serving as a fuel for skeletal muscle, modulation of the intracellular insulin/phosphatidylinositol-3 kinase (PI3-K) signaling cascade, a unique regulator of muscle protein synthesis and serving as a donor of an amino group for production of alanine or glutamine. In each of these pathways, the force of leucine is proportional to availability and is dependent on its intracellular concentration. Leucine is relatively plentiful in the food supply, accounting for 8% of dietary protein with dairy products being particularly rich in leucine and the BCAA. This amount of leucine intake is reasonable within the guidelines of the dietary reference intakes. These metabolic roles for leucine form the bases for the researcher's hypothesis for the importance of increased dietary protein during weight loss (Layman and Baum, 2004).

It is thought that Leucine, one of protein's amino acids, may be the key to keeping muscle and losing fat. In a study done by McVeigh, (2005), research showed that twenty-four women who averaged 107 g of protein daily (similar to high-protein diets) had 1 more pound of weigh loss than 24 others who averaged 57 g a day over 4 months. Both groups had limited calories of 1,700 a day. Other studies have shown that the leucine amino acids can promote muscle building when overall calories are low. Even though animal protein is richest in leucine (1,700 to 2,100 mg per serving), it's also a prime source of heart-harming sat fats.

The function of leucine in muscle protein synthesis is different from other essential amino acids. During catabolic phase such as energy restriction, supplementation with leucine or a complete mixture of the 3 BCAA's, leucine, isoleucine, and valine, rouses muscle protein synthesis. In a study done by Layman and Baum, (2004), it was suggested that there is a regulatory role of leucine that is dependent on intracellular concentration and is different from traditional substrate roles for protein synthesis or nitrogen balance. They found that leucine supplementation rouses recovery of muscle protein synthesis during food restriction or after endurance exercise. The molecular means for the actions of leucine in protein synthesis are now known to involve regulation of phosphorylation events and components of the insulin signaling pathway. The place for leucine action is a kinase in the insulin signaling cascade formerly identified as mTOR (mammalian target of rapamycin). This directive was first recognized associated with translational control of muscle protein synthesis. Raises in leucine concentration stimulate mTOR kinase activity for phosphorylation manages of the eIF4 initiation complex and of the S6 ribosomal protein. This exclusive role of leucine in rule of muscle protein synthesis is consistent with the sparing of lean body mass seen with use of higher protein diets during weight loss (Layman and Baum, 2004).

It is thought that Carnitine, tryptophan and phenylalanine may also help in the fight against obesity by burning fat more efficiently and suppressing appetite. The storage of fat is determined by the enzyme lipoprotein lipase (LPL). Some researchers speculate that LPL may act as a gatekeeper to determine the quantity of nutrients, such as glucose and fatty acids, the fat cell will take from the blood for storage. If they take too much, the brain senses a drop in blood sugar levels and signals the body to increase the appetite. Very important to the production of energy for the heart and other muscles, carnitine transfers fatty acids into the cell for burning. The body's increased metabolism of fatty acids sets off reactions that provide energy to both the brain and muscles and helps to alleviate the muscular weakness often associated with weight loss. Two other essential amino acids, phenylalanine and tryptophan, may also help dieters. Tryptophan supplements tend to diminish the desire for carbohydrates and since most overweight people seem to favor sweet, processed carbohydrate foods, it may be helpful in weight loss. Phenylalanine stems the appetite by increasing the production of the neurotransmitter norepinephrine (Taylor, 1989).

Drugs thought to enhance serotonin-mediated neurotransmission have been shown to diminish appetite for carbohydrates. In a study done by Heraief, Burckhardt, Wurtman and Wurtman, (1985), they examined the ability of tryptophan (TRP), serotonin's amino acid precursor, or a placebo to influence weight loss among 62 obese Swiss outpatients who were on a reducing diet known as the Protein-Sparing Modified Fast (PSMF) Diet which is often associated with severe carbohydrate craving. This diet provided relatively large amounts of protein but little carbohydrates, thus stimulating ketone body production. Its consumption also reduced the ratio of plasma TRP to the summed concentrations of the other large neutral amino acids, thereby probably diminishing brain TRP and serotonin levels. It was found that among moderately obese patients the TRP significantly enhanced weight loss, especially during the first treatment month but also during the total. The TRP didn't modify the reported adherence to the PSMF diet. The partial effectiveness of TRP among the moderately obese subjects did not justify its routine use as an adjunct to a PSMF diet. However, greater efficacy may be obtained with better patient selection and under metabolic conditions designed to amplify the uptake of TRP into the brain.

There is a wide-ranging consensus that the most critical factor in weight management is total energy intake. However the ideal balance of macronutrients for weight loss and adult weight management remains widely disputed. Often this debate center son the relative merits or risks of carbohydrates vs. lipids. When the energy amount of the diet is equal, the relative levels of carbohydrates and lipids in the diet appear to have minimal affect on either weight loss or body composition. There is a growing amount of evidence that diets with reduced levels of carbohydrates and higher levels of protein may be beneficial for weight loss. These studies have shown that diets with reduced carbohydrates and higher protein appear to increase weight loss, increase loss of body fat, or reduce loss of lean body mass. While there are potential benefits for higher protein diets during weight loss, a metabolic explanation for optimal levels of carbohydrates and proteins remains unknown (Layman and Baum, 2004).

Potential explanations for the beneficial effects of diets with higher protein and reduced levels of carbohydrates include lower energy intake associated with increased satiety, reduced energy efficiency or increased thermogenesis, sparing of muscle protein loss, and enhanced glycemic control. In a study done by Layman and Baum, (2004), their research focused on the role of amino acids in regulation of muscle protein metabolism and glycemic control. The role of protein in the diet is to make available the 20 naturally occurring amino acids and specifically to provide the 9 crucial amino acids. Each of these amino acids has a distinctive requirement as a building block for body proteins. Nonetheless, the dietary requirement is not tightly linked to substrate needs for protein synthesis. This study found that one cause for the lack of a direct relationship is the recycling of amino acids after degradation of existing proteins and Amino acids are efficiently reutilized for synthesis of new proteins

Plasma 42-amino-acid amyloid-? (a?42) levels appear to associate with BMI, according to a study done by Yong-Ho, Martin, Maple, Tharp and Pratley, (2009). They recently showed that adipocyte amyloid precursor protein (APP) expression is up regulated in obesity and correlates with insulin resistance and adipose tissue inflammation. In this study, they aimed to investigate the relation between adipocyte APP expression and plasma a? peptide levels. They carried out a pilot study in which we measured adipocyte APP gene expression and the circulating plasma levels of a?40 in 10 obese individuals before and after a 6-month behaviorally-based weight loss intervention. Subjects were given an oral glucose tolerance test with measurement of insulin levels, a?40 levels measured by ELISA and transcript levels of APP in subcutaneous abdominal adipocytes measured by quantitative real-time PCR. The results showed that at baseline, adipocyte APP expression correlated significantly with plasma a?40 levels and with 2-hour insulin concentrations. After the 6-month weight loss intervention, body weight and BMI decreased significantly (Yong-Ho, Martin, Maple, Tharp and Pratley, 2009).