Protein (nutrient)

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Retrieved 6 December A good source of dietary protein meets two requirements: Sucrolose is synthesized, thus artificial. Radiation therapy to any part of the digestive system has side effects that cause nutrition problems. Changes in the way food tastes. The limitations of the Kjeldahl method were at the heart of the Chinese protein export contamination in and the China milk scandal in which the industrial chemical melamine was added to the milk or glutens to increase the measured "protein".

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The protein content in roots, tubers and fruits is between 0 and 2 percent. Food staples with low protein content must be complemented with foods with complete, quality protein content for a healthy life, particularly in children for proper development. A good source of protein is often a combination of various foods, because different foods are rich in different amino acids. A good source of dietary protein meets two requirements: Healthy people eating a balanced diet rarely need protein supplements.

The table below presents the most important food groups as protein sources, from a worldwide perspective. It also lists their respective performance as source of the commonly limiting amino acids, in milligrams of limiting amino acid per gram of total protein in the food source. Protein powders — such as casein , whey , egg , rice and soy — are processed and manufactured sources of protein.

The type of protein is important in terms of its influence on protein metabolic response and possibly on the muscle's exercise performance. As a result, the amino acid availability and the accumulation of tissue protein is altered because of the various protein metabolic responses. The classic assays for protein concentration in food are the Kjeldahl method and the Dumas method. These tests determine the total nitrogen in a sample. The only major component of most food which contains nitrogen is protein fat, carbohydrate and dietary fiber do not contain nitrogen.

If the amount of nitrogen is multiplied by a factor depending on the kinds of protein expected in the food the total protein can be determined. This value is known as the "crude protein" content. On food labels the protein is given by the nitrogen multiplied by 6. The Kjeldahl test is typically used because it is the method the AOAC International has adopted and is therefore used by many food standards agencies around the world, though the Dumas method is also approved by some standards organizations.

Accidental contamination and intentional adulteration of protein meals with non-protein nitrogen sources that inflate crude protein content measurements have been known to occur in the food industry for decades. To ensure food quality , purchasers of protein meals routinely conduct quality control tests designed to detect the most common non-protein nitrogen contaminants, such as urea and ammonium nitrate. In at least one segment of the food industry, the dairy industry, some countries at least the U.

Current milk-testing equipment measures peptide bonds, a direct measure of true protein. The limitations of the Kjeldahl method were at the heart of the Chinese protein export contamination in and the China milk scandal in which the industrial chemical melamine was added to the milk or glutens to increase the measured "protein".

These organizations have suggested that other methods for evaluating the quality of protein are inferior. Most proteins are decomposed to single amino acids by digestion in the gastro-intestinal tract. Digestion typically begins in the stomach when pepsinogen is converted to pepsin by the action of hydrochloric acid , and continued by trypsin and chymotrypsin in the small intestine.

Most peptides longer than four amino acids are not absorbed. Absorption into the intestinal absorptive cells is not the end. There, most of the peptides are broken into single amino acids. Absorption of the amino acids and their derivatives into which dietary protein is degraded is done by the gastrointestinal tract.

The absorption rates of individual amino acids are highly dependent on the protein source; for example, the digestibilities of many amino acids in humans, the difference between soy and milk proteins [22] and between individual milk proteins, beta-lactoglobulin and casein. Newborns of mammals are exceptional in protein digestion and assimilation in that they can absorb intact proteins at the small intestine.

This enables passive immunity , i. Considerable debate has taken place regarding issues surrounding protein intake requirements. Requirements are also greater during childhood for growth and development, during pregnancy, or when breastfeeding in order to nourish a baby or when the body needs to recover from malnutrition or trauma or after an operation.

If not enough energy is taken in through diet, as in the process of starvation , the body will use protein from the muscle mass to meet its energy needs, leading to muscle wasting over time. If the individual does not consume adequate protein in nutrition, then muscle will also waste as more vital cellular processes e. Several studies have concluded that active people and athletes may require elevated protein intake compared to 0.

In addition, some have suggested that athletes using restricted-calorie diets for weight loss should further increase their protein consumption, possibly to 1. Endurance athletes differ from strength-building athletes in that endurance athletes do not build as much muscle mass from training as strength-building athletes do.

The overall protein requirement increases because of amino acid oxidation in endurance-trained athletes. Therefore, a slight increase in protein intake may be beneficial to endurance athletes by replacing the protein lost in energy expenditure and protein lost in repairing muscles.

One review concluded that endurance athletes may increase daily protein intake to a maximum of 1. Research also indicates that individuals performing strength-training activity require more protein than sedentary individuals.

Strength-training athletes may increase their daily protein intake to a maximum of 1. Many athletes maintain a high-protein diet as part of their training. In fact, some athletes who specialize in anaerobic sports e.

A food allergy is an abnormal immune response to proteins in food. The signs and symptoms may range from mild to severe. They may include itchiness , swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. These symptoms typically occurs within minutes to one hour after exposure. When the symptoms are severe, it is known as anaphylaxis.

While there is no conclusive evidence that a high protein diet can cause chronic kidney disease , there is a consensus that people with this disease should decrease consumption of protein. Individuals with phenylketonuria PKU must keep their intake of phenylalanine - an essential amino acid - extremely low to prevent a mental disability and other metabolic complications.

Phenylalanine is a component of the artificial sweetener aspartame, so people with PKU need to avoid low calorie beverages and foods with this ingredient. Maple syrup urine disease is associated with genetic anomalies in the metabolism of branched-chain amino acids BCAAs.

The amino acids in question are leucine, isoleucine and valine. The condition gets its name from the distinctive sweet odor of affected infants' urine. Children of Amish , Mennonite , and Ashkenazi Jewish descent have a high prevalence of this disease compared to other populations. Dietary protein is converted by the digestive process to individual amino acids, which are then absorbed.

When amino acids are in excess of needs, the liver takes up the amino acids and deaminates them, a process converting the nitrogen from the amino acids into ammonia , further processed in the liver into urea via the urea cycle. Excretion of urea occurs via the kidneys. Other parts of the amino acid molecules can be converted into glucose and used for fuel. However, unlike body fat as a reserve for future caloric needs, there is no protein storage for future needs.

Excessive protein intake may increase calcium excretion in urine, occurring to compensate for the pH imbalance from oxidation of sulfur amino acids. This may lead to a higher risk of kidney stone formation from calcium in the renal circulatory system. High protein diets have been shown to lead to an additional 1. There is little consensus on the potentially detrimental effects to healthy individuals of a long-term high protein diet, leading to caution advisories about using high protein intake as a form of weight loss.

The — Dietary Guidelines for Americans DGA recommends that men and teenage boys increase their consumption of fruits, vegetables and other under-consumed foods, and that a means of accomplishing this would be to reduce overall intake of protein foods. While the report acknowledges research showing that lower intake of red and processed meat is correlated with reduced risk of cardiovascular diseases in adults, it also notes the value of nutrients provided from these meats.

While the DGA report does advise for a reduced level of consumption of red and processed meats, the DGA key recommendations recommend that a variety of protein foods be consumed, including both vegetarian and non-vegetarian sources of protein.

Protein deficiency and malnutrition PEM can lead to variety of ailments including mental retardation and kwashiorkor. This edema is explained by the action of lipoxygenase on arachidonic acid to form leukotrienes and the normal functioning of proteins in fluid balance and lipoprotein transport.

PEM is fairly common worldwide in both children and adults and accounts for 6 million deaths annually. In the industrialized world, PEM is predominantly seen in hospitals, is associated with disease, or is often found in the elderly.

From Wikipedia, the free encyclopedia. Redirected from Protein in nutrition. The Sixers are considering a lot of options, including using both first first-rounders in a package to move up to the top five picks of the draft. Bridges is the Sixers' top target if they remain at No. Knox and former Kentucky teammate Shai Gilgeous-Alexander are high on their wish list if Bridges is off the board, according to sources.

As a 6-foot-6 freshman point guard, Gilgeous-Alexander was regarded as the Wildcats' best player at the conclusion of the season. The Toronto native is a good passer and facilitator who can run an offense. He can also slide to shooting guard, which makes him a good complement to Ben Simmons.

His defense and his 7-foot wingspan are arguably his best attributes. McConnell already on the roster. It was "just another opportunity for further diligence two days away from the draft," said Ned Cohen, the Sixers' vice president of basketball operations. Knox displayed a good-looking shot in a workout designed mostly around shooting drills.

However, as expected, the year-old looked tired and didn't match the enthusiasm he had displayed in Friday's group workout. That could have had a lot to do with his traveling schedule. Whatever it was, Sixers vice president of analytics and strategy Alex Rucker only had positive things to say about the , pounder. Six-nine, fluid, shot the ball great. Knox admitted that the individual workouts are harder than group workouts due to the constant moving.

In a group setting, players get breaks. But this meeting was set up in part because coach and interim general manager Brett Brown wanted to spend more time with Knox. The Sixers wanted to get another look at Smith shooting the ball. He did a better job than in last week's workout. He also displayed his trademark athleticism, dunking on an opponent in a drill. Seven players the Sixers could be considering. To be able to be a part of the Sixers' dynasty would definitely mean a lot to me.

They have 11 players under contract for next season.