Food And Nutrition 3rd Edition - Chapter 17 Testbank

The correct answer is "All of the above". Human protein requirements are difficult to determine because they rely on indirect measurements, such as nitrogen balance studies, which may not accurately reflect actual protein needs. Additionally, different groups of individuals have variable protein requirements based on factors like age, sex, and activity level. Furthermore, the nutritional quality of different foods can vary, making it challenging to determine the specific protein content and its bioavailability. Lastly, measuring all vehicles of protein excretion, such as urine and feces, can be difficult and may lead to inaccuracies in determining protein requirements.

Indispensable amino acids are amino acids that cannot be synthesized by the body and therefore must be obtained from the diet. They are essential for the synthesis of proteins in the body. This means that they are required for various biological processes and cannot be substituted by other amino acids. Hence, they must be supplied through the diet to meet the body's needs.

Eating a variety of foods from all the food groups is the best recommendation for ensuring adequate protein intake because different foods contain different types and amounts of protein. By consuming a variety of foods, individuals can ensure that they are getting a balanced and diverse range of proteins from sources such as meat, dairy, legumes, cereals, and vegetables. This approach helps to ensure that all essential amino acids are obtained and that the body receives a sufficient amount of protein for proper growth and maintenance.

Legumes are recommended to improve protein intake in vegan diets because they are a rich source of plant-based protein. They contain essential amino acids that are necessary for the body's protein synthesis. Legumes like lentils, chickpeas, and beans are also high in fiber, vitamins, and minerals, making them a nutritious addition to a vegan diet. By including legumes in their meals, vegans can ensure they are meeting their protein needs and maintaining a balanced diet.

A burns patient is a likely example of someone in negative nitrogen balance because burns cause extensive tissue damage, leading to increased protein breakdown and loss. This results in a higher demand for protein to repair and regenerate damaged tissues. However, if the intake of protein is insufficient to meet this demand, the patient will experience a negative nitrogen balance, where the body breaks down more protein than it synthesizes. This can lead to muscle wasting and impaired healing.

Vitamin B12 is essential for the production of red blood cells and the proper functioning of the nervous system. It is primarily found in animal-based foods, making it difficult for vegans to obtain enough of it from their diet alone. Since females of childbearing age are at a higher risk of developing vitamin deficiencies, it is recommended for them to take supplements of vitamin B12 to ensure they meet their nutritional needs and prevent any potential health issues.

The nutritional quality of dietary proteins depends on how closely their indispensable amino acid content matches the requirement of the human body and the digestibility of the protein. Indispensable amino acids are those that the body cannot produce on its own and must be obtained from food. Therefore, if the protein contains a good balance of these essential amino acids, it is considered to have high nutritional quality. Additionally, the digestibility of the protein is important as it determines how efficiently the body can break down and absorb the amino acids from the protein. Therefore, both factors, a and c, contribute to the nutritional quality of dietary proteins.

During short term fasts or periods of starvation, the body starts using protein for glucose production. This means that the body breaks down muscle tissue to obtain glucose, resulting in loss of muscle mass. Additionally, the production of ketones during fasting has a diuretic effect, causing water loss. Therefore, the correct answer is that short term fasts or periods of starvation often result in significant and rapid initial weight loss due to the use of protein for glucose production and the diuretic effect of ketone production causing loss of muscle mass and water.

The answer "Lentils with rice, fish, yoghurt" is correct because all three foods mentioned in the answer are good quality protein sources. Lentils and rice together provide a complete protein, as they contain all the essential amino acids. Fish is also a high-quality protein source, as it is rich in essential amino acids and omega-3 fatty acids. Yoghurt is another good protein source, especially Greek yoghurt, as it contains a higher protein content compared to regular yoghurt. Therefore, all three foods mentioned in the answer can be described as good quality protein sources.

Protein is made up of amino acids, and nitrogen is an essential component of amino acids. The nitrogen content of 4.8g in 100g of beef indicates the amount of nitrogen present in the protein. Since approximately 16% of protein is composed of nitrogen, we can calculate the protein content by dividing the nitrogen content by 0.16. Therefore, 4.8g of nitrogen corresponds to approximately 30g of protein in the beef.

Methionine is the correct answer because it is an essential amino acid that is necessary for protein synthesis in the human body. Beans, although a good source of protein, are often deficient in methionine. This means that the amount of methionine present in bean protein is not sufficient to meet the human requirement. Therefore, if someone relies heavily on bean protein as a source of their dietary protein, they may not be getting enough methionine, which can lead to deficiencies and health problems.

The proportion of energy contributed by protein can be calculated by dividing the energy provided by protein (370kJ) by the total energy (370kJ) and then multiplying by 100. This gives us 100%. Therefore, the proportion of energy contributed by protein is 20%.

Lysine is the correct answer because it is an essential amino acid that is necessary for human health but cannot be produced by the body. Wheat flour protein is known to be deficient in lysine, making it the amino acid in shortest supply in relation to human requirement. A deficiency in lysine can lead to impaired growth, weakened immune function, and other health issues.

A diet that provides 0.75g of protein per kilogram of body weight per day should be sufficient for 97.5% of healthy females. This means that for every kilogram of body weight, 0.75 grams of protein should be consumed daily. This amount of protein is considered adequate to meet the nutritional needs of the majority of healthy females.

The net protein utilization value of cow's milk is 81, which means that 81% of the milk protein is retained by the body. This indicates that the body is able to effectively use and absorb the protein present in cow's milk, leading to a high retention rate.