protein metabolism

• What are the main topics included in the learning outcomes for protein metabolism?

  Protein digestion, absorption, and transport; transamination and deamination; abnormal blood urea nitrogen and urine urea nitrogen levels; nitrogen balance; meeting protein needs; complementary protein combinations; health consequences of overconsumption of protein; protein-energy malnutrition, including marasmus and kwashiorkor.
• What are the key enzymes involved in protein digestion in the stomach?

  • Hydrochloric acid (HCl)
  • Pepsin (gastric enzyme)
• What types of peptides are formed during protein digestion in the small intestine by absorptive cells?

  Dipeptides and tripeptides.
• How are amino acids absorbed and transported after digestion?

  1. Carried to absorptive cells by carrier systems
  2. Enter the capillary of villus
  3. Travel to the liver via hepatic portal vein
  4. Liver keeps some amino acids and releases the rest into circulation
• What is protein turnover?

  • Cellular process of breaking down proteins and recycling their amino acids
• What occurs during deamination?

  The removal of the nitrogen-containing group from an amino acid.
• What is transamination?

  The transfer of the nitrogen-containing group from an unneeded amino acid to a carbon skeleton to form an amino acid.
• Where is ammonia converted to urea?

  In the liver.
• What does Blood Urea Nitrogen (BUN) measure?

  The concentration of urea in blood.
• What is positive nitrogen balance?

  The state in which the body retains more nitrogen than it loses.
• What is the Acceptable Macronutrient Distribution Range (AMDR) for protein intake in healthy adults?

  US: 10-35% of energy from protein

  UK: 56g/day for men, 45g/day for women of average body weights
• What chronic diseases have been associated with a high consumption of red and processed meats?

  Heart disease, colorectal cancer, diabetes, and cancers of the pancreas, stomach, and esophagus.
• What are the potential health consequences of high-protein diets?

  • Higher urinary losses of calcium
  • Osteoporosis
  • Dehydration
  • Poor kidney health
• What groups of people are at risk of protein deficiency?

  • People suffering from alcoholism
  • Individuals with anorexia nervosa
  • People with certain intestinal tract disorders
  • Individuals with low incomes, especially the elderly
• What are the two forms of protein-energy malnutrition?

  • Kwashiorkor
  • Marasmus
• What are the primary limiting amino acids in legumes?

  Methionine and tryptophan.
• With which chronic diseases is the consumption of red and processed meats associated?

  • Heart disease
  • Colorectal cancer
  • Diabetes
  • Cancers of the pancreas, stomach, and esophagus.
• What are potential health risks associated with high-protein diets?

  • Higher urinary losses of calcium
  • Osteoporosis
  • Dehydration
  • Poor kidney health.
• Which groups of people are at risk of protein deficiency in the US/UK?

  • People suffering from alcoholism
  • Anorexia nervosa
  • Certain intestinal tract disorders
  • Individuals with low incomes, especially the elderly.
• What are the symptoms of Kwashiorkor in children?

  • Stunted growth
  • Unnaturally blond, sparse, brittle hair
  • Patches of skin that have lost normal coloration
  • Swollen cheeks, arms, legs, and belly.
• How is Marasmus kwashiorkor characterized?

  A child with Kwashiorkor who then starts consuming insufficient energy, leading to edema and wasting.
• What is a food allergy?

  An inflammatory response caused by the immune system reacting inappropriately to harmless substances (allergens) in a food.
• What are the signs and symptoms of a food allergy?

  • Hives
  • Swollen or itchy lips
  • Eczema
  • Difficulty swallowing
  • Wheezing and difficulty breathing
  • Abdominal pain
  • Vomiting
  • Diarrhea.
• What is anaphylaxis and how is it treated?

  Anaphylaxis is a serious drop in blood pressure that occurs when sensitive people are exposed to food allergens; it can be fatal. Treatment involves injecting a medication that prevents or blunts the allergic response.
• What is skin patch testing used for in the diagnosis of food allergies?

  Skin patch testing involves applying an allergen to a patch placed on the skin. The skin becomes irritated and itchy if antibodies to the allergen are present, indicating a food allergy.
• Name five of the main 14 food allergens in the UK.

  • Celery
  • Cereals containing gluten (wheat, rye, barley, oats)
  • Crustaceans (prawns, crab, lobster)
  • Eggs
  • Fish.
• What are food manufacturers required to identify on food products in the UK?

  Whether a product contains any of the main 14 allergens as an ingredient or processing aid.
• What is Phenylketonuria (PKU)?

  A genetic metabolic disorder characterized by the inability to convert phenylalanine to tyrosine, leading to phenylalanine accumulation.
• What are food intolerances characterized by?

  • Unpleasant physical reactions following consumption of certain foods.
  • Symptoms may include skin flushing, hives, difficulty swallowing, vomiting, diarrhea, dizziness, and headache.
• What are the key features of Celiac Disease?

  • Inherited condition
  • Inability to absorb gluten
  • Results in damage to the small intestine
  • Poor absorption of nutrients.
• What are the signs and symptoms of celiac disease?

  • Abdominal bloating
  • Chronic diarrhea
  • Weight loss
  • Poor growth (children).
• What diagnostic tests are used to diagnose celiac disease?

  Blood tests and intestinal biopsies are used.
• Name five foods that contain gluten and should be avoided by those with celiac disease.

  • Barley
  • Rye
  • Triticale
  • Wheat
  • Wheat-enriched flour.
• What is the difference between celiac disease and gluten sensitivity?

  Gluten sensitivity is characterized by uncomfortable symptoms after gluten consumption without small intestine damage, unlike celiac disease which causes small intestine damage.
• What are the core features of Autism Spectrum Disorders (ASDs)?

  • Deficits in social interaction
  • Verbal and nonverbal communication difficulties
  • Repetitive behaviors or interests.
• How prevalent are ASDs in children in the United States?

  Affects 1 in 68 children in the United States.
• What are the different types of vegetarian diets?

  • Vegetarians: eat plant-based diets
  • Semivegetarians (Flexitarian): avoid red meat but consume other animal foods
  • Pescavegetarians: vegetarians who eat fish, milk products, and eggs for animal protein.
• What are the differences between Lactovegetarian, Ovovegetarian, Lactoovovegetarian, and Vegan diets?

  • Lactovegetarian: consumes milk and milk products for animal protein
  • Ovovegetarian: eats eggs for animal protein
  • Lactoovovegetarian: consumes milk products and eggs for animal protein
  • Vegan: eats only plant foods.
• What are some health benefits associated with vegetarian diets?

  • Often lower in fat and energy
  • Lower risk of obesity
  • Lower risk of Type 2 diabetes
  • Lower risk of hypertension
  • Lower risk of certain cancers.
• What are the nutritional advantages and possible disadvantages of vegetarian diets?

  Advantages:

  • High vitamins C, E, and folic acid
  • High phytochemicals
  • High fiber
  • High magnesium and potassium
  • Low saturated fatty acids

  
  

  Possible Disadvantages:

  • Low vitamins B-12, D, and riboflavin
  • Low zinc, iron, and calcium
  • Low omega-3 fatty acids
  • Low certain essential amino acids
  • Low energy.