Proteins and Fats

Discussion of amino acids presented as a list at the bottom of the page.
Varied diet is crucial for protein intake, leading to the correct storage and synthesis of proteins in the body.
Total of 20 amino acids; distinction between essential and nonessential amino acids.

Essential Amino Acids: Must be consumed in the diet as the body cannot synthesize them.
Nonessential Amino Acids: Can be synthesized in the body using the essential amino acids and other nutrients.
The liver plays a role in storing amino acids and breaking them down for reuse.

Over 40% of protein in the body is located in skeletal muscle; importance of protein to prevent muscle wasting (atrophy).
Significance of protein in various biological functions:
- Enzymes: Proteins that catalyze biochemical reactions, speeding processes in the body.
- Neurotransmitters: Chemical messengers transmitting signals in nerves.
- Antibodies: Proteins that defend against infections.
- Other substances: Breast milk, mucus, sperm, histamine, etc.
Albumin's role in blood protein composition and medication transport.
Maintenance of fluid balance in the body’s compartments: intravascular, intracellular, and interstitial fluids.
Proteins’ role in acid-base balance maintenance.
Oxygen transport facilitated by hemoglobin in red blood cells, emphasizing the importance of iron for binding.
Clotting factors involvement in blood coagulation processes (clotting cascade).

Protein digestion begins in the stomach with proteases and hydrochloric acid
- Hydrochloric acid breaks peptide bonds, enabling further breakdown in the small intestine by other enzymes: trypsin, chymotrypsin, carboxypeptidase.
Denaturation: Process by which proteins are broken down for digestion and metabolism.
Continuous need for proteins and amino acids due to ongoing bodily processes.
Importance of a varied diet to avoid deficiencies in amino acids.

The liver's role in amino acid clearance, synthesis of new compounds, and maintenance of nitrogen balance.
Plasma proteins include:
- Heparin: Involvement in blood clotting.
- Prothrombin: Precursor for thrombin, vital for coagulation.
- Albumin: Regulates osmotic pressure in blood plasma.
Metabolism: The sum of chemical reactions (anabolism and catabolism related to proteins).
- Anabolism: Building new proteins from amino acids.
- Catabolism: Breakdown of proteins into constituent amino acids.

Nitrogen Balance: Reflects the state of protein metabolism in the body:
- Neutral Nitrogen Balance: Balance between protein synthesis and breakdown.
- Positive Nitrogen Balance: Net protein synthesis exceeds breakdown (growth spurts, pregnancy, recovery from surgery).
- Negative Nitrogen Balance: Catabolism exceeds anabolism, leading to muscle wasting and malnutrition.

Complete Proteins: Provide all nine essential amino acids (animal proteins like meat, fish, dairy, eggs).
Incomplete Proteins: Lack certain amino acids; can be combined to form complete proteins (e.g., beans and rice).
Importance of pairing incomplete proteins to meet dietary needs, especially in vegetarian diets.

Recommended Dietary Allowance (RDA): 0.8 g/kg of body weight.
- Calculation example: Convert pounds to kilograms (e.g., 200 lbs = 91 kg) and multiply by 0.8 to find daily protein needs.
Discussed factors that influence protein needs:
- Activity levels, health status, growth or healing phases, and chronic diseases.
Healthy adult males and females have different protein requirements, reflecting variations in body composition.

Illness, surgery, infections, and stress can elevate the need for protein.
Strategies for ensuring adequate protein intake in vulnerable populations, including the elderly.

Risks associated with vegetarianism if not planned well.
Nutritional deficiencies in vegetarians, particularly concerning vitamin B12, iron, and protein.
- Vitamin B12: Essential for red blood cell formation; often lacking in plant-based diets.
Importance of fortified products for vegetarians (soy milk, breakfast cereals).

Function: Provide energy, absorb vitamins A, D, E, and K; insulation; protection of organs.
Classification of fats:
- Saturated Fats: Solid at room temperature, contribute to heart disease.
- Unsaturated Fats: Healthier fats that are liquid at room temperature (monounsaturated and polyunsaturated).
Trans Fats: Considered unhealthy; linked to higher cholesterol levels.
Each pound of fat equates to approximately 3,500 calories, relevant for weight management.

Triglycerides: The body’s storage form of fat, high triglyceride levels are associated with increased risk of heart disease and metabolic issues.
Healthy triglyceride levels: Below 150 mg/dL.

Importance of encouraging healthy diets low in saturated and trans fats.
Recommendations for increasing intake of omega-3 fatty acids and seafood while limiting red meat and high-fat dairy products to promote cardiovascular health.