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Proteins

Everything About Proteins and Amino Acids

What Are Proteins? Proteins are macronutrients made of chains of amino acids. They are essential for building tissues, hormones, enzymes, and neurotransmitters. Every cell in the body contains protein.

Amino Acids: The Building Blocks There are 20 amino acids, divided into:

  • Essential (9): Must be obtained through diet (e.g., leucine, lysine, tryptophan)
  • Non-essential (11): Can be synthesized by the body (e.g., glutamine, alanine)
  • Some are conditionally essential during illness or stress (e.g., arginine)

Daily Protein Needs

  • General recommendation: 0.8 g/kg of body weight
  • Active individuals or elderly: 1.2–1.6 g/kg
  • Bodybuilders or athletes: up to 2.2 g/kg

Best Sources of Protein

  • Animal-based: Eggs, poultry, beef, dairy, fish
  • Plant-based: Legumes, tofu, tempeh, quinoa, soy, chia seeds
  • Complete vs Incomplete: Animal sources usually complete. Plant sources often incomplete but can be combined (e.g., rice + beans).

Protein for Special Populations

  • Vegetarians/Vegans: Focus on legumes, soy, quinoa, nuts, seeds, and combining foods for a complete amino acid profile.
  • Diabetics: Lean protein sources (chicken, tofu, legumes), avoid processed meats. Protein can help with glycemic control.

Best Protein Powders

  • Whey Protein Isolate: High bioavailability, fast absorption
  • Casein: Slow digesting, good for nighttime
  • Pea Protein: Hypoallergenic, good for vegans
  • Soy Protein: Complete protein with isoflavones
  • Collagen: Not complete, but good for skin, joints, and gut

Side Effects of Too Much Protein

  • May turn into glucose (gluconeogenesis) in excess
  • Kidney strain in individuals with preexisting kidney issues
  • Digestive upset, dehydration
  • Calcium loss with very high intakes

When to Avoid or Limit Protein

  • Chronic kidney disease
  • Certain metabolic conditions
  • Post-liver failure without supervision

Protein and Hormones

  • Protein intake supports synthesis of hormones (e.g., insulin, growth hormone)
  • Amino acids like tyrosine and tryptophan are precursors to dopamine and serotonin
  • Inadequate protein can disrupt menstrual cycles, testosterone production, thyroid function

High-Protein Foods

  • Chicken breast
  • Eggs
  • Greek yogurt
  • Lentils
  • Quinoa
  • Tofu

Low-Protein Foods

  • Fruits
  • Some vegetables (e.g., cucumbers, lettuce)
  • Oils and fats
  • Sugary snacks

Interesting Facts

  • Collagen is the most abundant protein in the body
  • Leucine is the key amino acid for muscle protein synthesis
  • Tryptophan (from turkey) is a precursor to serotonin and melatonin

Conclusion Proteins are fundamental to overall health, influencing muscle mass, immunity, hormones, brain chemistry, and metabolism. The type and amount of protein needed vary by individual needs, lifestyle, and health conditions. Quality, variety, and balance are key.

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