Protein

Protein in Foods

Top contributors of protein in the North American diet:

  • Beef
  • Poultry
  • Milk
  • Eggs
  • Cheese

Worldwide meat consumption has been increasing, especially in developing countries

Overview of Protein

  • Form important structures in the body, make up a key part of blood, help regulate body functions, can fuel body cells
  • The body is made up of thousands of proteins
  • Contains nitrogen, carbon, hydrogen, and oxygen
  • North Americans generally consume more than they need to maintain health

  Functions:

  • Regulate and maintains body functions

Amino Acids—Building Blocks of Proteins

  • Provides an essential form of nitrogen (in the form of amino acids)
  • Proteins (peptides) are complex molecules made from smaller units called amino acids.
  • 20 different amino acids make up all proteins 9 essential amino acids
  • Not synthesized, must be consumed from diet 11 nonessential amino acids
  • Can be synthesized in the body
  • Typically supply 4 calories per gram
  • Amino acids with a branching carbon backbone include: leucine, isoleucine, and valine; all are essential amino acids.
  • Used by muscles for energy needs

Some people use Branched Chain Amino Acids as an Ergogenic Aid in Athletes; Ergogenic aid: is a substance used to enhance physical performance beyond the gains obtained from physical training alone

Using amino acid supplements is not considered safe

  • Overwhelms absorptive mechanisms in the small intestine
  • Excess amino acids cause toxicity
  • methionine, cysteine, and histidine most likely to cause toxicity

Branch Chain Amino Acids (BCAAs) in Foods:

  • Whey/Milk
  • Beef
  • Chicken
  • Fish
  • Soy Proteins
  • Eggs
  • Baked Beans
  • Whole Wheat
  • Brown Rice
  • Nuts
  • Pumpkin Seed

Protein Quality of Foods

Animal and plant proteins can differ greatly in the proportions of essential and nonessential amino acids.

  • Animal protein generally contains all 9 essential amino acids
  • Plant proteins in grains are often low in one or more of the 9 essential amino acids

High-quality (complete) proteins: contain ample amounts of all 9 essential amino acids

Lower-quality (incomplete) proteins: low in or lacking one or more essential amino acids, the all-or-none principle in protein synthesis.

Plant sources of quality proteins:

  • Legumes, beans, peas, and peanuts
  • Nuts and seeds
  • Per gram, many are a great source of nutrients
  • Also, contain phytochemicals

All contribute to protein, vitamins, and fiber in the meal

Protein Needs

The Recommended Dietary Allowance (RDA) for protein is a modest 0.8 grams of protein per kilogram of body weight. The RDA is the amount of a nutrient you need to meet your basic nutritional requirements.

  • Protein can be harmful if your body is low in plant foods (fiber), vitamins, phytochemicals
  • If your body is consuming high saturated fat and cholesterol it can be harmful
  • Excessive intake of processed red meat is linked with colon cancer
  • Too much protein burdens the kidney
  • Eating access protein may increase calcium loss in the urine

Eating access protein Increases urine production which increases the risk of dehydration

Protein Recommendations:

  • Incorporate seafood as the protein food choice in meals twice per week in place of meat, poultry, or eggs.
  • Use legumes or nuts and seeds in mixed dishes instead of some meat or poultry.
  • Shift to nutrient-dense options, including lean and lower sodium options, to improve the nutritional quality of protein food choices and support healthy eating patterns.

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