Nutrition Chapter 6 Notes

Summarize why proteins are important

• major component of all plant and animal tissues

• Vital to many aspects of health

• Provide energy and help keep skin, hair, and nails healthy

• Deficiency leads to wasting

• Excess protein intake a greater problem in the U.S.

What are proteins composed of?

Amino acids

What is the difference between essential and nonessential amino acids?

• essential amino acids- cannot be made by your body and must come from food

• Nonessential amino acids- produced by your body

Why is a protein's shape important?

it dictates the protein's specific function and how it interacts with other molecules in the body

What is the importance of structural and mechanical proteins in the body?

Form collagen, keratin, and actin/myosin

What is the importance of enzymes (proteins) in the body?

act as biological catalysts to speed up chemical reactions in the body

What is the importance of hormones (proteins) in the body?

vital chemical messengers that coordinate and regulate nearly every function in the body

What is the importance of immune functions (proteins) in the body?

Act as antibodies:

• blood proteins that attack and inactivate invaders

• Critical part of body’s immune response

What is the importance of fluid balance in the body?

the dynamic equilibrium where the water entering the body equals the water lost, which is vital for maintaining cellular function, blood pressure, and overall homeostasis

What is the importance of acid-base balance in the body?

keeps the pH of blood and body fluids within a normal, safe range

What is the importance of transport proteins in the body?

vital cellular gatekeepers that move essential nutrients, ions, and molecules across the hydrophobic cell membrane to maintain life

What is the importance of source of energy (proteins) in the body?

acts as an emergency and backup source of energy

Explain the role of the stomach in the digestive process of proteins

• proteins denatured (unfolds)

• Broken to large peptides by pepsin

1. Explain the role of the small intestine in the digestive process of proteins, including the roles of

   1. Proteases

   2. Trypsin & chymotrypsin

• large peptides broken down into smaller peptides by trypsin, chymotrypsin, and proteases (peptidases)

  • Trypsin- breaks down dietary proteins into smaller peptides and amino acids in the small intestine

  • Chymotrypsin- breaks down proteins in the small intestine

  • Protease- breaks down dietary proteins into smaller peptides and individual amino acids acids so the body can absorb them

How are proteins absorbed into the small intestine?

Proteins are broken down into individual amino acids and small peptides in the small intestine before being absorbed through the intestinal lining into the bloodstream

After traveling to the liver, what are amino acids used for?

• synthesize new proteins

• produce energy or glucose

• manufacture vital molecules

Summarize the process of protein synthesis, including the roles of transcription and translation

1. Transcription- an enzyme called RNA polymerase copies a DNA sequence into a complementary messenger RNA (mRNA) molecule

2. Translation- messenger RNA (mRNA) sequence is decoded by a ribosome to build a specific protein or polypeptide chain

How are proteins/amino acids recycled in the body?

Protein turnover- breaking down old cellular components into free amino acids and storing them in an internal "amino acid pool" to build new proteins and molecules

How is nitrogen excreted from the body?

converted into urea in the liver and filtered out through the kidneys into the urine

How can nitrogen balance be used to evaluate if someone is getting enough protein?

compares the nitrogen you eat in food with the nitrogen your body loses in waste to show if your protein intake is adequate

Nitrogen equilibrium

occurs when the amount of nitrogen consumed by the body through dietary protein equals the amount excreted through urine, feces, sweat, and skin

When would nitrogen equilibrium occur?

• In healthy adults

• Consistent diet

Positive nitrogen balance

happens when your body takes in more nitrogen—mostly through dietary protein—than it loses or excretes

When would positive nitrogen balance occur?

• growth and development

• Recovering from illness

Negative nitrogen balance

happens when the body loses more nitrogen than it takes in, meaning that protein breakdown is happening faster than protein synthesis

When would negative nitrogen balance occur?

• injury or illness

• Starvation or fasting

Outline how to calculate the RDA of protein for an adult

multiply your body weight in kilograms by 0.8 grams

How does necessary protein intake change throughout life stages?

Decreases by age

complete proteins

foods that contain adequate amounts of all nine essential amino acids that your body cannot make on its own

incomplete proteins

foods that lack adequate amounts of one or more of the nine essential amino acids your body cannot make on its own

complementary proteins

pairs or combinations of plant-based foods that, when eaten together or throughout the same day, supply all nine essential amino acids your body cannot make on its own

high-quality proteins

complete proteins that contain all nine essential amino acids your body cannot make on its own, and are easily digested and absorbed

Outline some of the reasons people become vegetarians

• religious beliefs

• Environmental concerns

• Aversion to eating another living creature

• Concerns about animal cruelty

• Health concerns

Summarize the health benefits of a plant-based diet

• less fat, saturated fat, trans fat, and cholesterol intake

• More antioxidants

• More fiber and phytochemicals

  • Reduces risk for heart disease, obesity, hypertension, and cancer

Summarize the health risks of a plant-based diet

• vegan diets may be low in some nutrients

• More restrictive food choices= more likely it is to cause nutritional problems

• Careful planning needed for growth and overall health

Define protein energy malnutrition and why it’s a health problem

• A deficiency of protein, energy or both

• Diets inadequate in energy inhibits the body’s use of dietary protein for protein synthesis

What are the health effects of excess dietary protein on kidney function?

does not harm kidney function, but in people with pre-existing or undiagnosed kidney disease, it can accelerate the decline of renal health

What are the health effects of excess dietary proteins on mineral losses?

increase urinary calcium excretion (calciuria), but it does not necessarily harm overall bone health if balanced with adequate nutrients

What are the health effects of excess dietary proteins on obesity?

promote weight loss and satiety in the short term, but eating more protein than your body needs in a caloric surplus still leads to weight and fat gain alongside potential strain on your organs

What are the health effects of excess dietary proteins on heart disease?

increase the risk of atherosclerosis, heart attacks, and major adverse cardiovascular events

What are the health effects of excess dietary proteins on cancer?

can influence cancer risk and patient health differently depending on the source of the protein, the person's age, and whether they have an active cancer diagnosis

What are the health effects of excess dietary proteins on gout (a type of arthritis)?

raise uric acid levels and trigger gout attacks when it comes from animal sources high in purines, whereas plant-based proteins do not carry the same risk