Chapter 06 - Macronutrients

Question 0

What is unique about dietary fiber and human digestion?

Answer 0

Fiber has beta-1,4 bonds what are resistant to enzymatic activity. We cannot break them down.

Question 1

What ere the different categories of carbohydrates? What sets them apart from each other?

Answer 1

Monosaccharides - contain only one sugar group
Oligosaccharides - short chains of mono units, disaccharides, trisaccharides, etc.
Polysaccharides- long complex chains, starches, glycogen, fiber.

Question 2

What is the end product of starch digestion?

Answer 2

Into monosaccharides glucose, fructose, and galactose for eventual release in blood stream as glucose.

Question 3

Explain the flow of carbohydrates from mouth to cell. What main organs must carbs pass through?

Answer 3

Mouth - salivary amylases
Small intestine - pancreatic amylases turn it into maltose disaccharides

Liver - takes for energy transfer and glycogen storage then ships out as glucose.

Question 4

How is fructose different from other monosaccharides?

Answer 4

Galactose and fructose converted to glucose by liver, fructose converted to glycogen. If high level fructose converted to triglyceride

Question 5

What is the glycemic index (GI)? Give examples of low-GI and high GI foods.

Answer 5

Measure of how quickly and significantly a given food can raise blood sugar-glucose levels

High- sugar, candy, breakfast cereal, bagels, white potatoes
Low- legumes, nuts, unprocessed high fiber grains, vegetables

Question 6

What hormone triggers glucose transporters? How is this relevant to peri-workout nutrition?

Answer 6

Insulin
Muscle contraction also increases facilitated diffusion.

That is why insulin sensitivity and glucose uptake is typically enhanced after exercise.

Question 7

Briefly explain the difference between glycogen synthase and glycogen phosphorylase.

Answer 7

Glycogen synthase is the enzyme that catalyzes the addition of glucose to glycogen.

Glycogen phosphorylase is the enzyme for removing glucose from glycogen.

Question 8

Is there a minimum amount of carb intake necessary each day? Why or why not? What function would a minimum amount serve for the body.

Answer 8

No, gluconeogenesis can create glucose ( 50 g)

Although DGAC recommends 130g a day to meet basic energy needs and supply brain

Question 9

When we eat adequate fiber, what will we notice?mwhat foods are optimal sources of fiber?

Answer 9

They are fermented by micro flora of small intestine producing short chain fatty acids. Can decrease enterohepatic recycling of bile salts which can decrease serum cholesterol levels, can add bulk to stools to decrease transit time.

Increased satiety, lowered blood fat and cholesterol, reduced risk of colon cancer, proper intestinal motility,and boost in gut health.

Optimal 35 g for women, 48g for men.

Soluble- oats, dried beans, dried peas,minutes,barley, flax, fruits
Insoluble- plant cell walls, veggies, seeds, nuts, whole grains

Question 10

Where is dietary fat primarily digested?

Answer 10

Small intestine, breaks down into fatty acids and glycerol.

Emulsified by bile, pancreatic lipase main enzyme

Question 11

Describe the end products of fat digestion and how they are unique to other nutrients (e.g. What path they travel in the body).

Answer 11

Into fatty acids and glycerol
Fatty acids can diffuse across the intestinal mucosa. Intestinal cells repackage them into lipoprotein particles called chylomicrons. Then these are released into lymphatic system the slowly into general circulation.

Then broken down again to go into tissues of our body. Then oxidized and used for energy in muscles or converted back to triglycerides for storage in adipose tissue, muscle, etc.

Question 12

Identify two essential fatty acids. Why are they essential? Compare and contrast how they act in the body.

Answer 12

Linoleic acid - an omega 6

Linolenic - omega 3

Question 13

What outcomes result from excessive intake of trans fats or imbalanced dietary fat profile?

Answer 13

Saturated fats- Alzheimer’s disease, poor blood viscosity, breast cancer, kidney disease, diabetes, multiple sclerosis, stroke and prostate cancer.

Trans fats- Alzheimer’s disease, lymphoma, suppression of bile acids, increase liver cholesterol synthesis, competition for essential fat uptake, exaggerated essential fatty acid deficiency.

Question 14

What about the chemical makeup of proteins is different (as compared to carbs and fats).

Answer 14

Proteins have an amino group (NH2) and a side chain

Question 15

What are proteins composed of?

Answer 15

Amino acids for peptides or peptide chains. These make up the primary protein structure.

Question 16

Explain the difference in absorption between short peptides and free form amino acids?

Answer 16

BCAA absorbed faster
Di- and tri- peptides use different carriers than do individual amino acids. These peptides are absorbed more quickly than few amino acids.

Question 17

Describe the main roles of protein in the body.

Answer 17

Structure, hormones, enzymes, immune chemicals, transport proteins,

Produces energy, glucose, ketones, cholesterol, fatty acids

Question 18

List and briefly describe the key points of each protein quality measurement technique.

Answer 18

Protein Efficiency Ratio (PER)
Uses rodents, calculated by growth of animal

Biological Value (BV)
Uses rodents, amount of nitrogen used for tissue formation divided by amount of nitrogen absorbed by food

Net Protein Utilzation (NPU)
Uses rodents, product if biological value and true digestibility

Protein Digestibility Corrected Amino Acid Score (PDCAAS)
Based on humans, limiting amino acid found in food, compared with high quality protein.

Question 19

Suggested protein amount

Answer 19

0.8 g of protein per kg of body mass
55g per day for 150lb person

High intensity training, 1.4 to 2.0 g per kg of body mass