Lecture 23- Nutrition Flashcards
Chemical E
ATP
Calorie=
Calorie= 1 kilocalorie= 1000 calories
1 Cal= Heat required for what?
1 Cal= Heat required to raise 1 kg H2O 1 degree C
From carbs, proteins, lipids
What is most E rich?
Lipids- 9 Cal/g
(4 Cal/g for carbs, proteins)
What are the organic building blocks required to make macromolecules?
Source of Carbon and source of Nitrogen
What are essential nutrients?
Cannot be made-> must be ingested
Can be synthesized (NOT via photosynthesis…)
True or False: Carbs are considered essential nutrients
False- sufficient E from other sources
Which essential vitamins are fat-soluble?
Vitamins A, D, and K
How many essential amino acids do humans lack the ability to synthesize?
8 essential amino acids must be dietary (9 in infants)
What are the main essential minerals?
Calcium / Phosphorus / Sulfur / Chloride / Magnesium / Sodium / Potassium
Which hormone stimulates appetite?
Ghrelin
What are the essential fatty acids and what food do they come from?
Linoleic acid & Linolenic acid (polyunsaturated) - from seeds/grains/vegetables
Which essential nutrients are directly required for the synthesis of amino acids?
Sulfur & Nitrogen
Which essential vitamins are water-soluble?
B complex vitamins & vitamin C (ascorbic acid)
What is vitamin B3 used for?
Niacin- Electron carriers (NAD & NADP)
What are the main essential trace elements?
Iron & Iodide
Which hormones suppress appetite?
Insulin / PYY / Leptin
What could potentially occur if there is a lack of vitamin B9?
Lack of folic acid- Anemia/problems with neural tube
The arrival of a food bolus causes the stomach to stretch and release _____.
Gastrin
What is vitamin C (ascorbic acid) used for?
Collagen / Iron absorption / Antioxidant / Scurvy prevention
PYY is secreted by the _____.
Small intestine
What is vitamin A (retinol) used for?
Converted to the retinal part of the protein rhodopsin (vision)
Cholecystokinin (CCK) is secreted by the _____.
Duodenum (small intestine)
Which vitamin aids in calcium absorption?
Vitamin D
What is the function of cholecystokinin (CCK)?
Stimulates pancreas to secrete digestive enzymes and gallbladder to secrete bile
From what source do humans get vitamin D?
UV (sunlight)
What is iodide used for?
Synthesis of thyroid hormones (T3/T4)
What is the direct result of a high concentration of CCK and secretin?
Inhibition of peristalsis/gastric juices & slows digestion
What could a lack of vitamin D lead to?
Rickets/Osteomalacia
True or False: When chyme is high in fat, the secretion of cholecystokinin (CCK) and secretin is inhibited.
False; when chyme is high in fat, the secretion of CCK and secretin is stimulated
Essential Amino Acids
20 AAs required
Most animals make ~1/2
S, organic N required
Must ingest the rest- 8 essential AA in adults, 9 in infants
“Complete” proteins- meat, cheese, eggs
“Incomplete” proteins- plant sources- challenge for vegetarian diet
Essential Fatty Acids
Can synthesize many FAs
But often cannot form specific double bonds
Essential fatty acids: linoleum, linolenic acid (both polyunsaturated)
In seeds, grains, veggies- deficiencies rare
Vitamins
Organic compounds- required in small amounts
Many are coenzymes- required for proper enzyme function
13 in humans
Can water-soluble and fat-soluble vitamins be stored?
Only fat-soluble vitamins can be stored. Excess is excreted in urine (water-soluble).
What are the water-soluble vitamins?
B-complex vitamins
B3 (niacin)
B9 (folic acid)
Vitamin C (Ascorbic Acid)
What is vitamin B3?
Niacin- component of NAD+, NADH
What is vitamin B9?
Folic acid- deficiencies lead to anemia, neural tube defects
What is vitamin C?
Abscorbic acid
Collagen synthesis
Antioxidant
Improves Fe absorption
Deficiency-> scurvy
- Degeneration of skin, teeth, blood vessels
- Weakness
- Impaired immunity, healing
What is scurvy and what vitamin deficiency is associated with it?
Deficiency of Vitamin C
Causes:
- Degeneration of skin, teeth, blood vessels
- Weakness
- Impaired immunity, healing
What is Vitamin A?
Fat-soluble vitamin
Vitamin A- retinol
Converted to retinal- part of rhodopsin
Severe deficiency-> blindness
What results from a deficiency in Vitamin A?
Blindness
What is Vitamin D?
Fat-soluble vitamin
Promotes calcium absorption
Produced when exposed to UV
Deficiency-> rickets/osteomalacia
What is Vitamin K?
Fat-soluble vitamin
Required for blood-clotting proteins
E. coli in LI primary source
Deficiency can follow treatment with antibiotics
What are minerals?
Inorganic nutrients
Major minerals, trace elements- macro, micronutrients
What are trace elements?
Less than 200 mg/day
Iron- hemoglobin, cytochromes
Iodide- thyroid
What are the major minerals?
Greater than 200 mg/day
Calcium- bones, teeth, clotting, synapses, muscles
Phosphorus- bones, teeth, ATP, FAs, phospholipids
Potassium, Sodium- APs, many other roles
Chlorine- principle neg ion- water balance, nerves, stomach
Magnesium- enzyme cofactor- muscles, nerves
What exocrine and endocrine things does the pancreas release?
Exocrine- Pancreatic juice-> SI
Endocrine- Glucagon, insulin
Pancreatic islets containing:
a- cells- secrete glucagon
B- cells- secrete insulin
What do alpha cells secrete?
Glucagon
What do beta cells secrete?
Insulin
What is the malfunction of glucose regulation?
Diabetes mellitus
Most common endocrine disorder
Caused either by insulin deficiency or decreased response to insulin
-> Both lead to high blood glucose levels
What are the consequences of diabetes?
Cells unable to take up glucose
-> Fat main fuel
Acidic metabolic byproducts accumulate in blood
Lower pH
Depletes Na+, K+
If severe, can cause blindness, kidney disorder, gangrene
Glucose in urine sign of severe case
What is Type 1 diabetes?
Insulin-dependent (10%)
Autoimmune- Beta cells destroyed
-> Insulin deficiency
Early onset, often in childhood
Treatment: Insulin injections
What is Type 2 diabetes?
Non-insulin-dependent (90%)
Insulin resistance
Risk factors- overweight, little exercise
Usually onset over age 40
Sometimes controlled with diet & exercise
Sometimes requires medication
What is the function of ghrelin?
Secreted by stomach wall, triggers hunger
What is the function of PYY?
Appetite suppressant from SI
What is the function of insulin?
Triggered by increased blood sugar, suppressed appetite
What is the function of leptin?
Produced by adipose tissue, suppresses appetite
Responds to levels of fat- longer term
How does the nervous system affect being full?
Sensory neurons detect information from digestive system
-> Regulates hormone secretion
Hormones target satiety center in brain
Generates impulses that are perceived as hungry or full
Bolus in Oral Cavity
NS-> saliva production
Swallowing triggered when bolus reaches pharynx
Bolus in Stomach
Food stretches walls
-> Gastrin released
-> Gastric juices produced
-> Churning
Via enteric division of autonomic NS
Bolus in Small intestine
AAs, fatty acids in chyme-> digestive hormones released
Cholecystokinin (CCK): Stimulates release of pancreatic enzymes, bile
Secretin: Stimulates release of bicarbonate (HCO3-)
If chyme rich in fat: very high CCK, secretin
-> Inhibit peristalsis, secretion of gastric juices, slows digestion
