Water Soluble Nutrients Flashcards
Characteristics/features of vitamins, are they micronutrients or macronutrients? How many kcals do vitamins provide?
Vitamins are micronutrients
Do not provide energy (no kcals)
Where do water-soluble vitamins get absorbed?
The small intestine
Basic function of a coenzyme
Coenzymes are ions or small molecules that interact with enzymes, enabling the enzymes to function
Most b vitamins function as components of coenzymes
Water soluble vitamins can be destroyed by what during cooking/preparation?
Can be destroyed by exposure to heat, light, air, and alkaline substances
Best cooking techniques to preserve water soluble vitamins
Steaming, stir frying, and microwaving
Thiamin, riboflavin, niacin – common food sources and common functions
Functions:
Thiamin: coenzymes form participates in glycolysis and in the citric acid cycle
Riboflavin: coenzymes in citric acid cycle
Niacin (B3): acts as a coenzyme in glycolysis, citric acid cycle
*Releasing energy from energy-yielding nutrients
Food sources:
Meats
Whole, fortified, or enriched grains
Milk, cheese, beans, mushrooms, yogurt, etc..
Which nutrient may lower the risk for neural tube defects?
Folate
Mandatory fortification of refined grains since 1988:
Supplies 200 ug/d
Reduce neural tube defects by 1/4
Megaloblastic anemia may develop from ___ ?
Anemia: decreased oxygen carrying capacity of the blood (can be caused by many factors, iron deficiency or blood loss).
Deficiency of folate and/or Vit B12
Characterized by large, immature RBCs (red blood cells)
Which population would be at risk for B12 deficiency?
Older adults:
Affects 20% of older adults
causes= atrophic gastritis, impaired synthesis or function of R-protein, proteases, or intrinsic factor
Those with malabsorptive disorders:
Complex digestion absorption of Vit B12
Long Term vegan or vegetarian diet
Infant ingestion of breast milk from Vit B12 deficient mothers
B12 digestion, absorption, and storage is unique – know role of intrinsic factor, and for how long B12 can be stored
Unique:
Foods of animal origin are the only reliable source of vit B12
Only vitamin that contains a mineral (cobalt) as part of its structure
Intrinsic factor is a substance in gastric juice that enhances vitamin B-12 absorption (protein like compound produced by parietal cells in the stomach to enhance vitamin B-12 absorption)
*Liver can store enough B12 to last several years
What water-soluble vitamin helps with the formation of collagen?
Vitamin C
Releasing energy from energy-yielding nutrients
Thiamin (B1)
Riboflavin (B2)
Niacin (B3)
Amino Acid Metabolism
Thiamin (B1)
Folate
Vitamin B12 (cobalamin)
Neurotransmitter synthesis
Niacin (B3)
Vitamin B6 (pyridoxine)
Folate
Vitamin C
Thiamin (B1): Food sources
Pork, tuna
whole, fortified, enriched grains
milk, cheese, yogurt
dried beans (lentils, soybeans, black, navy)
Thiamin (B1): Function
Coenzyme form participates in glycolysis and in the citric acid cycle
Thiamin (B1): Deficiencies
Beriberi
Symptoms: extreme weakness, paralysis, and fatigue; brain and nervous
system are especially affected because of their reliance on glucose
At risk populations:
Alcoholics
Elderly
Malabsorptive conditions
Wernicke-Korsakoff Syndrome: degenerative brain disorder associated
with deficiency of thiamin (also known as cerebral Beriberi)
- Related to alcohol abuse → decreased thiamin absorption, poor dietary intake, and increased thiamin excretion
- Affects central nervous system
- Symptoms: abnormal eye movements, staggering gait, distorted
thought processes
Riboflavin (B2): Food sources
Milk, yogurt, cheese, cottage cheese
Whole, fortified, or enriched grains
Eggs
Mushrooms
Beef liver, steak
Riboflavin (B2): Functions
Coenzyme in Citric Acid Cycle
Fatty acid breakdown
Electron Transport Chain
Activates other B-vitamins
Antioxidant function by
synthesizing glutathione
Riboflavin (B2): Deficiencies
Ariboflavinosis: primarily affects mouth, skin, and red blood cells
Symptoms: cracked tissue around the mouth; inflamed throat, tongue
Populations at risk:
* Alcoholics
* Malabsorptive disorders
* Poor diets
Niacin (B3): Food sources
Meats (all types)
Whole, fortified, or enriched grains
Dried beans, nuts
Milk, cheese, yogurt
Coffee
Mushrooms
Salmon, Cod, Shrimp, Clams, Halibut
Niacin (B3): Functions
Acts as a Coenzyme in:
* Glycolysis
* Citric Acid Cycle
* Pyruvate to Lactate
* Fatty acid synthesis
* Alcohol metabolism
Niacin (B3): Deficiences
Pellagra
Symptoms:
4 D’s – diarrhea, dermatitis, dementia, death
Niacin (B3): Toxicity
UL for niacin is 35 mg/day
Megadoses (>250 mg/day) are prescribed to:
* Reduce elevated LDL cholesterol levels
* Increase HDL cholesterol levels
Side effects:
* Flushing of skin, itching, painful tingling, GI tract upset, liver damage
Vitamin B6 (pyridoxine): food sources
Meat (pork/beef) and poultry
Fish (Halibut, Herring)
Enriched, fortified cereals
Seeds: sesame and sunflower
Garbanzo beans
White potato
Vitamin B6: functions
Involved in Transamination reactions/Amino Acid Metabolism
Involved in Synthesis of:
Heme - forms the protein hemoglobin, a compound that contains iron
Neurotransmitters – serotonin, dopamine and norepinephrine
Vitamin B6: Toxicity
The UL for vitamin B‒6 is 100 mg/day
Megadoses occur from supplementation
Recommended to treat premenstrual syndrome (PMS) and morning sickness,
however, there is not enough evidence to support this use
Can cause peripheral neuropathy – severe sensory nerve damage
Folate (folic acid): food sources
*Fortified or enriched grains
*Orange juice
Dried beans (kidney, pinto, black, lentils)
Broccoli, asparagus, artichokes, beets, avocado
*Dark green leafy vegetables (mustard & turnip greens, romaine
lettuce, spinach)
Folate: functions
Amino acid metabolism
DNA synthesis & function
Red blood cell formation
Neurotransmitter synthesis
Folate: deficiences
Factors lead to deficiency
* Low intake
* Malabsorption
* Increased requirements (pregnancy)
* Excessive excretion
* Use of certain medications
Associated with elevated blood levels of homocysteine
* Recognized risk factor for CVD
Neural Tube Defects
* Spina bifida – spinal cord or spinal fluid bulge through back
*recommended all women capable of becoming pregnant consume
400micrograms of folic acid daily from supplements or fortified foods
Vitamin B12 (cyanocobalamin):
Unique:
Foods of animal origin are the only reliable source of vit B12
Only vitamin that contains a mineral (cobalt) as part of its structure
Intrinsic factor is a substance in gastric juice that enhances vitamin B-12 absorption (protein like compound produced by parietal cells in the stomach to enhance vitamin B-12 absorption)
*Liver can store enough B12 to last several years
Vitamin B12: food sources
Meats (beef/pork/chicken)
Seafood(salmon/tuna/shrimp/oysters/crabs/clams)
Milk, cottage cheese, yogurt
Eggs
Fortified soymilk and cereals
Food sources: naturally present only in foods of animal origin
* Plants do not synthesize B12
* Synthesized by microorganisms, mainly bacteria
* Animals acquire B12 from soil ingested while eating and grazing
* Dietary vitamin B-12 is protein-bound
Vitamin B12: functions
Coenzyme functions
* 1-carbon transfer reactions
* Amino acid metabolism
* Metabolize some fatty acids
* DNA regulation
* Red blood cell formation
- Nerve function by maintaining the myelin sheath
*
Example: Folate and Vit B12 are needed for AA
conversion of homocysteine to methionine →
Yes or no: folate and vitamin b12 work together
In body cells
* Inactive folate is activated by the removal of the methyl group from the folate
compound by inactive Vit B12
* When Vitamin B12 acquires the methyl group, it becomes activated
Folate and B12 are closely linked=
a vitamin B12 coenzyme is required to recycle the folate
coenzyme needed for DNA synthesis, deficiencies can produce
identical signs and symptoms
Vitamin B12: deficiencies
Pernicious anemia:
* Result of impaired B-12 absorption secondary to atrophic gastritis and lack of
intrinsic factor
Neurological changes
Elevated plasma homocysteine
Population at risk:
Older adults
* Affects 20% of older Americans
* Causes = atrophic gastritis, impaired synthesis or function of R-protein, proteases, or
intrinsic factor
Those with malabsorptive disorders
* Complex digestion and absorption of Vitamin B12
Long-term vegan or vegetarian diet
Infant ingestion of breast milk from vitamin B-12-deficient mothers
Vitamin C: food sources
Citrus fruits
100% juices (cranberry/apple/orange)
Strawberries
Broccoli, cauliflower, kale, brussels sprouts
Green and red pepper
Vitamin C: functions
Antioxidant
Donates electrons to inactivate free radicals and prevents them from
damaging lipids, DNA, and proteins
Regenerate the active form of Vit E
Collagen synthesis
*does not cure the common cold
Vit C requirements
Minimum requirements: 10 mg/d
RDA:
* 90 mg/d for adult men
* 75 mg/d for adult women
Increased needs:
* Smokers (+35 mg/d)
* Oral contraceptives
Vitamin C: Deficiency
Scurvy – deficiency disease of Vitamin C
First signs/symptoms appear about 20-40 days into a diet free of Vitamin C
Disrupts synthesis of collagen (major fibrous protein that holds
together the various structures of the body, it is very strong and elastic)
Without Vitamin C → collagen is weak and fragile
Symptoms: bleeding swollen gums and joints, impaired wound healing,
pinpoint hemorrhages of the skin →
(spots on the skin are caused by slight bleeding,
Person may experience poor wound healing,
all signs and symptoms of defective collagen synthesis)
Vitamin C: toxicity
UL: 2000 mg/day
Consequences:
* Gastrointestinal effects (bloating, diarrhea)
* Kidney stone formation
* Excess iron absorption
* False readings on medical tests
Intakes >100 mg/d increase urinary excretion
