Midterm 1 (Lec 1) Flashcards
Macronutrients vs micronutrients
Macro:
- carbs, protein, fat
-in grams
- provide energy
Micro:
- vitamins, minerals
- in milli and micro grams
- do not provide energy
Vitamin definition
organic compound (contains carbon)
- distinct from fats, carbs, proteins
- non caloric
Natural component of food
Essential for normal physiological function
Specific deficiency syndrome
- caused by its absence orunder-utilization
Not synthesized by the host in amounts adequate to meet normal physiological needs ( means we need to get it externally)
Vitamin types
14 vitamins exist
B vitamins (8)
- thiamin (b1)
- riboflavin (b2)
- niacin (b3)
- pantothenic acid (b5)
- pyridoxine (b6)
- biotin
- folic acid
- cobalamin (b12)
Choline
Vitamin c
Vitamin d
Vitamin K
Vitamin e
Vitamin a
Beta-carotene
- pro vitamin a
- carotenoid
- orange yellow colour
Vitamin classification - water soluble
B vitamins and vitamin c
Hydrophilic (dissolve in water)
Cannot be stored
Move directly into blood ( no binding protein needed)
Easily taken up and released by body tissues
Excess excreted in urine
Vitamin classification - fat soluble
Vitamins a, d, e, k
Hydrophobic ( can’t dissolve in water)
Dissolve in fat ( dietary and body)
NEED fat to be absorbed
Enter blood via lymph: need transport protein
Can be stored (liver and fat) - daily supply not as important
- more concern about excess intake
Vitamins are organic
Contain carbon
Easily destroyed especially thiamin, riboflavin, vitamin C
- heat destroys thiamin
- uv light destroys riboflavin
- oxygen destroys vitamin c
Vitamin: metabolic vs general function
Metabolic
- each vitamin performs specific functions
- some functions performed by one vitamin
- others performed by many vitamins
General
- coenzymes; bind to other enzymes to function ( B vitamins, vitamin A, K, C)
- hydrogen/electron acceptor/donors ( B vitamins, vitamin C,E,K
- hormones (vitamin D)
Bioavailability
The rate and extent to which a nutrient is absorbed and used
Depends on two factors
- amount in food
- amount absorbed and utilized by body
Also other complex factors like gut microbiome, other food components, genetics, microbiome
Minerals
90 elements in environment - 22 essential to human life
Inorganic compounds - retain chemical identity always, never converted to something else
Absorption issues: bioavailability, they bind to other compounds (phytate, oxalate, tannins)
Toxicity also an issue
Minerals classification
Classified by amount present in the body
Macro minerals : > 5 grams
Trace minerals ( micro): < 5 grams
Ultra trace minerals (micro): < 1 mg, not proven to be essential for humans
Phytochemicals
Chemicals naturally occurring in plants
Generally non nutritive
Physiologically active components
Proposed to contribute toward disease prevention
Examples:
allicin in garlic
Flavonoids
Phytoestrogens
Phytosterols
Catechins
Lycopene
Glucosionolates
B vitamins general functions
Macronutrient metabolism
Energy production ( ATP)
Energy release
Carbon metabolism - transfer of single carbon units
B vitamins as co enzymes
Enzymes act as catalysts, driving many reactions and pathways
Coenzymes are required for the activity of enzymes
B vitamins are part of the structure
Symptoms of B vitamins deficiencies are indicative of their co enzyme role
Many B vitamins work together
Intermediary metabolism
Vitamins involved in all of these
Carbs: glycolysis, gluconeogeness
Protein: protein synthesis, AA oxidation
Fats: fatty acid synthesis, beta oxidation
ATP generation: respiratory chain, oxidative phosphorylation
Pentode phosphate pathway
