Lecture 7 - Micronutrients: Vitamins & Minerals Flashcards
Organic substances present in small amounts in natural foodstuffs; essential to normal metabolism and lacking them can cause deficiency issues
Vitamins
Vitamins A, D, E, and K are all ____ _________ vitamins.
Fat soluble
B vitamins (B1, B2, B3, B5, B6, B9, B12, biotin, and choline) and vitamin C are ______ __________ vitamins
Water soluble
True or False: Many vitamins are cofactors for enzymes
True
(Some can also be methyl donors and gene translators/activators)
True or False: Minerals are not important when it comes to diet
False; much like vitamins, a lack or insufficient amount of certain minerals in the diet can lead to disease
True or False: Some minerals may interact with each other, meaning the requirement for one mineral may be impacted by the amounts of other minerals
True
(Example: divalent cation minerals, like Zn2+, Ca2+, and Mg2+, may compete and decrease each other’s absorption)
A type of anemia caused by vitamin B12 deficiency
Macrocytic anemia
A type of anemia caused by iron deficiency
Microcytic anemia
Which four essential nutrients are required for normal RBC production?
- Iron (hemoglobin)
- Folate/B9 (nucleotide synth, vital to rapidly dividing cells)
- Pyridoxin/B6 (protein synth)
- Cobalamin/B12 (nucleotide synth, contains cobalt)
Ruminants and hindgut fermenters can rely on GI microbiota for cobalamin if their is enough ________ in their diet
Cobalt
Iron deficiency can occur as a result of low ________ or increased _______.
Intake; losses
Internal parasites, external parasites, tumor, and ulcers can cause chronic blood loss, which may lead to THIS type of deficiency in the animal…
Iron
What is heme iron?
Iron from hemoglobin in meat and fish that is in the reduced and highly absorbable form (Fe2+)
What is non-heme iron?
Iron from plants in the oxidized and less absorbable form (Fe3+)
True or False: Heme-iron has an absorption of 15 - 35%, while non-heme absorption is only 2 -20%
True
Which acidic vitamin seems to increase the absorption of non-heme iron?
Vitamin C
Which vitamin is important for epithelial health?
Vitamin A
What are the two forms Vitamin A can take?
- Retinol (retinoic acid)
- Beta carotene (provitamin A)
(Extra note: herbivores can efficiently transform beta carotene to retinol, but not all species can do this)
Where is retinol stored in the body?
Liver and kidneys
What are 3 important functions of vitamin A?
- maintain normal epithelial function
- maintain immune function
- vision
What are some clinical signs of beta carotene deficiency?
Night blindness (nyctalopia) and dry eye/corneal opacity (xerophthalmia)
Which enzyme is zinc a cofactor for?
Super Oxide Dismuase (SOD)
What is the significance of Super Oxide Dismutase?
It catalyzes the disputation of superoxide radicals (O2-) to O2 and H2O2, providing cellular defense against ROS
What foods are typically high in zinc?
Beans, legumes, internal viscera (like kidneys and liver), and red meat
What is the difference between primary and secondary zinc deficiency?
Primary = not enough zinc in diet
Secondary = indirect factors (result of GI disease or dietary inhibitors that affect zinc absorption)
What can be used to supplement zinc (and phosphorus) in pig diets?
Phytase/Phytic acid
What is a clinical sign of zinc deficiency in dogs (and other species as well)?
Hyperkeratosis around eyes, elbows, and joints
A process by which a substance loses one or more electrons
Oxidation
The substance that gains an electron during oxidation
Oxidant
Superoxide radical, hydrogen peroxide, and hydroxyl radical (OH-) generated from normal cellular respiration are all examples of…
Reactive oxygen species (ROS)
Which fatty acids are most susceptible to damage caused by ROS?
Polyunsaturated fatty acids
A component of phospholipids that compose cell and organelle membranes; they consist of unsaturated carbon or double bonds (C=C-)
Polyunsaturated fatty acids (PUFA)
What is lipid peroxidation?
The process of polyunsaturated fatty acids being damaged/broken down by ROS
What negative impacts can lipid peroxidation have on a cell?
(Hint: domino effect)
Lipid peroxides cause phospholipid bilayer to become excessively permeable, thus disrupting normal cell/organelle function (may lead to cell death if severe)
True or False: Vitamin E is amphipathic, allowing it to integrate into cellular membranes
True
Which selenium-containing enzyme can reactivate vitamin C after it reduces non-reactive, oxidized alpha tocopherol?
Thioredoxin reductase
What are some good dietary sources of vitamin E?
Leafy greens and seeds
Which mineral is coupled to vitamin E and necessary for reducing oxidized vitamin E?
Selenium
True or False: Vitamin E requirements decrease with dietary fat and PUFA
False; Vitamin E requirements INCREASE with dietary fat and PUFA
What is the PRIMARY function of selenium?
To act as a cofactor for enzymes with antioxidant function
An enzyme that reduces hydrogen peroxide to water and reduces lipid hydroperoxides to alcohols; contains selenium
(Hint: two words, G_______ P_______)
Glutathione peroxidase
Which animals most commonly suffer from selenium deficiency?
Cattle and livestock raised on selenium-poor soil (typically soil formed from volcanic activity or derived from sedentary rocks pre-dating major Cretaceous period)
What are some clinical signs of selenium deficiency, also called “white muscle disease”?
Muscle degeneration, necrosis, acute/extreme weakness
Swollen/edematous muscles and white streaks in the muscle are characteristic of…
White muscle disease
True or False: White muscle disease can affect the glottis and pharynx, causing secondary aspiration pneumonia
True
What is Zanker’s necrosis?
White streaks in the muscle caused by oxidation (characteristic of white muscle disease)
True or False: Selenium is required for proper testosterone, sperm, and thyroid function in dogs
True
Copper is a cofactor for _________ ___________, an enzyme that neutralizes reactive superoxide molecules
Superoxide dismutase
What are two physiological consequences of copper deficiency?
Anemia and decreased immune function
How does copper deficiency affect pigmentation?
It is a cofactor for tyrosine conversion to melanin (low copper = hypopigmentation)
Copper is also a cofactor for ______ ________, an enzyme important for collagen maturation
Lysyl oxidase
Physitis, inflammation, and abnormal maturation in the growth plates are all consequences of which deficiency?
Copper
What is the function of vitamin K?
Coagulation; to act as a cofactor for synthesizing blood clotting factor II, VII, IX, and X in the liver
Where do vitamins K1, K2, and K3 come from respectively?
K1 (phylloquinone) = leafy greens
K2 (menaquinone) = gut bacteria
K3 (menadione) = synthetic supplement
When is vitamin K supplementation required?
In any situation that interferes with synthesis of vit K dependent clotting factors
Examples: rodenticide (warfarin) toxicity, severe liver/intestinal disease, and moldy sweet clover exposure (livestock)
Which fat-soluble vitamin is involved in calcium, phosphorus, and bone metabolism?
Vitamin D
What are vitamins D2 and D3 derived from respectively?
D2 (ergocalciferol) = plant/fungal derived
D3 (cholecalciferol) = animal derived (milk/meat/egg)
True or False: Many animals can synthesize vitamin D3 from UVB light
True
What are some functions of active vitamin D (calcitriol)?
- Promote elevating plasma calcium and phosphate levels (for bone mineralization)
- Promote mobilization of calcium from bone (with PTH)
- Stimulate intestinal calcium absorption
- Increase calcium reabsorption in kidneys (distal tubules)
True or False: Dogs and cats have an exceptional ability to synthesize vitamin D in the skin, and thus they do not need supplementation in the diet
False; Dogs and cats are UNABLE to synthesize vitamin D in the skin and REQUIRE it in the diet
Abnormal growth plate closure, long bone deformity, and lack of mineralization are all clinical signs for which vitamin D deficiency (in growing animals)?
Rickets
True or False: Vitamin D in excess can be lethal, and the safety range is very narrow
True
(Extra note: Vitamin D is used in some rodenticides)
What are some clinical sings of excess vitamin D intake?
Hypercalcemia, hyperphosphatemia
(Can then lead to soft tissue mineralization, kidney injury, uroliths, and neuro signs)
Which B vitamin is commonly deficient in dog and cat food?
Vitamin B1 (thiamine)
B vitamins are synthesized by the GI microbiota in ________ and ________ fermenters
Foregut; hindgut
Which B vitamin requires cobalt?
Cobalamin
Where can the enzyme thiaminase be found (dietary source)?
Some raw fish/shellfish
What are clinical signs associated with cats who have a thiamin deficiency?
Neurologic and cardiac abnormalities
Changes in rumen microflora as a result of diet change or intake pattern can cause an increase in certain bacterial growth, and this can cause (clinical signs)…
Neurological signs such as aimless wandering, stargazing, blindness, and CCN (cerebral-cortical necrosis)
Which two hormones need iodine for proper function?
T3 (triiodothyronine) and T4 (thyroxine)
What happens to the thyroid when an animal has an iodine deficiency?
Enlargement, leading to goiter and decreased thyroid function (can obstruct airways in severe cases)
