Lecture 4: Micronutrients

What does complete and balanced micronutrients mean?

meets all essential nutrient needs and in appropriate ratios (too much of one mineral can cause a deficiency in others)

What are some macrominerals?

• calcium

• phosphorus

• sodium

• chloride

• magnesium

• potassium

• sulfur

What are some microminerals?

• zinc

• copper

• selenium

• iodine

• iron

• manganese

• molybdenum

• cobalt

What macromolecules are involved in nutritional hyperparathyroidism?

nutritional hyperparathyroidism occurs secondary to an inverse dietary calcium-to-phosphorus ratio

How does nutritional secondary hyperparathyroidism induced facial osteodystrophy occur?

reduced serum Ca and increased serum P → stimulate PTH → osteoclasts release Ca from bone and kidneys excrete more phosphorus → bone demineralization

What is the function of nutritional calcium?

• Develop and maintenance of bones, teeth (structural)

• Blood clotting

• Muscle contraction

• Cell signaling

• Acid/base (cation)

What are the sources of nutritional calcium?

• Bone

• Dairy

• Dicalcium phosphate

• Calcium carbonate

• Calcium citrate

• Greens (also oxalates, phytates)

• Legumes (e.g. alfalfa)

What negative effects are associated with calcium deficiency?

• decreased bone density (osteopenia, osteoporosis, rickets)

• Milk fever (cow)

• Eclampsia

• Ca:P ratio must be 1:1 to 2:1 for dogs and cats

What is associated with calcium toxicity?

• Musculoskeletal disorders

• Calcium oxalate urolithiasis

• Kidney disorders

What is the function of nutritional phosphorus?

• Develop and maintenance of bones, teeth (structural)

• Energy (ATP)

• Component of phospholipids

• Acid/base (anion)

What are the sources of nutritional phosphorus?

• Phospholipids (e.g. cell membranes)

• Meat

• Grain, brans

• Dicalcium phosphate

• Common preservative in human food

What negative effects are associated with phosphorus deficiency?

• Decreased appetite and growth

• Skeletal disorders

• Lethargy

What is associated with phosphorus toxicity?

• Bone loss

• Nutritional hyperparathyroidism / nutritional secondary hyperparathyroidism

• Maybe chronic kidney disease

What is the function of nutritional potassium?

• Cellular action potential: Muscle function, Nerve impulses

• Acid-base (strong cation)

• Osmotic balance

What are the sources of nutritional potassium?

• Forage, fruit, vegetables

• Potassium chloride

• Potassium citrate

• Potassium gluconate

What are the negative effects of potassium deficiency?

• Hypokalemia can occur secondary to diuretics and CKD

• Decreased appetite and growth

• Cardiac arrhythmias

• Cats – head and neck ventroflexion

What is associated with potassium toxicity?

• Hyperkalemia can occur secondary to CKD

• Decreased heart rate, arrhythmias

• Reduce magnesium absorption

What is the function of nutritional iodine?

component of thyroid hormones

What are the sources of nutritional iodine?

• Iodized salt

• Potassium iodine

• Seaweed

What negative effects are associated with iodine deficiency?

• Thyroid disorders (goiter)

• Poor skin and haircoat

What is associated with iodine toxicity?

• Decreased appetite, weight loss

• Goiter

What is the function of nutritional copper?

• Enzyme cofactor

• Hemoglobin synthesis

• Skin & coat

• Bone development

What are the sources of nutritional copper?

• Organ meat

• Copper sulfate

• Copper carbonate

• Copper oxide

What are the negative effects associated with copper deficiency?

• Anemia

• Poor skin and haircoat - Black coat dilution (rust)

• Aortic rupture

What is associated with copper toxicity?

• Copper hepatopathy (some dogs, esp. in predisposed individuals (e.g. Bedlingtons, Labs)

• Kidney disease (sheep)

What is the function of nutritional zinc?

• Enzyme cofactor

• Immune response

• Skin & coat

• Bone development

What are the sources of nutritional zinc?

• Organ meat

• Zinc methionine

• Zinc sulfate

• Zinc oxide

What negative effects are associated with zinc deficiency?

• Poor skin and haircoat

• Decreased appetite, weight loss

• Decreased reproduction

• Diarrhea

What is associated with zinc toxicity?

• Hemolytic anemia

• Vomiting

• Copper deficiency

A deficiency in which mineral results in a cleft palate?

folic acid

What is the active form of a fat soluble vitamin that is required/essential for cats?

retinal

What are the functions of vitamin A (beta-carotene, retinol, retinal)?

• Vision

• Immunity

• Antioxidant

• Cellular differentiation (e.g. growth, fetal development)

What are the sources of vitamin A?

• Plants (beta-carotene)

• Liver

• Animal-based oils

What are the signs of vitamin A deficiency?

• Poor appetite, weight loss

• Decreased vision or blindness

• Poor skin and haircoat

• Decreased reproduction

What are the signs of vitamin A toxicity?

• Cervical/thoracic exostosis (excess bone formation; top photo)

• Birth defects

• Hypercalcemia (2023 AAVN abstract; normal PTH & vitamin D)

Why do cats need to obtain vitamin A from animal products?

they cannot convert carotenoids from plants to active vitamin A like dogs can

What are the functions of vitamin D?

• Calcium and phosphorus metabolism

• Cell signaling

• Other metabolic reactions

What are the sources of vitamin D?

• Liver, kidneys

• Salmon

• Egg yolk

• Vitamin D2 (ergocalciferol) – plant-based

• Vitamin D3 (cholecalciferol) – animal- based

• Dogs and cats cannot synthesize vitamin D from sun exposure to skin (unlike humans)

What are the signs of vitamin D deficiency?

• Loss of bone, osteoporosis

• Similar signs as calcium deficiency (e.g. DOD)

• Rickets

What are the signs of vitamin D toxicity?

• Hypercalcemia

• Production of calcium oxalate urinary stones

• Developmental orthopedic disease (DOD)

What are the functions of vitamin E (alpha-, beta-, gamma-, delta-tocopherols; tocotrienols)?

• Lipid antioxidant – stabilizes cell membranes

• Acts as a preservative for pet foods and products that contain polyunsaturated fatty acids (PUFAs)

What are the signs of vitamin E deficiency?

• Steatitis (adipose inflammation/necrosis) – seen in cats eating diets inclusive of polyunsaturated fatty acids without adequate vitamin E to prevent oxidation

• Muscle weakness/myopathy

What is the function of thiamin (vitamin B1)?

coenzyme for metabolic processes

What are the sources of thiamin (vitamin B1)?

• Yeast

• Kidney, liver

• Legumes

• Grain (esp. germ)

• Thiamine hydrochloride

What are the signs of thiamin (vitamin B1) deficiency?

• Neurologic signs, weakness

• Ventroflexion of the head and neck (cats)

• Poor appetite, weight loss

• Heat sensitive

• Thiaminase in raw fish

What are the functions of cobalamin (vitamin B12)?

• Coenzyme

• Amino acid synthesis

• DNA synthesis

What are the sources of cobalamin (vitamin B12)?

• Animal tissue

• Yeast

• Gut microbes: Works for herbivores, doesn’t absolve the need for dietary B12 for dogs/cats

What are the signs of cobalamin (vitamin B12) deficiency?

• Anemia

• Deficiency can occur secondary to GI disease (Complex transport & absorption)