All Nutrition Articles Testable Points Flashcards
(112 cards)
In a study evaluating plasama vitamin D metabolites and CRP in Stage-Stop racing endurance sled dogs JVIM 2015
Dogs used as a model for examining effects of exercise on vitamin D status because of their lack of vitamin D synthesis by UV exposure. Inflammatory response of exercise may be associated with hypovitaminosis D
Racing dogs compared to controls
Racing dogs showed significant increase in calcidiol (25 (OH) D3) on day 2 and day 8 of race, while no increases were seen in controls.
Plasma concentrations of 24,25 (OH)D3 (dihydroxycholecalciferol) significantly increased by day 8
No significant changes in calcitriol concnetrations across all time points and groups
Racing dogs ahad signifcantly increased CRP concentrations by day 2 but not day 8
Overall - increases in vitamin D metabolites as well as increases in CRP observed in racing sled dogs - increases in dihydroxycholecalciferol may suggest metabolic variations in dogs that lead to enhanced disposal of vitamin D
What are tight regulators of the active form of vitamin D (calcitriol - or 1,25 (OH)D3?
Parathyroid hormone activation of renal 1 alpha hydroxylase
Which diseases have demonstrated low vitamin D concentrations?
PLE, renal disease, neoplasia, cardiovascular disease
In a Cohort Study evaluating the success of controlled weight loss programs for obese dogs (JVIM 2015)…
Successful weight loss was positively assocaited with a faster rate of weight loss, a longer duration, and feeding a dried weight management diet, but negatively associated with starting body fat and use of dirlotapide (gut selective microsomal triglyceride transfer protein inhibitor)
> 50% of obese dogs on a controlled weight loss program reach their target weight
61% completed program, 31% stopped prematurely, 8% euthanized
In a Study evaluating the association of obesity with serum leptin, adiponectin, and serotonin and gut microflora in beagle dogs (JVIM 2015)…
Peripheral leptin, adiponectin, serotonin and CSF serotonin levels measured in beagle dogs free fed vs good restricted
Fecal samples obtained in both groups for 16S rRNA sequencing
Leptin concentrations higher in obese group compared to lean group
Adiponectin and serotonin or CSF (5HT-CSF) concentrations, and TT4 were higher in lean group than in obese group
Leptin, cholesterol, and cortisol levels higher in obese group
Microbiome analysis revealed diversity of microbial community was lower in obese group
phylum firmicutes (85%) were predominant in group in lean dogs
Phylum proteobacteria (76%) were prdominant group in obese dogs
Decreased 5HT levels may increase risk of obesity b.c of increased appetite.
Name three bioactive peptides/ adipokines secreted from adipose tissue
Leptin, adiponectin, pro-inflammatory cytokines
Describe the actions of serotonin (5HT) in the body. What is Serotonin’s full chemical name?
5 hydroxytriptamine
Biochemical marker of mood and is association with several behavioral and psychological factors
Involved in hypothalamic regulation of energy consumption and serotoin levels in the CNS and is influenced by energy conditions
What is the theory behind the gut brain axis?
Gut microbiota can regulate gut/ brain axis. Hypothalamus and brain stem are central sites of appetite regulation, and gut microbiome can stimulate vagal sensory neurons, which is a major neural pathway that conveys information from gastrointestinal luminal contents to the brain and modulates GI motility and feeding behavior.
Gut microbiome can influence neuronal signaling to the brain through vagal afferent neurons
An enrichment of gram negative bacteria predominating in the gut can do what?
Influence the level of intestinal LPS (essential cell wall compartoment of gram negative bacteria that triggers systemic inflammation) - and this may be associated with chronic inflammation in obese subjects
In a study evaluating the effect of feeding a weight loss food beyond caloric restrition priord on body composition and resistance to weight gain in dogs. (JAVMA 2015)
Attempted determine if feeding a food with coconut oil and supplemental L-carnitine, lipoic acid, lysine, leucine, and fiber on weight loss and maintenance - prospective clinical study
Trial 1 - 30 dogs allocated to three groups to be fed dry maintenance dog food to maintain boy weight, or dry test food at same amount on mass or energy basis
Trial 2 - each of 20 dogs was fed test food and clorici ntake was adjusted to maintain weight loss rate of 1-2%/week
Trial 3- weight maintenance phase
Trial 1 - dogs in groups 2 and 3 lost significantly more weight than those in group 1
Trial 2 - dogs lost a significant amount of body weight and fat mass but retained lean body mass during weight loss phase
Trial 3- continued to lose body fat but gain lean body mass during weight maintenance phase
Metabolomic data evaluation suggested that fat metabolism and lean body mass retention were improved from baseline for dogs fed test food
What are metabolic consequences of obesity?
Insulin resistance, hyperlipidemia, low grade inflammation
Heart disease, etc
What body fat percentage is considered ideal in dogs?
15-25%
Waht is the primary means for reducing excessive bodyweight in overweight dogs?
Calorie restriction
Which dietary fats can increase energy expenditure at the expense of fat deposition
Medium chain fatty acids - more readily abosrbed and rapidly oxidized than are long chain fatty acids
Which micronutrients may increase conversion of dietary fat to energy?
Carnitine - essential cofactor in transfer of LCFA from cytosol into mitochondria of cells where they undergo beta oxidation - increasing L carnitine intake may increase oxidation of LCFAs
Lipoic acid - directly involved in energy metabolism and has antioxidant effects in reduced forms
Supplementation with which amino acids may reduce protein degradation and reduce loss of lean body mass during periods of restricted energy intake?
Lysine and leucine
How do weight loss diets compare to traditional weight loss diets?
Weight loss diets contain less energy and fat and ghigher concentrations of essential amino acids, vitamins, minerals, and fiber so that adeqaute nutrition is provided during periods of caloric restriction
Why are dogs and cats unique from humans/ other species in regards to vitamin D synthesis?
They lack ability to synthesize vitamin D3 in the skin, likely b/c of high acitvity of 7 dehydrocholesterol delta7 reductase
This means that dogs and cats require dietary supplementation with vitamin d to meet nutritional requirements
What are two dietary forms of vitamin D?
Cholecalciferol (vitamin D3) - typically comes from animal food sources
Ergocalciferol (vitamin D2) - plant sources
Cats don’t utilize plant source as easily, dogs can utlize both
What is the path that vitamin D takes once ingested?
Transported to liver via the portal system and intestinal lymphatics
Process requires digestive enzymes, chilomicrons, bile acids and VDBP or transcalciferon
After cholecalciferol is tranported to the liver, it is hydroxylated by 25 - hydroxylated by 25 hydroxylase to form 25 (OH)D aka calcidiol/ calcifediol
Calcidiol the binds to VDBP in circulation
Calcidiol - most reliable indicator of systemic vitamin D status in humans
How is vitamin D converted to its most active form (1,25 (OH)2D - Calcitriol)?
It is hydroxylated via 1 alpha hydroxylase in the kidney (predominantly) and other tissues that express the enzyme
How is the expression of 1 alpha hydroxylase regulated?
Serum concentrations of calcium, PTH, 1,25,OH2D (calcitriol), FGF23, and the klotho gene
How are calcidiol and calcitriol inactivated?
By 24 hydroxylase to form 24,25 (OH)2D and 1,24,25-trihydroxyvitamin D and other metabolites that are excreted in urine and bile
Name some roles of vitamin D
Influence on Ca-Phos homeostasis via the bone - parathyroid kidney axis, differentiation of immune cells, reductions in inflammation and proteinuria, increases in insulin secretion, improvement of hematopoiesis