Chapter 9 Part 3 Flashcards
Definition of malnutrition
consequence of inadequate intiake of proteins and calories or deficiency in digestion or absorption of proteins resulting in loss of fat and muscle tissue, weight loss, lethargy, and generalized weakness
An appropriate diet should consist of what three things?
sufficient energy source, amino acids/protein, vitamins and minerals
Definition of primary dietary insufficiency
one or all components of appropriate diet are missing
Definition of secondary malnutrition
results from malabsorption, impaired utilization or storage, excess loss, or increased need for nutrients
Things that lead to dietary insufficiency?
poverty, infection, acute and chronic illness, chronic alcoholism, ignorance and failure of supplementation, self-imposed restriction, etc.
What groups of people are most at risk for protein-energy malnutrition?
infants and children in developing countries, older and debilitated patients in nursing homes and hospitals
Two functional protein compartments in the body
somatic (skeletal m.) and visceral (liver)
Clinical sxs of secondary PEM
depletion of subcutaneous fat, wasting of quads and deltoids, ankle or sacral edema
Marasmus diagnostic criteria
weight<60% normal for sex, ht, and age
Clinical sxs of marasmus
growth retardation and muscle loss; serum albumin NL, anemia, immune deficiency
Pathogenesis of Marasmus
catabolism and depletion of somatic protein compartment
Fuels used by body in marasmic children
muscle proteins, subcutaneous fat
Etiology of Kwashiorkor
protein deficiency more severe than caloric deficit; due to chronic diarrhea, protein losing enteropathies, nephrotic syndrome, extensive burns
Clinical sxs of kwashiorkor
hypoalbuminea leading to generalized edema, vitamin and immune deficiency, hair and skin changes, fatty liver
Pathogenesis of Kwashiorkor
depletion of visceral protein compartment with sparing of subcutaneous fat and muscle
Small bowel changes in Kwashiorkor
decrease in mitotic index, mucosal atrophy and loss of villi
Bone marrow changes in PEM
hypoplastic
Brain changes in PEM
cerebral atrophy, reduced neurons, impaired myelination
Populations most affected by cachexia
AIDS, advanced cancers (esp. GI, pancreatic, lung)
Clinical characteristics of cachexia
extreme weight loss, fatigue, muscle atrophy, anemia, anorexia, edema
Pathogenesis of cachexia
proteolysis-inducing factor and lipid-mobilizing factor cause muscle breakdown through ubiquitin-proteasome pathway, typically breakdown structural proteins
Anorexia nervosa
self induced starvation leading to marked weight loss
What psychiatric DO has the highest death rate?
anorexia nervosa
Clinical sxs of anorexia nervosa
amenorrhea, decreased thyroid hormone, decreased bone density; death may result from cardiac arrhythmia or sudden death (hypokalemia)
Bulimia
binge eating and induced vomiting, often better prognosis than anorexia
Major complications of bulimia
electrolyte imbalance, pulmonary aspiration, esophageal and gastric rupture; due to vomiting and laxative use; hypokalemia/cardiac arrhythmia may result
Fat soluble vitamins
A, D, E, K
What vitamins can be synthesized endogenously
vitamin D, vitamin K, biotin, niacin
Major functions of vitamin A
maintenance of vision, regulation of cell growth and differentiation, and regulation of lipid metabolism
Transport/storage form of vitamin A
Retinol
Dietary source of vitamin A
liver, fish, eggs, milk, butter, yellow and green vegetables
Where is vitamin A absorbed?
small intestine
Causes of secondary vitamin A deficiency
fat malabsorption syndromes (Crohn, CF, colitis, celiac)
Causes of vitamin A deficiency i children
depletion in presence of infection, poor absorption in newborns
Side affects of vitamin A deficiency
night blindness, squamous metaplasia and keratinization of epithelia, xerophthalmia, bitot spots that erode cornea and lead to blindness, respiratory and UT squamous metaplasia, immune deficiency
Clinical sxs of vitamin A toxicity
headache, dizziness, vomiting, stupor, blurred vision; weight loss, anorexia, bone and joint pain
Major function of vitamin D
maintain plasma levels of calcium and phosphorus, bone mineralization, neuromuscular transmission
Hypocalcemic tetany
convulsive state caused by insufficient extracellular Ca required for muscle relaxation
Rickets clinical sxs
frontal bossing, squared head, rachitic rosary, pigeon breast deformity, lumbar lordosis, bowing of legs
Osteomalacia clinical sxs
inadequate mineralization of bone, weak and prone to fracture
Major source of vitamin D
endogenous synthesis from precursor, 7-dehyrocholesterol reaction that requires UV light
Dietary sources of vitamin D
deep-sea fish, plants, grains
Steps in vitamin D metabolism
- photochemical synthesis from 7-dehydrocholesterol in skin
- binding of vitamin D to DBP and transportation to liver
- conversion to 25-hydroxycholecalciferol through CYP27A1
- Conversion to 1,25 dehydroxytitamin D by 1alpha hydroxylase in kidney
What regulates production of active vitamin D?
parathyroid hormone (triggered by hypocalcemia), hypophosphatemia activating 1alpha-hydroxylase, feed back (inhibits its own activity)
Effects of vitamin D on Ca and PO4 homeostasis
stimulation of intestinal Ca absorption thru TRPV6, stimulation of kidney Ca absorption thru TRPV5, expression of RANKL on osteoblasts triggering osteoclast differentiation, mineralization of osteoid matrix
Morphological changes of bone in Rickets
loss of cartilage palisades, overgrowth of epiphyseal cartilage, persistence of cartilage masses that project into the marrow cavity, abnormal overgrowth of capillaries and fibroblasts, deformation of skeleton
Function of Vitamin K
cofactor for Factors II, VII, IX, X, Protein S and protein C
Clinical sxs of vitamin K deficiency
bleeding diathesis
Function of vitamin B1
thiamine, coenzyme in decarboxylation reactions
Clinical sxs of thiamine deficiency
dry and wet beriberi, Wernicke-Korsakoff syndrome
Function of niacin
incorporated into NAD and NADP, involved in redox readtions
Clinical sxs of niacin deficiency
dementia, dermatitis, diarrhea (pellagra)
Function of Vitamin B6
pyridoxine, derivatives used as coenzymes in intermediary reactions
Clinical sxs of pyridoxine deficiency
cheilosis, glossitis, dermatitis, peripheral neuropathy
Function of Vitamin C
re-dox reactions and hydroxylation of collagen
Dietary sources of vitamin C
milk, some animal products, many fruits and vegetables
Scurvy
bone disease in growing children, hemorrhages and healing defects
Populations most likely to have vitamin C deficiency
chronic alcoholic, people who live alone (have erratic and inadequate eating patterns)
Clinical signs of vitamin C deficiency
bleeding of skin, gums, and joints, inadequate osteoid synthesis, impaired wound healing
Clinical features of zinc deficiency
acrodermatitis enteropathica, anorexia, diarrhea, growth retardation, depressed mental function, impaired night vision, depressed wound healing
Clinical feature of iron deficiency
hypochromic microcytic anemia
Clinical feature of iodine deficiency
goiter and hypothyroidism
Clinical features of copper deficiency
muscle weakness, neuro defects, abnormal collagen cross-linking
Clinical features of fluoride deficiency
dental caries
Clinical features of selenium deficiency
myopathy, cardiomyopathy
Vitamin C excess sxs
iron overload, hemolytic anemia if G6PD deficient, calcium oxylate kidney stones
Vitamin D toxicity sxs
metastatic calcifications in kidney, bone pain, hypercalcemia
What diseases are obesity and excess body weight associated with?
increased incidence of type 2 diabetes, dyslipidemias, CV disease, HTN, CA
Definition of obesity
accumulation of adipose tissue sufficient magnitude to impair health
Normal BMI
18.5-25
BMI>30
obese
BMI25-30
overweight
Components of afferent system
leptin, adiponectin, ghrelin, PYY, insulin
Neurons in arcuate nucleus responsible for feeding
POMC and NPY/AgRP
Function of POMC neurons
satiety, anorexigenic
Function of NPY neurons
feeding, orexigenic
When is leptin release stimulated
abundance of fat stores
Functions of adiponectin
fatty acid oxidation, causing decrease in fat mass
Consequences of obesity
metabolic syndrome characterized by adiposity, insulin resistance, hyperinsulinemia, glucose intolerance, HTN, hypertriglyceridemia, decreased HDL
Increased risk of CAD for obese persons due to what two factors?
hypertriglyceridemia, low HDL
Percentage of cancers attributable to obesity
4% in men, 7% in women
What types of CAs associated with obesity
esophagus, pancreas, colon, rectum, breast, endometrium, kidney, thyroid, gallbladder
How might elevated insulin levels lead to CA?
elevated levels of IGF-1, a mitogen expressed in many CAs - promotes PI3/AKT path
Increased levels of what adipose-related hormone may cause CA?
estrogen
Aspects of diet that are of most concern in carcinogenesis?
content of exogenous carcinogens, endogenous synthesis of carcinogens, lack of protective factors
What might aflatoxin cause?
hepatocellular carcinoma
What two molecules are associated with generation of gastric tumors
nitrosamines, nitrosamides
Dietary causation of colon CA
high animal fat, low fiber
What vitamins and minerals are associated with anticarcinogenic effects?
Vitamin C, Vitamin E, B-carotenes, selenium
