Nutrition Fundamentals Flashcards
Question: 12
Phosphofructokinase, a rate-limiting enzyme of glycolysis, is inhibited when ATP is abundant. Why is this inhibition important?
1: Facilitates gluconeogenesis to maintain euglycemia
2: Allows the cell to divert glucose to be stored as glycogen
3: Promotes catabolism
4: Enhances the TCA cycle
- allows the cell to divert glucose to be stored as glycogen
Phosphofructokinase, a rate-limiting enzyme of glycolysis, is inhibited when ATP is plentiful. This step is necessary to prevent further breakdown of glucose and allows the cell to divert glucose to be stored as glycogen for later use.
References:
Ling P, McCowen K. Carbohydrates. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 33-47.
Which of the following vitamins requires formation of micelles for intestinal absorption?
1: A
2: B1
3: B12
4: C
- A
Absorption of fat-soluble vitamins (A, D, E, K) occurs in the proximal jejunum where mixed micelles are formed from bile salts. All other vitamins are water-soluble and, therefore, do not require formation of micelles for intestinal absorption.
References:
Clark S. Vitamins and Trace Elements. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 129-159.
Triglycerides that require bile acids to facilitate enzymatic digestion and absorption are typically
1: 3 carbons in length.
2: 6 carbons in length.
3: 9 carbons in length.
4: 12 carbons in length.
- 12 carbons in length
The overwhelming majority of enteral dietary lipids (approximately 90%) are ingested in the form of triglycerides. Bile acids are detergent-like derivatives of cholesterol produced by the liver, which aid in triglyceride emulsification and the formation of micelles in the small intestine. This emulsification process and micelle formation makes triglycerides and fatty esters available for hydrolysis by intestinal lipases and esterases. Fatty acids of up to 10 carbons in length and glycerol can be absorbed directly via the villi of the intestinal mucosa. However, long-chain triglycerides require bile salts for both enzymatic digestion and formation of micelles.
References:
Hise M, Brown J. Lipids. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 48-70.
A 50-year-old male weighs 80 kg. Calculate the estimated volume of his intravascular space.
1: 4 L
2: 8 L
3: 12 L
4: 16 L
1: 4 L
Water, the most abundant substance in the body, constitutes approximately 50% to 60% of body weight. Total body water (TBW) is a function not only of weight, age, and gender but also of the relative amount of body fat. TBW is distributed among three main compartments: intracellular, extracellular, and transcellular fluid compartments. Approximately two-thirds is contained in the intracellular fluid, and the remaining one-third is in the extracellular fluid. One-fourth of the extracellular fluid is the intravascular space and three-fourths is in the interstitial space. Calculations for this patient are: TBW = 48 L (80 x 0.6); Extracellular fluid = 16 L (1/3 x 48); Intravascular space = 4 L (1/4 x 16).
References:
Langley G. Fluid, Electrolytes, and Acid-Base Disorders. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 104-128
A 50-year-old male weighs 80 kg. Calculate the estimated volume of his interstitial space.
1: 4 L
2: 8 L
3: 12 L
4: 16 L
- 12 L
When determining nitrogen balance, urea accounts for what percentage of total urine nitrogen losses?
1: 50%
2: 60%
3: 70%
4: 80%
- 80%
Determining nitrogen balance using urine urea is an approximation based on certain assumptions such as urea accounting for about 80% of the total urine nitrogen losses.
References:
Young L, Kearns L, Schoepfel S. Protein. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 71-87.
Question: 38
In which part of the body are essential amino acids oxidized?
1: Muscle
2: Kidney
3: Small intestine
4: Liver
- liver
The hepatocyte is the only site for oxidation of essential amino acids. About 57% of the amino acids extracted by the liver are used for protein synthesis and oxidation.
References:
Young L, Kearns L, Schoepfel S. Protein. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 71-87.
Question: 39
Which of the following is a common effect of enteral fiber on the intestinal tract?
1: Faster transit throughout
2: Increased fecal bacteria concentrations
3: Improvement in constipation
4: Improvement in diarrhea
- Improvement in diarrhea
The influence of dietary fiber on total or oral–anal transit time seems to depend on the type and source of dietary fiber. Both non-fiber and fructooligosaccharide (FOS) containing enteral formulas can decrease overall concentration of fecal bacteria as compared with a normal diet. At present there is no clear indication that existing constipation can be effectively resolved by increasing the intake of dietary fiber. Using soluble fiber suggests possible benefits in reducing diarrhea during tube feeding.
References:
Zimmaro-Bliss D, Jung HJ. Fiber. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 88-103.
Which statement is true regarding effects of fiber-supplemented diets on altered bowel elimination?
1: Soluble fiber intake corrects constipation
2: Fiber-containing formulas will reduce diarrhea in tube fed patients
3: Wheat bran increases irritable bowel syndrome (IBS) symptoms of abdominal pain and bloating
4: High fiber diet increases incidence of involuntary stool leakage
Although there are reports that constipation is relieved by fiber intake, there is no definitive or consistent evidence to confirm this finding. Studies lack clear definitions of diarrhea and its incidence to conclude that dietary fiber reduces diarrhea in tube-fed patients. Psyllium fiber and gum arabic supplements have been shown to reduce the incidence of involuntary stool leakage. Several studies have shown that addition of wheat bran causes increased IBS symptoms of abdominal bloating, pain, and altered bowel habits.
References:
Zimmaro-Bliss D, Jung HJ. Fiber. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 88-103.
Symptoms of diarrhea, bloating, and flatulence after ingestion of sugar are caused by
1: hydrolysis of lactose into monosaccharides.
2: deficiency of brush border oligosaccharidases.
3: decreased osmotic pressure in the colon.
4: digestion of starches in the small intestine.
2: deficiency of brush border oligosaccharidases.
A deficiency in brush border oligosaccharidases allows osmotically active undigested oligosaccharides to cause a shift of water into the intestinal lumen. The resulting increased pressure exerted by luminal contents increases further when colonic bacteria act on remaining oligosaccharides, thus increasing the number of osmotically active particles. Formation of CO2 and H2 from disaccharides futher increases fatulence and bloating.
References:
Colaizzo-Anas T. Nutrient Intake, Digestion, Absorption, and Excretion. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 3-18.
The only two organs in the body that have the necessary enzymes for gluconeogenesis are the liver and the
1: stomach.
2: brain.
3: kidney.
4: small intestine.
3: kidney.
The liver and kidney are the only organs with the necessary enzymes for gluconeogenesis. The liver plays a major role in prodution of glucose from amino acids when glucose supplies are limited in a fasting state.
References:
Young L, Kearns L, Schoepfel S. Protein. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 71-87.
A 32-year old female presents to the clinic seeking treatment for a sunburn-like rash. She also reports that she feels very sad and has no energy. Which of the following deficiencies should be considered?
1: Vitamin A
2: Vitamin K
3: Lipid
4: Protein
- Protein
Clinically significant protein deficiencies secondary to enterocyte amino acid transport abnormalities are very unusual. Both inherited and acquired defects exist. Hartnup’s syndrome is an autosomal recessive disorder in which basic amino acids are not abosbed and may present as a pellagra-like syndrome. Pellagra-like symptoms include dermtitis, diarrhea, and dementia.
References:
Colaizzo-Anas T. Nutrient Intake, Digestion, Absorption, and Excretion. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 3-18.
Ursodiol facilitates absorption of
1: carbohydrate.
2: protein.
3: fat.
4: vitamin K.
- Fat
Bile is central to the digestion of fat and is comprised of bile salts, bile pigments, cholesterol, lecithin, alkaline phosphatase, and electrolytes. Bile salts are sodium and potassium salts of bile acids, which are metabolites of cholesterol. Bile salts form micelles in which their hydrophilic portions face out and their hydrophobic portions face toward the center where lipids collect. Lipids are transported to the brush border of the intestine where they are absorbed by yet-to-be confirmed mechanisms. Ursodiol (ursodeoxycholic acid) is a form of bile acid that when used in conventional dosages of 300 mg twice daily can potentially improve fat absorption.
References:
Colaizzo-Anas T. Nutrient Intake, Digestion, Absorption, and Excretion. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 3-18.
AF has had a nasogastric tube in place for 48 hours secondary to a post-operative ileus. Which of the following electrolytes will be affected?
1: Bicarbonate
2: Potassium
3: Calcium
4: Phosphorus
Prolonged nasogastric output results in a loss of gastrointestinal secretions primarily from the stomach. Hypokalemia is a common issue with continued nasogastric output as the normal potassium concentration of gastric fluid is 10 mEq/L. Other possible electrolyte abnormalities include hyponatremia and hypochloremia. Bicarbonate, calcium and phosphorus are not directly affected.
References:
Langley G. Fluid, Electrolytes, and Acid-Base Disorders. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 104-128
Which water-soluble vitamins do not require Na+ co-transporters for absorption?
1: Vitamin C and Vitamin B6
2: Vitamin E and Vitamin D
3: Vitamin B12 and Folic acid
4: B1 and Choline
- Vitamin B12 and Folic Acid
Vitamin B12 requires intrinsic factor for absorption. Intrinsic factor binds to B12 and is taken up by receptors in the distal ileum. Folic acid is absorbed by a carrier-mediated process, primarily in the proximal part of the small intestine.
References:
Colaizzo-Anas T. Nutrient Intake, Digestion, Absorption, and Excretion. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach – The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007: 3-18.
