Chapter 8 NUTR
"This molecule when consumed in excess is readily excreted in the urine. On the other hand, when the diet is deficient in this molecule it will rapidly disappear from the body." What is being described?
A water-soluble vitamin that cannot be readily stored in the body.
Which of the following statements regarding vitamin C is FALSE?
Studies have shown that vitamin C supplementation decreases the number of colds a person gets.
"Beginning to take folic acid supplements after a pregnancy is confirmed is too late." Why is this statement correct?
The neural tube forms before most women know they are pregnant
What is the purpose of using dietary folate equivalents to report folate intake from all sources?
To account for the fact that synthetic folic acid is more bioavailable that naturally-occurring folate
"Vitamins lost when food is processed are added back to the processed food at the same or higher level." What is being described?
enrichment
What is a primary function of thiamin in the body?
facilitating production of energy from glucose
Which of the following is NOT recognized as a major function of vitamin C in the body?
facilitating release of energy from glucose
Where are the majority of vitamins are absorbed?
small intestine.
Which lifestyle factor has the greatest impact on the requirement for vitamin C?
smoking cigarettes
Which is NOT an appropriate use of supplements?
the use of vitamin C by someone with a healthy immune system
Beriberi is a disease caused by lack of what vitamin?
thiamin
What are the implications of low urinary excretion of thiamin?
thiamin intake may be inadequate and available vitamin is being retained by the bod
What causes the following symptoms: diarrhea, nausea, and abdominal cramps?
unabsorbed vitamin C drawing water into the large intestine
Which is NOT due to folate deficiency?
microcytic anemia.
Which of the following is NOT required for the absorption of vitamin B12?
rennin
What is indicated by the presence of megaloblasts in the blood?
Anemia because megaloblasts cannot be converted into red blood cells.
What is the relationship between folate and DNA synthesis?
Coenzyme forms of folate are required to transfer single carbons for the synthesis of bases incorporated into DNA
Which of the following statements about B12 deficiency is FALSE?
Deficiency is common among young adults eating a mixed diet.
Which statement best describes the impact of the Canadian folic acid fortification program on neural tube defects?
Folic acid was added to white flour, cornmeal and pasta, and neural tube defects were substantially reduced.
High intake of folate is cause for which of the following concerns?
High levels may mask a B12 deficiency, giving rise to permanent nerve damage.
Which statement concerning vitamins is FALSE?
If a vitamin is not provided by the diet, the body will synthesize it.
What do animal studies suggest about the relationship between high folate intakes and colon cancer tumours?
In cancer-free animals, high intakes of folate prevent tumour development, but in the presence of pre-existing tumours, high intakes increase tumour growth.
Martin is 77 years old and was recently diagnosed with low levels of a vitamin in the blood. These low levels contribute to nerve damage and occurred despite the fact there were adequate levels of the vitamin in his diet. What is one explanation for this observation?
Martin has an autoimmune disease that reduces the levels of a specific protein that is needed to absorb the vitamin from the small intestine.
Vitamin C deficiency causes which of the following?
bleeding gums, easy bruising, depression
What is the criterion of adequacy used to determine the RDA for vitamin B12?
Normal red blood cells
Which of the following statements regarding vitamin B12 is FALSE?
Vitamin B12 supplements have been proven to aid tired, run-down individuals.
Which is an example of how vitamins function together?
Vitamin B6, folate and vitamin B12 in single carbon metabolism
How does vitamin C protect cells from damage caused by reactive oxygen species?
Vitamin C donates electrons to a reactive oxygen species like the superoxide molecule. The superoxide molecule is neutralized and, at the same time, ascorbic acid is converted to dehydroascorbic acid.
Which of the following statements is NOT true?
Vitamins provide energy.
Under what circumstances do thiamin supplements enhance the production of ATP?
When consumed in high doses by someone with thiamine deficiency
What is a possible risk of arising from the fortification of foods in Canada?
While trying to benefit one group through fortification another segment of the population might be put at risk.
Jane is at a health foods store and is wondering whether or not to try a new vitamin supplement. She takes a bottle off the store shelf. What is the first thing she should look for to confirm the product has been authorized for sale in Canada?
a Natural Products Number (NPN)
Which statement best describes the criteria used to set the EAR for vitamin C?
a) high levels of vitamin C in neutrophils, a component of the immune system **choice (a) in combination with low levels of vitamin C excretion in the urine.
Which group is LEAST at risk for developing vitamin C deficiency?
adults who consume plenty of fruits and vegetables
Which of the following terms is used to describe how much of a vitamin is absorbed and used by the body?
bioavailability
Low folate status is associated with increased increases the risk of which conditions?
cancer, heart disease ,neural tube defects.
Which of the following groups is at highest risk for developing a thiamin deficiency?
chronic alcoholics
Many B vitamins are essential for the metabolism of energy-yielding nutrients. In this role, they are components of what type of molecules?
coenzymes
Very high intakes of folate bypass the need for the reaction that requires vitamin B12. What is this reaction?
conversion of methyl folate to folate.
Why are folate deficiency symptoms less frequent in Canada today than 40 years ago?
most grain products are fortified with folic acid.
For which of the following is vitamin B12 NOT essential?
division of mature red blood cells
Which statement best describes the difference between folate and folic acid?
folate is the polyglutamate form and is less bioavailable than folic acid
To reduce the risk of abnormalities in the brain or spinal cord of the developing baby women who might get pregnant should take a multivitamin that contains vitamin B12 and which other vitamin?
folic acid
What is the process of adding nutrients to foods?
fortification
Which of the following foods is the best source of vitamin C?
green pepper
Consumption of orange juice enhances the absorption of which mineral
iron
Why is folate important for rapidly-dividing cells?
it is required for DNA synthesis
Which organ excretes large intakes of vitamin C from the body?
kidneys
When a food is fortified where must the added nutrient be listed?
on the nutrition facts table
Which of the following foods is the best source of folate?
oranges
For which group is taking vitamin B12 supplements the LEAST beneficial?
people eating diets high in animal products
Meeting vitamin B12 needs from the diet is especially difficult for what population group?
people following strict vegan diets.
Vitamin B12 deficiency, caused by a the absence of intrinsic factor, results in what disease?
pernicious anemia.
Which of the following groups is at risk for folate deficiency?
premature infants, elderly, smokers
Which of the following does NOT affect the thiamin availability in food?
presence of other vitamins
According to the Canadian Community Health Survey, which water-soluble vitamin has the highest prevalence of inadequate intake?
vitamin C in smokers
Folic acid supplements are most often recommended to which population?
women who are considering pregnancy.
