Ch. 10

Which of the following processes require thiamin pyrophosphate? Check all that apply.

Breakdown of carbohydrates to yield ATP Synthesis of fatty acids Conversion of homocysteine to methionine

Which of the following processes require thiamin pyrophosphate? Check all that apply.

Breakdown of carbohydrates to yield ATP Synthesis of neurotransmitters

Metastasized

Cancer that has moved from one tissue to other parts of the body. (330)

Which of the following are physical signs that may indicate ariboflavinosis? Check all that apply.

Cheilosis Petechiae

Neurotransmitters

Chemicals produced by nerve cells that enable the cells to communicate with other nerve cells. (305)

Vitamins are classified as being either water soluble or fat soluble. There is disagreement in the scientific community as to whether one vitamin-like nutrient is really a vitamin. Which nutrient is not technically classified as a vitamin?

Choline

Collagen

Fibrous protein that gives strength to connective tissue such as bone, cartilage, and tendons. (324)

Which of the following are functions of vitamin C? Check all that apply.

Formation and maintenance of collagen Catabolism of carbohydrates

Which of the following can result from exceeding the UL for vitamin C? Check all that apply.

Gastrointestinal distress, such as nausea or diarrhea Iron deficiency

Which metabolic process requires biotin as a coenzyme?

Gluconeogenesis. Biotin is involved in the synthesis of glucose and fatty acids, and the breakdown of certain amino acids. (Quiz)

Which of the following can result from exceeding the UL for vitamin C? Check all that apply.

Kidney stones False readings for medical tests for diabetes or blood in the feces

Megadoses of nicotinic acid (one form of niacin) may be beneficial for decreasing _______.

LDL

Total parenteral solution

Liquid mixture that provides nourishment to those who are unable to eat normally, administered intravenously. (327)

Food cobalamin malasorption

Malabsorption of vitamin B-12 due to the inability to release the vitamin from animal protein during the digestive process. (322)

Malignant tumors

Masses of cancerous cells. (330)

Myelin Sheath

Structure that wraps around and insulates a part of certain nerve cells. (320)

Prooxidant

Substance that promotes production of free radicals. (324)

Vitamin-like compounds

Substances that maintain normal metabolism, the body synthesizes these compounds. (326)

Glossitis

Swollen and sore tongue. (308)

Functions of vitamin B-6

Synthesis of niacin from tryptophan, production of heme, and synthesis of dopamine from tyrosine. The vitamin B-6 coenzyme is essential for amino acid metabolism, heme synthesis, and production of some neurotransmitters. (Quiz)

Flavin adenine dinucleotide and flavin mononucleotide are critical coenzymes involved in which of the following chemical processes? Check all that apply.

The breakdown of carbohydrates to yield energy

Megaloblastic anemia is a type of anemia characterized by large and immature red blood cells. This type of deficiency can occur as a result of a deficiency of which vitamin(s)? Check all that apply.

Vitamin B-12 Folate

Thiamin

Vitamin B-1; vitamin component of a coenzyme that is important for energy metabolism as part of thiamin pyrophosphate. (305)

Riboflavin

Vitamin B-2 important for energy metabolism as part of flavin mononucleotide and flavin adenine dinucleotide. (307)(Quiz)

In human cells, many B vitamins _______.

are needed to make coenzymes

Gabe's elderly neighbor told him that when he was growing up, the milkman would deliver glass bottles of milk to his family's doorstep. He wonders why milk is not available in glass bottles anymore. Gabe explains to him that light destroys certain water-soluble vitamins in milk and milk is now stored in opaque containers to protect _______ from destruction.

riboflavin

Painful cracks at the corners of the mouth and a swollen, red tongue are signs of a deficiency of _______.

riboflavin

A deficiency of folate during the early stages of embryonic development can lead to neural tube defects. When the neural tube fails to close properly, part of the spinal cord or a sac of spinal fluid may bulge through the back. This condition is called _______.

spina bifida

The bleeding gums, easy bruising, and poor wound healing that characterize scurvy are all related to vitamin C's role in _______.

synthesis of collagen

A deficiency of pantothenic acid is rare because _______.

the vitamin is widespread in the food supply

Choline, carnitine, inositol, taurine, and lipoic acid each have important functions in human health, but they are not classified as vitamins because _______.

these compounds can be synthesized in the body

Why are intakes of vitamin C above 100% of the RDA generally not recommended?

As intake of vitamin C increases, absorption efficiency decreases, such that most of the excess vitamin is excreted in urine or feces. (Quiz)

Why are older adults at increased risk for vitamin B-12 deficiency compared to younger people?

As you age, your stomach produces less acid, which limits cleavage of vitamin B-12 from food. In addition, decreased production of intrinsic factor by the stomach limits vitamin B-12 absorption. (Quiz)

Vitamin C

Ascorbic acid, cofactor that performs a variety of important cellular functions, primarily by donating electrons to other compounds. (323)

Vitamin B-6

B vitamin component of the coenzyme pyridoxal phosphate (PLP), important for energy metabolism, particularly protein metabolism, as a part of PLP. (313)

Vitamin B-12 or cobalamin

B vitamin that is a component of coenzymes that participate in a variety of cellular processes, including transfer of CH3 groups in the metabolism of folate. Vitamin B-12 absorption depends on several steps. (320)(Quiz)

Folate

B vitamin that is a component of the coenzyme tetrahydrofolic acid (THFA), includes folic acid, and is important for energy metabolism, DNA synthesis, and homocysteine metabolism. The folate that occurs in food is in a polyglutamate form. Folate polyglutamate must be broken down by intestinal enzymes before the monoglutamate form of folate (folic acid) can be absorbed. The synthetic folic acid that is added to dietary supplements and fortified foods is already in a monoglutamate form. Because of the additional steps required to remove the glutamates, naturally occurring folate is not as bio available as folic acid. (315)

Processes requiring thiamin pyrophosphate

Breakdown of carbohydrates to yield ATP, Synthesis of neurotransmitters, and conversion of homocysteine to methionine. (Quiz)

Megadoses of vitamin B-6

Can damage the nervous system by causing peripheral neuropathy, which leads to walking difficulties, and numbness of the hands and feet. (Quiz)

Name the coenzyme form of pantothenic acid, which is required for the breakdown of nutrients to yield energy and the synthesis of fatty acids.

Coenzyme A (CoA)

Pernicious (deadly) anemia

Condition caused by the lack of intrinsic factor and characterized by vitamin B-12 deficiency, nerve damage, and megaloblastic red blood cells. (322)

Peripheral Neuropathy

Condition characterized by severe sensory nerve damage. (313)

Premenstrual Syndrome (PMS)

Condition that many women experience a few days before their menstrual period begins. (313)

Sandra's grandmother recently underwent chemotherapy for colon cancer. Seeing her grandmother go through cancer treatment inspired Sandra to make some changes to her diet and lifestyle. Which of the following foods should Sandra limit or avoid if she wants to protect herself against development of colon cancer? Check all that apply.

Processed meats Foods preserved with irradiation

Sandra's grandmother recently underwent chemotherapy for colon cancer. Seeing her grandmother go through cancer treatment inspired Sandra to make some changes to her diet and lifestyle. Which of the following foods should Sandra limit or avoid if she wants to protect herself against development of colon cancer? Check all that apply.

Processed meats Meats cooked at high temperatures (e.g., grilled meats) Alcoholic beverages

Foods to limit or avoid to protect against developing colon cancer.

Processed meats, meats cooked at high temperatures (grilled), foods preserved with irradiation, and alcoholic beverages. Nitrates and nitrites used to preserve some processed meats can be converted to nitrosamines, which are known carcinogens. Heterocyclic amines, which are formed when food proteins and exposed to high heat cooking methods, are related to risk for colorectal and pancreatic cancers. Alcohol is toxic

Niacin

Vitamin B-3, important for energy metabolism as part of nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate. For those who cannot tolerate statins, mega doses of niacin may reduce a persons risk of stroke and heart attack. (309)

Which of the following B vitamins plays a direct role in the production or maintenance of red blood cells? Check all that apply.

Vitamin B-6 Vitamin B-12 Folate

Mr. Stockton is a 64-year-old man who was admitted to the emergency room with extreme weakness, poor coordination, back-and-forth eye movements, and mental confusion. He had a CT scan to check for signs of stroke, but his results came back normal. After speaking with his family, his doctor learned that Mr. Stockton has a history of alcohol abuse. Based on this information, the physician should test the patient for a deficiency of _______.

thiamin

During the refining of grains, many vitamins and minerals are lost as the germ and the bran layers of the grain are discarded. Mandatory enrichment procedures replace some of the nutrients during food processing. Enrichment of refined grain products adds all of the following nutrients EXCEPT _______.

vitamin B-6

Synthesis of collagen

(Quiz)

Oxalate

A byproduct of vitamin C metabolism. With excessive intakes of vitamin C, increased urinary excretion of oxalate may cause kidney stone formation in susceptible individuals. (Quiz)

Which of the following metabolic processes require biotin as a coenzyme? Check all that apply.

Amino acid metabolism Fatty acid synthesis

Many people take megadoses of vitamin C for the prevention or treatment of the common cold. Why are intakes of vitamin C above 100% of the RDA generally not recommended?

As intake of vitamin C increases, absorption efficiency decreases, such that most of the excess vitamin is excreted in urine or feces.

Acetylcholine

Neurotransmitter associated with attention, learning and memory, muscle control, and other nervous system functions. (327)

The micronutrient content of a whole grain is dramatically decreased during the refining process. To counteract these losses, in the United States, food manufacturers are required to enrich breads and cereals made from milled, refined grains with which B vitamins? Check all that apply.

Niacin Riboflavin Thiamin Folic acid

Pellagra

Niacin deficiency disease characterized by dermatitis, diarrhea, dementia, and death. (310)

Only four of the water-soluble vitamins have an established UL. Identify the problems associated with excessive intakes of each of the following water-soluble vitamins.

NiacinSkin flushing Vitamin B-6 Nerve damage Vitamin C Diarrhea and GI tract discomfort Folic acid Can mask vitamin B-12 deficiency

Benign masses (tumors)

Noncancerous tumors that are usually harmless. (330)

Which of the following are functions of vitamin B-6? Check all that apply.

None

Coenzyme A

Pantothenic acid-containing coenzyme that helps release energy from carbohydrates, fat, and protein, and is necessary for fatty acid synthesis. (311)

Lecithin

Phosphatidylcholine, phospholipid found in egg yolk that acts as an emulsifier in certain foods. (327)

Avidin

Protein found in raw egg whites that binds biotin, thus preventing absorption of the vitamin. (312)

Choline, carnitine, inositol, taurine, and lipoic acid are vitamin like compounds necessary to maintain normal metabolism. However, because the body synthesizes these vitamin like compounds, they are not considered essential nutrients.

Quiz

Many vitamins were named in the order in which they were discovered. Some vitamins have more than one name. Match the vitamin with another name for that same vitamin.

Riboflavin Vitamin B-2 Niacin Vitamin B-3 Ascorbic acid C Pyridoxine B-6

Ariboflavinosis

Riboflavin deficiency disease characterized by fatigue, inflammation of the mucous membranes that line the mouth and throat, and glossitis. (308)

Cheilosis

Scaling and cracking of the skin around the corners of the mouth. (308)

Functions of vitamin C

Vitamin C has widespread roles in the body. Although it is not a coenzyme for energy and amino acid metabolism, it does serve as a cofactor for many chemical processes, including synthesis of collagen, carnitine, several hormones, and some neurotransmitters. It also can donate electrons to free radicals to stop oxidative damage and it supports the function of white blood cells. (quiz)

Synthesis of collagen

Vitamin C participates in reactions that form and maintain collagen, a fibrous protein that gives strength to connective tissue. Connective tissues, such as bone, cartilage, and tendons, hold together and support structures in the body. When vitamin C is in short supply, connective tissue weaken, leading to poor wound healing, spongy gums, tooth loss, pinpoint hemorrhages under the skin, and easy bruising. (Quiz)

What is the result when you exceed the UL for vitamin C?

Vitamin C toxicity can result in gastrointestinal distress, kidney stones in susceptible people, and false readings for some medical tests. Because vitamin C enhances iron absorption, iron overload can be a concern for people with hemochromatosis, a condition that leads to excessive iron stores. (Quiz)

Biotin

Vitamin component of a coenzyme that participates in chemical reactions that add carbon dioxide to other compounds. Intestinal bacteria produce some biotin that can be absorbed and used to meet human nutrient needs. Biotin can be synthesized by bacteria present in the large intestine. (312)

Pantothenic acid

Vitamin component of coenzyme A (CoA). (311)

Consuming excessive amounts of B vitamins _______.

increases urinary losses of most B vitamins

Tom read in a body building magazine that vitamin B-6 is needed for absorption of amino acids to support muscle tissue synthesis. He bought a container of Mega B-6 capsules, which contain 250 milligrams of vitamin B-6 per capsule. The recommended dosage is 1 capsule per day, but Tom reasons that he has a long way to go to reach his body building goals, so he will take one with each meal. Vitamin B-6 intakes at this level are most likely to damage the _______ system.

nervous

Tom read in a body building magazine that vitamin B-6 is needed for absorption of amino acids to support muscle tissue synthesis. He bought a container of Mega B-6 capsules, which contain 250 milligrams of vitamin B-6 per capsule. The recommended dosage is 1 capsule per day, but Tom reasons that he has a long way to go to reach his body building goals, so he will take one with each meal. Vitamin B-6 intakes at this level are most likely to damage the.

nervous

Mateo was recently diagnosed with high cholesterol and put on a statin medication. The statin medication led to side-effects and Mateo's physician told him to stop taking the medication. Mateo has now been advised to take megadoses of ______ to lower his risk of stroke and heart attack.

niacin

Nicotinamide adenine dinucleotide (NAD) is a coenzyme that carries high-energy electrons released by the catabolism of macronutrients within the cells. Nicotinamide adenine dinucleotide is the coenzyme form of _______.

niacin

With excessive intakes of vitamin C, increased urinary excretion of ______ (a by-product of vitamin C metabolism) may cause kidney stone formation in susceptible individuals.

oxalate

Taking a dietary supplement of coenzyme A is likely to increase urinary excretion of pantothenic acid.

true

Even though eggs and milk contain very little niacin, these foods can support the body's niacin status because some of the _______ in these foods can be converted into niacin in the body.

tryptophan

Excess intakes of most water-soluble vitamins are excreted in _______.

urine

Which of the following factors limit vitamin B-12 absorption and thereby may lead to vitamin B-12 deficiency? Check all that apply.

Decreased production of intrinsic factor Decreased production of hydrochloric acid Use of certain medications to reduce heartburn

Wernicke-Korsakoff syndrome

Degenerative brain disorder associated with a deficiency of thiamin and most commonly caused by excessive alcohol consumption. (306)

Alyssa is trying to become pregnant, and she wants to increase her dietary intake of folate. Which of the following key recommendations from the 2015-2020 Dietary Guidelines for Americans will help to improve Alyssa's folate intake?

Eat a variety of vegetables, especially dark-green, and red and orange vegetables, and beans and peas.

Neural Tube

Embryonic structure that eventually develops into the brain and spinal cord. (318)

Carcinogen

Environmental factor, such as radiation, tobacco smoke, or a virus, that triggers cancer. (330)

Based on the results of large clinical trials, dietary supplements of folate, vitamin C, and vitamin E are recommended to lower cancer risk.

False

Natural sources of folate from foods are more efficiently absorbed than the synthetic form of folate (folic acid) that is added to dietary supplements and fortified foods.

False

Gastritis

Inflammation of the lining of the stomach. (322)

Hemoglobin

Iron-containing protein in red blood cells that transports oxygen. (313)

Deficiency of pantothenic acid

Is rare because the vitamin is widespread in the food supply.

Beriberi

Thiamin deficiency disease characterized by weakness, poor muscular coordination, and abnormal functioning of the cardiovascular, digestive, and nervous systems. (306)

Identify the coenzyme forms of the following B vitamins that function in energy metabolism.

Thiamin-TPP Riboflavin-FAD Niacin-NAD Vitamin B-6-PLP Pantothenic acid-CoA

Megaloblastic anemia

Type of anemia characterized by large, immature red blood cells, deficiency of folate and/or vitamin B-12 can lead to this form of anemia. (318)

Anencephaly

Type of neural tube defect in which the brain does not form properly or is missing. (318)

Spina Bifida

Type of neural tube defect in which the spine does not form properly before birth and fails to enclose the spinal cord. (318)

Scurvy

Vitamin C deficiency disease. (323)