Water Soluble Vitamins

b. rapidly dividing cells

Folate's role in DNA synthesis makes it particularly important in: a. lipid synthesis b. rapidly dividing cells c. nerve cells d. old age

b. women who are considering pregnancy

Folic acid supplements are most often recommended for: a. post-menopausal women b. women who are considering pregnancy c. toddlers d. the elderly

b. flushing of the skin

A common adverse effect of niacin toxicity includes: a. dermatitis b. flushing of the skin c. dementia d. hives

c. vitamin B6, folate, and vitamin B12

An elevation in homocysteine has been associated with an increased risk of cardiovascular disease. In clinical studies, which vitamins have been shown to decrease levels of homocysteine in the blood? a. vitamin A, vitamin E, and vitamin C b. riboflavin, vitamin A, and folate c. vitamin B6, folate, and vitamin B12 d. pantothenic acid, riboflavin, and biotin

b. pyridoxine

Another name for vitamin B6 is a. pantothenic acid b. pyridoxine c. pyruvate d. biotin

c. pernicious anemia

B12 deficiency caused by a deficiency of intrinsic factor results in: a. beriberi b. scurvy c. pernicious anemia d. pellagra

b. thiamin

Beriberi is a disease caused by lack of _____________ in the diet. a. riboflavin b. thiamin c. vitamin C d. niacin

b. iron

Consumption of orange juice enhances the absorption of which mineral? a. calcium b. iron c. zinc d. fluoride

Vitamin B6, vitamin B12, and folate are all involved in homocysteine metabolism. Vitamin B6 is needed to convert homocysteine to cysteine. Vitamin B12 and folate are needed to convert homocysteine to methionine. A deficiency of any of these vitamins can lead to the accumulation of homocysteine, which is associated with an increased risk of cardiovascular disease.

Explain why a deficiency of vitamin B6, folate, or vitamin B12 can all cause an increase in homocysteine levels.

a. grain products have been fortified with folate

Folate deficiency symptoms are less of a problem recently because: a. grain products have been fortified with folate b. more people are taking supplements c. more people are drinking low-fat milk d. green tea is more popular

a. people eating diets high in animal products

For which group is taking B12 supplements the least beneficial? a. people eating diets high in animal products b. older adults with significantly reduced stomach acid c. people who do not consume any animal products d. breast- fed infants whose mothers are vegans

c. the activation of niacin

For which of the following is B12 essential? a. the division of red blood cells b. the synthesis of proteins c. the activation of niacin d. the maintenance of myelin and normal nerve transmission

c. High levels may mask a B12 deficiency, giving rise to permanent nerve damage.

High intake of folate is cause for which of the following concerns? a. High levels may increase the incidence of colon cancer. b. High levels may cause other vitamin deficiencies because folate competes for absorption sites. c. High levels may mask a B12 deficiency, giving rise to permanent nerve damage. d. High levels may cause acne.

d. folic acid

Increased amounts of which vitamin are recommended during pregnancy to reduce incidences of abnormalities in the brain or spinal cord of the developing baby? a. riboflavin b. biotin c. vitamin B12 d. folic acid

Low folate status increases the risk of developing forms of cancer that affect epithelial tissues such as the uterus, cervix, lung, stomach, oesophagus, and colon. Although folate deficiency does not cause cancer, it has been hypothesized that low folate intake enhances an underlying predisposition to cancer. Epidemiological data have shown that higher plasma levels of folate are associated with a reduced risk of developing breast cancer, particularly in women at high risk due to alcohol consumption. Alcohol consumption greatly increases the cancer risk associated with a low folate diet. Epidemiological and clinical studies indicate that higher dietary folate intake and blood folate levels are associated with a lower risk of colorectal cancer. Studies suggest an approximately 40% reduction in the risk of colorectal cancer in individuals with the highest dietary folate intake compared with those with the lowest intake. A deficiency of folate, which prevents DNA synthesis, can help kill cancer cells. A number of chemotherapeutic agents act by blocking folic acid function, stopping the cancer cells from dividing

Is there a link between folate and cancer?

1. This can be affected by the composition of the diet. For example, the absorption of fat-soluble vitamins is reduced if the amount of fat in the diet is very low. The presence of other substances in the diet that interfere with absorption are also important. For example, anti-thiamine factors may destroy the thiamin in some foods. 2. Digestive processes. For example, if the amount of acid in the stomach is low it may prevent some vitamins from being released from foods. 3. Once inside the body the availability of transport proteins needed to transport vitamins in the blood affect how much is available to the body 4. Conditions in the body, such as the ability to convert a provitamin to its active form.

List four factors that affect how much of a vitamin is available to the body.

d. all of the above

Low folate status increases the risk of: a. cancer that affects epithelial tissue b. heart disease c. neural tube defects d. all of the above

c. coenzymes

Many B vitamins are essential for the metabolism of energy yielding nutrients. They perform this function by binding to and promoting the activity of enzymes. When B vitamins perform in this way, they are ____? a. provitamins b. transport proteins c. coenzymes d. hormones

c. people following strict vegan diets

Meeting B12 needs from the diet is especially difficult for: a. infants b. pregnant women c. people following strict vegan diets d. athletes undergoing rigorous training

c. decrease LDL cholesterol and increase HDL cholesterol.

Niacin supplements a. are used in the US since niacin deficiency is a public health concern. b. provide an essential energy boost. c. decrease LDL cholesterol and increase HDL cholesterol. d. are associated with an increase in heart attacks.

a. corn

Pellagra occurs when _____ is the staple grain in the diet and the diet does not provide adequate variety. a. corn b. wheat c. rice d. barley

d. send messages between nerve cells

Riboflavin forms active coenzymes that do all the following except a. help produce energy from carbohydrate, protein and fat. b. function as electron carriers. c. function in the citric acid cycle. d. send messages between nerve cells

a. light

Riboflavin is most easily destroyed when exposed to: a. light b. vitamin C c. oxygen d. acid

d. dairy foods

Riboflavin needs are more difficult to meet when the diet is low in a. meats b. grains c. vegetables d. dairy foods

c. small intestine

The __________ is the site of most vitamin absorption into the body. a. mouth b. stomach c. small intestine d. large intestine

c. anemia with large, deeply colored red blood cells

The symptoms of B6 deficiency do not include: a. depression b. numbness in the extremities c. anemia with large, deeply colored red blood cells d. headaches

a. depression and weakness

The symptoms of thiamin deficiency best explained by its role in glucose metabolism are? a. depression and weakness b. paralysis c. hunger d. atherosclerosis

c. It is necessary in collagen formation.

Vitamin B6 does not perform which of the following roles? a. It is vital in the formation of non-essential amino acids. b. It is required for the synthesis of hemoglobin. c. It is necessary in collagen formation. d. It supports the immune system since it is necessary for the formation of white blood cells.

It has been hypothesized that vitamin B6 affects the risk of heart disease through its role in the breakdown of homocysteine, an intermediate in methionine metabolism. Individuals with homocystinuria, a rare genetic disorder that causes chronically high blood levels of homocysteine, develop atherosclerosis at an early age. Large doses of vitamin B6 (100 to 1000 mg/day) have been successfully used to reduce elevated homocysteine and the risk of atherosclerosis in patients with this disease but these doses are not recommended for the general public. Among healthy individuals, a mild elevation in blood homocysteine has been shown to be a risk factor for cardiovascular disease. It has been proposed that a deficiency of vitamin B6, vitamin B12, or folate, the latter two of which are also involved in homocysteine metabolism, may cause homocysteine accumulation and eventually lead to atherosclerosis. A study that examined the effect of folate and vitamin B6 intake in women found that those with the highest levels of folate and vitamin B6 in their diets had about half the risk of coronary heart disease as women with the lowest levels. Supplements of all three of these vitamins have been used to reduce homocysteine levels in individuals with mild homocysteine elevation. At this time, however, the DRI (Dietary Reference Intake) panel believes that it is premature to conclude that increased intakes of vitamin B6, vitamin B12, or folate could decrease the risk of cardiovascular disease.

Vitamin B6, Homocysteine, and Cardiovascular Disease

It has been suggested that high doses of vitamin C both treat and prevent cancer. Although controlled trials have not found any benefits of vitamin C in the treatment of patients with advanced cancer, there is evidence supporting a role for vitamin C in cancer prevention. Epidemiological studies have found inverse relationships between the intake of fruits and vegetables, foods high in vitamin C, and cancer incidence. Higher plasma vitamin C levels are associated with a lower cancer mortality in men. As an antioxidant, vitamin C may protect against cancers caused by oxidative damage. In the case of gastrointestinal cancers, vitamin C may prevent cancer by inhibiting the formation of carcinogenic nitrosamines in the gut. Despite the association between higher intakes of vitamin C and a lower incidence of various cancers, a low risk of cancer is more closely linked to a dietary pattern that is rich in whole-food sources of antioxidants than to any individual antioxidant. Factors other than vitamin C found in fruits and vegetables are likely to contribute to the overall protective effect

Vitamin C and cancer

Vitamin C supplements have been suggested to reduce the risk of cardiovascular disease by lowering blood pressure, preventing the oxidation of LDL cholesterol, and reducing blood cholesterol levels. Several studies have suggested that blood pressure is inversely related to vitamin C status; however, the data are not conclusive, Vitamin C is suggested to prevent LDL oxidation because of its antioxidant function. Vitamin C may reduce blood cholesterol because it is involved in the synthesis of bile acids from cholesterol in the liver. Adequate vitamin C allows cholesterol to be used for bile synthesis and therefore may reduce the amount of cholesterol in the blood. Despite these roles of vitamin C in protecting LDL cholesterol from oxidation and modulating blood cholesterol levels, data thus far from epidemiology and human intervention trials have provided little evidence to support the use of vitamin C supplements in preventing atherosclerosis in humans.

Vitamin C and heart disease

d. all of the above

Vitamin C deficiency causes which of the following? a. bleeding gums b. easy bruising. c. depression. d. all of the above

Reactive oxygen molecules such as free radicals are highly reactive molecules that come from environmental sources such as air pollution or cigarette smoke or from normal oxygen-requiring reactions inside the body. Free radicals cause damage by snatching electrons from DNA, proteins, carbohydrates, or unsaturated fatty acids. This results in changes in the structure and function of these molecules. DNA damage is hypothesized to be a major reason for the increase in cancer incidence that occurs with age. Free radical damage to lipoproteins and lipids in membranes is implicated in the development of atherosclerosis.

What are reactive oxygen molecules, and how do they cause damage?

A vitamin is an organic compound needed in the diet in small amounts to promote and regulate the chemical reactions and processes needed for growth, reproduction, and maintenance of health.

What is a vitamin?

Intrinsic protein is produced in your promote vitamin B12 absorption. It binds with B12 in the small intestine, where the vitamin is absorbed. Individuals who cannot make intrinsic factor are diagnosed with pernicious anemia and must be given injections of B12 which bypass need for intrinsic factor. Individuals who cannot make intrinsic factor are diagnosed with pernicious anemia and must be given injections of B12 which bypass need for intrinsic factor

What is intrinsic factor and what is its relationship to Vitamin B12. What happens if a person no longer makes intrinsic factor?

Pellagra is the disease resulting from a deficiency of niacin. The symptoms of pellagra include the 3 Ds: dermatitis, diarrhea, and dementia.

What is pellagra?

Low intakes of folate have been associated with an increased risk of heart disease. Its effect on heart disease is related to its role in the metabolism of the amino acid homocysteine. Folate is needed to convert homocysteine to methionine. When folate is deficient homocysteine levels rise because less is converted to methionine. The risk of cardiovascular disease increases with elevated. Homocysteine levels, and therefore the risk of cardiovascular disease, are reduced by increasing intakes of folate.

What is the relationship between folate and heart disease?

Oxidative stress is a condition that occurs when there are more reactive oxygen molecules than can be neutralized by available antioxidant defenses. It can occur because antioxidant defenses are deficient. Agents that can induce oxidative stress by causing an increase in reactive oxygen molecules, a decrease in antioxidant defenses, or an increase in oxidative damage are called pro-oxidants.

What is the role of antioxidants and pro-oxidants in oxidative stress?

c. pellagra

Which disease is caused by a niacin deficiency? a. ariboflavinosis b. beriberi c. pellagra d. scurvy

a. adults who consume plenty of fruits and vegetables

Which group is LEAST at risk for developing vitamin C deficiency? a. adults who consume plenty of fruits and vegetables b. infants fed cow's milk c. alcoholics d. elderly people consuming nutrient poor diets

d. chronic alcoholics

Which group of people is most at risk for developing a thiamin deficiency? a. cigarette smokers b. endurance athletes c. older adults d. chronic alcoholics

c. Studies have shown that vitamin C supplementation decreases the number of colds a person gets.

Which is the FALSE statement regarding vitamin C? a. Vitamin C has been shown to decrease the duration and severity of the common cold. b. People who are prone to developing certain kinds of kidney stones should avoid Vitamin C supplementation. c. Studies have shown that vitamin C supplementation decreases the number of colds a person gets. d. Chewing vitamin C supplements can cause dental problems.

a. green pepper

Which is the best source of vitamin C? a. green pepper b. milk c. eggs d. beef

c. smoking cigarettes

Which lifestyle factor increases the requirement for vitamin C? a. drinking alcohol b. exercising frequently and intensely c. smoking cigarettes d. eating a diet high in fiber

b. facilitating release of energy from glucose

Which of the following is NOT recognized as a major function of vitamin C in the body? a. formation of collagen b. facilitating release of energy from glucose c. protection against damage from free radicals d. helps in the absorption of iron

b. Niacin is important in the production of energy from energy yielding nutrients

Which statement about niacin is true? a. Niacin is active in the removal of bile from the body. b. Niacin is important in the production of energy from energy yielding nutrients. c. The damage caused by a niacin deficiency affects few parts of the body. d. Niacin is needed to synthesize tryptophan.

b. if a vitamin is not provided by the diet, the body will synthesize

Which statement concerning vitamins is incorrect? a. vitamins are organic compounds b. if a vitamin is not provided by the diet, the body will synthesize it c. vitamins are essential d. vitamins are essential for growth, reproduction and health

a. Vitamins provide energy.

Which statement is NOT true? a. Vitamins provide energy. b. Vitamin deficiencies are rare in the United States. c. Vitamins are necessary in many biochemical reactions in the body. d. It generally takes longer to develop a deficiency of a fat-soluble vitamin than a deficiency of a water soluble vitamin.

Vitamin C is needed for the synthesis of healthy collagen. Since collagen is needed to synthesize the tissue that heals wounds a deficiency of vitamin C would prevent normal wound healing.

Why does vitamin C deficiency cause poor wound healing?

Folate intake is a particular concern for women of child bearing because if the woman becomes pregnant low folate status is associated with an increased risk of a type of birth defect called a neural tube defect that affects the unborn child's brain or spinal cord. For the extra folic acid to be beneficial, it must be consumed for at least a month before conception and continued for a month after. Since many pregnancies are not planned, it is recommended that all women of childbearing age consume 400 mg of folic acid from fortified foods or supplements.

Why is low folate intake of particular concern for women of childbearing age?

Alcoholics are particularly vulnerable to thiamin deficiency because thiamin absorption is decreased due to the effect of alcohol on the GI tract. In addition, the liver damage that occurs with chronic alcohol consumption reduces conversion of thiamin to active coenzyme forms; thiamin intake also may be low due to a diet high in alcohol and low in nutrient-dense foods.

Why is thiamin deficiency common in alcoholics?

Vitamin B12 deficiency is a concern among vegans because vitamin B12 is only found in foods of animal origin. However, many vegans are regarded as healthier than meat eaters. B12 is readily available as a supplement and found in soil associated with many vegetables especially mushrooms etc. It is also very well recycled in the body. The elderly are at risk of vitamin B12 deficiency because about 10% to 30% of individuals over 50 years of age are unable to absorb food-bound vitamin B12 normally because they have atrophic gastritis. This causes a reduction in stomach acid. When stomach acid is reduced, the enzymes that release protein-bound vitamin B12 cannot function properly and the bound vitamin B12 cannot be released and absorbed. Atrophic gastritis also causes microbial overgrowth in the intestine. These microbes reduce vitamin B12 absorption by competing for available vitamin B12. To ensure adequate amounts of B12 it is recommended that individuals over the age of 50 meet their RDA by consuming foods fortified with vitamin B12 such as breakfast cereals or soy-based products or by taking a vitamin B12-containing supplement.

Why may vegans be at risk for vitamin B12 deficiency? The elderly?

Opaque milk containers protect riboflavin from destruction by light.

Why should milk be packaged in opaque containers?

Injections would be needed because without the stomach no intrinsic factor would be produced. Intrinsic factor is a protein produced in the stomach that is needed for the absorption of adequate amounts of vitamin B12. Without intrinsic factor, vitamin B12 cannot be absorbed normally. Injections of vitamin B12 bypass the gastrointestinal tract, and thus the need for intrinsic factor.

Why would someone who has had his stomach removed (or had gastric bypass surgery) need to receive injections of vitamin B12 to meet his needs?