Nutrition Chapter 8

Vitamin A can be stored in the liver for at least:

1 year.

Alopecia, diplopia, and increased activity of osteoclasts are most associated with an excess of which vitamin?

A

Each is true of vitamin requirements and deficiencies, except one. Which is the exception?

Although nutrients rely on each other for utilization, they are not considered codependent.

Each is accurate regarding the relationship between vitamin D levels and periodontitis, except one. Which is the exception?

Although vitamin D has been found to affect alveolar bone positively, an effect on wound healing has not been observed.

Large amounts of vitamin A supplements can exceed the storage capacity of the kidneys. When present in high concentrations, unbound vitamin A causes damage to cell nuclei, especially in the white blood cells and lysosomes.

Both statements are false.

Studies suggest that leukoplakia is caused by excess vitamin A (a fat-soluble vitamin), retinoids, and beta-carotene. Leukoplakia is an erythematous lesion that appears on the lateral borders of the tongue.

Both statements are false.

Toxicity from excessive intake of vitamin A food sources is common and results in hypercarotenemia. This condition is initially manifested by yellowing of the skin on upper chest and inner forearms.

Both statements are false.

During early tooth development, vitamin A deficiency leads to enamel hypoplasia and defective dentin formation. Because of its effect on soft tissues and bone, vitamin A contributes to normal spacing of teeth.

Both statements are true.

When rickets occurs, the alveolar bone is affected similar to other bones in the body. The trabeculae of the alveolar bone also weaken.

Both statements are true.

Although vitamins are synthesized during metabolic processes, they also must be obtained through external sources because vitamins cannot be produced in adequate amounts to meet body needs.

Both the statement and the reason are correct and related.

Dental hygienists should advocate that fortified foods and vitamin supplements be used judiciously because chronic use in excess of the RDA can result in severe, life-threatening liver damage.

Both the statement and the reason are correct and related.

Hypercarotenemia may be distinguished from jaundice because the sclera of the eye retains its normal white color in hypercarotenemia.

Both the statement and the reason are correct and related.

In older patients, vitamin D deficiency frequently results in falls because this deficiency is associated with muscle weakness.

Both the statement and the reason are correct and related.

Inadequate intake of vitamin A occurs in lower socioeconomic groups because these individuals often lack resources to purchase and consume vegetables and fruits.

Both the statement and the reason are correct and related.

Uncontrolled use of vitamin D supplements by older patients with osteoporosis can result in diminished bone mass because excess levels result in vitamin D intoxication.

Both the statement and the reason are correct and related.

Oily fish are considered excellent sources of vitamin D. Which is NOT considered an oily fish?

Cod

Which vitamin acts most like a hormone?

D

Each is true of vitamin D, except one. Which is the exception?

Diets low in fiber can result in less vitamin D absorption.

Each is true of retinoic acid, except one. Which is the exception?

Formation of odontoblasts in enamel requires retinoic acid.

Each is true of xerophthalmia, except one. Which is the exception?

It stimulates secretion of tears and causes light sensitivity.

Each is a function of vitamin A, except one. Which is the exception?

Maintenance of more than 200 genes

Which is the most potent form of vitamin K?

Menadione

International units (IUs) are the designation used to measure and recommend vitamin A levels because it better represents the absorption rates in humans than retinol activity equivalent (REA).

Neither the statement nor the reason is correct.

Rickets is no longer prevalent in the United States because increased breastfeeding provides ample vitamin D reserves.

Neither the statement nor the reason is correct.

Rickets results in shortened bones because the epiphyses of bones form earlier than normal.

Neither the statement nor the reason is correct.

Supplementing dietary intake of beta-carotene is advised for patients with leukoplakia who smoke because research documents that exogenous beta-carotene protects lung tissues from dangers of smoking.

Neither the statement nor the reason is correct.

Each is true of osteomalacia, except one. Which is the exception?

Oral manifestations include increased dental caries especially erosion of exposed root surfaces.

Each form of vitamin A is involved in the prevention of night blindness, except one. Which is the exception?

Retinoic acid

Each is true of rickets, except one. Which is the exception?

Rickets is caused by vitamin C deficiency.

Each correlation between vitamin D and sun exposure is accurate, except one. Which is the exception?

Sunscreen does not block the formation of vitamin D3.

Each is a physiologic role of vitamin D, except one. Which is the exception?

Synthesis of blood-clotting factors

Follicular hyperkeratosis, in which the skin is thickened, dry, and wrinkled, is preceded by hypervitaminosis A. The keratinization of this disorder can also affect the oral mucosa and the respiratory and gastrointestinal tracts.

The first statement is false; the second is true.

Antioxidants prevent cell membrane damage by free radicals that are produced by cells and tissue using free oxygen. Research conclusively documents that the antioxidant beta-carotene is effective in preventing cancer.

The first statement is true; the second is false.

Calcitonin, a hormone secreted by the thyroid gland, helps regulate mineralization of bones and teeth. Without adequate levels of vitamin C, calcitonin cannot regulate blood calcium and phosphorus levels.

The first statement is true; the second is false.

Fat-soluble vitamins are fairly stable when heated, as in cooking. In contrast to water-soluble vitamins, fat-soluble vitamins contain nitrogen.

The first statement is true; the second is false.

For patients with osteomalacia, a health care provider may recommend a vitamin D supplement to increase calcium absorption. However, for women of childbearing age, supplementations should be minimized because of interference with hormonal balances.

The first statement is true; the second is false.

Vitamin K is derived from bacterial flora and microflora in the gut. The only dietary source of vitamin K is green leafy vegetables.

The first statement is true; the second is false.

A restriction of dietary vitamin K can alter clotting factors because synthesis of vitamin K by intestinal flora supplies less than 10% of the body's requirement.

The statement is correct, but the reason is not correct.

Although limited amounts of vitamin K are stored in the body, a shortage of vitamin K is unlikely because like vitamin D it is provided by sunlight.

The statement is correct, but the reason is not correct.

Daily intake of water-soluble vitamins is important because although the body can store large amounts of these nutrients, they are better utilized when consumed daily.

The statement is correct, but the reason is not correct.

Fat-soluble vitamins are different from water-soluble vitamins because the body is able to store only small amounts of fat-soluble vitamins.

The statement is correct, but the reason is not correct.

It is postulated that vitamin D deficiency is linked to enamel hypoplasia and dental decay because deficiency in vitamin D results in deep narrow occlusal grooves.

The statement is correct, but the reason is not correct.

Most milk in the United States is fortified because the calcium and phosphorus content is beneficial for absorption and use of vitamin A.

The statement is correct, but the reason is not correct.

Osteoporosis is characterized by fragile bones and is associated with an increased incidence of bone fractures. Current research indicates that osteoporosis is caused primarily by a deficiency of water-soluble vitamins.

The statement is correct, but the reason is not correct.

Each is true of water-soluble vitamins, except one. Which is the exception?

They have vital roles as enzymes.

Each is a form of vitamin K, except one. Which is the exception?

Tocopherol

Each is a fat-soluble vitamin, except one. Which is the exception?

Vitamin C

Each is true of vitamin K, except one. Which is the exception?

Vitamin K absorption increases with high levels of vitamin E supplementation.