Dudek’s Nutrition Essentials for Nursing PracticeNursing Practice

Chapter 5: Vitamins

Vitamins

• do not provide energy (calories) but they are needed for metabolism of energy

• function as coenzymes to activate enzymes

Vitamins

• The body needs vitamins in small amounts (microgram or milligram quantities) - micronutrients

• Vitamins are essential in the diet because they cannot be made by the body or they are synthesized in inadequate amounts

Vitamins

• Vitamins were discovered a mere 100 years ago as scientists searched to identify what components in food prevented the development of deficiency diseases such as scurvy

• As knowledge of vitamin functions and requirements grew, policies were enacted to enrich and fortify foods

• Fortification and enrichment have virtually eliminated vitamin deficiencies in the general American population

Enrichment and Fortification

• Enrich: to add nutrients back that were lost during processing, e.g., white flour is enriched with B vitamins that are lost when the bran and germ layers are removed

• Fortify: to add nutrients that are not naturally found in the food, e.g., milk is fortified with vitamin D, and some breakfast cereals are fortified with vitamin

Vitamins and diet

• It is assumed that if a variety of nutritious foods are consumed, the diet's vitamin content generally will be adequate for most people

Vitamins and solubility

• Vitamins are organic compounds that are soluble in either water or fat; their solubility determines how they are absorbed, transported through the blood, stored, and excreted

Fat-Soluble Vitamins

• Vitamins A, D, E, and K

• Because they are stored in liver and adipose tissue, Vitamins A, D, E, and K do not need to be consumed daily

• Vitamins A and D are toxic when consumed in large quantities over a long period

Water-Soluble Vitamins

• B-complex vitamins and Vitamin C

• not generally stored in the body so a daily intake is necessary

• are considered nontoxic

• adverse side effects, however, can occur from taking megadoses of certain water-soluble vitamins over a prolonged period

Vitamins, diet and health

• Although diets rich in fruits and vegetables appear to be protective against chronic diseases such as heart disease, cancer, and hypertension, it is not known what components in them are responsible for the health benefits

• Antioxidant vitamins in foods are suspected of being beneficial

Free Radicals

• Are produced continuously in cells as they burn oxygen during normal metabolism

• Problem - they oxidize body cells and DNA in their quest to gain an electron and become stable

• These structurally and functionally damaged cells are believed to contribute to aging and various health problems such as cancer, heart disease, and cataracts

Antioxidants and free radicals

• Antioxidants - substances that donate electrons to free radicals to prevent oxidation

• Antioxidants protect body cells from being oxidized (destroyed) by free radicals by undergoing oxidization themselves, which renders free radicals harmless

• Vitamin C, Vitamin E, and beta-carotene are major antioxidants

Vitamins and supplements: more is not better• High-dose supplements have not been

proven to prevent disease and may disrupt nutrient balances

• Megadoses: amounts at least ten times greater than the RDA

• In megadoses vitamins function like drugs, not nutrients

• Long-term safety has not been established

• Some reports indicate that single-nutrient supplements may actually increase, not decrease, health risks

Dispel the myth that more is better

• Advise clients that %DV and current RDAs are not consistent

• Point out that a better choice than fortified foods and vitamin supplements may be fortified foods OR vitamin supplements

• Exception--milk because vitamin A is present naturally in whole milk and added to lowfat milks

Vitamins and special needs populations

• It is recommended that women who are capable of becoming pregnant consume 400 micrograms of folic acid through supplements or fortified food daily

• People over the age of 50 are urged to consume most of their B12 requirement from supplements or fortified food

• Vegans need supplemental B12 and D, if exposure to sunshine is inadequate

Vitamins and limited diets

• Multivitamin supplements provide a limited safeguard when food choices are less than optimal

• Other groups who may benefit from taking a daily multivitamin are the elderly, dieters, finicky eaters, and alcoholics

Vitamin supplements: quantity & quality

• People who choose to take an all-purpose multivitamin should select one that provides 100% of the DV for vitamins with an established DV

• The USP stamp ensures the quality, but not safety or benefits

• High-cost supplements are not necessarily superior to lower-cost ones

Facts about fruit and vegetable intake among Americans

• When French fries and potato chips are excluded, Americans eat only about 3.6 servings of fruits and vegetables daily

• 9 out of 10 teenage girls do not eat five servings of fruit and vegetables daily

• Fruit and vegetable intake is declining--romaine lettuce and bag lettuce are the only vegetables Americans are eating more of.

• Obesity levels are lowest for people who eat the most fruit and vegetables

To boost intake of vegetables and fruits:

• Eat at least five servings of fruits and vegetables every day

• Choose wholesome, nutrient-dense foods over refined or processed foods

• Concentrate on variety and color

• Make an effort to preserve the vitamin content of foods during storage and preparation

• Avoid overcooking vegetables

• Microwave vegetables instead of boiling

To boost intake of vegetables and fruits:• Start at least one meal each day with a fresh

salad

• Eat raw vegetables or fresh fruits for snacks

• Add vegetables to other foods

• Double the normal portion size of vegetables

• Buy a new fruit or vegetable when you go grocery shopping

•Eat occasional meatless entrees

To boost intake of vegetables and fruits:• Order a vegetable when you eat out

• Choose 100% fruit juice at breakfast and instead of drinks, cocktails, ades, and/or carbonated beverages during the day

• Eat fruit for dessert

• Make fruits and vegetables more visible

– Leave a bowl of fruit on the center of your table

– Keep fresh vegetables on the top shelf of the refrigerator in plain view