Role in Wellness

Vitamins seem to have a magical aura. Take enough and you’ll have more energy and be healthier, smarter, and even better looking. If only it were that easy. Although vitamins are essential for life, they are only one of many factors required for wellness.

Knowledge of the existence of vitamins is recent; the discovery of vitamins slowly evolved, beginning in the early part of the twentieth century. The focus of research was to discover the amounts of vitamins needed to prevent deficiency symptoms and diseases that undermine the health and well-being of populations throughout the world.

The scientific view of vitamins, however, is in flux. Additional effects of vitamin use are surfacing as more is learned about the functions of vitamins as antioxidants and hormone-like substances. Some vitamins and related substances such as carotenoids may reduce the risk of developing certain chronic diseases. New information points to relationships between consuming foods high in vitamins and a lower incidence of developing diseases.

The Dietary Reference Intake (DRI) considers the concern of providing nutrient requirements necessary to prevent deficiencies and toxicity from overdoses and accounting for the value of nutrient intake as a means of reducing disease risk.¹ Recommendations within the DRI documents include the use of fortified foods or supplements for particular nutrients, such as folic acid for women of childbearing age to ensure proper neural tube formation of the fetus during pregnancy.

Vitamins are organic molecules required in very small amounts for cellular metabolism. Each vitamin performs a specific metabolic function. Vitamins, except for vitamin D, are not synthesized by our bodies and thus are essential nutrients that must be provided through dietary intake (see the Personal Perspectives box, Joseph Aguilar’s Mercado [San Antonio]: A Street Kitchen Vision). Vitamin D is the only vitamin created by the human body.

Vitamins are vital to life and therefore to the physical, intellectual, emotional, social, and spiritual dimensions of health. Vitamins are essential nutrients without which the body cannot continue functioning within the physical dimension. Dietary recommendations to eat at least five fruits and vegetables per day throughout the life span are made to reduce the risk of diet-related diseases in the future. Intellectual health skills are used to envision future benefits that accrue from food choices today. Deficiencies of several B vitamins can produce irritability, confusion, and paranoia, thereby affecting the emotional health dimension. Older adults may be at risk for deficiencies because of their inability to get to the store to buy fruits and vegetables; the physical health of older adults may depend on their social health in relation to neighbors who may provide assistance with shopping needs. Sometimes following religious teachings may jeopardize health, as noted by the development of rickets, the vitamin D deficiency disorder, among some African American children of families following the dietary and dress customs of the Islamic faith. Spiritual health is interdependent on the other dimensions of health.

As vitamins are discussed, note that some are referred to by specific names or by letters and numbers. Each vitamin has a history that affects how we refer to it today. In 1929 Henrik Dam in Copenhagen, Denmark, discovered vitamin K. It was the only substance capable of halting a hemorrhagic disease in which blood does not coagulate. Dam named the vitamin K for the Danish word koagulation.

In another case, several B vitamins were isolated into the same test tube labeled B, and we therefore have vitamins numbered B₁, B₂, and B₃. In the 1970s the science community decreed that all vitamins should be called by their formal biochemical titles. The public and many health professionals still refer to the simpler letter and number names for vitamins. Both the formal and informal names are used in this chapter.

This chapter lists vitamin DRI. Because DRI is an umbrella term that includes Recommended Dietary Allowance (RDA), Adequate Intake (AI), and Tolerable Upper Intake Level (UL), applicable standards will be identified. Because there are different RDAs and AIs based on age, gender, and physiologic need, only those for men and women ages 19 to 30 are included for each vitamin, unless special circumstances surrounding the need for a vitamin warrant discussion. The DRI tables are located inside the front cover of this book.

A primary deficiency of a vitamin occurs when the vitamin is not consumed in sufficient amounts to meet physiologic needs. A secondary deficiency develops when absorption is impaired or excess excretion occurs, limiting bioavailability. Most deficiencies are detected through clinical and biochemical assessment; specific diagnostic and laboratory procedures are beyond the scope of this text and are available elsewhere.²

Although vitamin deficiencies are no longer common among Americans, subgroups are at risk. Because of their increased needs, pregnant women are often at risk for marginal deficiencies of essential vitamins. Older adults may also be at risk because of decreased absorptive ability and limited economic and physical resources for food availability. Poverty is an overwhelming factor that affects the nutritional status of children and adults. Chronic alcohol and drug abuse not only alters psychologic and mental capacities but also limits the body’s ability to absorb and use essential vitamins.

Health professionals can also take into account other special circumstances that may initiate vitamin deficiencies. Individuals dealing with long-term chronic disorders that affect the total body response, such as acquired immunodeficiency syndrome (AIDS) or liver or kidney disorders, have special vitamin concerns because the metabolic processes of the body may be compromised by these disorders and by the medications prescribed. Deficiencies have been documented that were possibly caused by the effects of cancer treatment, use of multiple alternative therapies, and lifestyle behaviors. These deficiencies were at first misdiagnosed because vitamin deficiencies were no longer thought to occur.3–5

Toxicities of vitamins rarely occur naturally from food consumption. Instead, inappropriate use of supplements may be toxic to our bodies. Vitamins have been studied for their physiologic effect or basic need for health maintenance (Box 7-1). The recommended levels reflect this knowledge. Use of vitamin supplements at megadose levels is equivalent to a pharmacologic effect, with potential druglike physical responses. Some vitamins have UL; for others, a megadose (i.e., 10 times the RDA for a specific nutrient) of a vitamin is considered the highest amount of the nutrient that will not cause adverse health effects. Because most vitamins have not been studied to determine function and safety at these megadose levels, extensive use without guidance can be problematic.

Vitamin Categories

Vitamins are divided into two categories based on their solubility in solutions. Water-soluble vitamins dissolve or disperse in water; they are the B complex vitamins (thiamine, riboflavin, niacin, pyridoxine, folate, vitamin B₁₂, biotin, and pantothenic acid), choline, and vitamin C. Fat-soluble vitamins dissolve in fatty tissues or substances; they are vitamins A, D, E, and K.

Solubility characteristics affect how vitamins are absorbed and transported in the body. Water-soluble vitamins are easily absorbed in the small intestine and then pass into the bloodstream for circulation throughout the body. Fat-soluble vitamins follow the more complicated route of other fat-containing substances; bile is required for absorption from the small intestine. Fat malabsorption problems may also lead to potential deficiencies of fat-soluble vitamins.

The water solubility of the B vitamins and vitamin C allows for minimal storage of any excess vitamin consumed; tissues may be saturated with these vitamins, but they usually are not stored. Deficiencies can develop quickly—within weeks—so we need to consume these vitamins on a daily basis. Excesses are generally not toxic and are simply excreted in urine. However, damage may result if vitamin levels are chronically high because of supplementation.

If we consume more than the daily requirement of a fat-soluble vitamin, our bodies store the excess rather than excrete it (Box 7-2). The DRI for fat-soluble vitamins takes into account this storage capacity. Although storage is expected in organs such as the liver and spleen, other fatty tissues in the body can also retain excessive amounts of fat-soluble vitamins. Overloading the storage capabilities can be toxic and produce illness; toxicity rarely comes from excessive dietary intake but rather from improper use of vitamin supplements.

BOX 7-2   MyPlate

Fruits

The health benefits of eating fruits overlap with those of eating vegetables. Both the fruit and vegetable categories of MyPlate provide rich sources of vitamins and are valuable components of an overall healthy diet, providing nutrients essential for the health and maintenance of our bodies (see also Boxes 8-5 and 8-6). Health benefits of eating fruits and vegetables as part of an overall health diet include reduced risk for stroke, coronary artery disease, and type 2 diabetes mellitus; protection against some cancers (mouth, stomach, colorectal cancer); and, as an excellent source of fiber, possible decreased risk of several chronic diet-related disorders. The recommendation is to eat at least 2 cups of fruits every day.

What Counts as a Cup of Fruit?*

The focus of this MyPlate box is on portions of the fruits group.

In general, 1 cup of fruit or 100% fruit juice, or cup of dried fruit can be considered as 1 cup from the fruit group. The specific amounts outlined in the following table count as 1 cup of fruit (in some cases equivalents for cup are also shown) toward your daily recommended intake.

FRUIT	AMOUNT THAT COUNTS AS 1 CUP OF FRUIT	AMOUNT THAT COUNTS AS CUP OF FRUIT
Apple	large (-inch diameter)	cup sliced or chopped, raw or cooked
	1 small (-inch diameter)
	1 cup sliced or chopped, raw or cooked
Applesauce	1 cup	1 snack container (4 oz)
Banana	1 cup sliced	1 small (less than 6 inches long)
	1 large (8-9 inches long)
Cantaloupe	1 cup diced or melon balls	1 medium wedge ( of a medium melon)
Grapes	1 cup whole or cut up
	32 seedless grapes	16 seedless grapes
Grapefruit	1 medium (4-inch diameter)	medium (4-inch diameter)
	1 cup sections
Mixed fruit (fruit cocktail)	1 cup diced or sliced, raw or canned, drained	1 snack container (4 oz), drained = cup
Orange	1 large (-inch diameter)	1 small -inch diameter)
	1 cup sections
Orange, mandarin	1 cup canned, drained
Peach	1 large (-inch diameter)	1 small (2-inch diameter)
	1 cup sliced or diced; raw, cooked, or canned; drained	1 snack container (4oz), drained = cup
	2 halves, canned
Pear	1 medium ( per lb)
	1 cup sliced or diced; raw, cooked, or canned; drained	1 snack container (4 oz), drained = cup
Pineapple	1 cup chunks; sliced or crushed; raw, cooked, or canned; drained	1 snack container (4 oz), drained = cup
Plum	1 cup sliced, raw or cooked	1 large
	3 medium or 2 large
Strawberries	Approximately 8 large
	1 cup whole, halved, or sliced; fresh or frozen	cup whole, halved, or sliced
Watermelon	1 small wedge (1 inch thick)	6 melon balls
	1 cup diced or balls
Dried fruit (raisins, prunes, apricots, etc.)	cup dried fruit is equivalent to 1 cup fruit ( cup raisins, cup prunes, cup dried apricots)	cup dried fruit is equivalent to cup fruit (1 small box raisins [ oz])
100% fruit juice (orange, apple, grape, grapefruit, etc.)	1 cup	cup

---

^*Accessed June 14, 2012, from www.choosemyplate.gov/food-groups/fruits-counts.html.

Food Sources

Vitamins are in almost all foods, yet no one food group is a good source of all vitamins. Fresh fruits and vegetables are particularly rich sources. Others include legumes, whole grains, and animal foods of meat, fish, poultry, eggs, and dairy products. Even the almost pure fats of vegetable oils and butter provide vitamins E and A, respectively. Although this does not mean we should consume these products for their vitamin content, it does mean we have a wide range of foods from which to choose for our vitamin nutrition.

It is always best to consume vitamins from food sources. Although synthetic forms of vitamins will perform vitamin functions, there may be other factors in foods that provide benefits. For instance, broccoli and other cruciferous vegetables contain a wide variety of chemicals, including sulforaphane, which is a phytochemical (Box 7-3). Phytochemicals are nonnutritive substances in plant-based foods that appear to have disease-fighting properties Sulforaphane appears to block the growth of tumors in animals. Broccoli, along with onions and grapes, also contains flavonols, which seems to reduce the risk of coronary artery disease (CAD) and cancer while having an anti-inflammatory effect.⁶

For centuries, a mysterious disease afflicted people of all ages and status throughout Asia. The disease so wasted muscles that Thai sufferers who tried to stand would cry out, “Beri, beri,” meaning “I can’t! I can’t!” This phrase, beriberi, became the name of a serious disease resulting from thiamine deficiency. In the 1890s it was discovered that beriberi resulted from consumption of hulled (white) rice and that unhulled (brown) rice prevented or cured this disease. Later, researchers found that the thiamine in the hulls of whole grains prevents or cures beriberi.

Riboflavin (B₂)

Have you ever wondered why milk is sold in opaque cardboard or nontransparent plastic containers? These containers protect riboflavin from exposure to light. Riboflavin is sensitive to ultraviolet rays in sunlight and artificial light; much of the riboflavin is destroyed if milk, an excellent source of riboflavin, is sold in clear glass or clear plastic receptacles. Why risk loss of a valuable vitamin?

Function

Like thiamine, riboflavin’s main function is as a coenzyme in the release of energy from nutrients in every cell of the body.

Recommended Intake and Sources

The RDA for riboflavin is 1.3 mg per day for men and 1.1 mg for women. The body’s need is related to total kcal intake, energy needs, body size, metabolic rate, and growth rate. Conditions requiring increased protein also require increased riboflavin, such as during wound healing or the growth periods of childhood, pregnancy, and lactation.

Riboflavin is found in both plant and animal foods. In the United States, however, milk is a major source, with small amounts coming from other foods such as enriched grain. Good plant sources are broccoli, asparagus, dark leafy greens, whole grains, and enriched breads and cereals. Rich sources of animal origin include dairy products, meats, fish, poultry, and eggs.

As mentioned, riboflavin is sensitive to light and irradiation. It also can be lost in cooking water but is heat stable.

Deficiency

Ariboflavinosis is the name for a group of symptoms associated with riboflavin deficiency. The lips become swollen, and cracks develop in the corners of the mouth (cheilosis). The tongue becomes inflamed, swollen, and purplish red (glossitis), a common symptom of riboflavin and other B vitamins. Seborrheic dermatitis, a skin condition characterized by greasy scales, may occur in the regions of the ears, nose, and mouth. Riboflavin deficiency may also affect the availability and use of pyridoxine and niacin.

Nutritional deficiencies tend to be multiple rather than single, and it is difficult to separate symptoms. If an individual is deficient in a nutrient such as riboflavin, more than likely a deficiency of other nutrients also will be present. For example, esophageal cancer is associated with deficiencies of riboflavin and zinc, particularly in Africa, Iran, and China. In the United States, riboflavin deficiency may be related to anorexia nervosa, inadequate intake when active individuals restrict caloric intake, and lactose intolerance⁹—all of which are associated with potential multiple nutritional deficiencies.

Toxicity

Toxicity to riboflavin has not been reported. Absorption of riboflavin tends to be limited under normal circumstances; excessive absorption is extremely unlikely.⁹

Niacin (B₃)

Niacin occurs naturally in two forms: nicotinic acid and niacinamide. It’s hard to imagine, but before niacin was identified, people who were actually suffering from niacin deficiency were so psychologically disoriented that they were sent to mental institutions for treatment. Niacin deficiency can bring on a psychosis that dissipates once sufficient quantities are consumed.

Function

Niacin is involved as a coenzyme for many enzymes, especially those involved in energy metabolism; it is critical for glycolysis and the tricarboxylic acid (TCA) cycle.

Recommended Intake and Sources

Niacin is available in foods as the active vitamin or as its precursor, the amino acid tryptophan. That is, tryptophan can be converted to niacin, and some niacin can be provided this way. Diets adequate in protein tend to be adequate in niacin.

Niacin requirements are measured in niacin equivalents (NE), reflecting the body’s ability to convert tryptophan to niacin. To form 1 mg of niacin, 60 mg of tryptophan is needed, both of which equal 1 mg NE. The RDA recommends that men and women consume 16 mg NE and 14 mg NE per day, respectively. The DRI for niacin includes a UL of 35 mg NE per day because of the adverse reactions experienced when excess amounts are taken in supplement form (see the section titled “Toxicity”).

Protein-containing foods are good sources of both niacin and tryptophan. Meats, poultry, fish, legumes, enriched cereals, milk, and even coffee and tea are sources of niacin.

Deficiency

Pellagra, the niacin deficiency disorder, is characterized by the three D’s, as follows:¹⁰

1. Diarrhea: Damage to the GI tract affects digestion, absorption, and excretion of food, leading to glossitis, vomiting, and diarrhea.

2. Dermatitis: A symmetric scaly rash occurs only on skin exposed to the sun (Figure 7-1).

3. Dementia: As the central nervous system becomes affected in severe deficiencies, confusion, anxiety, insomnia, and paranoia develop.

In the early 1900s, pellagra was common in the southern United States among the poor who subsisted on corn-based diets. The niacin in corn is in a bound form unavailable for absorption, and many people subsisting on low incomes had such a limited intake of protein food that neither tryptophan nor preformed niacin was available. Since the discovery of the cause of pellagra, flours have been enriched with niacin, and the incidence of pellagra has decreased dramatically.

In the United States, health professionals need to be vigilant to recognize the symptoms of vitamin deficiencies among patients undergoing specialized treatments or experiencing disorders that may negatively affect their nutritional status. For example, pellagra may develop among people with chronic excessive alcohol ingestion, particularly if combined with homelessness and failure to eat regularly (not using shelter-based meal programs).¹¹ Several cases have been reported in which the symptom of dermatitis was not recognized as pellagra. In one situation, the simultaneous use of several alternative remedies initiated pellagra, although the individual consumed sufficient dietary niacin.⁴ Another report discusses pellagra dermatitis possibly caused by cancer treatment (5-fluorouracil) exacerbating the low niacin levels of the patient.¹ Pellagra may even occur, as a secondary condition to anorexia nervosa.¹² In contrast, in Africa and Asia, pellagra still occurs among the general population.

Toxicity

The UL for niacin is 35 mg NE per day. When preformed niacin and nicotinic acid (but not niacinamide) are consumed in levels greater than the UL, the vascular system is affected, producing a flushing effect throughout the body. A pharmacologic dose is 3 to 9 g of niacin, compared with the RDA of 16 mg NE. Niacin has been used therapeutically because megadoses may lower total cholesterol and low-density lipoprotein (LDL) and increase high-density lipoprotein (HDL).¹⁰ These therapeutic doses, however, must be medically administered to guard against liver damage and related gout and arthritic reactions.

Pyridoxine (B₆)

Vitamin B₆ and pyridoxine are generic terms representing a group of related chemicals. The three main members are pyridoxine, pyridoxal, and pyridoxamine. All three forms can be converted to the coenzyme pyridoxal phosphate (PLP) for use in the body.

Function

The major function of vitamin B₆, in the form of PLP, is to act as a coenzyme in the metabolism of amino acids and proteins. These reactions are involved in the formation of neurotransmitters and are essential for proper functioning of the nervous system. PLP is essential for hemoglobin synthesis. It is required for the conversion of tryptophan to niacin. It also serves as a coenzyme for fatty acid and carbohydrate metabolism.

Supplements of B₆, folate, and B₁₂ may reduce risk of CAD by lowering homocysteine levels (see also “Overcoming Barriers” later in this chapter). Several epidemiologic studies suggest that the greater the dietary intake of B₆, the lower the risk of colorectal cancer in women.13,14

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