Vitamins Health Article

Definition

Vitamins are compounds that are essential in small amounts for proper body function and growth. Vitamins are either fat soluble: A, D, E, and K; or water soluble: vitamin B and C. The B vitamins include vitamins B₁ (thiamine), B₂ (riboflavin), and B ₆ (pyridoxine), pantothenic acid, niacin, biotin, folic acid (folate), and vitamin B ₁₂ (cobalamin). Vitamins may also be referred to as micronutrients.

Description

A guide to the amount an average person needs each day to remain healthy has been determined for each vita-min. In the United States, this guide is called the recommended daily allowance (RDA). Consumption of too little or too much of certain vitamins may lead to a nutrient deficiency or a nutrient toxicity respectively.

Consumption of a wide variety of foods, with adequate vitamin and mineral intake is the basis of a healthy diet. Good nutrition may assist in the prevention of cancer, or for those with existing malignancies, may help cancer patients to feel better and fight infection during treatments. Obtaining nutrients through food remains the best method for obtaining vitamins, however, requirements may be higher because of the tumor or cancer therapy. Therefore supplements may be necessary.

The following vitamins are important in a healthy diet and also may assist in cancer prevention. Their role in maintaining health and best food sources are listed below.

Vitamin A (retinal, carotene)

• role in growth and repair of body tissues
• important in night vision
• immune function
• best sources: eggs, dark green and yellow fruits and vegetables, lowfat dairy products, liver

Vitamin B6 (pyridoxine)

• role in formation of antibodies
• important in carbohydrate and protein metabolism
• red blood cells
• nerve function
• best sources: lean meat, fish, poultry, whole grains, and potatoes

Folic acid (folate)

• assists in red blood cell formation
• important in protein metabolism
• growth and cell division
• best sources: green leafy vegetables, poultry, dried beans, fortified cereals, nuts, and oranges

Vitamin C (ascorbic acid)

• resistance to infection
• important in collagen maintenance
• contributes to wound healing
• strengthens blood vessels
• assists in maintaining healthy gums
• best sources: citrus fruits, tomatoes, melons, broccoli, green and red peppers, and berries

Vitamin E (tocopherol)

• may assist in immune function
• important in preventing oxidation of red blood cells and cell membranes
• best sources: vegetable oils, wheat germ, nuts, dark green vegetables, beans, and whole grains

Causes

Specific nutrients have been linked to prevention of several cancers of the colon, breast, prostate, stomach, and other types of tumors. A high intake of fruits and vegetables as well as fiber appears particularly protective, while a diet high in fat has been implicated as a cancer risk.

Vitamins important for cancer prevention

Antioxidant vitamins are believed to protect the body from harmful free radicals that can contribute to diseases such as cancer. Antioxidant vitamins include vitamin A, C, and E. However, doses too high may increase oxidative stress and therefore may be detrimental to cancer risk.

A diet rich in fruits and vegetables (containing B6, folate, and niacin) appears to protect against stomach cancer and in particular, intestinal cancer.

One study reported that cruciferous vegetables, especially broccoli, brussel sprouts, cauliflower, and cabbage were associated with a decreased risk of prostate cancer. Other foods were also associated with a lower risk such as carrots, beans, and cooked tomatoes.

A component of Vitamin E, tocotrienol, has been linked to a decreased risk of breast cancer in lab animals. Tocotrienol has been shown to readily kill tumor cells grown in culture. Tocotrienol is not the same type of substance found in generic Vitamin E supplements, but is plentiful in palm oil. Palm oil is difficult to obtain in the Western world, but lower concentrations of tocotrienol are found in rice bran oil and wheat bran oil.

Researchers state that no single nutrient is the answer, but that the effects are cumulative and depend on eating a variety of fruits and vegetables. Because there are many more nutrients available in foods such as fruits and vegetables than in vitamin supplements, food is the best source for acquiring needed vitamins and minerals.