Vitamins

Charles Lohman

Vitamins - An Overview

• Vitamins– a vitamin is defined as a complex organic

compound that regulates certain metabolic processes in the body

– classified as either fat soluble (A,D,K,E) or water soluble (B vitamins and Vitamin C)

– in general vitamins regulate a variety of body processes such as cell division and development and growth and maintenance of tissues

B Vitamins • Thiamin• RDA for Thiamin– men 1.2mg/day– women 1.1mg/day

• Thiamin Food Sources– prolonged cooking can destroy thiamin because they

leach into water from boiling blanchings – cooking methods that use little to no water such as

steaming and microwaving can conserve thiamin and other water soluble vitamins

– found in breads, cereals, vegetables, fruits, milk and milk products, legumes, nuts, seeds and meats

B Vitamins

• Riboflavin• RDA for Riboflavin– men: 1.3mg/day– women:1.1mg/day

• Food Sources– milk and milk products– dark, green, leafy vegetables such as broccoli,

turnip greens, asparagus, and spinach

B Vitamins

• Niacin• RDA for Niacin– Men: 16mg /day– women: 14mg/day

• Food sources– found in meat, poultry, legumes, and enriched

and whole grains– also found in mushrooms, potatoes, and tomatoes

B Vitamins • Vitamin B 6

– unlike the other water soluble vitamins, vitamin B6 is stored extensively in muscle tissue

– needed for amino acid metabolism– needed or conversion of tryptophan to niacin– Lack of vitamin B 6 can contribute to cardiovascular disease in

some individuals• RDA for Vitamin B6

– adults 19 to 50 years old: 1.3 mg/day• Vitamin B6 Food Sources

– B6 found in meat, fish, and poultry, potatoes, and some other vegetables, and fruits

– foods loose vitamin B6 when heated

B Vitamins

• Folate or Folic Acid– the need for folate rises considerably during

pregnancy and whenever cells are multiplying– FDA’s decision to fortify grain products with folate

was strengthened by research indicating an important role for folate in defending against heart disease

B Vitamins

• Folate and Neural Tube Defects– folate has been proven to be critical in reducing

the risks of neural tube defects– neural tube defects are defined as malformations

of the brain, spine cord, or both during embryonic development that often results in lifelong disability or death

– plays an important role in protecting against pancreatic cancer and breast cancer

B Vitamins

• RDA for Folic Acid– adults: 400 micrograms/day

• Folate Food Sources– folate is abundant in legumes, fruits, and

vegetables– with fortification, grain products also contribute

folate

B Vitamins

• Vitamin B 12– Contributes to the metabolism of folate – Converts folate for metabolic processes such as DNA

synthesis– Insulation of nerve cells

• RDA for Vitamin B 12– adults: 2.4 micrograms/day

• Food Sources– found in meat, milk and milk products, eggs, fortified

cereals and fortified soy milk• microwaving foods containing vit B 12 inactivates it

Vitamin C

• Vitamin C as an antioxidant– in the body antioxidants defend against free radicals – vitamin C protects tissues from oxidative stress and

thus may play an important role in disease prevention– oxidative stress is defined as a condition in which the

production of oxidants and free radicals exceeds the body’s ability to handle them and prevent damage

– in the intestines, vitamin C enhances iron absorption by protecting iron from oxidation

Vitamin C

• Vitamin C Recommendations– RDA• men: 90mg/day• women: 75 mg/day• smokers: 35+ mg/day

• Food Sources– fruits and vegetables such as peppers, citrus fruits,

papaya, broccoli, cabbage and berries

Vitamin A

• Vitamin A – Contributes to normal vision and reproduction,

cellular growth and immune system function

• RDA– 700-900 mcg (micro-grams)

• Food Sources– Milk, fortified cereals, yellow, orange, and dark

green fruits and vegetables

Vitamin D and Roles in the Body • Vitamin D is different than all other nutrients

in that the body can synthesize it, with the help from sunlight, from a precursor that the body makes from cholesterol

• vitamin D is not considered a essential nutrient as long as enough time is spent in the sun

• inadequate vitamin D can contribute to the development of osteoporosis

Vitamin D and Roles in the Body

• adults in sunny regions do not need to make a special effort to obtain vitamin D from food

• vegetarians who do not include milk in their diet may use vitamin D fortified soy milk and cereals

• No RDA’s for vitamin D, but instead an AI’s (adequate intake)

• People under 50, the AI is 5mcg/day

Vitamin E• Vitamin E as an Antioxidant– protects polyunsaturated fatty acids in cells from

being damaged by radicals– Such oxidative damage may contribute to

atherosclerosis, cancer, and premature cellular aging and death

– Important for nervous tissue and immune system function

• RDA– 15mg/day

• Food Sources– nuts, seeds, plant oils such as canola and olive oil, fish

and whole grains

Vitamin K • Roles of vitamins K– acts primarily in blood clotting– helps bone building by producing a protein needed for

normal bone mineralization– low levels of vitamin K are associated to the risk of

osteoporosis• No RDA’s for vitamin K – AI’s for vitamin K are 120 mcg/day for men and 90

mcg/day for women • Food sources – green leafy vegetables such as kale, salad green, spinach,

broccoli, green beans and soybean and canola

Preserving the Vitamin Content in Foods

• Produce is highly perishable and should be eaten as soon as they are harvested or purchased to ensure maximum retention

• Bulk fresh fruits or vegetables that are sold in supermarkets do not have use by dates and consumers have no way of knowing when the produce was harvested

Preserving the Vitamin Content in Foods

• Fresh fruits and vegetables can lose substantial amounts of vitamins as a result of improper handling or lengthy storage conditions

• Avoid produce that is bruised, wilted, or shriveled

• Keep fruits and vegetables in plastic packaging and chilled until ready for use

Preserving the Vitamin Content in Foods

• Exposure to excessive heat, alkaline substances, light and air can destroy certain vitamins, especially vitamin C

• To reduce such losses trim, peel, and cut raw fruits and vegetables just right before eating them

• Water soluble vitamins can leach out of food and dissolve in the cooking water

Preserving the Vitamin Content in Foods

• Cook vegetables in small amounts of water and reuse water if possible for soups or sauces

• Reduce the amount of surface area that will be exposed to heat, water, and other conditions by cutting produce into large pieces

• Try to cook fruits and vegetables in their skins and if the skin is edible eat them too

• Microwaving, steaming, and stir frying can conserve much of the vitamin content of foods

Preserving the Vitamin Content in Foods

• During canning process of fruits or vegetables, the heating of the food can cause destruction of certain vitamins

• Produce that is frozen immediately after harvest and properly stored can be just as nutritious as fresh produce

• Remember try to cook frozen foods without thawing whereas the thawing process causes some of the water that was naturally in the produce to drip out, taking the water soluble vitamins with it