10 Water soluble vitamins B & C

Fat - Soluble vitamins A,D,E, and K

Absorption: First in the lymph, then the blood Transport: Many require transport proteins Storage: Stored in the cells associated with fat Excretion: Less readily excreted; tend to remain in fat-storage sites Toxicity: Likely to reach toxic levels when consumed from supplements Needed in periodic doses (perhaps weeks or even months).

Water- Soluble vitamins: B and C

Absorption: directly into the blood Transport: Travel freely Storage: Circulate freely in water-filled parts of the body Excretion: kidneys detect and remove excess in urine Toxicity: Possible to reach toxic levels when consumed form supplements Requirements: Needed in frequent doses (perhaps 1 to 3 days)

Vitamins

are soluble in either water or fat

what risks are associated with high doses of niacin? Vitamin B6? Vitamin C?

Niacin toxicity - niacin flush - tingling, painful sensation. B6 toxicity - causes nerve damage numb feet, lost sensation in hands, Vitamin C - diarrhea, GI distress

10.2 Identify the main roles, deficiency symptoms, and food sources for each of the B vitamins. pg 304

The B vitamins serve as coenzymes that facilitate the work of every cell. They are active in carbohydrate, fat, and protein metabolism and in the making of DNA and thus new cells. Historically famous B vitamin - deficiency diseases are beriberi (thiamin), pellagra(niacin), and pernicious anemia (b12). Pellagra can be prevented by and adequate protein intake because the amino acid tryptophan can be converted to niacin in the body. A high intake of folate can mask the blood symptoms of a vitamin b12 deficiency, but it will not prevent the associated nerve damage. Vitamin b6 participates in amino acid metabolism and can be harmful in excess. Biotin and pantothenic acid serve important roles in energy metabolism and are common in a variety of foods. Many substances that people claim as B vitamins are not. Fortunately, a variety of foods form each of the food groups provides an adequate supply of all of the b vitamins.

types of b vitamins

Vitamin B1, thiamin, riboflavin, pantothenic acid, vitamin b6, vitamin b12

10.3 Identify the main roles, deficiency symptoms, and food sources for vitamin C pg 332

Vitamin C acts primarily as an antioxidant and a cofactor. Recommendations are set well above the amount needed to prevent the deficiency disease scurvy. A variety of fruits and vegetables - most notably citrus fruits - provide generous amounts of vitamin C. The accompanying table provide a summary of vitamin C.

A,B, and CD compounds pg 305

WITHOUT coenzymes, compounds A, B, and CD don't respond to their enzymes. WITH the coenzymes in place compounds are attracted to their sites on the enzymes..... and the reactions proceed instantaneously. the coenzymes often donate or accept electrons, atoms, or group atoms. The reactions are completed with either the formation of a new product, AB, or the breaking apart of a compound into two new products, C and D, and the release of energy.

Vitamin C serves as an

antioxidant

The rate at and the extent to which a vitamin is absorbed and used in the body is known as its?

bioavailability

many of the B vitamins serve as?

coenzymes

the vitamin that protects against neural tube defects?

folate

describe the relationship between folate and b12

folate is part of the coenzyme THF that activates vitamin b12, synthesizes DNA, and regenerates the amino acid methionine form homocysteine. Folate helps prevent neural tube defects. Excessive folate can mask the anemia of a vitamin b12 deficiency, but it will not prevent the associated nerve damage. folate is abundant in legumes, fruits, and vegetables.

a lack of intrinsic factor may lead to ?

pernicious anemia

The best vitamin and mineral supplements

provide 50 to 150 percent of the daily value

the requirement of vitamin C is highest for

smokers

Precursors (provitamins)

some vitamins are available form foods in inactive forms known as precursors, or provitamins. once inside the body the precursor is converted to an active form of the vitamin. For example beta-carotene, a red-orange pigment found in fruits and vegetables is a precursor to vitamin A. Thus, in measuring a persons vitamin intake, it is important to count both the amount of the active vitamin and the potential amount available form its precursors.

10.1 describe how vitamins differ form the energy nutrients and how fat soluble vitamin differ form water soluble vitamins pg 302

the vitamins are essential nutrients needed in tiny amounts in the diet both to prevent deficiency diseases and to support optimal health. the water-soluble vitamins are the B vitamins and vitamin C; the fat soluble vitamins are vitamins A,D,E, and K.

Which B vitamins are involved in energy metabolism?

thiamin, riboflavin, niacin

the body can make niacin from ?

tryptophan & B6

What is the relationship of tryptophan to niacin?

tryptophan can be converted to niacin in the body.

Which B vitamin is involved in protein metabolism and cell division?

vitamin b6