Chapter 8

1900s mysterious epidemic

  • signs: scaly skin, mouth sores, diarrhea, confusion, and ultimately mental deterioration

Water-soluble vitamins include the B vitamins, vitamin C, and the vitamin-like nutrient, choline

 

B vitamins were initially thought to be a single large vitamin B complex, but each has a distinct structure and function

Thiamine (B1)
Riboflavin (B2)
Niacin (B3)
Pantothenic acid (B5)
Pyridoxine (B6)
Biotin (B7)
Folate (B9)
Cobalamin (B12)

B vitamins function as coenzymes in energy metabolism—chemical reactions that release energy from carbohydrates, proteins, and fats

Thiamine is the common name for vitamin B1

function:

  • energy metabolism
  • synthesis RNA and DNA
  • production of neurotransmitters
  • in pork and fortified grain products
  • deficiency leads to beriberi(muscle wasting, fatigue), wernicke-korsakoff syndrome (neurological disturbance)

Niacin (vitamin B3) has vital functions in the body

function:

  • Energy metabolism
  • Synthesis of glucose, fatty acids, cholesterol, and steroid hormones
  • DNA repair
  • Cell signaling
  • Regulation of gene expression
  • meats and fortified grains good

Grain products may be fortified or enriched with B vitamins and other nutrients to replace nutrients lost in processing or to increase nutrient content

Niacin deficiency disease is called pellagra

Symptoms

  • Fatigue
  • Dermatitis
  • Diarrhea
  • Mental deterioration
  • Death

Riboflavin (vitamin B2) functions in energy metabolism

Riboflavin deficiency may be seen with chronic alcohol abuse or malabsorptive conditions

Ariboflavinosis Symptoms: cracks and redness of the lips and corners of the mouth, swelling of the mouth and sore throat

Riboflavin deficiency is rare by itself, typically with other B-vitamin deficiencies

B6

Deficiency can cause various symptoms:
Anemia
Impaired immune function
Weakness
Dermatitis
Neurological disorders
Excess intake above the UL from supplements can cause neurological effects

Pantothenic acid has a critical role in energy metabolism

Functions:

Helps with energy metabolism Synthesizes fatty acids, cholesterol, steroid hormones, and two neurotransmitters

Food sources:

Widespread in virtually all foods Deficiency is rare

The RDA for folate is 400 micrograms for adults older than 19 years of age

Folate deficiency causes megaloblastic anemia

UL for synthetic forms of folic acid: 1000 mcg/day

Vitamin B12 acts as a coenzyme in two important reactions

animal origin

Vitamin b12 deficiency increase with age

Choline is a vitamin-like compound classified as an essential nutrient

Functions
Intertwined with the functions of folate and vitamin B12
Forms a neurotransmitter, acetylcholine
Is part of phospholipids in cell membranes
Choline deficiency
Liver damage
Excessive intake
Only through supplementation

Vitamin C is also known as ascorbic acid

Involved in collagen synthesis

hormone production

Enhances iron absorption

Antioxidant

Vitamin C deficiency results in scurvy

RDA
Men = 90 mg
Women = 75 mg
UL = 2000 mg