Nutrition - Chapter 6 - Vitamins

Essentials of Nutrition & Diet Therapy - Chapter 6 (vitamins) review

What are the fat soluble vitamins?

Vitamin A

Vitamin D

Vitamin E

Vitamin K

What are the water soluble vitamins?

Vitamin C & the Vitamin B Complex family

Who developed the Vitamin Requirements?

A subcommittee of the food & nutrition board of the NAS

What is responsible when deficiencies occur due to overall poor intake?

More than one vitamin and/or mineral

What is considered adequate vitamin intake?

2/3 of the RDA

What Vitamin deficiency is responsible for Scurvy?

Vitamin C

What Vitamin deficiency is responsible for BeriBeri

Thiamin

What Vitamin deficiency is responsible for Pellagra?

Niacin

What Vitamin Deficiency is responsible for Goiter and Cretinism?

Iodine

What Vitamin deficiency is responsible for Rickets?

Vitamin D

What Vitamin deficiency is responsible for Pernicious Anemia?

Vitamin B₁₂

What can happen with large doses of Vitamin C?

Predisposition for oxalate stones and cause false negative urine glucose results in patients with diabetes.

What are Phytochemicals?

Non-nutritive substances in plant based foods that appear to have disease fighting properties

What class of vitamin is more commonly reported for toxicity?

fat-soluble vitamins

What do fat soluble vitamins require for absorption?

Bile & dietary fat

Once absorbed, what happens to fat soluble vitamins?

They are transported with fats through the lymphatic system in chylomicrons before entering the blood.

What are the 2 dietary forms of Vitamin A?

Preformed Vitamin A (Retinol)

Provitamin A (Beta-Carotene)

What is Retinol?

Natural form of Vitamin A found only in animal foods & usually associated with fat.

What is the percentage of total vitamin intake that Beta Carotene accounts for?

37%

What compounds are produced when plants can’t synthesize Vitamin A?

Beta-Carotene

Where is Vitamin A stored?

Liver (contains up to 80% of body’s total supply)

What prevents Vitamin A deficiency in developing countries?

A prophylactic does of Vitamin A every 6 months

What is Xerophthalmia?

Night Blindness due to keratomalacia

Vitamin A aids in the formation of what to prevent night blindness?

Rhodopsin

What is keratinization?

When flat dry cells harden forming keratin

What is Vitamin A toxicity called?

Hypervitaminosis A

What is the Upper Limit for Vitamin A?

3000 ug/day

What are the food sources of Retinol?

Liver, milk, cheese, butter, egg yolk, fish, kidney

What are the food sources for Beta Carotene?

Lower fat milks, soymilk, rice milk

Margarine, ready to eat cereals

deep yellow, orange, red and dark green veggies & Fruits

What is a carotenoid?

precursors of vitamin A

What are the 2 forms of Vitamin D?

D₂ Ergo-calciferol (plant)

D₃ cholecalciferol (animal)

Where does Vitamin D absorption occur?

Small intestines (with fat & joins with micelles)

What can prevent the final step in Vitamin D₃ activation?

Impaired kidney function

What are the key functions of Vitamin D hormone?

Controls Phosphorus & Calcium levels in bone & blood

Stimulate active transport of Phosphorus and calcium in small intestine

Associated with calcium and phosphorus absorption and bone formation

Synthesis of 7-Dehydrocholesterol in skin

What happens with the synthesis of 7-Dehydrochlesterol?

It converts to cholecalciferol (active form of Vitamin D)

What is Hypercalcemia?

Too much calcium in the blood.

What is Osteomalacia?

Previously deposited bone mineral is mobilized leading to bone pain and weak, brittle bones.

What is the Upper Limit for Vitamin D?

100 mcg (4000 IU)

What is the most toxic vitamin?

Vitamin D

What are the food sources of Vitamin D?

Fatty fish - mackeral, salmon

Fortified Milk, margarine,

fortified OJ

Ready to eat cereals

Which Vitamin’s most important role is as an antioxidant?

Vitamin E

Where is Vitamin E stored?

Liver & adipose tissue (mobilized very slowly)

What is another name for Vitamin E?

Tocopherol

Where is Vitamin E absorbed?

in the micelles with the help of bile

How is Vitamin E transported?

in Chylomicrons

What are free radicals?

elements or molecules with unpaired electrons that attack double bonds in membranes & other body tissue

What Vitamin can be spared by Selenium to reduce that Vitamin’s requirement?

Vitamin E

What substance is made of fat & protein that forms a fatty sheath around the nerve axons to protect and insulate the nerves AND facilitate transmission of neuro-muscular impulses?

Myelin

What causes Hemolytic Anemia?

A breakdown of the outer membrane of red blood cells and loss of their hemoglobin - in people with Vitamin E deficiency

What are the richest food sources of Vitamin E?

Vegetable Oils (sunflower, safflower, canola, corn, olive)

Nuts and Peanut butter

Mustard Greens

What makes up a large portion of cell membranes and is vulnerable to attack from free radicals?

Polyunsaturated fats

Mega doses of Vitamin E can exacerbate what effect of drugs?

The anticoagulant effect to reduce blood clotting

What are the 3 forms of Vitamin K?

Phylloquinone

Menaquinone

Menadione

Phylloquinone & Menaquinone require what for absorption?

Pancreatic lipase & bile salts

What Vitamin is the newest and most important?

Vitamin K

What is Vitamin Ks function in Blood Clotting?

It initiates the liver synthesis of 4 blood clotting proteins

Converts prothrombin to thrombin (which in turn converts fibrinogen to fibrin

What is Vitamin Ks role in Bone Metabolism?

Stimulates the synthesis of osteocalcin & other proteins important in bone.

Proteins dependent on it are necessary for the formation of bone matrix and mineral deposition.

How does Vitamin K travel in the body?

Via lymphatic system, then portal blood to the liver.

What form of Vitamin K can be absorbed directly into the portal blood and is water soluble?

Menadione

What is the form of Vitamin K found in plants and is the major dietary form?

Phylloquinone

Why is a prophylactic dose of Vitamin K given to newborns?

To prevent hemorrhagic disease

What can lead to malabsorption of Vitamin K?

Defects in fat absorption

Anticlotting drugs therapy

Extended use of antibiotics

What are the richest food sources of Vitamin K?

Kiwi

Mustard Greens

Liver

Spinach

Brussel Sprouts

Canned Tuna (packed in oil)

What form of Vitamin K is synthesized by the intestinal bacteria?

Menaquinone

What substance bearing a close structural resemblance to an essential nutrient or metabolite interferes with is physiologic function?

Antimetabolite

What are the results of Vitamin A deficiency?

Poor dark adaptation (night blindness)

Keratinization of epithelial tissue

Growth Failure

Reproductive Failure

What are the Physiological Functions of Vitamin A?

Production of rhodopsin and other light-receptor pigments

Formation and maintenance of epithelial tissue

Immune function

Growth

Reproduction

What are the Physiological Function of Vitamin D?

Calcium and Phosphorus absorption

Calcitriol is major hormone regulator of bone mineral metabolism

Possible roles in muscle function and control of cell growth

What are the Physiological Functions of Vitamin E?

Antioxidant

Protect cell membranes including red blood cell membranes

Partner with selenium in antioxidant function

What are the Physiological Functions of Vitamin K?

Activates blood clotting factors

Participates in bone formation and remodeling

Interferes with anticoagulant therapy

What is the result of Vitamin D deficiency?

Defective bone growth

Rickets in children and youth

Osteomalacia in adults

What are the results of Vitamin K deficiency?

Hemorrhagic disease in newborns

Defective blood clotting

Deficiency symptoms produced by anticoagulant and antibiotic therapy

Where is Vitamin C absorbed by the body?

Small intestine (but needs acidic environment)

What are the signs of Vitamin C deficiency?

Easy Bruising

Pinpoint hemorrhages of the skin (petechiae)

Weak bones that fracture easily

poor wound healing

bleeding gums (gingivitis)

Anemia

What are the Physiological Functions of Vitamin C?

Antioxidant activity

Collagen synthesis

General Metabolism

Makes iron available for hemoglobin synthesis

Controls conversion of the amino acid phenylalanine to tryosine

What are major food sources of Vitamin C?

Citrus fruits

Berries

Veggies: Broccoli, cabbage, chili peppers, potatoes, tomatoes

What is caused by high levels of Vitamin C?

Kidney stones

GI symptoms

Diarrhea

What are the clinical applications of Vitamin C

wound healing

fever & infection

growth

stress & body response

chronic disease prevention

What does the formation of intercellular cement do?

Helps build & maintain many body tissues including bone matrix, cartilage, dentin, collagen & connective tissue

What form of milk contains Vitamin C?

Human breast milk

What is the toxic level of Vitamin C?

2000 mg

Who requires more Vitamin C?

Smokers (require 35 mg/d more)

Which B Vitamins are associated with classic deficiency disease?

Thamin, riboflavin & niacin

What are the important blood-forming factors?

Folate & Vitamin B₁₂ (Cobalamin)

*recently discovered coenzyme factors - Vitamin B₆ (pyridoxine), pantothenic acid & biotin

Where does the name for Thiamin (B₁) come from?

its chemical ring-like structure (Thiazole Ring)

Where is Thiamin absorbed?

Upper small intestine (before the acidity of food mass is buffered by the alkaline secretions from the pancreas)

What spares Thiamin?

Fat & Protein

What is the excretion process for Thiamin?

Excess is excreted in urine after tissues are saturated

What is the co-enzyme role of Thiamin?

When combined with phosphorus to form thiamin pryo-phosphate (TPP) it helps with reactions involving glucose.

Symptoms of Beriberi are related to what?

Loss of energy from glucose metabolism

What systems are effected by a deficiency of Thiamin?

Gastrointestinal

Nervous

CVD

Muscularskeletal

What food sources are rich in Thiamin?

Lean pork, beef, liver

Whole & enriched breads and ready to eat cereals

legumes.

Where is Thiamin stored?

It’s not stored - a continuous supply needed

What is the chemical/physical nature of Riboflavin (B₂)?

Stable to heat

Easily destroyed by light & irradiation

Where is Riboflavin stored?

in small amounts - the liver and kidneys (limited)

Where is Riboflavin absorbed?

The upper small intestine

What is ariboflavinosis?

A riboflavin deficiency that includes a combination of tissue inflammation and breakdown, along with poor healing

Who is at risk for Riboflavin deficiency?

Hemodialysis patients

Pregnant & Lactating women

Infants and Children

Lactose intolerant individuals

Infants treated with phototherapy

What is Cheilosis?

Cracks and scaly lesions on the lips and mouth from riboflavin deficiency

What is Glossitis?

Swollen, reddened tongue - a symptom of riboflavin deficiency