Unit 5 - Vitamins Flashcards
What are vitamins?
Organic compounds that are vital to life and indispensable to body functions
Do vitamins have calories?
No
Are vitamins linked together?
No
What are provitamins?
Vitamins that are available in foods in inactive forms
What are the 2 classes of vitamins and which vitamins are in each category?
- Fat soluble (A, D, E, and K)
- Water soluble (B and C)
Fat soluble vitamins require ____ for absorption
Bile
Where are fat soluble vitamins absorbed and how do they travel through the body?
- Absorbed into lymph
- Travel through blood w/ protein carriers
Where can fat soluble vitamins be stored?
- Liver
- Fatty tissues w/ other lipids
Why are fat soluble vitamin supplements not normally used?
Can build up in toxic amounts
Where are water soluble vitamins absorbed and how do they travel through the body?
Absorbed directly into bloodstream where they travel freely
Why are water soluble vitamin toxicities less likely?
Most are not stored in the tissue and excesses are excreted in urine
How often are fat soluble and water soluble vitamins needed?
- Fat soluble needs in periodic doses (weekly or monthly)
- Water soluble needed more frequently (every 1-3 days)
What are the 3 active forms of vitamin A and what does each do?
- Retinol supports reproduction and is the major transport and storage form
- Retinal is active in vision
- Retinoic acid acts as a hormone, regulating cell differentiation, growth, and embryonic development
Is beta carotene found in the body?
No, it is found in plant based foods and is converted to active vitamin A
What are sources of retinol?
- Milk and milk products
- Eggs
- Liver
What are symptoms of vitamin A deficiency?
- Leading cause of preventable blindness in children
- Symptoms generally take about a year to develop
What are symptoms of vitamin A toxicity?
- Seen from supplements and fortified foods
- Can weaken bones
- Can cause malformations in a fetus
Who are most susceptible to vitamin A toxicity?
Children
Can beta carotene cause vitamin A toxicity?
No
What is the overall function of B vitamins?
Act as coenzymes and some are involved in energy metabolism
Which B vitamins are involved in energy metabolism?
- Thiamin
- Riboflavin
- Niacin
- Pantothenic acid
- Biotin
What is the function of folate and vitamin B12?
- Cell division
- Folate activates vitamin B12
What is the function of vitamin B6?
Protein and amino acid metabolism
What can a vitamin B12 deficiency cause?
Damage to nerves
Which B vitamins are found in meats?
- Thiamin (pork)
- Niacin
- Pantothenic acid
- Biotin
- Vitamin B6
- Vitamin B12
In North America, which products are fortified w/ B vitamins?
Grain products
What destroys folate in foods?
Heat and oxidation
Thiamin deficiency is called _____ which is ____
Beriberi; edema/muscle wasting
What is severe thiamin deficiency called and who is it seen in?
Wernicke-Korsakoff syndrome; seen in alcoholics
What effect does alcohol have on thiamin?
- Impairs absorption
- Speeds up excretion
Riboflavin deficiency is called ____ which is ______
Ariboflavinosis; inflammation of the mouth, skin, & eyelids
Why does riboflavin deficiency usually go undetected?
It commonly occurs w/ thiamin deficiency, but thiamin deficiency has more severe symptoms
Niacin deficiency is called _____ which is ______
Pellagra; diarrhea, dermatitis, and dementia
What are folate deficiencies associated with?
Neural tube defects
What are 2 of the first symptoms of folate deficiency?
- Type of anemia
- GI tract deterioration
What can vitamin B12 deficiency during pregnancy cause to the fetus?
Irreversible NS damage that can’t be detected until the baby is born
Which B vitamins have symptoms of toxicity and what are they for each?
- Niacin – “niacin flush” which is dilation of capillaries of the skin
- Vitamin B6 – loss of sensation of feet and legs from supplements
- Folate – can mask symptoms of vitamin B12 deficiency
What are the most common functions of vitamin C?
- Maintains connective tissue
- Antioxidant
What is the RDA for vitamin C?
- 90 mg for men and 75 mg for women
- 125 mg for men that smoke and 110 mg for women that smoke
What are symptoms of vitamin C deficiency?
- Scurvy, which is caused by breakdown of collagen in the absence of vitamin C
- First symptoms are bleeding gums and pinpoint hemorrhages
What is the UL for vitamin C?
2000 mg/day
What are symptoms of vitamin C toxicity?
- Nausea
- Abdominal cramps
- Diarrhea
What happens when vitamin D is absorbed from the sun?
- UV light converts a cholesterol compound in skin into a vitamin D precursor which is directly absorbed into blood
- Liver and kidneys finish converting the precursor to active vitamin D
What is the function of vitamin D?
Mineralization of bones
What are some sources of vitamin D?
- Eggs
- Butter
- Fortified milk and margarine
- Some fatty fish
What are the 2 diseases that can result from vitamin D deficiency?
- Rickets (bone disease in children)
- Osteomalacia (bone disease in adults)
Vitamin __ is the most potentially toxic
D
What is the function of vitamin E?
Antioxidant, especially important in RBC’s and lungs
What are some sources of vitamin E?
- Vegetable oils
- Fruits and vegetables
- Meats and milk products
- Fortified cereals/grains
Why is vitamin E deficiency rare?
1) Vitamin E is found in many foods
2) Body stores lots of vitamin E in fatty tissue
3) Cells recycle vitamin E
What causes symptoms of vitamin E toxicity?
Supplements or fortified foods
What is the function of vitamin K?
Synthesis of proteins that help clot blood
What are some sources of vitamin K?
- Can be derived from a non-food source, our intestinal bacteria
- Dark, leafy green vegetables
What are phytochemicals?
Compounds derived from plants that have biological activity in the body and may support health beyond roles of traditional nutrients
Are phytochemicals effective at fighting disease?
Not enough evidence
What is the safest and most effective source of phytochemicals?
Food, not supplements
What are functional foods?
Whole or modified foods that demonstrate physiological benefits or can reduce chronic disease risk due to the phytochemicals they contain
What do functional foods have added to them?
Phytochemicals, nutrients, or other chemicals
What is the function of flavonoids?
- Antioxidants that may help protect LDL against oxidation
- Minimize inflammation
- Reduce blood platelet stickiness => slowing progression of atherosclerosis
What are sources of flavonoids?
- Whole grains
- Fruits and vegetables
- Soy
- Herbs, spices, teas
- Olive oil
When do flavonoids show benefits?
When an abundance of flavonoid containing foods are consumed
___ and ___ are rich in carotenoids
Fruits and vegetables
What are carotenoids believed to lower the risk of?
Hypertension and heart disease
What is the function of lycopene?
Antioxidant
What are sources of lycopene?
- Guava
- Pink grapefruit
- Tomatoes
- Watermelon
- Papaya
Does the body handle concentrated or diluted phytochemicals better?
Diluted, mixed w/ all of the other constituents of foods
What can soy’s cholesterol-like plant sterols do?
COULD inhibit cholesterol absorption in the intestine, lowering blood cholesterol
