Viewing All Flashcards for Nutrition Midterm 2
Essential, non-caloric nutrients that are needed in tiny amounts from diet to help drive cell processes.
Fat-soluble & water soluble.
The B vitamins & vitamin C
Because developed countries usually promote a high in fat diet.
Because they aren't water-soluble, this limits their routes of excretion; which can lead to toxicity if taken in high amounts.
Can occur with fat-free diet over a long period of time.
Vitamin A; this one is not found in fast food.
In the liver and fatty tissues for longer periods
Retinol, retinal, retinoic acid
Retinol is stored in the liver and released in bloodstream, where it is picked up by cells and converted to retinal and retinoic acid.
Beta-carotene is the precursor form of Vitamin A. Beta-carotene from food is converted to retinol in the body.
Preformed active vitamin A; found in animal sources like liver, and fish oil, fortified milk and milk productsPre-cursor: Beta-carotene found in yellow/orange fruits and vegetables (yellow squash, sweet potato, cantaloupe, apricots, mango) also dark green vegetables (spinach, romaine salad). The orange colour masked by chlorophyll. The deeper the colour; the richer the source.
Food from animal sources (retinyl esters) are converted to retinol in body; which can be converted to retinal and retinoic acid and used by tissues. Retinol is the form that circulates in the blood. Retinol itself is important for reproduction. Beta-carotene from plant food is converted to retinal in the body, which is important for vision. Retinal can be converted to retinoic acid or retinol. Retinoic acid regulates growth.
Vision: deficiency can cause night blindnessCornea maintenance: deficiency can cause keratinization in cornea, which leads to blindnessSkin & mucous membrane: deficiency can cause keratinization. Prevents infections by maintaining healthy cells in mucous membrane (deficiency changes structure and function).Cell differentiation: turns cells on and off - reproduction: determines what cells will grow to what organs- immunity: in bone marrow, some cells differentiate to white blood cells (also red blood cells)- bones & teeth: turns on genes and tells them to break down or remineralize bone- epithelial cells: turns on genes and tells them to differentiate to epithelia cells (skin maintenance)
Vitamin A is involved in the perception of light. In the eye, the retinal form of Vitamin A combines with the protein opsin to form the visual pigment rhodopsin. The rhodopsin helps transform the energy from light into a nerve impulse that is transmitted to the brain; which allows us to see. As rhodopsin absorbs light, retinal changes from cis to trans, which triggers the nerve impulse to carry information to brain. Some retinal is lost from the cycle when this happens. Normal vitamin A levels replace this retinal that is lost.When vitamin A is deficient, regulation of rhodopsin is delayed; causes night blindness.
Expressed in retinol equivalents. New DRI values have lowered requirements for Vitamin A.
Blindness, keratinization, stunted growth, impaired immunity, poor appetite and death.Also measles is worsened with vitamin A deficiency.
Because vitamin A is stored in liver and adipose tissue and accumulates.
Because conversion to retinol is inefficient.
Abdonminal pain, hair loss, joint pain, stunted growth, bone and muscle soreness, cessation of menstruation, nausea, diarrhea, rashes, damage to liver, enlargement of spleen