Week 2: proteins

proteins

20 different amino acids; has specific number of amino acids; ranges 100-300

dipeptide

2 amino acids joined by a peptide bond

polypeptide

several amino acids joined

high quality - high biological value, lower quality - intermediate biological value, low quality - low biological value

what are 3 classifications of protein foods?

protein digestion

occus in stomach and then in small intestines

high quality protein

all 9 EAAs present in adequate amounts to sustain optimal growth, maintenance and repair and maintains nitrogen balance

lower quality protein

contain the 9 EAAs, however one or more EAAs are insufficient to support optimum protein synthesis; can support life but not growth; plant foods are sources of protein but are considered this level

low quality protein

missing one or more EAAs required for growth

nitrogen balance

equilibrium in breakdown and consumption of protein - healthy individuals excrete same about of protein as consumed

negative nitrogen balance

malnutrition or illness excretes more nitrogen than is ingested

positive nitrogen balance

in periods of growth, more protein retained than lost

physiological roles of protein

generation of new body tissues; repair of body tissues; production of essential compounds; regulation of fluid balance - maintains blood volume; resistance to disease; transport proteins; energy

lactovegetarian

plant foods & dairy products; no meat, fish, poultry or eggs; good for children; cheese and dairy products complement plant foods and provide good source of amino acids

ovolactovegetarian

plant foods & dairy products & eggs; no meat, fish or poultry; all nutrients are likely to be provided in diet; caution and concerns arise if serum cholesterol levels become too high and fat consumption must be reduced

ovovegetarian

plant foods & eggs; no meat, fish, dairy products

semi-vegetarian

avoids red meat

fruitarian

eats mainly fruits