NTDT401 Lecture Notes - Lecture 12: Grapefruit Juice, Citrus, Papaya
8 Nov 2016
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Forms of vitamin c: ascorbic acid (ah2) Ah2 is oxidized to dha; within enterocytes, dha is reduced back to ah2 (need gsh for reaction) Absorption occurs via ___ transport in the ___ ~90 mg/d; water-soluble nutrients leak out of blood into urine. Relationship with vitamin c and the common cold. Can help to improve immunity, but won"t cure a cold! Some studies say that it causes no differences; others say it decreases duration of symptoms. Inverse relationship between vitamin c and cancers. Effective in reducing pain and improving quality of life, but not prevention or treatment. Functions of vitamin c: antioxidant & pro-oxidant activity, collagen transformation, carnitine synthesis, tyrosine (aa) metabolism, neurotransmitter formation (dopamine & norepinephrine) Ah- acts as a reducing agent to react with free radicals and reactive oxygen species. Attack phospholipids and protein in membrane and oxidize ldl & rbc. Equation of vitamin c acting as a pro-oxidant.
