Guest guest Posted September 27, 2004 Report Share Posted September 27, 2004 Nat, There are substances (drugs, herbs, etc.) that induce or inhibit specific P450 enzymes. There are hundreds of these enzymes but humans have only 50, nine of which metabolize drugs. Cytochrome P450 enzymes CYP3A4 and CYP2D6 biotransform (i.e., metabolize/detoxify) more than 70% of the drugs/substances tested. For example, cigarette smoke induces (speeds up) CYP1A2. Prozac (and many other SRRIs) inhibit CYP2D6. Grapefruit juice inhibits the CYP3A4 enzyme which can cause toxic levels of drugs that are also metabolized by CYP3A4 (such as Xanax, caffeine, codeine, DHEA, erythromycin, Ambien, theophylline, etc.) As far as I can tell, it doesn't make any sense to say that any substance speeds up Phase I detox because no substance either affects all the P450 enzymes. Do you know which of the P450 enzymes is affected by grapefruit seed extract (active ingredient 'Citricide')? I couldn't find anything with a Google search. Understanding which P450 enzymes metabolize specific drugs/substances has helped me to understand my daughter's poor reaction to drugs and other substances. Many things affect the expression of P450 enzymes (lack of certain vitamins, iron deficiency, etc.) There are genetic tests for CYP2D6 because some people lack this enzyme while others have low levels. According to www.prozactruth.com, this test is used by Drug Companies to screen out individuals that have non-performing or low levels of CYP2D6 from participating in drug trials of antidepressants that are metabolized by CYP2D6. More information at http://www.edhayes.com/startp450.html Janet McAuley >I have learned that grapefruit seed extract can affect Phase I of the liver's detox scheme. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted September 28, 2004 Report Share Posted September 28, 2004 I think GSE might help people with a naturally fast phase I, where the liver phase II can't keep up. I think a lot of toxins get even more toxic in phase I and only get less toxic after phase II. Therefore you don't want phase I more efficient than phase II. Maybe inhibiting CYP3A4 is exactly what benefits some people. Just a guess, Dagmar. [ ] grapefruit seed extract & Phase I Liver Detox Nat, There are substances (drugs, herbs, etc.) that induce or inhibit specific P450 enzymes. There are hundreds of these enzymes but humans have only 50, nine of which metabolize drugs. Cytochrome P450 enzymes CYP3A4 and CYP2D6 biotransform (i.e., metabolize/detoxify) more than 70% of the drugs/substances tested. For example, cigarette smoke induces (speeds up) CYP1A2. Prozac (and many other SRRIs) inhibit CYP2D6. Grapefruit juice inhibits the CYP3A4 enzyme which can cause toxic levels of drugs that are also metabolized by CYP3A4 (such as Xanax, caffeine, codeine, DHEA, erythromycin, Ambien, theophylline, etc.) As far as I can tell, it doesn't make any sense to say that any substance speeds up Phase I detox because no substance either affects all the P450 enzymes. Do you know which of the P450 enzymes is affected by grapefruit seed extract (active ingredient 'Citricide')? I couldn't find anything with a Google search. Understanding which P450 enzymes metabolize specific drugs/substances has helped me to understand my daughter's poor reaction to drugs and other substances. Many things affect the expression of P450 enzymes (lack of certain vitamins, iron deficiency, etc.) There are genetic tests for CYP2D6 because some people lack this enzyme while others have low levels. According to www.prozactruth.com, this test is used by Drug Companies to screen out individuals that have non-performing or low levels of CYP2D6 from participating in drug trials of antidepressants that are metabolized by CYP2D6. More information at http://www.edhayes.com/startp450.html Janet McAuley >I have learned that grapefruit seed extract can affect Phase I of the liver's detox scheme. Quote Link to comment Share on other sites More sharing options...
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