Detoxification – what is it?
OK, this is quite technical, but quite handy to know as background to how your liver works:
The liver is one of the most important organs in the body when it comes to detoxifying or getting rid of foreign substances or toxins. The liver neutralizes a wide range of toxic chemicals, both those produced by your own body and those from the environment.
One of the liver’s primary functions is filtering the blood. Almost 2 quarts of blood pass through the liver every minute for detoxification. Filtration of toxins is absolutely critical as the blood from the intestines contains high levels of bacteria, and various other toxic substances. When working properly, the liver clears 99% of the bacteria and other toxins during the first pass.
The liver’s second detoxification process involves the synthesis and secretion of bile. Each day the liver manufactures approximately 1 quart of bile, which serves as a carrier in which many toxic substances are dumped into the intestines. In the intestines, the bile and its toxic load are absorbed by fibre and excreted. However, a diet low in fibre results in inadequate binding and reabsorption of the toxins.
Phase I and Phase II Detoxification
The liver’s third role in detoxification involves a two-step process, Phase 1 and Phase 2. If the phases are out of balance, as in Gilbert’s Syndrome where Phase 2 is impaired, then you are more sensitive to toxins. These toxins not only include drugs, pesticides, and toxins from the gut, but also normal body chemicals such as hormones and inflammatory chemicals (e.g. histamine) which become toxic if allowed to build up.
Phase I enzymes directly neutralize some chemicals, but most are converted to intermediate forms that are then processed by phase II enzymes. These intermediate forms are much more chemically active and therefore more toxic.
Phase II detoxification typically involves ‘conjugation’. Conjugation is where various enzymes in the liver attach small chemicals to the toxin. This conjugation (or binding together) reaction either neutralizes the toxin or makes the toxin more easily excreted through the urine or bile. Phase II enzymes act on some toxins directly, while others must first be activated by the phase I enzymes. There are essentially six phase II detoxification pathways:
· Glutathione conjugation, Amino acid conjugation, Methylation, Sulfation, Acetylation and , Glucuronidation – this last one is impaired in GS sufferers.
Glucuronidation, the combining of glucuronic acid with toxins, requires the enzyme UDP-glucuronyl transferase (UDPGT). Many of the commonly prescribed drugs are detoxified through this pathway. It also helps to detoxify aspirin, menthol, vanillin (synthetic vanilla), food additives such as benzoates, and some hormones. Glucuronidation appears to work well, except for those with Gilbert’s syndrome.
The activity of UDPGT is increased by foods rich in the monoterpene limonene (citris peel, dill weed oil, and caraway oil). Methionine, administered as SAM, has been shown to be quite beneficial in treating Gilbert’s syndrome.
Nutrients needed by phase II detoxification enzymes
Glutathione conjugation: Glutathione, vitamin B6
Amino acid conjugation: Glycine
Sulfation: Cysteine, methionine, molybdenum
Glucuronidation: Glucuronic acid
phase II detoxification enzymes can be encouraged by :
Glutathione conjugation: Brassica family foods (cabbage, broccoli, Brussels sprouts); limonene-containing foods (citrus peel, dill weed oil, caraway oil)
Amino acid conjugation: Glycine
Methylation: Lipotropic nutrients (choline, methionine, betaine, folic acid, vitamin B12)
Sulfation: Cysteine, methionine, taurine
Acetylation: None found
Glucuronidation: Fish oils, cigarette smoking, birth control pills, Phenobarbital, limonene-containing foods
phase II detoxification enzymes can be blocked or slowed down by:
Glutathione conjugation: Selenium deficiency, vitamin B2 deficiency, glutathione deficiency, zinc deficiency
Amino acid conjugation: Low protein diet
Methylation: Folic acid or vitamin B12 deficiency
Sulfation: Non-steroidal anti-inflammatory drugs (e.g. aspirin), tartrazine (yellow food dye), molybdenum deficiency
Acetylation: Vitamin B2, B5, or C deficiency
Glucuronidation: Aspirin, probenecid