Detoxification mechanisms of the liver
Primary functions of the liver explained including filtration of the blood, formation of bile, and detoxification. We also discuss what to look for when assessing liver function.

November 26th 2011 - Felicity Marsland is the naturopath at Adelaide Natural Health. She specialises in detoxification of the liver and body and managing irritable bowel syndrome through better nutrition.

1.1 Filtration of the blood

One of the primary functions of the liver is to filter the blood. Blood from the intestines is loaded with bacteria, endotoxins and by products of the immune system when invaders are neutralized – antigen-antibody complexes. A well functioning liver clears 99% of bacteria from the blood before it re-enters circulation.

1.2 Formation of bile

Bile is synthesized and secreted by the liver; it is a carrier by which many toxic substances are eliminated by the body via the intestines when it is absorbed by fibre and excreted. A diet low in fibre results in the toxins not being bound very well in the faeces and are reabsorbed. Bacteria in the gut can modify toxins further and make them more damaging to the body.

Bile also emulsifies fats and fat soluble vitamins.

1.3 Phase I detoxification

Enzymes neutralize unwanted chemical compounds in a 2 phase process. Phase I will directly neutralize some chemicals, but the rest are modified to be converted to neutral forms in phase II. These mid conversion chemicals are more toxic in this intermediate state, and the body relies on an active phase II to quickly neutralize these toxins.

The phase I enzymes are collectively known as cytochrome p450. These enzymes are all capable of metabolizing the same chemicals but some enzymes neutralize more efficiently than others. The activity of the individual enzymes will depend on genetic inheritance, nutritional status and previous exposure to toxic chemicals.

Cytochrome p450enzymes will convert a toxin to a neutral water soluble form where it is excreted by the kidneys or to a more active chemical form where it will be neutralized in phase II. A by-product of any enzyme activity in phase I is free radicals. Every time a toxin is neutralized, the liver is damaged by the free radical produced, hence the importance of antioxidants. The most important antioxidant for the liver is glutathione, as it is required as an antioxidant for phase I, plus has a key role in phase II detoxification. If the body has low levels of glutathione and it is used up during phase I, then phase II glutathione-dependant process stop.

An active phase I/ inactive phase II exposes the body to large amounts of toxin.

Cytochrome P450 enzymes require the following nutrients to function:

* Copper
* Magnesium
* Zinc
* Vitamin C

Phase I detoxification is activated by:

* Drugs- alcohol, nicotine, steroids sulphonamides, Phenobarbital
* Environmental toxins
* Foods – brassica family, charcoal meats, high protein diet, oranges
* Nutrients vitamin B1, B3, C
* Herbs – caraway and dill

* note that the brassica family stimulates both phase I and II detox. enzymes, including an anti-cancer enzyme. Limonene is a phytochemical present in oranges and the seeds of caraway and dill, this too induces phase I and II enzymes which neutralize carcinogens.

Inhibiting phase I enzymes without increasing phase II is not advised as toxins then remain longer in the body. Grapefruit juice and grapefruit contains a flavonoid called naringenin which inhibits cytochrome p450 activity by 30%.

Other inhibitors of phase I enzymes include:

* Drugs – benzodiazepines, antihistamines, cimetidine ie. zantac,
* Curcumin from tumeric
* Capsaicin from capsicums
* Old age – toxicity from drugs occurs more easily.

* note that curcumin inhibits phase I but stimulates phase II, effective in preventing cancer.

A healthy phase I detoxification depends on:

* Brassica family food – cabbage broccoli, brussel sprouts
* Vitamin B rich food – whole grains, nutritional yeast.
* Vitamin C rich food – oranges, tomatoes, cabbage.

What to look for when assessing liver function.

Symptoms of liver dysfunction:

* Bloating and nausea especially after fatty foods
* Weight gain and constipation
* Waking in the morning with a coated tongue and halitosis
* Exacerbation of skin rashes, eczema, asthma, hayfever.
* Headaches
* Fluid retention
* Mood changes, depression caused by excessive toxins in the blood stream
* Poor immunity

Conditions associated with liver dysfunction:

* Hypoglycaemia
* Reduced alcohol tolerance
* Impaired gallbladder function
* Increased blood pressure
* Gout
* Impaired kidney function
* Fatty liver
* Hormonal imbalances

Contact Member:
Adelaide Natural Health
Suite 11, 132 O'Connell Street
North Adelaide, SA 5006