Bile Acids Facts
Interesting studies related to bile acids:
The effects of bile acids are well known in traditional Chinese medicine.
Remember that everything is about the balance. The point is to allow the liver to regenerate and not to supplement the bile acids forever (if you still have the gallbladder). There are the studies that concluded the carcinogenic effects some of the bile acids like – deoxycholic acid.
One of them is study in mice – the study concluded that 17 out of 18 deoxycholic acid (DOC) fed mice developed the tumors (10 of them was colon cancer) in 8 – 10 months. However the authors concluded that adding the antioxidant to the diet significantly reduced the tumor formation in DOC acid fed mice. But there is another fact yet – the mice was fed also with the significant amount (20 % of food content) of casein (protein) which the researchers and the authors of the book The China Study identified as a carcinogen if consumed at amounts of 20% of a diet. At concentrations of 5% in diet the casein didn’t cause the cancer.[168, 169] So it seems like it is still all just about the balance and importance of consuming the enough amounts of antioxidants.
In the other hand another study disproved that the deoxycholic acid (DOC) levels are higher in the colon cancer patients. However it could be so that after the colon cancer develop it weakens the body up to the point that the deoxycholic acid production is lower.
Another study concluded that the dietary fat-soluble vitamins A and D inhibit the bile acid synthesis. This process may be evolved as self-regulation of fat-soluble vitamin absorption since the bile acids are needed for the dietary fat-soluble vitamins assimilation.
Also the another carcinogenic bile acid – lithocholic acid (LCA) has interesting properties. It can bind to vitamin D receptor (VDR) what activates the lithocholic acid detoxification in the liver and intestine – self-regulated detoxification. The same detoxification path of lithocholic acid is activated also by the vitamin D. This fact may explain the protective effects of vitamin D against the colon cancer. The activated VDR receptor in the hepatocytes (liver cells) may play an important role in inhibition of bile acid synthesis to protect the liver during the cholestasis (low bile flow from the liver).
The colon carcinogenesis may be inhibited by several protective mechanisms of vitamin D: detoxification, raising the cell apoptosis sensitivity, or by inhibition of the proliferation of colon carcinoma cells.
LCA can also substitute the vitamin D in elevation of the serum calcium in vitamin D deficient rats. The researchers confirmed that the LCA can activate the genes in the kidneys of vitamin D deficient rats. So the LCA is able to circulate through the body and bind to the VDR receptors in the tissues.
VDR receptor mediates the most if not all vitamin D (1,25(OH)2D3) actions, so it is very important to have functional VDR receptors.[176, 193]
What are the bile acids?
Bile acids are strongly cytotoxic and their main functions are performed in the small intestine (digestion of fats and breaking down the bacterial cell walls and the toxins).
The conjugation of the bile acids is done in the liver – it improves the fat digestion properties of bile acids and restricts the absorption of the bile acids into the blood from the upper part of the small intestine. The glycine-conjugated bile acids are the most abundant of all bile acids – 70%. The taurine-conjugated bile acids represent about the 20% of produced bile acids.
Main bile acids in bile:
cholic acid – trace amounts
deoxycholic acid – trace amounts
chenodeoxycholic acid – trace amounts
glycocholic acid – 30%
glycodeoxycholic acid – 15%
glycochenodeoxycholic acid – 30%
taurocholic acid – 10%
taurodeoxycholic acid – 10%
taurochenodeoxycholic acid – 5%
In the enterohepatic circulation (bile