LCA and DCA are secondary bile acids.

What are bile acids?

Bile acids are the final product of cholesterol metabolism in the liver. They play an important role in fat digestion and absorption. The primary bile acids are chenodeoxycholic acid (CDCA) and cholic acid (CA).

These bile acids can be converted into secondary bile acids in the colon.

CDCA is converted into lithocholic acid (LCA) and CA is converted into deoxycholic acid (DCA).

What are secondary bile acids?

These secondary bile acids are associated with disease. An LCA:DCA ratio greater than 1 is associated with increased risk of gallstones, breast cancer, and colorectal cancer. 

Colonic bacteria metabolize primary bile acids to secondary bile acids. Dietary fiber and bacteria flora determine the rates of metabolism for the secondary bile acids, lithocholic acid (LCA) and deoxycholic acid (DCA).

The LCA:DCA ratio may be an important discriminating marker in colorectal cancer susceptibility. An elevated secondary bile acid ratio is associated with an increased risk of breast and colorectal cancer. Elevated levels may also occur in patients with gall stones and after cholecystectomy.

References:

- Steroids and cancer: faecal bile acid screening for early detection of cancer risk. - [L]

- Rye Bread Improves Bowel Function and Decreases the Concentrations of Some Compounds That Are Putative Colon Cancer Risk Markers in Middle-Aged Women and Men [L]

- Fecal steroids and colorectal cancer. [L]

- A prospective study of serum bile acid concentrations and colorectal cancer risk in post-menopausal women on the island of Guernsey [L]