Lignans and health

A high intake of lignans has been associated with lower mortality among breast cancer patients. Similar potential effects in patients with other chronic diseases calls for further research. This will be investigated in the ELIN research project.

When we eat lignans, they are converted to enterolignans (enterolactone and enterodiol) in by the colonic microbiota, after which they are absorbed through the colonic barrier. Of the two enterolignans, enterolactone has attracted most interest, as it accounts for more than 95% of the circulating levels of enterolignans.

 

Lignans and health

The biological activity of enterolignans is related to the estrogen-like structure, and especially enterolactone has been found to bind weakly to estrogen receptors, have estrogenic effects in cultured cells and to modulate the response to endogenous estrogens. Anti-oxidative, anti-neo-angiogenetic, anti-estrogenic and growth factor modulating effects constitute the mechanistic rationale for the potential role of enterolactone in carcinogenesis. Animal models support that these factors may play an important role in prevention of cancer at the early stages leading to lower cancer incidence as well as in the progression of already established tumors. Enterolignans also have the capacity to increase expression of the hepatic low density lipoprotein (LDL) receptor and thereby reduce the circulating levels of LDL, which is of specific interest for heart disease; further advantageous effects related to C-reactive protein and apolipoprotein B have been suggested.

Specific hypotheses in ELIN:

    • High pre-diagnostic blood levels of enterolactone are associated with improved mortality outcome in patients with breast, colorectal and prostate cancer

    • High pre-diagnostic blood levels of enterolactone are associated with improved mortality outcome in patients with acute coronary syndrome and type 2 diabetes

    • Use of antibiotics within the year before blood sampling and clinical disease characteristics may modify the enterolignan-mortality outcome associations

    • Intake of plant lignans from whole grain rye is related to plasma levels of enterolignans in prostate cancer patients and further to improved metabolic profile in blood and tumor tissue

    • The absorption of plant lignans is affected by the matrix in which they are provided and can be improved by enzymatic preparation of the food items

    • High content lignan foods are well accepted and test products will lead to high, stable levels of circulating enterolignans and changes in the microbiome