The phytochemical contents of the Longissimus lumborum muscle
are shown in Table 7. Few studies have examined phytoestrogen
concentrations in tissues or body fluids other than plasma and urine.
Despite the potential importance of lignans in reducing the risk of
disease and cancer, little is known of the metabolic fate of these compounds
or direct metabolites and their distribution in the body tissues
resulting from the ingestion of the precursor compounds (Saarinen
and Thompson, 2010; Whitten and Patisau, 2001).
Dietary supplementation with sprouts produced higher total phytoestrogen
content (approximately 30%) than was found in the control
group. This change was mainly due to secoisolariciresinol diglucoside.
Despite the fact that the secoisolariciresinol diglucoside content was
definitively higher in flaxseed than in alfalfa sprouts, the difference in
the tissue levels of animals fed sprouts was not significant. A similar
trend was observed for other lignans such as hydroxymatairesinol
and secoisolariciresinol with differences even less pronounced. The
isolariciresinol content was lower in the alfalfa sprouts than in the
controls, and this difference was also found in the respective muscle
tissues. In contrast, the supplementation with flaxseed sprouts seemed
to induce a slight increase in isolariciresinol levels whereas no difference
in the matairesinol content was observed.
The major classes of phytochemical compounds are isoflavones,
lignans and coumestans (Bingham, Atkinson, Liggins, Bluck & Coward,
1998). In plants, these compounds occur as glycosides, which are
deconjugated by intestinal glucosidases to aglycones (Webb and
McCullough, 2005) and further metabolized by the intestinal microflora
into hormone-like compounds with weak estrogenic activity.
Lignans can be converted into the mammalian lignans enterodiol
and enterolactone, whereas the isoflavone daidzein can be converted
into O-desmethylangolensin (O-DMA) and equol. The phytoestrogen
content of rabbit meat (150–220 μg/100 g) is lower than that of soybased
foods (approximately 6mg/100 g) but similar to that of commonly
consumed meat and vegetables (Kuhnle et al. 2008).
A number of studies have reported a correlation between lignan
intake and risk of certain illnesses such as cancer and CHD. The benefits
of lignan and lignan metabolites are thought to be associated with the
estrogen-like activity of these compounds; however, the exact mechanisms
are not entirely known.
Recently, Almario and Karakas (2013) found that diets high in lignan
decreased total cholesterol, LDL-C, and oxidized (Ox)-LDL levels by 25%,
thus contributing to a decrease in one of themain risk factors for cardiovascular
disease.