Lignans (Flaxseed) are phytoestrogens with estrogenic or anti-estrogenic activity. Flaxseed has the highest content of phytoestrogen, (see chart), however it also antagonizes it's estrogenic effect, and btw, so does phytoestrogens themselves.
So why doesn't flaxseed work for everyone?, well here's why: and the text is highlighted:
When plant lignans are ingested, they can be metabolized by intestinal bacteria to the enterolignans, enterodiol and enterolactone, in the intestinal lumen (4). Enterodiol can also be converted to enterolactone by intestinal bacteria. Not surprisingly, antibiotic use has been associated with lower serum enterolactone levels (5). Thus, enterolactone levels measured in serum and urine reflect the activity of intestinal bacteria in addition to dietary intake of plant lignans. Because data on the lignan content of foods are limited, serum and urinary enterolactone levels are sometimes used as markers of dietary lignan intake. A pharmacokinetic study that measured plasma and urinary levels of enterodiol and enterolactone after a single dose (0.9 mg/kg of body weight) of secoisolariciresinol, the principal lignan in flaxseed, found that at least 40% was available to the body as enterodiol and enterolactone (6). Plasma enterodiol concentrations peaked at 73 nanomoles/liter (nmol/L) an average of 15 hours after ingestion of secoisolariciresinol, and plasma enterolactone concentrations peaked at 56 nmol/L an average of 20 hours after ingestion. Thus, substantial amounts of ingested plant lignans are available to humans in the form of enterodiol and enterolactone. Considerable variation among individuals in urinary and serum enterodiol:enterolactone ratios has been observed in flaxseed feeding studies, suggesting that some individuals convert most enterodiol to enterolactone, while others convert relatively little (1). It is likely that individual differences in the metabolism of lignans, possibly due to gut microbes, influence the biological activities and health effects of these compounds.
Biological Activities
Estrogenic and Anti-Estrogenic Activities
Estrogens are signaling molecules (hormones) that exert their effects by binding to estrogen receptors within cells (see chemical structures). The estrogen-receptor complex interacts with DNA to change the expression of estrogen-responsive genes. Estrogen receptors are present in numerous tissues other than those associated with reproduction, including bone, liver, heart, and brain (7). Although phytoestrogens can also bind to estrogen receptors, their estrogenic activity is much weaker than endogenous estrogens, and they may actually block or antagonize the effects of estrogen in some tissues (8). Scientists are interested in the tissue-selective activities of phytoestrogens because anti-estrogenic effects in reproductive tissue could help reduce the risk of hormone-associated cancers (breast, uterine, ovarian, and prostate), while estrogenic effects in bone could help maintain bone density. The enterolignans, enterodiol and enterolactone, are known to have weak estrogenic activity. At present, the extent to which enterolignans exert weak estrogenic and/or anti-estrogenic effects in humans is not well understood.
Estrogen Receptor-Independent Activities
Enterolignans also have biological activities that are unrelated to their interactions with estrogen receptors. By altering the activity of enzymes involved in estrogen metabolism, lignans may change the biological activity of endogenous estrogens (9). Lignans can act as antioxidants in the test tube, but the significance of such antioxidant activity in humans is not clear because lignans are rapidly and extensively metabolized (4). Although one cross-sectional study found that a biomarker of oxidative damage was inversely associated with serum enterolactone levels in men (10), it is not clear whether this effect was related to enterolactone or other antioxidants present in lignan-rich foods.
http://lpi.oregonstate.edu/infocenter/ph...s/#sources
So why doesn't flaxseed work for everyone?, well here's why: and the text is highlighted:
When plant lignans are ingested, they can be metabolized by intestinal bacteria to the enterolignans, enterodiol and enterolactone, in the intestinal lumen (4). Enterodiol can also be converted to enterolactone by intestinal bacteria. Not surprisingly, antibiotic use has been associated with lower serum enterolactone levels (5). Thus, enterolactone levels measured in serum and urine reflect the activity of intestinal bacteria in addition to dietary intake of plant lignans. Because data on the lignan content of foods are limited, serum and urinary enterolactone levels are sometimes used as markers of dietary lignan intake. A pharmacokinetic study that measured plasma and urinary levels of enterodiol and enterolactone after a single dose (0.9 mg/kg of body weight) of secoisolariciresinol, the principal lignan in flaxseed, found that at least 40% was available to the body as enterodiol and enterolactone (6). Plasma enterodiol concentrations peaked at 73 nanomoles/liter (nmol/L) an average of 15 hours after ingestion of secoisolariciresinol, and plasma enterolactone concentrations peaked at 56 nmol/L an average of 20 hours after ingestion. Thus, substantial amounts of ingested plant lignans are available to humans in the form of enterodiol and enterolactone. Considerable variation among individuals in urinary and serum enterodiol:enterolactone ratios has been observed in flaxseed feeding studies, suggesting that some individuals convert most enterodiol to enterolactone, while others convert relatively little (1). It is likely that individual differences in the metabolism of lignans, possibly due to gut microbes, influence the biological activities and health effects of these compounds.
Biological Activities
Estrogenic and Anti-Estrogenic Activities
Estrogens are signaling molecules (hormones) that exert their effects by binding to estrogen receptors within cells (see chemical structures). The estrogen-receptor complex interacts with DNA to change the expression of estrogen-responsive genes. Estrogen receptors are present in numerous tissues other than those associated with reproduction, including bone, liver, heart, and brain (7). Although phytoestrogens can also bind to estrogen receptors, their estrogenic activity is much weaker than endogenous estrogens, and they may actually block or antagonize the effects of estrogen in some tissues (8). Scientists are interested in the tissue-selective activities of phytoestrogens because anti-estrogenic effects in reproductive tissue could help reduce the risk of hormone-associated cancers (breast, uterine, ovarian, and prostate), while estrogenic effects in bone could help maintain bone density. The enterolignans, enterodiol and enterolactone, are known to have weak estrogenic activity. At present, the extent to which enterolignans exert weak estrogenic and/or anti-estrogenic effects in humans is not well understood.
Estrogen Receptor-Independent Activities
Enterolignans also have biological activities that are unrelated to their interactions with estrogen receptors. By altering the activity of enzymes involved in estrogen metabolism, lignans may change the biological activity of endogenous estrogens (9). Lignans can act as antioxidants in the test tube, but the significance of such antioxidant activity in humans is not clear because lignans are rapidly and extensively metabolized (4). Although one cross-sectional study found that a biomarker of oxidative damage was inversely associated with serum enterolactone levels in men (10), it is not clear whether this effect was related to enterolactone or other antioxidants present in lignan-rich foods.
http://lpi.oregonstate.edu/infocenter/ph...s/#sources
Did the member you referred to use the oil topically or ingest it?
