sure id like to hear his opinion
For one, it's a moot issue if you are talking about flax
oil. The main flaxseed lignan is secoisolariciresinol diglucoside (SDG), which is found in the hull but which occurs in the oil in very small quantities. I don't generally recommend large amounts of ground flax
seed to men, but it's also a far more complicated issue than you realize, and no simple lignan = estrogenic effects should be made. The term "phyto estrogen" is not automatically a negative per se, as it may act as an anti estrogen depending on the tissue in question and other variables.
For example, flax lignans were found to reduce mammary carcinogenesis, which means it's acting as an anti estrogen in those tissues. For example: "phytoestrogens, like certain
selective estrogen receptor modulators, have an antiproliferative effect on the breast, and positive effects on the lipoprotein profile and bone density. They might also improve some of the climacteric symptoms." (Brzezinski A & Debi A, Eur J Obstet Gynecol Reprod Biol, 85(1): 47, 1999)
The bottom line here is, it's WAY more complicated than you think. Should men run out and eat large amounts of ground flax
seed in hopes of getting an anti estrogenic effect? No, as large amounts of weak estrogens in the male system can still act as an estrogen, but the effects, dose needed, etc, etc are far from clear at this time.
Should men worry about the tiny amounts of lignans found in flax
oil? No. As mentioned, I have known and or trained some high level men using up to 7tbl spoons per day of flax oil, with no negative impact on them that I could see, and one mentioned a reduction in gyno, which he attributed to the addition of the flax oil, bu of course that's an n =1 observation and not objective science by any means. Studies in animals, again, suggest interesting effects:
J Toxicol Environ Health A. 1999 Apr 23;56(
:555-70.
Dose, timing, and duration of flaxseed exposure affect reproductive indices and sex hormone levels in rats.
Tou JC, Chen J, Thompson LU.
Department of Nutritional Sciences, University of Toronto, Ontario, Canada.
Flaxseed ingestion produces large amounts of mammalian lignans. Since lignans have weak estrogenic/antiestrogenic properties, the objective of this study was to determine in rats whether exposure to 5% or 10% flaxseed affects sex hormone levels and reproductive indices when given at different developmental stages. Rats were exposed to either a basal diet (control), 5%, or 10%
flaxseed diet starting at weaning on postnatal day (PND) 21 or continuously from gestation to PND 132 for lifetime exposure. Compared to the control, exposure to 5% or 10% flaxseed after weaning produced no marked reproductive effects, whereas lifetime flaxseed exposure caused significant changes that differed depending on the dose. In female rats, lifetime exposure to 5% flaxseed affected the reproductive tract as indicated by delayed puberty onset. In contrast, lifetime exposure to 10% flaxseed caused earlier puberty onset, higher relative ovarian weight, higher serum estradiol levels, and lengthened estrous cycles.
In male rats, lifetime 10% flaxseed exposure raised serum testosterone and estradiol levels and produced higher relative sex organ weights and prostate cell proliferation. In contrast, lifetime exposure to 5% flaxseed reduced adult relative prostate weight and cell proliferation, suggesting potential protection against prostatic disease, although sex hormone levels were unaffected. In conclusion, flaxseed can potentially alter reproduction, depending on the dose and timing of exposure.
PS, I plan on writing about this topic in my next news letter. Last two if you are interested can be found:
April:
http://www.brinkzone.com/articledetails.php?aid=119&acatid=8March:
http://www.brinkzone.com/articledetails.php?aid=116&acatid=8Will @
www.BrinkZone.com