@JamesCollier I find it interesting that you say this with such conviction.
(Background: I’ve been following this, and similar, threads with interest as a young female who takes a low dose combined pill primarily to control dysmenorrhea and secondarily as birth control, and who also suffers from hormone triggered migraines. I started having Huel earlier this year but have since stopped, somewhat begrudgingly, because of the phytoestrogen levels, until I have had an opportunity to read the literature and talk to my doctor. However, to add another anecdote to the pile, during the three weeks I was having Huel I had also noticed that my “monthly” migraines were unusually bad.)
I believe that you and the Huel team genuinely aim to produce a product which is nutritionally complete and suitable for the majority of the population (and wouldn’t have purchased it in the first place if I didn’t) but I do wonder if flaxseed is really the ingredient of choice for this given the uncertainty around the effects of phytoestrogens. I note that a fair bit of the discussion on the topic revolves around the effects of additional oestrogen on males - I personally would be more concerned about the effects on females given the proportion of the population who take hormonal birth control or with sensitivity to hormone level fluctuation.
Going back to your comment above, I would like to hear your thoughts on the results of this particular study from the American Journal of Clinical Nutrition: “Supplementation with flaxseed alters estrogen metabolism in postmenopausal women to a greater extent than does supplementation with an equal amount of soy”. You mentioned in another post that there is 12g of flaxseed per 100g Huel, so two portions of Huel with 24g of flaxseed correlates fairly well to the 25g portion of flaxseed in the muffins used in the study.
Sections of particular relevance (bolded for emphasis):
Results:
Urinary concentrations of 2-hydroxyestrone, but not of 16α-hydroxyestrone, increased significantly in the flaxseed group (P = 0.05). In the flaxseed group, the ratio of 2-hydroxyestrone to 16α-hydroxyestrone was positively correlated with urinary lignan excretion (r = 0.579, P = 0.02). In the soy and placebo groups, no significant correlation was observed.
[…]
Discussion:
This study showed that dietary supplementation with 25 g ground flaxseed but not with 25 g soy flour significantly alters the metabolism of estradiol in favor of the less biologically active estrogen metabolite (2OHE1) in postmenopausal women. Our study showed for the first time that changes in urinary lignan excretion with flaxseed supplementation are positively related to significant changes in 2OHE1:16αOHE1.
[…]
Results concerning the effects of phytoestrogen supplementation on serum hormones are conflicting. Although the present study reports no change in serum hormone concentrations, another study reported that consumption of 5 or 10 g ground flaxseed/d for 7 wk significantly reduced serum estradiol concentrations in postmenopausal women (3). The 10-g dose also reduced serum estrone sulfate concentrations (3). In support of our results, Lucas et al (35) found that supplementation with 40 g flaxseed/d for 3 mo had no effect on serum estradiol or estrone concentrations in postmenopausal women."