Does flaxseed aid in hormone imbalances, particularly those related to estrogen levels?

From the Guidelines

Flaxseed may aid in hormone imbalances related to estrogen levels due to its high content of lignans, which are phytoestrogens that can have mild estrogenic or anti-estrogenic effects. The study by 1 suggests that phytoestrogens, such as those found in flaxseed, may have beneficial effects on prostate cancer growth, although the evidence is not yet conclusive. For those interested in trying flaxseed for hormone balance, a typical recommended amount is 1-2 tablespoons (10-20 grams) of ground flaxseed daily, which can be sprinkled on food or mixed into smoothies.

• Ground flaxseed is preferable to whole seeds as it's more easily digested and the nutrients are more bioavailable.
• The lignans in flaxseed are converted by gut bacteria into enterolactone and enterodiol, compounds that can weakly mimic estrogen in the body when natural estrogen is low or block stronger estrogens when levels are high.
• This adaptogenic quality makes flaxseed potentially beneficial for conditions like menopause (when estrogen is low) or conditions where estrogen dominance may be a concern.
• Additionally, flaxseed contains omega-3 fatty acids which support overall hormonal health by reducing inflammation.
• For best results, consistency is key, and benefits may take several weeks to become noticeable.
• Store ground flaxseed in the refrigerator to prevent rancidity of the oils.

From the Research

Flaxseed and Hormone Imbalances

• Flaxseed has been suggested to have an effect on hormone imbalances, particularly those related to estrogen levels 2, 3.
• The phytoestrogens present in flaxseed, such as lignans, have been shown to modulate estrogen metabolism and estrogen receptor and growth factor receptor signalling pathways 2.
• Studies have found that flaxseed supplementation can alter estrogen metabolism in postmenopausal women to a greater extent than soy supplementation 3.
• The consumption of flaxseed has been associated with a reduction in the risk of breast cancer, particularly in postmenopausal women, which may be related to its effect on estrogen metabolism 2.

Effects on Estrogen Levels

• Flaxseed has been shown to increase the urinary excretion of 2-hydroxyestrone, a less biologically active estrogen metabolite, which may have a beneficial effect on hormone-dependent diseases 3.
• The lignans present in flaxseed have been found to reduce breast cancer and all-cause mortality by 33%-70% and 40%-53%, respectively, without reducing tamoxifen effectiveness 2.
• However, the effects of flaxseed on estrogen levels in premenopausal women are less clear, and more studies are needed to fully understand its impact on hormone imbalances in this population.

Comparison with Other Phytoestrogens

• Flaxseed has been compared to other phytoestrogen-rich foods, such as soy, in terms of its effect on hormone imbalances 3, 4.
• While soy phytoestrogens have been found to have a beneficial effect on reproductive hormones and lipid profiles in women with polycystic ovary syndrome, the effects of flaxseed on these outcomes are less clear 4.
• A review of human studies on dietary phytoestrogens found that the effects of these compounds on hormones depend on various factors, including the type and concentration of phytoestrogen, ethnicity, and health status of the consumer 5.