From the Guidelines
Vitamin E does not have a significant impact on estrogen levels in the body. While some studies suggest that high doses of vitamin E might have slight effects on estrogen in certain contexts, the current evidence is insufficient to support its use for this purpose 1. The most recent and highest quality study available on this topic is from 2008, published in the Annals of Oncology, which focuses on guidelines for managing menopausal symptoms after breast cancer and mentions vitamin E as part of lifestyle modifications for mild or moderate symptoms, but does not specifically address its effect on estrogen levels 1.
Key Points to Consider
- Vitamin E exists in several forms, with alpha-tocopherol being the most biologically active in humans.
- The recommended dietary allowance for vitamin E is 15 mg (22.4 IU) daily for adults, and high doses may increase bleeding risk.
- Vitamin E primarily functions as an antioxidant, protecting cells from oxidative damage rather than directly regulating hormone levels.
- If concerned about estrogen levels, consulting with a healthcare provider is recommended to discuss evidence-based approaches tailored to the individual's health situation.
Clinical Implications
Given the lack of strong evidence supporting the use of vitamin E to affect estrogen levels, and considering its primary role as an antioxidant, the use of vitamin E for the purpose of altering estrogen levels is not recommended. Instead, individuals concerned about their estrogen levels should focus on evidence-based medical approaches under the guidance of a healthcare provider. The potential risks associated with high doses of vitamin E, such as increased bleeding risk, further support a cautious approach to its use for hormonal effects 1.
From the Research
Vitamin E and Estrogen Levels
- The relationship between vitamin E and estrogen levels is complex, with some studies suggesting that vitamin E may affect estrogen levels, while others find no significant impact 2, 3.
- Studies have investigated the effect of hormone replacement therapy (HRT) on vitamin E levels in postmenopausal women, with findings indicating that HRT does not alter vitamin E status 2, 3.
- However, other research suggests that vitamin E may increase biomarkers of estrogen stimulation when taken with tamoxifen, a hormone therapy used to treat breast cancer 4.
- Additionally, studies have found that vitamin E can inhibit the growth of estrogen receptor-positive breast cancer cells by altering the cellular response to estrogen 5.
Effects of Vitamin E on Estrogen
- Vitamin E has been shown to reduce the response of breast cancer cells to estrogen, leading to decreased cell proliferation 5.
- The combination of vitamin E and estrogen has been found to decrease cell proliferation in estrogen receptor-positive cells 5.
- However, vitamin E has also been found to alter and decrease the growth inhibition induced by tamoxifen, a hormone therapy used to treat breast cancer 5.
- The immunostaining of estrogen receptors in breast cancer cells has been found to be reduced by vitamin E, suggesting an effect of vitamin E on the expression of estrogen receptors 5.
Interactions between Vitamin E and Hormone Therapy
- Vitamin E has been found to increase biomarkers of estrogen stimulation when taken with tamoxifen, which may interfere with the therapeutic effects of tamoxifen 4.
- The combination of vitamin E and hormone therapy has been found to have varying effects on inflammatory markers in postmenopausal women, with some studies finding no significant impact 6.
- However, vitamin E has been found to attenuate the increase in C-reactive protein levels induced by estrogen replacement therapy, but not by hormone therapy 6.