Should Women Consider DIM To Manage Estrogen?

3 min

Diindolylmethane (DIM) is one of the phytonutrients found in cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts, cabbage, turnips, and kale. The market for DIM supplements is expanding rapidly; they are often advertised as a means of managing estrogen levels and reducing the risk of estrogen-dependent cancers. Because the market is growing faster than research to support effectiveness, I would encourage you to get DIM from foods rather than from supplements.

Estrogen is associated with the development of several different cancers. The most common type of breast cancer is estrogen-dependent, and thyroid cancer is four to five times more common in women than in men, suggesting that there is a hormonal factor in its development. The 2002 bombshell report from the Women’s Health Initiative associating hormone replacement therapy (HRT) with increased risk of breast cancer was followed by a decrease in breast cancer cases as thousands of women stopped HRT. It would seem logical that reducing estrogen levels would also reduce the risk of developing cancer.

Investigations have shown that DIM does help the body metabolize estrogen. A study published in 2024 in the journal BMC Complementary Medicine and Therapies looked at urine samples from more than 19,000 women to see how supplemental DIM affected their urinary estrogen profile; those in the study who took it had lower levels. Since elevated levels of estrogen in urine are associated with increased risk of breast cancer, it would again seem to make sense to conclude that taking DIM supplements would be a reasonable option. So why am I not recommending it?

My concern is that no comprehensive clinical investigation has yet reported a direct link between supplementing with DIM and reduced risk of cancer. We do know that these supplements have common side effects (headache, nausea, vomiting, gas, diarrhea), and there are also instances where DIM appears to act like estrogen in the body instead of helping the body metabolize it. That’s why individuals with hormone-sensitive conditions are advised not to take DIM supplements. Also, if you are taking a diuretic (“water pills”), which lower your sodium levels, you should not take DIM, since it also decreases sodium levels and the combination can be dangerous.

I look forward to seeing the results of several clinical trials that are underway right now to assess the potential of DIM in preventing or treating different types of cancers. In the meantime, I advise you to keep eating your broccoli, cauliflower, and other cruciferous vegetables – they contain DIM as well as lots of other healthy antioxidants with almost no down side. (If broccoli makes you feel gassy, I have some suggestions for you here.)

Andrew Weil, M.D.

Sources
Yager JD, Davidson NE. “Estrogen carcinogenesis in breast cancer.” New England Journal of Medicine 2006 Jan 19;354(3):270-82. doi: 10.1056/NEJMra050776. PMID: 16421368. nejm/doi/full/10.1056/NEJMra050776

Clusan L, Ferrière F, Flouriot G, Pakdel F. “A Basic Review on Estrogen Receptor Signaling Pathways in Breast Cancer.” Int J Mol Sci. 2023 Apr 6;24(7):6834. doi: 10.3390/ijms24076834. PMID: 37047814; PMCID: PMC10095386. pubmed.ncbi.nlm.nih/37047814/

Rajoria S, Suriano R, Parmar PS, Wilson YL, Megwalu U, Moscatello A, Bradlow HL, Sepkovic DW, Geliebter J, Schantz SP, Tiwari RK. “3,3′-diindolylmethane modulates estrogen metabolism in patients with thyroid proliferative disease: a pilot study.” Thyroid. 2011 Mar;21(3):299-304. doi: 10.1089/thy.2010.0245. Epub 2011 Jan 22. PMID: 21254914; PMCID: PMC3048776. pmc.ncbi.nlm.nih/articles/PMC3048776

Rossouw JE, Anderson GL, Prentice RL, LaCroix AZ, Kooperberg C, Stefanick ML, Jackson RD, Beresford SA, Howard BV, Johnson KC, Kotchen JM, Ockene J; Writing Group for the Women’s Health Initiative Investigators. “Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women’s Health Initiative randomized controlled trial.” JAMA. 2002 Jul 17;288(3):321-33. doi: 10.1001/jama.288.3.321. PMID: 12117397. pubmed.ncbi.nlm.nih/12117397/

Newman M, Smeaton J. “Exploring the impact of 3,3′-diindolylmethane on the urinary estrogen profile of premenopausal women.” BMC Complement Med Ther. 2024 Nov 22;24(1):405. doi: 10.1186/s12906-024-04708-7. PMID: 39578798; PMCID: PMC11583660. pubmed.ncbi.nlm.nih/39578798/

Onland-Moret NC, Kaaks R, van Noord PA, Rinaldi S, Key T, Grobbee DE, Peeters PH. “Urinary endogenous sex hormone levels and the risk of postmenopausal breast cancer.” Br J Cancer. 2003 May 6;88(9):1394-9. doi: 10.1038/sj.bjc.6600890. PMID: 12778067; PMCID: PMC2741036. pubmed.ncbi.nlm.nih/12778067/