I commonly see patients in my clinic seeking natural solutions for symptoms of estrogen dominance and other hormonal issues. Estrogen dominance is a common condition characterized by an imbalance between estrogen and progesterone. It can lead to weight gain, mood swings, and reproductive issues.
Diindolylmethane (DIM) and indole-3-carbinol (I3C) are common natural options for estrogen dominance and hormonal imbalance. They are both derived from cruciferous vegetables. So what’s the difference between the two? Which one is better? This is what we’re going to find out.
In this article, I will discuss the difference between DIM and I3C. You will learn about their benefits and which one I prefer to use for estrogen dominance and hormonal imbalance. Let’s get into it.
What Is Estrogen Dominance
Estrogen is one of the primary female sex hormones. The other one is progesterone. Progesterone is the other. In a healthy body, estrogen and progesterone work together supporting the female cycle and reproductive health. Estrogen is also important for thyroid health, overall hormonal function, bone health, metabolism, skin health, brain health, and mental health. Progesterone helps to reduce inflammation, balance your nervous system, and support your thyroid function.
These two hormones have to be in balance. When estrogen and progesterone get out of balance and you have high levels of estrogen relative to progesterone, it means you have estrogen dominance. This develops for a variety of reasons. In many cases, the body is making too much estrogen causing estrogen excess. In some other cases, a reduction in progesterone levels is behind estrogen dominance and hormonal imbalances. When estrogens become dominant in comparison to progesterone, it can lead to a list of chronic symptoms (1, 2).
Symptoms of Estrogen Dominance
Symptoms of estrogen dominance include:
- Premenstrual symptoms (PMS)
- Irregular periods, heavy periods, menstrual cramps, and other changes in menstruation
- Breast tenderness, swelling, or soreness
- Endometriosis
- Infertility or miscarriages
- Hot flashes
- Decreased libido
- Weight gain and fat deposits
- Cravings for sweets
- Fatigue or insomnia
- Brain fog or trouble concentrating
- Depression, mood swings, anxiety, and mood imbalance
Estrogen dominance increases the risk of ovarian cysts, PCOS, uterine fibroids, endometriosis, insulin resistance, thyroid issues, autoimmunity, and cancer, including breast, ovarian, and uterine cancer.
DIM vs I3C for Estrogen Dominance
Broccoli is a fantastic source of antioxidants, vitamins, and minerals. Did you know that only half a cup of cooked broccoli has similar amounts of vitamin C as an orange (3). Broccoli is fantastic for your immune system! It is full of fibre and prebiotics, so it’s great for your microbiome balance and digestion. It even has some protein in it (2.6 grams in one cup).
Broccoli is also loaded with antioxidants, including flavonoids, carotenoids, and glucosinolates (4, 5, 6). Flavonoids are essential for improving the inflammatory response and lowering inflammation (6). Carotenoids are great for eye health. Glucosinolates, including sulforaphane, DIM, and indole-3-carbinol (I3C), have been studied for liver detoxification, the neutralization of free radicals, and hormonal health.
What Is I3C?
Indole-3-carbinol (I3C) is a compound your body makes when you eat cruciferous vegetables, including broccoli, Brussels sprouts, cauliflower, kale, and cabbage. It supports detoxifying enzymes in your liver and gut. I3C may help to support liver detoxification and support people with liver disease (7). It may be beneficial for respiratory tract issues, fibromyalgia, and inflammatory issues (8, 9).
Most importantly, due to its anti-estrogenic benefits, it may reduce tumor growth in hormone-dependent cancers, including breast cancer (10, 11, 12, 13). According to a 2018 review published in F1000 Research, a diet rich in cruciferous vegetables can be cancer-protective due to I3C action (12). It seems that I3C affects various cellular processes that may help to slow down the growth of cancer cells, especially in hormone-related cancers.
What Is DIM?
Diindolylmethane (DIM) is a compound that your body makes when you eat broccoli, Brussels sprouts, and certain other cruciferous vegetables. Since DIM affects your estrogen levels, DIM supplements have become increasingly popular to address estrogen dominance, menopause symptoms, acne, prostate issues, and other hormonal problems, as well as certain forms of cancer (14, 15).
How does DIM work? When you consume broccoli or other cruciferous vegetables, the stomach acid in your body breaks down the compound indole-3-carbinol (I3C) to make DIM (16). Several research studies have shown that eating a diet high in cruciferous vegetables may help lower the risk of certain cancers, including breast and prostate cancer (17, 18, 19). While we don’t understand the mechanism behind this completely, it could be partly related to I3C and DIM.
According to a 2016 review published in Nutrition Reviews, DIM can help to balance your estrogen levels, which may help to reduce the risk of breast cancer (14). DIM also supports phase 1 of liver detoxification. This means that DIM can help to improve estrogen breakdown by your liver and increase estrogen conversion into beneficial metabolites (20).
DIM seems to help the production of 2-hydroxyestrone, which is a more beneficial type of estrogen, while reducing the production and effects of 16 alpha-hydroxyestrone, a stronger and more harmful form of estrogen linked to an increased risk of weight gain and breast, uterine, and other cancers. Diindolylmethane also reduces aromatase action, which is an enzyme that converts testosterone to estrogen. This can help to reduce high estrogen levels. DIM can also block androgen receptors, which may reduce the effects of dihydrotestosterone (DHT), a potent form of testosterone. For women that have acne and/or unwanted facial hair, reducing the effects of testosterone and DHT are often desirable.
Reducing Cancer
One of the main potential benefits of DIM lies in cancer prevention and treatment, especially in hormone-related cancers. Some test-tube and human studies have found that DIM may help to reduce or prevent cancer cell growth and spread in breast cancer (21, 22). Human studies are more limited, though promising. A 2004 study published in Nutrition and Cancer found that using 108 mg of DIM for 30 days helped to improve estrogen metabolism in postmenopausal women with a history of early-stage breast cancer (23).
A 2017 randomized controlled trial published in Breast Cancer Research and Treatment has found that using 150 mg of DIM supplementations twice a day helps to improve 2-hydroxyestrone and 16-hydroxyestrone ratio (24). Improving this ratio may help to lower the risk of breast cancer. Other studies have found that DIM may be protective against other hormonal cancers, including ovarian, cervical, and prostate cancer, as well as, colon cancer (25, 26, 27, 28).
Reducing Prostate Problems
DIM is not only for women. It may be beneficial for men as well, particularly by protecting the prostate, and potentially reducing the risk of prostate enlargement and prostate cancer. According to the 2016 study published in EPMA Journal, 900 mg of DIM a day may help to reduce the risk of prostate intraepithelial neoplasia (PIN), which is a precursor to prostate cancer (29). Participants experience significant improvements by the end of the one-year study. Animal and test-tube studies have also shown that DIM may help fight prostate cancer, however, we still need more human studies (30).
Other Hormonal Benefits
Unwanted weight gain is one of the symptoms of estrogen dominance and estrogen imbalance. A 2017 study published in Molecular Nutrition and Food Research has found that 23 mg of DIM per one pound of body weight a day has helped to reduce fat cell formation in mice (31). DIM can be beneficial for a variety of hormone-related complaints, including hot flashes, menopause, PMS, hormonal acne, erectile dysfunction, male infertility related to high estrogen, and male breast growth. Though anecdotal evidence supports these claims, we don’t have enough research evidence to confirm the effectiveness of DIM for these hormonal issues.
What’s the Difference? Which One Is Better for Estrogen Dominance?
So what is the difference between DIM and I3C? Are they the same? Is one better than the other? DIM and I3C come from the same source, cruciferous vegetables, but they are not the same. I3C is converted into DIM. According to a 2006 study published in Cancer Epidemiology, Biomarkers & Prevention, after taking I3C supplements, DIM will be detectable in your blood soon after (32). However, the molecules of DIM and I3C have a similar but different structure. According to this same study, after using I3C for four weeks, only DIM was detectable in the blood of the subjects, not I3C.
Why Choose DIM Instead of I3C?
This may suggest that using DIM directly instead of I3C that converts into DIM may be better. While I3C is an unstable molecule that can convert into DIM rather quickly, DIM is more stable. DIM can remain active longer and progress its journey beyond its stomach, while I3C converts as soon as it hits your stomach.
Since I3C converts into DIM quickly, they may provide similar results as supplements. However, DIM is generally preferred because it’s more stable and you are starting your journey with an active molecule, skipping the step of conversion from I3C to DIM (33). In fact, some of us can have a genetic variation that prevents adequate conversion of I3C to DIM.
DIM moves through your stomach. After this step, it will get absorbed from your gut and move through your liver to improve hormone detoxification and estrogen balance, estrogen-to-testosterone ratio, and hormonal health.
An important consideration is that estrogen is broken down in stages, with DIM supporting phase 1. Accelerating phase 1 metabolism of estrogen, without attention to phase 2, might be problematic for some patients. The efficiency of these metabolic processes is in part determined by genetic factors. With less effective phase 2 breakdown of estrogens, other supplements need to be considered to assist. Your healthcare provider will determine what is best for you.
Though we often think of women when we hear about estrogen dominance and estrogen-related issues, men are also affected by estrogen and estrogen-testosterone balance. Due to its hormone-balancing effects, both women and men can potentially benefit from DIM supplementation for various hormone-related issues. Of course, as with all supplements, you should always consult your doctor to see if DIM is right for you.
Side Effects of DIM
There isn’t enough human research on DIM to fully understand long-term safety and side effects. Current research and clinical experiences show that DIM doesn’t seem to have serious side effects. Headaches, gas, increased bowel movements, and dark urine are the most common side effects of DIM, whereas diarrhea, nausea, vomiting, and skin rashes are less common (34, 35).
Since DIM affects your estrogen levels, DIM may not be right for you, or only be taken with medical supervision, if you have a hormone-sensitive cancer or are receiving hormone therapy.
It’s critical that you talk to your doctor to determine if DIM is best for you and if it interferes with other medications or supplements you are taking, especially.
Dosage of DIM
Since human studies are limited, we don’t have clear enough evidence on the proper or the best dosage. The dosage of DIM in studies varies from 108 to 900 mg per day, depending on the study (36, 37, 38). A 2008 study published in Cancer Epidemiology, Biomarkers & Prevention has found that DIM was tolerated at doses up to 200 mg, however, taking 300 mg increased the risk of headaches, nausea, and vomiting (39).
I find that starting with 100 mg for many female patients, then increasing to 200 mg per day, is an effective clinical strategy to assess benefits and mitigate side effects. Talk to your healthcare professional, listen to their recommendations, and pay attention to your body. If you experience any side effects, talk to your healthcare provider.
Next Steps
If you are experiencing symptoms of estrogen dominance or hormonal health issues, I recommend following my tips in this article. Or if you need help in improving your symptoms of estrogen dominance, I recommend reaching out for guidance.
If you are dealing with any chronic health issues and need advice on how to improve your nutrition and health, I welcome you to start a functional medicine consultation with me for further personalized guidance. Book your consultation here.
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