Indole-3-Carbinol Benefits, Common Uses and Research

Research into the health benefits of indole-3-carbinol (I3C) is ongoing. I3C is a plant chemical found in cruciferous vegetables, including broccoli, kale and Brussels sprouts.

It is now available as a dietary supplement and is commonly used to support estrogen metabolism, balance hormones, treat symptoms of menopause, prevent cancer and treat acne. Indole-3-Carbinol benefits are said to include weight loss and reducing symptoms of estrogen dominance.

I3C is not bioactive, meaning that on its own it does not seem to interact with the human body. However, when I3C is exposed to stomach acid it is broken down to form two bioactive compounds: diindolylmethane (DIM) and indolylcarbazole.

The health benefits of I3C are attributed primarily to the effects of DIM. How does indole-3-carbinol work and what is the research evidence supporting its use?

I3C (Indole-3-Carbinol)

Hormone Supplement

Hormone Balance

Weight Loss

Liver Health

How It Works:

• Supports healthy estrogen metabolism
• Improve hormone balance & fat burning
• Promotes liver detoxification

Dosage:

Between 200 - 400 mg per day

Safety:

Rated Possibly Safe

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Indole-3-Carbinol Benefits

Indole-3-Carbinol gets converted into DIM when it is digested. DIM has been observed to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, hormone-modulating and chemopreventive properties.

Both I3C and DIM are available as dietary supplements. They are often taken together to support the metabolism of estrogen. Many of the uses of DIM relate it its ability to promote estrogen metabolism and help reduce the levels of harmful estrogens in the body.

Estrogen does not refer to one hormone, but rather a group of hormones that exhibit similar properties. For instance, some of the most common estrogens are estradiol, estriol and estrone.

Estrogens are present in both men and women, but they play a primary role in the development of female sexual characteristics. Because estrogens play such a dynamic role in the female body, the concentrations of different estrogens will vary over the course of a lifetime.

For instance, during child-bearing years, women have higher concentrations of estradiol, but more estrone after menopause.

Indole-3-Carbinol for Estrogen Balance

Estrogen metabolism is crucial to maintain healthy hormone levels. When the body is functioning normally, estrogen is used and then metabolized (broken down) and excreted from the body.

Metabolites of estrogen can have varying impacts on the body. For instance, when estradiol is metabolized, it can be broken down into a number of metabolites, including 2-alpha-hydroxyestrone and 16-alpha-hydroxyestrone.

The first is thought to play a protective role in the body while the second has been associated with an increased risk of breast and cervical cancer.

Taking indole-3-carbinol as a source of DIM may support improved estrogen metabolism in cases where this balance has been disrupted.

The ways that DIM supports estrogen metabolism are not fully understood; however, DIM has been observed to increase production of the benign 2-alpha-hydroxyestrone and reduce the production of 16-alpha-hydroxyestrone.

In addition, DIM has been observed to support overall estrogen metabolism and excretion, helping to reduce estrogen levels. These observations have mostly been made in laboratory and animal experiments. More research is needed to clearly establish how I3C and DIM impacts estrogen metabolism in the human body.

Although research is ongoing, users often report a great deal of success in using indole-3-carbinol or DIM for estrogen metabolism. They report improvements in estrogen-related conditions like acne, menopause and levels of body fat.

Indole-3-Carbinol Effects on Cancer

Researchers initially became interested in I3C health benefits as a possibly chemopreventive (cancer preventing) agent. Researchers have observed that diets high in cruciferous vegetables, such as broccoli, watercress, kale and Brussels sprouts, are correlated with a reduced risk of developing some cancers.

Researchers are now investigating the capacity of I3C to ward off the development of some cancers. In animal tests, oral administration of I3C has been observed to inhibit the development of cancer in breast, colon, liver, stomach, uterus and lung tissues.

However, there is some contradictory evidence concerning indole-3-carbinol benefits for cancer prevention: in rat experiments, I3C has been observed to promote cancer in the thyroid, uterus and colon, but these observations have not been made in a human population.

Because of the conflicting data to date, widespread supplementation of I3C for cancer is not recommended by most healthcare professionals.

The National Institutes of Health has reviewed the use of I3C for cancer prevention and is now funding clinical trials focusing on I3C and breast cancer prevention.

Indole-3-Carbinol Research

I3C is being investigated for its capacity to prevent cancer, especially hormone-sensitive cancers like breast cancer. In laboratory studies, I3C has been observed to modulate estrogen receptors, which may help support balanced estrogen levels.

Clinical data also indicates I3C may be effective in the treatment of cervical dysplasia, which is characterized by pre-cancerous cell growth in the lining of the cervix.

In a placebo-controlled trial, nearly half of the women in the supplementation group experienced a full remission of cervical dysplasia with 12 weeks of supplementation. Further study is necessary to establish a definitive connection, but the initial results seem promising for this use.

Indole-3-Carbinol Benefits for RRP

Recurrent respiratory papillomatosis (RRP) is an uncommon condition that develops in both adults and children. It is marked by the formation of papillomas (benign growths) that manifest primarily in the larynx, but may also develop in the lungs, bronchi, trachea and/or vocal cords.

The papillomas are caused by the human papillomavirus, commonly abbreviated as HPV. The most common conventional treatment for RRP is surgery to remove the papillomas, but they often return.

Indole-3-carbinol has been observed to reduce the recurrence of RRP. In animal tests, mice with compromised immune systems received transplants of laryngeal tissues that had been infected with HPV.

Twenty-five percent of the mice that received I3C developed papillomas in their larynxes while 100 % of mice in the control group developed laryngeal papillomas.

In an uncontrolled human pilot study, indole-3-carbinol benefits for RRP were studied over five years. The study began with 49 subjects. Daily I3C supplementation began with adults receiving doses of 400 mg, and children receiving 10 mg/kg of bodyweight.

The following data was reporyed:

• 11 of 49 subjects experienced no recurrence of symptoms;
• 10 of 49 experienced a reduction of RRP symptoms;
• 12 experienced no improvements of RRP symptoms;
• The remaining subjects were lost to follow-up measures.

More extensive, controlled human studies are warranted to understand the full therapeutic effects of I3C for RRP.

Indole-3-Carbinol and Systemic Lupus

Systemic lupus erythematosus (SLE) is a condition marked by chronic inflammation. It is an autoimmune disorder that may affect the brain, blood vessels, skin, heart, kidneys, lungs and/or joints.

The pathology of SLE is believed to be dependent on estrogen levels, particularly because SLE is far more prevalent in women than men. Also, the onset of SLE is most common during the reproductive years when estrogen levels are at their highest.

In animal studies, oral administration of indole-3-carbinol was observed to decrease the severity of kidney disease symptoms. It was also observed to increase survival rates and longevity.

More research is underway to determine the specific advantages of I3C supplementation for systemic lupus erythematosus.

Safety of I3C

Indole-3-carbinol is generally well tolerated, especially at dosages between 20 and 120 mg, which is the range of I3C commonly ingested in the average diet.

In rare cases, skin rashes and minute increases in certain liver enzymes may be experienced when supplemental I3C is consumed.

Dosages ranging between 120 mg and 200 mg daily have been used for up to 15 months. Doses between 200 mg and 400 mg daily may be safe for periods of up to three months.

High doses (above 400 mg daily), may cause more serious side effects, including tremors, nausea, vomiting, loss of balance and/or severe headaches.

There is not enough information available on the safety of supplementing I3C during pregnancy. Pregnant or nursing women should not supplement with I3C.

There is a moderate risk of drug interaction with I3C. Certain pharmaceuticals that are broken down by the liver may not mix well with this supplement. When these medications are broken down by the liver, their effects and side effects may be altered.

Supplementing with I3C may cause some medications to be broken down too quickly, which may either increase or decrease the strength of their effects.

Be sure to speak with your doctor about before you take I3C to better understand the benefits you can expect from indole-3-carbinol supplementation, and to make sure this supplement is safe for you.

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