Why Take I3C Supplements? Overview of Mechanisms of Action

Indole-3-carbinol (I3C) supplements contain a nutrient derived from cruciferous vegetables, incuding bok choy, cauliflower, Brussels sprouts, broccoli and cabbage.

These vegetables are a source of glucosinolates, including glucobrassicin.

Indole-3-carbinol is produced in the human body when glucobrassicin is acted on by a digestive enzyme called myrosinase. On average, individuals consume anywhere from 20 to 120 mg of I3C a day through their diet.

Some use I3C supplements to promote health, improve hormone balance in the body, support weight loss and enhance muscle building.

I3C is thought to exhibit a number of chemopreventive (cancer preventing) properties, which include inducing cellular apoptosis (cell death) in some tumor cells, prohibiting angiogenesis (the development of blood vessels) in tumors and inducing cell cycle arrest.

I3C is under investigation for its effects against breast cancer. However, it has not been approved by the FDA for the prevention or treatment of cancer.

There is not enough conclusive clinical evidence to establish the efficacy of I3C. Widespread research sponsored by major health organizations, such as the National Institutes of Health in the United States, is currently underway.

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

Top I3C Products* ❯

View User Ratings* ❯

What are I3C Supplements?

Researchers were initially attracted to I3C because individuals who eat a diet high in fruits and vegetables appear to have a lower risk of developing cancer.

In particular, cruciferous vegetables seem to possess a number of plant nutrients, which may reduce the risk of developing cancer.

Crucifers are also concentrated sources of many other phytonutrients, such as vitamins, flavonoids and minerals.

However, the amount of I3C in these vegetables is low. Dietary consumption typically yields between 20-120 mg per day of Indole-3-Carbinol.

In research studies, the benefits of I3C are most apparent at dosages between 200-400 mg per day. This means that you would have to eat between 3 to 10 times more vegetables than you are currently consuming to derive benefits.

For this reason, many individuals rely on I3C supplements in capsule or tablet form to increase their consumption of this nutrient. I3C may also be used together with Diindolylmethane (DIM).

I3C Supplement: Mechanisms of Action

I3C supplement use is claimed to support good health. I3C has been observed to exhibit anticancer, antioxidant, immunomodulatory, anti-inflammatory, antidiabetic, cardioprotective and hepatoprotective effects in lab trials.

When I3C is digested from foods that we eat, it gets converted into Diindolylmethane and indolylcarbazole. This conversion occurs both in the mouth and in the stomach when indole-3-carbinol comes in contact with stomach acids.

Many of the benefits of I3C come specifically from the DIM that is created during digestion of this product. This is why much of the current research is focusing on this metabolite as opposed to I3C.

However, indole-3-carbinol itself does exhibit some beneficial mechanisms of action as well.

Anti-Cancer Effects

Indole-3-carbinol is implicated as having anti-cancer effects, but there is insufficient clinical evidence to definitively support this claim. It has shown action against breast, prostate, cervical and other cancers cell lines in laboratory experiments.

It is hypothesized to exhibit a number of characteristics that work in conjunction to suppress the onset and progression of cancerous tumors.

I3C may reduce risk factors for cancer cancer by altering levels of liver enzymes. Some of these enzymes play an important role in metabolizing and excreting carcinogens (compounds that may cause cancer).

Taking an I3C supplement may help lower the risk of developing cancer by affecting enzymes that are known to breakdown and eliminate carcinogens, toxins, steroid hormones, drugs and various biologically active compounds from the body.

The liver enzyme referred to as cytochrome P450 (CYP), along with other phase-1 and phase-2 biotransformation enzymes, work to breakdown both water-soluble and fat-soluble substances and excrete them through the body’s waste.

Inducing Cell Cycle Arrest

I3C supplements have also been shown to interfere with the cancer cell cycle, which is necessary for proliferation or growth of cancers.

Once cellular division is completed, a cell must undergo a series of stages before it can divide again. This process is known as the “cell cycle”. If DNA is damaged in a cell, the cell cycle can be stopped until the damage is assessed and repaired.

If irreparable, enzymes are stimulated that cause cellular death (apoptosis). Improper cell cycle modulation may lead to the propagation of cellular mutations, which may subsequently lead to the development of cancer.

Catalyzing Cellular Apoptosis

Cancer cells lose the capacity to react to apoptosis signals from the central nervous system. These are the signals that tell a cancer cell to die off.

When the cancer cell becomes resistant to instructions to from the body, the cell continues to live and divide.

I3C has been observed to induce cellular apoptosis in cancer cells while leaving non-cancerous cells unaffected. Indole-3-carbinol supplementation has induced cellular apoptosis in pancreatic, prostate, breast and cervical cancer cells.

While these observations are promising, further research is necessary and ongoing to establish what effect I3C has on cancer in humans.

Spread of Cancer Cells

Preliminary research on cell cultures indicates that I3C supplementation may prevent the metastasis (spread) of tumor cells. Cancerous cells are prevented from invading and overtaking healthy cells, in part, by the strengthening of their cell walls.

This makes them more rigid and less able to shift and overtake neighboring cells. Also, I3C has been observed to prevent the formation of new blood vessels in tumors, which disrupts the supply of blood needed for development and function.

Safety and Side Effects of I3C Supplements

Indole-3-carbinol is generally well tolerated if taken appropriately. Natural Medicines rates I3C as likely safe in amounts up to 120 mg a day.

Doses between 120 and 200 mg a day has been rated possibly safe for periods of up to fifteen months. Doses between 200 mg and 400 mg daily are also considered possibly safe for up to three months.

Supplementation is not generally recommended for pregnant or nursing women. Speak with your doctor before you begin taking an I3C supplement to avoid drug interactions and possible side effects.

Rate This Article

(3 votes, average: 4.67 out of 5, rated)