Sulforaphanes – A promising phytochemical and another reason to eat your dark leafy greens

I have a confession to make. I’m a professional dodger of broccoli. I’ve hidden it in napkins as a child, flatly refused it as a teenager, and given it away to my fellow diners as an adult. I pretty much hate the stuff, along with most of its relatives in the cruciferous family: cabbage, brussel sprouts, bok choy, radish, cauliflower, etc. So then why am I eating it now? Blame it on kale.

Touted as a superfood, kale was the first cruciferous vegetable I had that didn’t taste terrible. Interest piqued, I decided to look further into why it was considered ‘super’. Sure it’s full of vitamins such as C, A, K as well as being high in dietary fiber. But what really caught my attention is that it, and other cruciferous vegetables, contains a substance that has generated hundreds of research papers on subjects such as cancer protection, antioxidant activity, anti-inflammatory effects, antibacterial activity and much more.

That substance is called sulforaphanes.

Why the excitement?

Preliminary epidemiologic research shows an inverse relationship between some cancers (leukemia, prostate, liver) and the amount of cruciferous vegetables you eat. Simply put, people who ate more kale or broccoli seemed to have lower incidences of certain cancers.

In vitro (in the lab), sulforaphanes eradicated h. pylori, a nasty bacteria that can cause heart burn, stomach ulcers, and rarely, stomach cancer. Studies with small numbers of human participants showed lower amounts of h. pylori and improved symptoms of heart burn after ingesting broccoli sprouts.

Sulforaphanes and selenium together may also protect cells against oxidative damage.

A bit of background

Plants in the cruciferous family (ex: broccoli, kale) contain glucoraphanins, a precursor of isothiocyanates. Sulforaphane is one such isothiocyanates.

How do they work?

Sulforaphanes are very potent inducers of phase 2 enzymes in the liver. These enzymes help the body inactivate many carcinogens. The theory goes that if sulforaphanes help increase those enzymes, then logically they should help the body inactivate more carcinogens. Other theories include anti-inflammatory mechanisms, induction of cell cycle arrest, increasing anti-cancer defense enzymes, inhibiting cancer-activating enzymes and so on.


While studied in hundreds of research papers, evidence for the effectiveness of sulforaphane is still considered to be in its preliminary stages. This means that while the studies have been promising, larger and more vigorous studies are needed before any claim can be stated as fact. Certainly no conventional treatment should be forgone in favor of supplementing with sulforaphane alone.

Patients on blood thinners such as warfarin should not suddenly increase their intake of dark leafy green vegetables as the extra vitamin K may increase risk of bleeds. As sulforaphane affects liver enzymes, those with liver diseases or taking certain drugs that are metabolized by those enzymes need seek medical advice before taking supplements. Really, any supplementation should be done under the supervision of your doctor or health care professional.

While eating my cruciferous veggies may not be my favorite part of the meal, the benefits certainly seem to be worth the aggravation. For those who are reluctant, I offer you the following dining strategy. Boiling or baking destroys the valuable nutrients. Try steaming, microwaving, or stir frying. Broccoli sprouts have the highest content of glucoraphanins and thus sulforaphanes. Regular broccoli heads come in at a distant second and the rest of the family fair even worse than that. So eating steamed broccoli sprouts is the best bang for your buck.

Or if that sounds like too much of a fuss, you can take a supplement instead. (1 capsule equals 8oz of broccoli or 0.33oz of broccoli sprouts.) Our pharmacy can help you with that and I certainly won’t blame you.