Just eat the broccoli, preferably steamed
July 15, 2010 Leave a comment
A presidential/vegetable debacle
When the first President Bush indicated a distaste for broccoli during his presidency, he set off a firestorm of vegetable-based controversy. Broccoli haters sympathized, but nutritionists were horrified. Turns out, the data are all on the side of the nutritionists.
Research has shown that people who eat cruciferous vegetables—for example, broccoli, cabbage, or cauliflower—have lower rates of cancer. Armed with this information, researchers around the country have sought the cancer-fighting ingredient in broccoli and tried different ways to maximize the benefits we can get from it.
Yes, it’s got healthy stuff in it
They pinpointed the compound of interest in 1992. It is sulforaphane, a phytochemical in a group called the isothiocyanates. These compounds are known to induce apoptosis, or programmed cell death, of cancer cells. Epidemiologists—people who trace and track diseases and their causes—have found lower rates of prostate cancer in men who eat diets high in isothiocyanates. Scientists found that the way we release these cancer-fighting compounds from our veggies is to cut or chew them.
Sulforaphane, one of the most powerful anticarcinogens—anti-cancer compounds—in our food, works through the liver. Our livers are responsible for detoxifying our bodies, which happens in phases. In some cases, liver enzymes can actually turn compounds into carcinogens. But our phase II liver enzymes break down toxins before they can damage our DNA, the molecule that houses our genetic code. Sulforaphane boosts these phase II enzymes, thus wielding its anti-cancer power.
Broccoli pill–or just broccoli?
When the world found out broccoli’s secrets, there was a craze for broccoli-derived supplements that contained sulforaphane. Broccoli-based pills, powders, and teas hit the shelves, and people everywhere crunched into broccoli, possibly wincing like our former president might have as they chewed it up and forced it down. But what they may not have realized is that mature broccoli also has some compounds help liver enzymes that turn compounds into carcinogens. The goal was to find a way to deliver sulforaphane without delivering too much of these less-benign accompaniments, or too much sulforaphane, which can be toxic in large amounts.
One approach was to synthesize a sulforaphane that retained its anti-cancer powers, but was not as toxic in high doses. This compound is called oxomate, and it has been successful in the lab in reducing breast tumors in rats. Another approach was to try to find a broccoli growth stage that made sulforaphane in reasonable amounts, but that did not produce the compounds that elicited the liver’s carcinogen-producing enzymes. Scientists following that line of research discovered that broccoli sprouts, tiny alfalfa-like sprouts grown from broccoli seeds, contain abundant and safe levels of sulforaphane, but do not synthesize the unwelcome compounds that boost carcinogenesis.
When proteins attack
But one thing that food scientists had found was that even when broccoli was consumed, its sulforaphane could be immediately disabled by broccoli protein called the epithiospecifier protein. Sulforaphane in the plant is attached to a sugar via a sulfur bond. When we cut or chew the broccoli, we can activate the enzyme that breaks the sulforaphane off of the sugar. But then there’s that sulfur flapping in the breeze, and the epithiospecifier comes along, yanks off the sulfur, and inactivates the sulforphane. Food researchers have found that cooking broccoli for 10 minutes at 140 degrees Fahrenheit kills off the epithiospecifier protein, leaving behind intact sulforaphane and the enzyme that releases it from the sugar to do its good work in our bodies.
So if you’ve been choking down overcooked broccoli all in the name of health, you may have been reaping the benefits of fiber or other broccoli-derived nutrients, but you weren’t getting much sulforaphane out of it. Your best bet, according to researchers, is to steam fresh broccoli for about three or four minutes and eat it, cheese sauce optional.