Broccoli and its cruciferous vegetable cousins have had a bumpy ride. For years, they’ve periodically been the “it” vegetables to which people attribute super-food status, only to be displaced by another star when a study seems to show no effect on cancer risk.
With a new study now supporting one of the active compounds in broccoli as a protector against breast cancer, perhaps it’s time to try for a realistic understanding of what we can expect from the broccoli family of vegetables.
Broccoli belongs to the large family of cruciferous vegetables, which includes cabbage, cauliflower, radishes and parsnips. When the vegetable cells are broken by chewing or chopping, the inactive compounds are converted into compounds that have significant anti-cancer effects.
In the latest study generating buzz about broccoli for breast cancer prevention, one of its active compounds called sulforaphane was found to inhibit the growth of human breast cancer cells.
Sulforaphane is an isothiocyanate, an organic chemical compound that has been shown to inhibit the growth of carcinogen-induced cancer. Sulforaphane is found in cruciferous vegetables and is especially high in broccoli, and more so in broccoli sprouts.
High isothiocyanate intake from broccoli may also reduce breast cancer risk.
Indole-3-carbinol conjugates are phytochemicals present in cruciferous vegetables such as broccoli, and studies have shown them to have anti-cancer properties.
In a study at the International Agency for Research on Cancer in France, results demonstrated the protective effect of cruciferous vegetable consumption on lung cancer.
Cruciferous vegetable intake has also been associated with a decrease in gastrointestinal and bladder cancers.
Research conducted at The Johns Hopkins University School of Medicine concluded that sulforaphane inhibits the bacteria helicobacter pylori, which is a major cause of gastric infection. These infections are known to cause gastritis and peptic ulcers, and increase the risk of gastric cancer.
Inconsistencies loom when we look at the research into how human cancer risk is affected by cruciferous vegetable consumption. One recent summary concludes that links to reducing stomach and lung cancer seem valid, but the evidence is not consistent in supporting links to reducing breast and other cancers.
Large population studies often show a link between cruciferous vegetable consumption and lower cancer risk, but these studies have many factors that can affect the data. Many scientists now say that may be the point.
Research shows that some people inherit genes that make them more affected by broccoli’s phytochemicals than others. And we even seem to inherit differences in how we process the compounds; those who quickly metabolize and excrete cruciferous’ protective compounds almost surely get less protection from them than people in whom they are actively working longer.
Although studies often group cruciferous vegetables together, they differ in the particular phytochemicals they contain, which could lead to different effects. Also, overcooking cruciferous vegetables will dramatically lower the amount of protective phytochemicals, compared to eating them raw or lightly cooked in little or no water.
The bottom line is that when population studies don’t consistently show lower cancer risk from eating cruciferous vegetables, we shouldn’t give up on them. Overall research is strong in suggesting that if they’re prepared right, the benefit could be substantial. However, this doesn’t make them super foods to be eaten at the exclusion of other vegetables.
References:
1. Karen Collins, MS, RD, CDN American Institute for Cancer Research.
