Broccoli has added to its ‘superfood’ credentials after new research showed it can protect against liver cancer.
The vegetable has soared in popularity in recent years after scientists showed that eating it three to five times per week can lower the risk of many types of cancer including breast, prostate, and colon cancers.
Now a new study reports that including broccoli in the diet may also protect against liver cancer.
And broccoli may also help counter the development of fatty liver or non-alcoholic fatty liver disease (NAFLD), which can cause malfunction of the liver and lead to hepatocellular carcinoma (HCC), a liver cancer with a high mortality rate.
Professor Elizabeth Jeffery, of Illinois University in the United States, said: ‘The normal story about broccoli and health is that it can protect against a number of different cancers. But nobody had looked at liver cancer.
‘We decided that liver cancer needed to be studied particularly because of the obesity epidemic.
‘It is already in the literature that obesity enhances the risk for liver cancer and this is particularly true for men. They have almost a five-fold greater risk for liver cancer if they are obese.’
Prof Jeffery said eating a high-fat, high-sugar diet and having excess body fat is linked with the development of NAFLD, which can lead to diseases such as cirrhosis and liver cancer.
She said: ‘We called this a Westernised-style diet in the study because we wanted to model how so many of us are eating today.’
Previous research suggests that broccoli, a brassica vegetable containing bioactive compounds, may impede the accumulation of fat in the liver and protect against NAFLD in mice.
Prof Jeffery and her team wanted to find out the impact of feeding broccoli to mice with a known liver cancer-causing carcinogen.
The researchers studied four groups of mice; some of which were on a control diet or the Westernised diet, and some were given or not given broccoli.
Prof Jeffery said: ‘We wanted to look at this liver carcinogen in mice that were either obese or not obese.
‘We did not do it using a genetic strain of obese mice, but mice that became obese the way that people do, by eating a high-fat, high-sugar diet.’
Although the researchers were predominantly interested in broccoli’s impact on the formation and progression of cancerous tumors in the liver, Prof Jeffery explained that they also wanted to observe the health of the liver and how the liver was metabolising lipids because of the high-fat diet.
The study shows that in mice on the Westernised diet both the number of cancer nodules and the size of the cancer nodules increased in the liver.
But when broccoli was added to the diet, the number of nodules decreased.
Prof Jeffery said: ‘That was what we really set out to show. But on top of that we were looking at the liver health.
‘There are actually two ways of getting fatty liver: one, by eating a high-fat, high-sugar diet and the other by drinking too much alcohol.
‘In this case, it is called non-alcoholic fatty liver, because we didn’t use the alcohol.
‘We found that the Westernised diet did increase fatty liver, but we saw that the broccoli protected against it.
‘Broccoli stopped too much uptake of fat into the liver by decreasing the uptake and increasing the output of lipid from the liver.
‘I think it’s very difficult, particularly given the choices in fast food restaurants, for everybody to eat a lower-fat diet.
‘But more and more now you can get broccoli almost everywhere you go.
Most restaurants will offer broccoli, and it’s really a good idea to have it with your meal.’
Prof Jeffery’s previous research shows that eating broccoli freshly chopped or lightly steamed is the best way to get to the vegetables’ cancer-fighting compound, sulforaphane.
She added that other brassica vegetables, such as cauliflower or Brussel sprouts, may have the same effect.