Broccoli may offer protection against liver cancer

A new study from the University of Illinois (U of I) reports that including broccoli in the diet may protect against liver cancer.

Broccoli consumption may also aid in countering the development of fatty liver or nonalcoholic 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.

“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,” says Elizabeth Jeffery, a U of I emeritus professor of nutrition. “We decided that liver cancer needed to be studied particularly because of the obesity epidemic in the US. 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 5-fold greater risk for liver cancer if they are obese.”

Consuming 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. Previous research suggests that broccoli may impede the accumulation of fat in the liver and protect against NAFLD in mice. Therefore, 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 high-fat, high-sugar diet, and some were given or not given broccoli.

“We wanted to look at this liver carcinogen in mice that were either obese or not obese,” Jeffery explains. “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 tumours in the liver, 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. “There is almost no information about broccoli and high-fat associated diseases,” she says.

The study shows that in mice on the high-fat, high-sugar 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. Size was not affected.

“That was what we really set out to show,” Jeffery says. “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.”

Broccoli stopped too much uptake of fat into the liver

With NAFLD, lipid globules form on the liver. During the study, the researchers observed these globules in the livers of the mice on the high-fat, high-sugar diet diet. The researchers saw that broccoli protected against a fatty liver.

“Broccoli stopped too much uptake of fat into the liver by decreasing the uptake and increasing the output of lipid from the liver,” Jeffery explains.

Jeffery notes that adding broccoli to the diet of the mice did not make them “thin,” or affect their body weight, but it did bring the liver under control, ultimately making them healthier.

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.