In Summary

Selenium is a chemical element contained in certain foods. Our bodies need a small but sufficient amount of selenium to keep our cells and immune system functioning healthily. HRB-funded research has linked higher levels of selenium in the blood with a decreased risk of developing colorectal cancer (bowel cancer) or the major type of liver cancer called hepatocellular carcinoma. The findings will inform recommendations for selenium in the diet.

The Problem

The cells in our bodies naturally produce by-products that need to be cleared away. Several proteins involved in this process depend on sufficient selenium being present in order to be made by the body and to work more effectively – a key example is selenoprotein P. However, many people in areas such as Europe have a relatively low amount of selenium in their diets – particularly where food is grown in soils that are low in selenium – and this has been linked to a higher risk of inflammation and DNA damage, which can lead to cancer.

The Project

Dr David Hughes and colleagues looked at data collected in a large, long-term study called EPIC, where around 500,000 people donated blood samples and provided detailed information on their diets and lifestyles. These people are being followed up over time.

The researchers measured the levels of selenium and selenoprotein P in the samples of hundreds of people who developed colorectal or liver cancer compared to an equal number on the study who did not develop any cancer.

They found that higher levels of both selenium and selenoprotein P were linked in both men and women to a significantly lower risk of developing bowel cancer (which was even more evident for women for this cancer) and liver cancer.

The Outcomes

We now know that: –

Higher levels of selenium are linked with a lower risk of colorectal cancer and liver cancer.

The findings are informing debate about guidelines and recommendations for selenium in the diet.

The functional measure of selenium in blood samples (selenoprotein P) used in the research could offer a more accurate approach to identify and monitor people who would benefit from more of this nutrient in their diet or as a supplement to their diet.

Dr David Hughes, Conway Institute, UCD, says:

‘The research findings suggest that where selenium is lower than the optimal level, such as for most people in Europe, increasing selenium intake may help to prevent liver and bowel cancer in addition to moderating or avoiding alcohol consumption, maintaining a healthy body weight, and stopping smoking. This is important for public health as some people may particularly benefit from increasing the selenium in their diet’.