Cancer Research UK : Diet and cancer- the EPIC study

Diet and cancer- the EPIC study

The EPIC study looks at links between diet and cancer in 10 European countries.

The links between health and diet are very complex and human population studies must look at large numbers of people to provide the most meaningful results.

Many previous studies on diet and cancer have been flawed for the following reasons:

They were too small. Even thousands of people may not be enough to detect links between cancer and diet.
They focused on one population with limited variation in diet. For example, if you only study a group of people who eat very little fibre, your study would miss out the beneficial effects of eating large amounts of fibre.
They did not measure dietary intakes accurately. In many cases, scientists determined their subjects’ diets by asking them to remember what they ate months or years in the past.

The EPIC study

Cancer Research UK is co-funding the UK arm of a massive study called EPIC, the European Prospective Investigation of Cancer. EPIC researchers have carefully designed the study to overcome the limitations of previous investigations.

EPIC is a long-term study of more than 500,000 people in ten European countries. This includes around 90,000 British men and women, including about 30,000 vegetarians, recruited by Cancer Research UK groups in Oxford and Cambridge.

EPIC aims to produce detailed, reliable information about diet and cancer. Unlike many other studies, it has the following important design features:

It’s huge. At over 500,000 participants, EPIC is the largest study of diet and health ever undertaken.
It looks forward. Only healthy people were recruited and their health was then followed for many years. This type of study is called a prospective study. Many other studies ask patients who already have cancer to recall their lifestyles before their diagnosis - a much less accurate approach.
It’s accurate. Each participant completed detailed diet and lifestyle questionnaires and most also provided blood and urine samples so the researchers could analyse their nutrient levels.
It’s long-term. EPIC participants will be followed for at least 10 years. Participants fill out repeat surveys every three years or so.
It has a wide geographical coverage. People from the 10 EPIC countries have very varied diets. This will allow the researchers to make more reliable assessments of the effects of different aspects of our diet.

EPIC results so far

EPIC scientists have published several papers in the last few years. They have found, among other things, that:

High intakes of fibre reduce the risk of bowel cancer.
High intakes of red or processed meat increase the risk of bowel cancer and stomach cancer.
Eating lots of fish may reduce the risk of bowel cancer, but this effect varied between different countries.
Beingoverweight or obese increases the risk of breast cancer in women after their menopause.
Beingoverweight or obese also increases the risk of kidney and oesophageal cancers.
People with large waist circumferences of large waist-to-hip ratios have higher risk of pancreatic cancer.
High intakes of saturated fat increase the risk of breast cancer. People with the most fat in their diet had twice the risk of those with the least.
Women who eat high-fat diets have higher risks of dying from cancer than those who eat low-fat diets.
High levels of fruit and vegetables, as indicated by vitamin C levels, reduce the risk of dying early from any cause by 20%. People could gain this benefit by eating just one extra portion of fruit or vegetables a day.
High intakes of fruit and vegetables do not reduce the risk of breast and prostate cancers. High intakes of fruit may reduce the risk of lung cancer.
High intakes of milk and cheese, and high levels of calcium in our diet, are linked to a reduced risk of bowel cancer.
Smoking increases the risk of stomach cancer, and passive smoking increases the risk of lung cancer.
High levels of hormones such as oestrogen and testosterone affect breast cancer risk.

What’s next?

EPIC is expected to produce many more publications in the coming years. Scientists across Europe will study virtually every item in our diets including fruit and vegetables, meat, fish, fibre and fat.

The study will also look at the effects of other lifestyle factors including bodyweight, physical activity, alcohol, hormones and infections. And it will determine how our genes interact with these factors to affect our risk of cancer.

The Healthy Living pages will be updated as new EPIC results are published.