Is there a link between nutrition and cancer?

Q: Is there a link between nutrition and cancer?

A: Many patients have asked what types of food are regarded as 'good food' and 'bad food' for cancer.

Although many foods have been studied for cancer prevention, it is difficult to establish a specific link between food and cancer.

This is because food contains many components, including nutrients such as carbohydrates, protein, fat, vitamins and minerals , as well as non-nutrients such as phytonutrients from plants, which may help prevent cancer.

Most people eat and drink a variety of foods, which can make the study a challenge.

Food preparation methods also contribute to the variation, for example, deep-frying or steaming chicken can affect a person's overall health differently.

Here is what is known about selected types of food and their connection to cancer:

- Fruits and vegetables

They may protect against several cancers, including mouth, pharynx (part of throat), larynx (voice box), esophagus and stomach.

Current recommendation: Consume 5 portions of fruits and vegetables daily.

- Dietary fibers

They are linked to a reduced risk of cancer, particularly colorectal cancer.

Current recommendation: Women below 50 years old should consume 25g while men below 50 years old should consume 38g of fibre daily.

Women over 50 years old should consume 21g while men over 50 years old consume 30g of fiber daily.

- Protein

Our diets' main sources of animal protein come from meat, fish, shellfish, cheese and eggs.

The consumption of red meat and processed meat such as hot dogs, bacon, and salami has been found to increase a person's risk of colorectal cancer .

However, a study has shown that a person can consume up to 500 grams of red meat a week without raising his cancer risk.

- Dairy foods

Dairy foods are a varied food group and are usually a good source of calcium. However, multiple studies of dairy foods and cancer have shown conflicting results.

While milk has been found to protect against colorectal cancer and bladder cancer, there is no concrete evidence to suggest any link between breast cancer and dairy foods.

Dr Sue Lo, senior medical oncologist and director of The Harley Street Heart & Cancer Centre, has been treating cancer patients for 18 years.