Information sheet: Sugar and cancer risk

Key messages and recommendations

• Sugar provides little nutritional value to a diet
• Sugar is not carcinogenic
• Overconsumption of sugar, especially sugar sweetened beverages, can lead to weight gain and obesity which is associated with thirteen different types of cancer
• Cancer Council Australia supports the Australian Dietary Guidelines and The World Health Organization’s guidelines to reduce consumption of ‘free sugars’

Background

Sugar in all forms provides little nutritional value and excess consumption is one key factor contributing to the rising obesity rates. ⁽¹⁾ Sugars can take a number of different forms including monosaccharides (e.g. glucose and fructose) and disaccharides (e.g. sucrose and lactose) and can be found on a food label’s ingredients list under many different names.

Natural sugars found in intact fruits, vegetables, and milk are called ‘intrinsic sugars’ and differ from ‘free’ or ‘added sugars’ because they are part of a food that is a source of other nutrients including fibre, vitamins, and minerals. Intact fruit, vegetables, and milk are part of a healthy diet. ⁽²⁾

‘Free sugar’ includes ‘added sugars’ –added to foods and beverages by the manufacturer, cook, or consumer – plus sugars naturally present in honey, syrups, and fruit juices and fruit juice concentrate. ⁽²⁾

Coconut sugar, agave syrup, rice malt syrup, brown sugar, honey, and maple syrup are all different forms of sugar that may be promoted as a ‘healthier’ form of sugar, but they are no better for your health. Regardless of the form sugar takes once it enters the body the effect it has on your health is the same.

Epidemiological evidence

Sugar does not cause cancer directly; however excessive intake of sugar is a key contributor to the current obesity and overweight rates. The World Cancer Research Fund has stated that there is convincing evidence that consumption of sugar sweetened beverages causes weight gain and obesity. There is strong evidence that having excess body fat or gaining weight in adulthood increases the risk of thirteen different types of cancer.⁽³⁾

Glucose metabolism

Glucose is the primary fuel for the body. For example, the brain needs glucose so that neurons can communicate with other parts of the body, and red blood cells need glucose for energy. Carbohydrates and sugars are broken down into glucose in the body. Lipids and protein may also be broken down into glucose when carbohydrate intake is low.

Simple carbohydrates (e.g. white bread), are digested quickly and cause glucose levels to increase quickly. As blood glucose levels increase, the pancreas produces insulin, a hormone that prompts cells to absorb glucose. Glucose can be stored or used for energy. As cells absorb glucose, levels in the blood begin to fall and the pancreas produces glucagon, a hormone that signals the liver to start releasing stored glucose. This biological process ensures that cells throughout the body have a steady supply of glucose.

Research saying that sugar “feeds” cancer cells refers to sugar as the fuel source for cells. Some cancer research investigates stopping sugar getting to cancer cells as a way of stopping cancer cells growing. But that is different to eating foods including sugar. All cells, including cancer cells, use sugar for energy. As we eat food, it gets broken down in the body into sugar, our energy source, but we can’t control where our body uses that energy. There is no strong evidence to date that links sugar intake directly to cancer.

Body fatness, weight gain and cancer

There is convincing evidence that intake of sugar sweetened beverages plays a key role in body fatness and weight gain and consequently convincing evidence that this is linked to several types of cancer.⁽⁴⁾ Sugar sweetened beverages do not provide satiety, are easy to overconsume and can lead to weight gain. One pathway excess body weight can lead to cancer is it can cause insulin and other growth factor levels to rise, and this can make cancer cells grow.⁽³⁾

Current levels of sugar consumption

The Australian Health Survey 2011-12 reported that Australians consumed 60 grams of free sugars per day (equivalent to 14 teaspoons of white sugar). The majority of ‘free sugars’ intake comes from ‘added sugars’, an average of 52 grams (or 12 teaspoons); and 7 grams from honey and fruit juice.⁽⁵⁾

The majority (81%) of ‘free sugars’ were consumed from the energy-dense, nutrient-poor ‘discretionary’ foods and beverages.

The major source of ‘free sugars’ in Australian diets were:

• Beverages (52%)
  • soft drinks, electrolyte and energy drinks (19%)
  • fruit and vegetable juices and drinks (13%)
  • cordial (4.9%)
• Foods:
  • Confectionary (8.7%)
  • cakes/muffins (8.7%)

Based on self-reported data from the Australian Bureau of Statistics (ABS) 2017–18 National Health Survey (NHS), 9.1% of adults aged 18 and over consumed sugar sweetened drinks daily.

On average, Australians reduced the proportion of energy consumed from ‘free sugars’ from 12.5% in 1995 to 10.9% in 2011-12.⁽⁶⁾ However, at both timepoints, this exceeded the WHO recommendations for ‘free sugar’ consumption.

Dietary recommendations

The World Health Organization (WHO) recommends that ‘free sugars’ make up no more than 10% of daily kilojoule intake and states that a further reduction to below 5% per day would provide additional health benefits. For an average adult with a healthy body weight 10% of daily kilojoule intake equates to about 12-14 teaspoons (or 50-60 grams) of ‘free sugars’.⁽²⁾

The Australian Dietary Guidelines recommend limiting the intake of foods and drinks containing added sugars, including confectionery, sugar-sweetened soft drinks, fruit drinks and energy drinks.⁽⁷⁾

Policy context

Cancer Council Australia supports:

• The WHO guidelines and Australian Dietary Guidelines recommendations to limit intake of ‘free’ sugar
• Implementing a sugar-sweetened beverage health levy to increase the price by at least 20%
• Including added sugar on the Nutrition Information Panel on food labels
• Restricting marketing of sugar-sweetened beverages to children

Information sheet details

This information sheet was reviewed and approved by the Public Health Committee August 2015.