Limit sugar-sweetened drinks

Evidence

There is convincing evidence that consumption of sugar sweetened drinks is a cause of weight gain and overweight and obesity in both children and adults, especially when consumed frequently or in large portions. Sugar sweetened drinks do this by promoting excess energy intake relative to energy expenditure.

It’s best to drink water or unsweetened drinks, such as tea or coffee without added sugar. Fruit juices should not be consumed in large quantities, as even with no added sugar they are likely to promote weight gain in a similar way to sugar sweetened drinks.

There is no strong evidence in humans to suggest that artificially sweetened drinks with minimal energy content, such as diet sodas, are a cause of cancer. At the same time, the evidence that they help prevent weight gain and overweight and obesity is not consistent.

The available evidence is insufficient to make a recommendation regarding artificially-sweetened drinks and we, therefore, recommend water or other unsweetened alternatives.

Additional information

In addition to sugary drinks the Panel assessed the evidence on other types of drinks and found strong evidence that:

• Arsenic in drinking water INCREASES the risk of lung, bladder and skin cancers
  • A recommendation for arsenic in drinking water has not been made, as people cannot control whether or not their local water supply is contaminated. However, contamination of water supplies with arsenic is a public health issue, particularly in Bangladesh, China and West Bengal. Authorities should ensure that safe water supplies are available when such contamination occurs.
• Maté, as drunk scalding hot in the traditional style in South America, INCREASES the risk of oesophageal squamous cell carcinoma
  • A recommendation on maté has not been made as it is consumed only in specific parts of the world, but the Panel advises that maté should not be consumed scalding hot in the traditional style.
• Coffee DECREASES the risk of liver and endometrial cancers
  • A recommendation has not been made about coffee as there are many unanswered questions, for example around coffee type and preparation method
• Milk DECREASES the risk of colorectal cancer
  • A recommendation has not been made about milk (and dairy) as there is suggestive evidence that dairy products may INCREASE the risk of prostate cancer

Mechanisms

The mechanisms underpinning links between cancer and sugar sweetened drinks are indirect in that they are linked to the multiple mechanisms involved in the development of overweight and obesity.

Mechanistic evidence about the other types of drinks discussed here, that may increase/decrease cancer risk, is briefly detailed below:

• Arsenic in drinking water: exposure to arsenic and its metabolites may induce production of reactive oxygen species, which induces DNA damage and modulates the expression of genes involved in cell growth, survival and cancer risk.
• Maté: the carcinogenic effects of mate are due to consumption at very hot temperatures (over 65°C), which can cause chronic mucosal injury and promote tumorigenesis.
• Coffee: coffee drinking provides exposure to a range of biologically active compounds, many of which have been demonstrated to target pathways associated with carcinogenesis in a variety of tissues. Coffee is also a source of natural diterpenes, such as cafestol and kahweol, which have been shown to induce apoptosis (cell death) and have anti-oxidative and anti-inflammatory effects.
• Milk (dairy): milk and other dairy products contain high levels of calcium, and the casein and lactose in milk may increase calcium bioavailability.

Implications for other diseases

There is strong evidence that regular consumption of sugar sweetened drinks increases the risk of weight gain and overweight and obesity. Greater body weight is a common risk factor for many diseases and disorders, including CVD and type 2 diabetes.