Added sugars in processed foods could have more impact on high blood pressure, heart disease and stroke than added salt, according to an analysis of published evidence in the online journal Open Heart. The findings prompted the authors to recommend that dietary guidelines should emphasis the role played by added sugars in the fight to curb the prevalence of cardiovascular disease.
Cardiovascular disease is the number-one cause of premature death in the developed world, with high blood pressure the prime risk factor, accounting for almost 350,000 deaths in the US in 2009 and costing more than US$50bn every year. In Australia in 2011/12, 32 per cent of adults over 18 had high blood pressure.
A key strategy for normalising blood pressure has historically focused on reducing salt intake. However, the potential benefits of this approach are debatable, say the authors, with average reductions in blood pressure tending to be relatively small.
Moreover, some evidence suggests three to six grams of salt daily may be necessary for optimal health, and that an intake of less than three grams is potentially harmful.
The authors point out that most salt in the diet comes from processed foods, which also happen to be loaded with added sugars. They say compelling evidence from basic science, population studies, and clinical trials implicates sugars generally, and fructose in particular, as a contributor to overall cardiovascular risk through a variety of mechanisms.
High fructose corn syrup dangers
High fructose corn syrup – the most frequently used sweetener in processed foods, especially fruit-flavoured and fizzy drinks – is especially problematic. Internationally, sugar-sweetened beverage consumption has been implicated in 180,000 deaths annually.
Until relatively recently, sugar consumption was just a few kilograms annually, whereas current estimates suggest that average consumption in the US is 34 to 69 kilograms a year; in Australian, that figure is 108 kilograms.
The evidence suggests:
- People whose dietary intake of added sugars accounts for at least a quarter of their total daily kilojoules have almost triple the cardiovascular disease risk of those who consume less than 10 percent.
- A daily intake of more than 74 grams of fructose is associated with a 30 percent greater risk of blood pressure above 140/90, and a 77 percent increased risk of blood pressure above 160/100.
- A high-fructose diet is also linked to an unfavorable blood fat profile, higher fasting blood insulin levels, and a doubling in the risk of metabolic syndrome.
Of particular concern is that UK and US teens may be consuming added sugars up to 16 times the recommended limit.
The authors would like to see more stringent recommendations about daily intake of added sugars in dietary guidelines, along with specific recommendations about fructose. They emphasise that naturally occurring sugars found in fruit and vegetables are not harmful to health: eating fruit and vegetables is almost certainly beneficial.
“The evidence is clear that even moderate doses of added sugar for short durations may cause substantial harm,” the authors caution.
Written for the Australian Traditional-Medicine Society (ATMS) by Rosemary Ann Ogilvie from materials released by BMJ.