The warnings came after another study highlighted that fruit juices and smoothies often contained much more sugar that sugar-sweetened drinks, posing an increased risk of mortality.
A six-year study, published in the Journal of the American Medical Association, examined the intake of sugary drinks and fruit juice in 13,440 adults in the US over the age of 45 years.
Those who drank a 12 oz (350 ml) glass of juice daily had a 24% greater chance of dying during the study, compared to an 11% rise among those drinking any sugary soft drink daily.
“These findings suggest that consumption of sugary beverages, including fruit juices, is associated with all-cause mortality. Well-powered and longer-term studies are needed to inform their association with CHD mortality risk,” the study concluded.
Katharine Jenner, a nutritionist at Action on Sugar, told FoodNavigator: “If you blend fruit, the natural sugars are released from within the cell walls of the fruit and become ‘free sugars’ which we should all be cutting down on to protect our teeth and help maintain a healthy weight. Whilst some fruit juices can contribute to one of our five a day, we should not consume more than 150 ml per day as too much sugar and calories leads to obesity, Type 2 Diabetes, cancer and tooth decay. Our advice is eat the fruit, don’t drink it!"
Dr Saul Konviser from the Dental Wellness Trust charity said: "As a dentist, I see a large number of children that require not just a simple filling but multiple fillings or extractions often as a result of consuming excessive fizzy drinks and fruit juices which, in my opinion, is bordering on dental neglect. Whilst our recent independent survey found that over 97% of parents are aware that fizzy drinks lead to tooth decay, followed by 93% of parents associating fruit juice with the disease, many consumers are still ignoring the warning signs."
‘More research needed on mortality risks associated with fruit juices’
High consumption of dietary sugars and sugar-sweetened beverages (SSBs) in particular was associated with several CHD risk factors, including dyslipidemia, diabetes, and obesity, the US research noted.
But it added that: “no one has yet examined the extent to which mortality risk is elevated with sugary beverages, including SSBs and fruit juices.”
SSBs, such as carbonated and noncarbonated soft drinks, fruit punch, fruit juice concentrates, powdered drink mixes, and energy drinks typically contained 140 to 150 kcal and 35 to 37.5 g of sugar per 12-oz serving, and were the largest source of added sugars in the US diet, it said.
“Fruit juices are still widely perceived as a healthier option than SSBs. However, they often contain as much sugar and as many calories as SSBs. Although the sugar in 100% fruit juices is naturally occurring rather than added, once metabolized, the biological response is essentially the same.”
It suggested that more efforts were needed to change the perception of fruit juices among consumers.
“Substantial efforts have been devoted to discouraging the consumption of SSBs, including policies for taxation and restrictions on marketing to children.
“In recent years, public health efforts to promote a reduction in the consumption of SSBs and other sources of added sugars in the US have intensified, despite some declines, consumption remains well above recommended levels.
“Less attention has been given to the role of 100% fruit juice consumption, which tends to be perceived as a healthy beverage option.
“Therefore, to inform policy and the development of dietary guidelines, it is critical to understand how beverages high in naturally occurring sugars, in addition to those high in added sugars, are associated with cardiovascular health and mortality risk.”
‘The nutrient content of 100% fruit juices and sugary drinks is very similar’
While 100% fruit juices contain some vitamins and phytonutrients that are missing from most SSBs, the predominant ingredients in both are sugar and water, said the study.
“Although the sugar in SSBs is added during processing and the sugar in 100% fruit juice occurs naturally, the specific sugars they provide for the body to process are essentially the same, and the biochemical response when metabolized is the same.
“The sugars contained in all sugary beverages are primarily the monosaccharides glucose and fructose or the disaccharide sucrose, which is quickly broken down with digestion and metabolized into equal parts fructose and glucose.”
‘No beneficial health effect from so-called antioxidants’
Dr Gunter Kuhnle, associate professor in nutrition and health at the University of Reading, said: “This is a very important study, especially as fruit juices are often seen as a ‘healthy’ alternative to sugar-sweetened beverages, even though they often contain much more sugar (especially smoothies).
"Fruit juices can provide vitamins and even some fibre, but there is little health benefit beyond this: the amount of phytochemical found in juices is too low to have any further beneficial effect, and there is no beneficial health effect from so-called antioxidants.
"If the association is shown to be causal (which we don’t know yet), this would have a number of implications: first of all, it would suggest that it does not matter whether sugary drinks are lemonades or fruit juices.
"This is important, as fruit juices and smoothies are not commonly perceived as sugary drinks.
"Secondly, it would suggest purported health benefits of fruit juices are not sufficient to counteract their sugar content."
New fruit juice research is misleading
The British Soft Drinks Association said the study was misleading. Gavin Partington, director-general, said: "All age groups in the UK are falling short on their five a day consumption of fruit and vegetables. Therefore, warning against consuming a small 150ml portion of pure fruit juice – which counts as one of your five a day – risks people foregoing the vitamin and phytonutrient benefits of fruit juice that this study acknowledges.
“Our research hows adults and teenagers who drink fruit juice are about twice as likely to reach their recommended minimum of five a day, than non-drinkers.”