University College London (UCL) report a link between men consuming the highest amounts of sugar a day and a heightened increase in risk of suffering a mental disorder after five years.
The report highlights an especially strong association between these sugar levels and episodes of depression in men.
“There is increasing evidence for the physical damage sugar has on our health,” said lead author Dr Anika Knüppel from the UCL Institute of Epidemiology and Public Health.
“Our work suggests an additional mental health effect. This further supports the evidence for policy action such as the new sugar levy in the UK, but this is not addressed in many other European countries.”
As well as the UK, countries such as Hungary, Ireland and Norway have introduced, or are about to introduce, a levy designed to improve the health of the nation.
The move is all the more urgent particularly with the rise in obesity, diabetes and dental caries amongst children and young adults.
The study, in which 5000 men and over 2000 women took part over 22 years between 1983 and 2013, began by categorising daily sugar intake from sweet food and beverages into three groups.
The top group featured men, who consumed more than 67 grams (g) of sugar, had a 23% increased chance of incident common mental disorders compared to those in the bottom group, who consumed less than 39.5 g.
The role of ‘reverse causation’ in which people with anxiety and/or depression tended to consume more sugary foods and drinks, was also looked at but was not observed in the resulting data.
“There are numerous factors that influence chances for mood disorders, but having a diet high in sugary foods and drinks might be the straw that breaks the camel's back,” said Dr Knüppel.
“The study found no link between sugar intake and new mood disorders in women and it is unclear why. More research is needed to test the sugar-depression effect in large population samples.”
In Britain, adults consume approximately double, and in the US triple, the recommended level of added sugar, with sweet foods and drinks contributing three-quarters of the intakes.
Commenting on the UK sugar tax that will take effect in April 2018, senior study author Professor Eric Brunner from UCL’s Institute of Epidemiology and Public Health, said the tax would be “protection from the commercial forces which exploit the human ‘sweet tooth’”.
Taste, texture and preservative qualities
The food industry’s relationship with sugar has traditionally been one of excess. Confectionary and snack makers along with beverage producers have relied on the ingredient’s properties to provide taste, texture and preservation.
Such is the industry’s reliance on sugar that efforts to reduce its content in food have proved difficult.
Current approaches focus on product reformulation, reducing portion sizes and shifting consumer purchasing towards lower or no added sugar products.
Nestlé’s commitment to reduce added sugars in its products globally by 5% by 2020, was announced in its March CSR report.
It pledged to remove 7,500 metric tons of sugar in its UK confectionery range via reformulation, replacing sugar with larger quantities of existing ingredients or other non-artificial ingredients.
The company said the move would not affect taste.
More reformulation efforts
Meanwhile, in an effort to pre-empt the UK sugar tax, Lucozade Ribena Suntory also stepped up its reformulation efforts, ensuring its drinks would contain less than 4.5 g of total sugar per 100 millilitres (ml) from July onwards.
Catherine Collins, registered dietitian, and spokesperson for the British Dietetic Association, criticised the use of ‘standard portion’ measurements in the UCL study, stating that guides were “out of date compared to current estimates, and you can’t ‘scale’ up an intake accordingly “.
“A can of Coke is usually 330 ml (but can now also be a downsized 250 ml), a muffin or doughnut has almost doubled in size over the last 10 years. Food portion sizes would have distorted the calculated sugar intake significantly.”
She added that sugar intake from foods and drinks could not be used to predict energy intake overall.
“For example, a 45 g bar of Cadburys Dairy Milk provides 25 g of sugar and 240 (kilocalories) kcals, due to the 14 g of fat in the bar, too."
“But a 330 ml can of sugary cola has 35 g of sugar. That’s 10 g more sugar than the bar of chocolate, but it has fewer calories – 140 kcal – because sugar is the only source of calories in this sugary drink.”
Source: Scientific Reports
Published online ahead of print: doi:10.1038/s41598-017-05649-7
“Sugar intake from sweet food and beverages, common mental disorder and depression: prospective findings from the Whitehall II study.”
Authors: Anika Knüppel, Martin Shipley, Clare Llewellyn & Eric Brunner