A comprehensive survey of ingredients in yogurts has highlighted high sugar levels in many – particularly organic yogurts and those marketed towards children.

Scientists from the Universities of Leeds and Surrey analysed the product information for 921 yogurts available in major UK supermarkets. 

Their study, published in journal BMJ Open, examined the sugar and nutrient content of yogurts across eight product categories. Natural, ‘plain’ and Greek-style yogurts were found to have a dramatically different nutrient profile from all other categories, containing much higher levels of protein, lower carbohydrates level and the least amount of sugar, with the average of five grams per 100g – this was largely naturally-occurring lactose.

All the other categories were found to contain more than five grams per 100g. Unsurprisingly, yoghurt desserts contained the most sugar – an average of 16.4g per 100g. This category also included some products that did not contain yoghurt, such as chocolate mousse and creme caramel. 

The second most sugary product was organic yoghurts with a typical 13.1g per 100g. While, children's yoghurts typically contained 10.8g per 100g, the equivalent of more than two sugar cubes, the study found. 

For comparison a standard sugar cube weighs roughly four grams – equivalent to a level teaspoon of granulated sugar. 100g serving of a typical cola contains 9g of sugar.

The NHS recommends that children aged four to six have no more than 19g of sugar, or five sugar cubes a day, and it is advised that those aged seven to 10 consume less than 24g daily. While, the Scottish Dietry Goals recommend that sugar intake should not exceed 5% of total energy intake in adults and children over 2 years old.

To be classed as “low sugar” and carry a green “traffic light” nutritional label for sugar on their packaging, food products must contain a maximum of 5g of sugar per 100g. Only 9% of products surveyed were below this threshold.

How much sugar was in the yoghurt?

·      Desserts – 16.4g per 100g

·      Organic – 13.1g per 100g

·      Flavoured – 12g per 100g

·      Fruit – 11.9g per 100g

·      Children's – 10.8g per 100g

·      Dairy alternatives – 9.2g per 100g

·      Drinks – 9.1g per 100g

·      Natural and Greek – 5g per 100g

As part of a plan to combat childhood obesity, the UK government implemented a soft drinks sugar levy in May. Public Health England has commissioned a structured programme of monitored sugar reduction as part of a wider plan to tackle calories, salt and saturated fat. Yogurt is one of the products identified and highlighted for a 20% reduction of sugar by 2020.

Lead author Dr Bernadette Moore, from the School of Food Science and Nutrition at Leeds, said: “While there is good evidence that yogurt can be beneficial to health, products on the market vary widely in nutrient content. 

"Items labelled ‘organic’ are often thought of as the ‘healthiest’ option, but they may be an unrecognised source of added sugars in many people’s diet.”

 “Many of the products that were suggested for children’s lunchboxes were high sugar dessert yogurts, rather than lower sugar options. Retailers could play a positive role in promoting health by establishing boundaries for lunchbox recommendations and clearly labelling the amount of added sugar.” 

“Our study highlights the challenges and mixed messages that come from the marketing and packaging of yogurt products,” she said. 

Dr Moore explained that while yogurts contained their own naturally-occurring sugar – called lactose or milk sugar –current UK labelling laws do not require the declaration of added sugars on nutrition labels: ‘total sugar’ on the package indicates the weight of lactose as well as any added sugars.

Study co-author Dr Barbara Fielding, from the University of Surrey, said: “Diets high in added sugars are now unequivocally linked to obesity and dental problems. An alarming 58% of women and 68% of men – along with one in three of UK children aged ten to eleven – were overweight or obese in 2015. 

“In the UK, on average, children eat more yogurt than adults, with children under three years old eating the most. It can be a great source of protein, calcium, and vitamin B12. 

"However, we found that in many of the yogurt products marketed towards children, a single serving could contain close to half of a child’s recommended daily maximum sugar intake. Many portion sizes for children’s yogurts were identical to adult portion sizes.”

Study co-author Annabelle Horti, who conducted this research while at the Leeds’ School of Food and Nutrition, said: “Changing the public desire for ‘sweeter’ yogurts may be a real challenge when it comes to reducing its sugar content. In general, consumers’ liking for yogurt is often correlated with sweetness. 

“Sugar is often used as a sweetener to counteract the natural sourness from the lactic acid produced by live cultures in yogurt. These live cultures – or microorganisms – are what make yogurt a ‘good for your gut’ food and tend to be found in higher amounts in organic yogurts. This may be why these products had higher amounts of added sugar to offset the sourness. 

“Helping people to understand the quantity of sugar that is in their yogurt and its possible ill effects on health may go a long way to smoothing the road for when the sugar is reduced.”