At a member company day last month, organised by the British Nutrition Foundation, eminent scientists in nutritional metabolism pointed out the dangers of focusing too much on single nutrients, such as sugar, at the expense of whole diets. They also warned that replacement of individual nutrients in compound foods could have adverse unintended consequences.
Professor Julie Lovegrove, reader in nutritional metabolism at the University of Reading, spoke of the “incontrovertible evidence” linking levels of so-called ‘bad fats’ – low density lipoprotein (LDL) cholesterol – in the bloodstream, associated with consumption of saturated fats, with increased risk of cardiovascular disease (CVD).
She was speaking following the publication by the Scientific Advisory Committee on Nutrition (SACN) of a draft report on carbohydrates at the end of June which, among other proposals, argued that the UK population should get no more than 5% of its daily energy intake from “free sugars” – half the current recommendations. Campaigners arguing against adding sugar to processed foods widely welcomed the SACN report.
However, Lovegrove and fellow presenter, Professor Bruce Griffin, a world renowned expert on lipid metabolism at the University of Surrey, were particularly critical of recent research into sugar metabolism, together with some medics who had gained a high media profile by claiming that sugar in the diet was the real problem of obesity and CVD rather than saturated fats.
Lovegrove noted that the ratio of total cholesterol to high density lipoproteins (HDL) or good cholesterol) in blood was a critical consideration when evaluating risk of CVD. “There is weak, but consistent, evidence that reducing saturated fat in a postprandial [after eating] and chronic state had benefit,” she said. “The dietary guidelines we have at the moment, I am confident, are correct in reducing cardiovascular risk.”
The latest National Diet and Nutrition Survey (NDNS) results have also shown that maximum levels of saturated fat in the diet continue to be exceeded by all demographics within the UK population.
But, while milk and dairy products had over the years gained a “bad reputation” for contributing to increased sat fat intake, Lovegrove stressed it shouldn’t be forgotten that they were also an important source of essential micronutrients, such as vitamin B-12, calcium, phosphorus and iodine. This is important, when the NDNS identified that teenage girls had a low micronutrient status. Increased milk consumption also helped to reduce blood pressure, while butter had the opposite effect, added Lovegrove: “Milk seems to have a benefit, however the fat content doesn’t.”
Griffin also disputed the arguments promoted by the likes of Robert Lustig, professor of paediatric endocrinology at University of California and Dr Aseem Malhotra, a cardiology registrar at Croydon University Hospital, who promote the view that sugar and not fat is the real “villain” behind CVD and rising levels of liver disease that are also associated with obesity.