High intakes of refined crystalline fructose cause insulin resistance in mammals. For example, rat experiments (here, here and here) have shown that fructose in high concentrations is a metabolic poison and leads to insulin resistance in just a few weeks. Originally such animal experiments were criticised for the high levels of fructose administered to the rats, detractor insisting that this was not reflective of the more modest intakes of humans. However, evidence shows that in the few decades, fructose consumption has increased significantly and levels used in animal studies are reflective of human intakes, body weight corrected. In the United Kingdom, fructose intake come mainly from the use of sucrose as a sweetener, sucrose containing a molecule of glucose bonded to a molecule of fructose. In the United states, high fructose corn syrup is the prefered sweetener in soft drinks. Increases in fructose sweetened soft drinks explains the rise in fructose intakes in both of these countries, and this mirrors obesity rates.
Fructose, sucrose and high fructose corn syrup have received much attention because of their metabolic toxicity. However, in reality any refined crystalline sugar can be problematic because removing sugars from their original plant material removes the fibre and micronutrients that are required for their correct digestion, absorption and assimilation. In this regard, it might be more important to consider total sugar intake rather than focussing on fructose. The total sugar intake of children has been assessed in the nutritional literature with this aim in mind. For example, in one study, researchers1 estimated the total sugar intake of American children between the ages of 6 and 12 years using 7-day food diaries. Sugars included sucrose, maltose, lactose, and other reducing sugars that were present in any foods. The total sugar consumption for the children was 134.3 grams per day. Milk, cakes, biscuits, cookies and other confectionary, sugar sweetened soft drinks, fruit and fruit juices contributed the largest contribution to the total sugar intake.
However, while the average consumption of sugars was 134.3 grams per day, some children were consuming as much as 280 grams. When the food diaries of these children were analysed it was found that the foods most likely to contribute to this high sugars intake were fruit juices, soft drinks, cakes and biscuits. Those with the lowest sugar intake consumed around 44 grams per day, and to consume this low amount necessitated the avoidance of such junk foods. Although milk contributed a large amount of sugars to the diet, there is little evidence that the lactose in milk is detrimental to the health unless an underlying lactose intolerance exists. In this regard the quality of the food eaten should be considered as generally milk is an unprocessed food (excluding pasteurisation and homogenisation in some cases), and the sugars contained within are slowly digested and absorbed with causes controlled rises in blood sugar. Milk is more also likely to be consumed with other foods that may be beneficial to the health such as oats and tea.
Dr Robert Barrington’s Nutritional Recommendation: This paper was published in 1981 and since this time sugar intake has increased further. Childhood obesity is increasing in prevalence and this can be linked to an increased intake of refined crystalline sweetening sugar. Fruit juices and soft drinks are particularly problematic and are drivers of weight gain and obesity. Sugars in the diet should be limited to natural sources where the sugar is still retained within it original plant material. Sweetening foods with honey and molasses is a better option than using refined sucrose, because the honey and molasses contain vitamins, minerals and other factors that are beneficial to the health. Although fruit contains high concentrations of simple sugars that sugar is encased within fibrous cell walls, is relatively dilute in most fruits, and is present with vitamins and minerals required for the correct metabolism of the sugars.
RdB
