Refined crystalline sugar consumption is increasing in developed countries and is mirrored by an increases in Western lifestyle diseases such as obesity, cardiovascular disease and type 2 diabetes. Sugars are present naturally in fruits and other foods traditionally eaten by humans, but these natural sugars tend not to be detrimental to the health. This is because the sugars in fruits are diluted in the high water content of the fruit and are encased in fibrous cells that delay the digestion rate of the sugars. Further, vitamins and minerals are also present in the naturally occurring sugary foods including honey and fruits. These vitamins and minerals are required as accessory nutrients for the correct metabolism of sugars, chromium for example being required for the correct function of the insulin receptor and B vitamins being required for the correct function of energy harvesting pathways. Honey is very high in sugar, but traditionally is not a quantitatively important source because obtaining honey was historically difficult.
When refined crystalline sugars including sucrose, fructose and high fructose corn syrup are added to the diet they have deleterious effects on health. These deleterious effects are increasingly being shown to relate to the fructose component of added sugar. Fructose when refined and crystalline is deleterious because it causes a large influx of energy to the liver and this shifts the metabolism to one of synthesising fatty acids. These fatty acids accumulate in skeletal muscle and the liver where they interfere with the insulin signal cascade and are a primary driver of insulin resistance. The association between fructose in its refined crystalline state and disease is well established, and studies have also shown associations between intakes of added sugars and mortality. As awareness of the detrimental effects of added sugars has increased, more studies have assessed their impacts on health. In one recent study for example, the association between added sugar and total mortality was investigated.
In the study1, over 300,000 individual between the ages of 50 and 71 were followed for up to 13 years in order to record mortality rates. At the beginning of the study the subjects also had their food intakes for total added sugars recorded from the previous year. The result of the study showed that all cause mortality was positively associated with the intake of total sugars, total fructose, and added fructose in women, and all cause mortality was positively associated with total fructose intake in men. There was also an inverse association between added sugars, sucrose and added sucrose with mortality in men, however this association was weak, suggesting that confounding variables might be involved. When the authors analysed the data further to include the source of the sugars, they observed that the positive association with mortality was confined to the intakes of added sugars from soft drinks, whereas the weak inverse association between sugar and mortality was confined to whole foods.
Dr Robert Barrington’s Nutritional Recommendations: These results support previous studies that show a correlation between sugar consumption and disease. In this regard, the study identified sugar added to soft drinks as the main culprit. Sugar in soft drinks is particularly damaging for two reasons. Firstly, it is very easy to overconsume energy from sugars when in liquid form. Secondly, the absence of fibre and other food matrix components results is a rapid absorption of the sugar that overloads the liver with energy, and it is this energy overload that is required to shift the metabolism of the liver to one of fatty acid synthesis by activation of the de novo lipogenesis pathway. Sugars in fruits juices are also detrimental for this reason. Sugar in food, including fruits and other foods is less damaging because of the food matrix effect during digestion that slow the absorption of the sugars. The present of sugar in fruit likely explains the inverse association with mortality and sucrose intake, some fruits being high in sucrose.
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