Soft drinks are the leading source of fructose, and the increase in soft drink and fruit juice consumption has largely replaced milk intake, especially in children. This means children today are consuming more sugar and less protein, calcium, and vitamin D than their parents and grandparents did.
Intake of fructose has increased in the typical US diets to more than 10% of energy intake, according to the results of a study by Miriam B. Vos, MD, MSPH, from Emory University in Atlanta, Georgia.
Dansinger, MD, MS, from the Division of Endocrinology, Diabetes, and Metabolism at Tufts Medical Center in Boston, stated that "Sadly, less than 20% of the fructose in the American diet is consumed in natural form from fruits and vegetables. "In fruits and vegetables, fructose is not highly concentrated and is accompanied by fiber and other healthy nutrients. These foods are low in calories and they decrease hunger and appetite, and they help maintain a healthy body weight."
"In contrast, the fructose added to soft drinks and processed foods typically lead to increased calorie intake and possible weight gain because the fructose is not accompanied by comparable amounts of fiber or other nutrients that promote healthy weight." "Instead, the fructose acts as an unhindered appetite stimulant. In this regard, fruit juice is much like a soft drink because the fiber is lacking and the fructose is much more highly concentrated that in the original fruit."
Dietary data from a nationally representative sample from 1977 to 1978 showed that mean estimated fructose intake was 37 g/day, or 8% of total intake. However, little is known about more recent patterns of fructose consumption.
The goal of the study by Dr. Vos and colleagues was to determine the amount and sources (natural fruit vs fructose added to beverages and other foods) of dietary fructose in 21,483 US adults and children. Estimated mean consumption of fructose was 54.7 g/day (range, 38.4 – 72.8 g/day), accounting for 10.2% of total energy intake. Adolescents (12 – 18 years of age) had the highest intake (72.8 g/day, or 12.1% of total energy intake). For 25% of adolescents, at least 15% of energy consumed came from fructose. Sugar-sweetened beverages were the largest source of fructose (30%) followed by grains (22%) and fruit or fruit juice (19%). When compared with a previous nationally representative study, these findings suggest that fructose consumption has increased.
High fructose intake has been linked to increased lipogenesis in the liver as well as increased plasma triglyceride levels, insulin resistance, and obesity. In short-term studies, fructose intake increases plasma triglyceride levels in healthy adults.
In children aged 6 to 19 years, dietary sucrose has been linked to increased plasma triglyceride and low high-density lipoprotein (HDL) cholesterol levels. Total fructose intake in normal-weight and overweight children was a significant predictor of smaller low-density lipoprotein (LDL) cholesterol particle size, which in turn has been linked to an increased risk for cardiovascular disease.
In an accompanying editorial, George A. Bray, MD, chief of clinical obesity and metabolism at the Pennington Biomedical Research Center in Baton Rouge, notes that dietary fructose comes from 3 main sources: sucrose (common table sugar), high-fructose corn syrup (HFCS) made from corn starch, and fruit. Fructose intake from sugar or HFCS-sweetened beverages provides no other nutrients, whereas intake of fruit containing fructose provides a variety of natural, beneficial nutrients.
The more energetically (calorically) sweetened soft drinks consumed by young people, the more they are shortchanged of valuable nutrients found in natural foods, and the less milk they consume, which also shortchanges them on calcium and vitamin D. The amount of energy (calories) in energetically (calorically) sweetened beverages is not perceived by the body in the same way as those in solid food, in that they do not suppress intake of other foods by the amount of energy (calories) in the soft drinks, thereby contributing to the current epidemic of obesity.
The main cause of the obesity epidemic is increased calorie intake throughout society during the past 50 years. The addition of sugar and high-fructose corn syrup (which are both around 50% fructose) to processed foods and beverages is a major cause of the increased caloric intake, not only from the calories in the sugars themselves, but [because] they are added to foods that already have high calorie counts, such as doughnuts and ice cream. In other words, many high calorie foods have sugar added, and this drives much of the obesity epidemic.
Other negative effects of fructose consumption include increased levels of serum uric acid, indirectly contributing to hypertension and cardiovascular disease and directly related to the risk for gout in men. Consumption of soft drinks has been associated with the development of cardiometabolic risk factors and the metabolic syndrome in participants in the Framingham Study.
- The estimated mean fructose consumption was 54.7 g/day (approximately 10% of total energy). Adolescents aged 12 to 18 years had the highest energy intake (72.8 g/day), or 12.1% of total energy. The largest sources of fructose were sugar-sweetened beverages (30%), grains (22%), and fruit or fruit juice (19%).
- Fructose consumption may adversely affect health outcomes. In short-term studies, fructose intake increases plasma triglyceride levels in healthy adults, and correlations between fructose intake and plasma lipid levels have been reported in children. Other negative effects of fructose consumption include increased serum uric acid levels, increased risk for cardiovascular disease, increased risk for gout in men, and development of cardiometabolic risk factors.
J Med. Published online July 9, 2008.
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