Excessive intake of sugar-sweetened beverages like soft drinks and fruit juices that offer no nutritional value other than calories to the diet of teenagers can elevate their risk of heart disease in later life, claims a new study. According to health experts, there is growing evidence of the link between excess sugar consumption among youngsters and a number of health conditions such as obesity, hypertension, elevated triglycerides that are considered markers for heart disease. Lead author of the study, Jean Welsh, post-doctoral fellow at Emory University School of Medicine in Atlanta stated, “We need to be aware of sugar consumption. “It’s a significant contributor of calories to our diet and there are these associations that may prove to be very negative. “Sugar-sweetened soft drinks and sodas are the major contributor of added sugar and are a major source of calories without other important nutrients. “Parents and adolescents need to become aware of the amount of added sugar they are consuming and be aware that there may be some negative health implications if not now, then down the line.”
According to the American Heart Association (AHA) recommendations, a teenager who requires 2,200 calories may have an upper limit of 150 calories from added sugar while someone with an energy requirement of 1,800 calories per day should limit added sugar to 100 calories. However, the National Health and Nutrition Survey (NHANES) of 2,157 teenagers aged 12 to 18 years found that the average teenager consumes close to 500 calories added sugars each day. “Adolescents are eating 20 per cent of their daily calories in sugars that provide few if any other nutrients,” said Jean Welsh.
In order to get an insight into the impact of high sugar consumption in adolescence on the risk of cardiovascular disease in later life the researchers studied 646 teenagers. For the purpose of the study, they analyzed the 24-hour dietary recall by teens with data from the US Department of Agriculture on sugar content in foods. It was noted that the teens’ average daily consumption of added sugars was three to five times higher that the limit acceptable by the AHA.
The study found, that teens who consumed 30 percent or more of total calories from added sugars exhibited lower levels of HDL, or “good” cholesterol and higher levels of triglycerides and LDL or “bad” cholesterol, compared to those who ate less than 10 percent of added sugar. In addition, it was observed that obese and overweight teenagers who consumed more sugar also had the most insulin resistance.
Although the study hints at a possible association between added sugar intake and poor cholesterol profiles as well as other heart disease risk factors, researchers feel there is need for more research to substantiate the findings. Welsh stated, “We need controlled studies to really understand the role of added sugars in cardiovascular disease. But it is important to be aware of the added sugar in the foods we all eat.”
The study is published in the American Heart Association (AHA) journal ‘Circulation.’
Teens whose diets include lots of sugary drinks and foods show physical signs that they are at increased risk for heart disease as adults, researchers from Emory University report. Among 2,157 teens who took part in the National Health and Nutrition Examination Survey, the average amount of added sugar eaten in a day was 119 grams (476 calories), which was 21.4 percent of all the calories these teens consumed daily, the researchers noted. “We need to be aware of sugar consumption,” said lead researcher and postdoctoral fellow Jean Welsh. “It's a significant contributor of calories to our diet and there are these associations that may prove to be very negative,” she said. “Sugar-sweetened soft drinks and sodas are the major contributor of added sugar and are a major source of calories without other important nutrients.” Awareness of the negative effects of added sugar may help people, particularly teens, cut down on the amount of sugar they consume, Welsh added. “Parents and adolescents need to become aware of the amount of added sugar they are consuming and be aware that there may be some negative health implications if not now, then down the line,” she said.
The report is published in the Jan. 10 online edition of Circulation.
Welsh's team found that teens who consumed the most added sugar had 9 percent higher LDL (“bad”) cholesterol levels, and 10 percent higher triglyceride levels (another type of blood fat), compared with those who consumed the least added sugar. Teens who took in the highest amount of added sugar also had lower levels of HDL (“good”) cholesterol than those who consumed the least amount of added sugar. In addition, teens who consumed the highest amount of added sugar showed signs of insulin resistance, which can lead to diabetes and its associated risk of heart disease, the researchers found.
The American Heart Association has recommended an upper limit for added sugars intake, based on the number of calories you need. “Most American women [teens included] should consume no more than 100 calories of added sugars per day; most men, no more than 150 calories,” the association states.
One caveat to these findings is that because of the way the study was done it is not clear if added sugars caused the differing cholesterol levels, only that they are linked. In addition, the data are only for one day and may not reflect the teen's usual diet, the researchers noted. Commenting on the study, Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine, said that “this study does not prove that dietary sugar is a cardiac risk factor in this population, but it strongly suggests it.”
The paper has three important messages, he said. First, dietary sugar intake in a representative population of teenagers is nearly double the recommended level. Second, the higher the intake of sugar, the greater the signs of cardiac risk, including elevated LDL (“bad”) cholesterol and low HDL (“good”) cholesterol. Third, the apparent harms of excess sugar are greater in overweight than in lean adolescents.
“Sugar is by no means the sole dietary threat to the health of adolescents, or adults,” Katz said. “But we now have evidence it certainly counts among the important threats to both. Reducing sugar intake by adolescents, to prevent them becoming adults with diabetes or heart disease, is a legitimate priority in public health nutrition,” he said.
SOURCES: HealthDay; Jean Welsh, M.P.H., Ph.D., R.N., postdoctoral fellow, Emory University, Atlanta; David L. Katz, M.D., M.P.H., director, Prevention Research Center, Yale University School of Medicine, New Haven, Conn.; Jan. 10, 2011, Circulation, online
The paper directly compared findings from two separate studies: 'The Diets of British Schoolchildren' conducted by the Department of health (DH) in 1983 (Department of Health 1989); and the National Diet and Nutrition Survey (NDNS) from 1997 (Gregory & Lowe, 2000).
Gibson's analysis found that total sugar intake averaged at 115g/day in 1983, compared with 113g/day in 1997. Allowing for exclusions of low and high energy reporters, intake levels were 122g/day (1983) and 127g/day (1997), showing a marginal and insignificant increase over the study period. Contrastingly, mean body weight increased significantly during the period of the DH and NDNS surveys, showing a rise of 1.9kg for 10-11 year olds and 3.4kg among 14-15 year olds. BMI increased from 17.9 to 18.6 units in the younger group, and 20.2 to 21.3 units in the older group. According to these calculations, the prevalence of being overweight (plus obesity), as defined by the International Obesity Taskforce (IOTF) cut-offs (91st percentile) rose from 13% to 21-22% between surveys. Gibson concluded that the slight increase in consumption of total sugars did not account for the significant increase in BMI, equivalent to 2-3 kg over the review period.
During the same period, Gibson found that mean energy intake (EI) was 3% lower in 1997 than in 1983, mainly as a result of lower fat intake. This change in overall energy consumption meant that sugars represented a higher proportion of daily energy intake in 1997 (23.6% versus 22.3%), despite total sugar consumption remaining relatively static in comparison. The review surmises that the most likely cause for the increased BMI is a decline in energy expenditure.
In addition, Gibson's paper found that basal metabolic rate (BMR) increased by approximately 3% between surveys as a result of higher body weights, and it is estimated that EI in relation to basal requirements was even lower at 6%. Gibson found that the paradox of rising BMI, despite a 2-3% rise in BMR and an EI that is static or falling, pointed to declining energy expenditure as an important factor in the change.
The Gibson analysis showed that the key sources of sugars in the diet have changed with a marked shift away from table sugar and smaller falls in consumption of sugars through milk, biscuits and cakes, counterbalanced by a significant increase in sugars consumed in soft drinks and, to a lesser extent, fruit juice and breakfast cereals.
A conclusion of Gibson's reanalysis of data from the DH and NDNS studies, that consumption of total sugars remained relatively static during the period, providing an estimated 22% of energy, is supported by findings from a repeated cross sectional study of children's food and drink intake, conducted in Northumberland in 1989, 1990 and 2000 which looked at trends in children's food and drink intake.
Sigrid Gibson, the paper's author, said: “There are very few studies that have assessed trends in sugar intake over time and particularly over such an extended period. The findings of the reanalysis strongly contradict widespread assumptions that sugar levels in the diet are responsible for rising obesity levels. With dietary sugar intakes relatively static, and overall energy consumption showing decline, increased BMI levels cannot be attributed to sugar consumption.”
Researchers analyzed 84 hours of primetime and 12 hours of Saturday morning broadcast television over a 28-day period in 2004. ABC, CBS, Fox and NBC were sampled on a rotating basis to develop a complete profile of each network. The Saturday-morning cartoon segment (from 8:00 am to 11:00 am) was included to capture food advertisements marketed primarily to children.
All 96 hours of observations were videotaped and reviewed later to identify food advertisements and specific food items being promoted. Only food items that were clearly promoted for sale during an advertisement were recorded. Each food item was then analyzed for nutritional content. Observed portion sizes were converted to the number of servings.
The article indicates that the observed food items fail to comply with Food Guide Pyramid recommendations in every food group except grains. The average observed food item contained excessive servings of sugars, fat, and meat and inadequate servings of dairy, fruit and vegetables. The situation was similar for essential nutrients, with the observed foods oversupplying eight nutrients: protein, selenium, sodium, niacin, total fat, saturated fat, thiamin and cholesterol. These same foods undersupplied 12 nutrients: iron, phosphorus, vitamin A, carbohydrates, calcium, vitamin E, magnesium, copper, potassium, pantothenic acid, fiber, and vitamin D.
The authors advocate nutritional warnings for imbalanced foods similar to those mandated on direct-to-consumer drug advertisements. They recommend investigating health promotion strategies that target consumers, the food industry, public media, and regulation focusing on a three-pronged approach.
“First, the public should be informed about the nature and extent of the bias in televised food advertisements. Educational efforts should identify the specific nutrients that tend to be oversupplied and undersupplied in advertised foods and should specify the single food items that surpass an entire day's worth of sugar and fat servings. Second, educational efforts should also provide consumers with skills for distinguishing balanced food selections from imbalanced food selections. For example, interactive websites could be developed that test a participant's ability to identify imbalanced food selections from a list of options. This type of game-based approach would likely appeal to youth and adults. Third, the public should be directed to established nutritional guidelines and other credible resources for making healthful food choices.”