• Research Review
• Journal Summary

Authors: J Welsh, A Sharma, J Abramson, V Vaccarino, et al.
http://jama.ama-assn.org/cgi/content/abstract/303/15/1490

Reference: JAMA 2010; 303:1490-1497

Reviewer: Robert Goldberg, PhD, Contributing editor, ProCor; Professor of Medicine and Epidemiology, Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA

Reviewer comments: Consumption of large amounts of added sugars is a relatively recent phenomenon among Americans as sugar sweeteners became available for general population consumption from the mid-19th century on. As reflected by the results of the present study, which was carried out in a nationally representative sample of the US population, Americans presently ingest nearly one-sixth of their daily calories from added sugars. Indeed, in the late 1970's, added sugars contributed "only", but a still very large percentage, 11% of the calories consumed by American men and women.

While a variety of individual foods, food groups, and selected nutrients have been shown to have an adverse effect on various serum lipids, little data are available about the association between added sugars and levels of various serum lipids and/or lipoproteins. It is well known, however, that the consumption of foods high in added sugars has been associated with obesity, diabetes, dental caries, and a lower overall quality diet.

The results of the present observational study suggest an association between self-reported consumption of dietary added sugars and serum lipid levels in US men and women. Since this cross-sectional study cannot determine cause and effect, long-term prospective studies are needed to more systematically examine the effects of added sugars on serum lipid profiles and possibly other important CVD risk factors including hemostasis, blood glucose levels, and blood pressure. Moreover, further studies are needed to identify the potential mechanisms involved in this association, if real. Given the nutritional emptiness of these added sugars, and ongoing epidemic of obesity and physical inactivity in American men and women, dietary guidelines should be strongly considered to reduce the levels of added sugar to commonly consumed food products and American teens and adults should be encouraged to eat more healthy food products that are low in salt, fat, and added sugars. These efforts would hopefully lead to an improved nutritional profile in US adults, smaller waistlines, and improved overall health status.

Purpose of study: To examine the association between the consumption of caloric sweeteners in foods and beverages with serum lipid levels in US men and women.

Location of study: Atlanta, GA

Study design: Cross-sectional

Results: Data from the nationally representative National Health and Nutrition Examination Survey (NHANES), which was conducted over the period 1999 and 2006, were used for purposes of the present investigation. After a variety of exclusion criteria were applied, the final study sample consisted of 3088 women and 3023 men. Information was collected about survey respondent's age, sex, race/ethnicity, physical activity levels, smoking habits, alcohol consumption patterns, and use of antihypertensive medication, in addition to information about food intake.

Dietary intake was assessed by an interviewer assisted dietary recall of all foods and beverages consumed in the 24 hour period prior to the standardized interview.

The nutrient content of a variety of foods was determined through a USDA nutrient database, including the assessment of added sugar intake. Several key lipid abnormalities were examined including low HDL-C levels (<40 mg/dl for men; <50 mg/dl for women), high LDL-C levels (>130 mg/dl), or elevated triglyceride levels (>150 mg/dl).

In examining the association between the percentage of total energy from added sugars expressed in quintiles (range from <5% to >25%), as the intake of added sugars increased, survey respondents were more likely to be younger, black, of low income, smoke more cigarettes, but were less likely to be hypertensive. Total energy and the percentage of total energy from carbohydrates increased as the proportion of energy from added sugars increased; on the other hand, as the intake of added sugars increased, the percentage of energy from fats, protein, and fiber decreased. Individuals who reported the highest intake of added sugars (>25% of total energy consumed) were more likely to have gained an average of 2.8 pounds during the previous year as compared to a weight loss of 0.3 pounds among those consuming less than 5% of their total energy from added sugars. The daily consumption of added sugars averaged 90 grams, or approximately 16% of their total daily caloric intake, and nearly one third of their total carbohydrate intake.

In examining the association between the intake of added sugars with serum lipid levels, the adjusted average HDL-C levels declined with an increasing proportion of total energy coming from added sugars. For example, the odds ratios for having a low HDL-C level increased from 1.5, to 1.9, and to 3.1 in persons who consumed 10-17.4%, 17.5-24.9%, and >25% of their total energy from added sugar compared to those who consumed <5%. On the other hand, average serum triglyceride levels increased with increasing levels of added sugar in the diet, as did serum LDL-C levels, with these associations stronger among women as compared with men.