April 21, 2010 (Atlanta, Georgia) — It's been clear enough that a high-fat diet can worsen serum lipids, but less so that a diet with a lot of added sugar may do it as well. The case for it is stronger with a cross-sectional look at >6000 US adults that found significant, independent associations between increased intake of sugar-sweetened foods, which typically have added sucrose or high-fructose corn syrup, and elevated triglycerides (TG) and reduced HDL-cholesterol levels [1].

The analysis, based on 1999–2006 data from a National Health and Nutrition Examination Survey (NHANES) population, also suggested a big jump in consumption of added sugar compared with NHANES data from almost 30 years earlier, from 10.6% to 15.8% of daily calories, report its authors, led by Jean A Welsh (Emory University, Atlanta, GA), in the April 21, 2010 issue of the Journal of the American Medical Association.

The dyslipidemia findings echo those from the Framingham Heart Study three years ago that associated elevated TG and low HDL-C, among other markers of the metabolic syndrome, with consumption of at least one sweetened soft drink daily [2]. However, in that study, as reported by heartwire at the time, high intake of soft drinks worsened lipids regardless of whether they contained sugar or artificial sweeteners.

But the NHANES analysis is also consistent with a body of literature linking high-carbohydrate diets with elevated risk of stroke and heart-disease events, prospective short-term studies suggesting that increased sugar consumption promotes dyslipidemia, and the well-recognized worsening effects of greater carbohydrate intake on TG and HDL-C levels, senior author Dr Miriam B Vos (Emory University) told heartwire .

The current study, she said, is noteworthy for extending those prospective observations "to a nationally representative free-living population, people consuming their normal diets." It may also be the first of its kind to associate cardiovascular risk factors with dietary added sugars, which may be a more easily modifiable source of calories than simply "sugar" or "carbohydrates," which take many forms naturally in whole foods, according to Vos.

She proposes that a public-health message to cut back on added sugars, which could be easily identified on food labels, may also be easier to understand and accomplish than a recommendation to reduce sugar in general.

The NHANES sample consisted of 3088 nonpregnant women and 3025 men who didn't have "extremely high" triglyceride levels. Diabetics had also been excluded from the cohort, Vos said, "because we felt they would have been given advice that would have substantially changed their diet." Data on sugar intake was collected by interviewer-assisted 24-hour dietary recall.

Persons consuming the most added sugar showed significantly increased adjusted risks of having low HDL-C (<40 mg/dL for men; <50 mg/dL for women) and high TG (>150 mg/dL) according to National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) definitions, compared with those consuming the least. And the likelihoods of having low HDL-C and high TG went up with increasing intake levels (p<0.05 for both trends).

Odds Ratioa for Dyslipidemia Indicatorb by % Total Energy From Added Sugar in NHANES Analysis

Indicator 5% to <10%, (n=893) 10% to <17.5% (n=1751) 17.5% to <25% (n=1210) >25% (n=1135)
Low HDL-C 1.0 (0.8–1.4) 1.5 (1.2–1.9) 1.9 (1.5–2.6) 3.1 (2.3–4.3)c
High triglycerides 0.8 (0.7–1.1) 1.1 (0.9–1.4) 1.3 (1.0–1.6) 1.2 (0.9–1.6)c
High LDL-C 0.9 (0.7–1.2) 1.1 (0.9–1.3) 1.1 (0.9–1.5) 1.2 (0.9–1.7)


a. OR (95% CI) vs reference group (<5% energy from added sugar, n=593); adjusted for age; sex; race/ethnicity; poverty; body-mass index; waist circumference; weight change; physical activity; total energy intake; intake of monounsaturated fatty acids, polyunsaturated fatty acids, saturated fatty acids, cholesterol, fiber, and other carbohydrates; hypertension; cigarette smoking; and alcohol use

b. low and high levels as defined by NCEP-ATP III guidelines

c. p<0.05 for trend

Neither finding was true for high LDL-C levels, which appeared unaffected by consumption of added sugar in the population overall. The investigators considered a trend of rising LDL-C with greater sugar intake among women to be of uncertain reliability, as it was only weakly significant (p=0.047) and based on a subgroup analysis, according to Vos.

"Our results support the importance of dietary guidelines that encourage consumers to limit their intake of added sugars," the group concludes, pointing out that the US guidelines caution against excess added sugars without specifying limits on intake and that the government's "Food Guide Pyramid" portrays calories from added sugars as "discretionary" in that they don't satisfy nutritional needs.

"Most discretionary calorie allowances are small, between 100 and 300 calories, especially for individuals who are not physically active," they write. That level is "substantially lower than that currently consumed by adults in the United States."

As heartwire reported last year, the American Heart Association released recommendations for maximum intake of "added sugars," putting "prudent upper limits" on daily intake at 140 kcal for most US men and 100 kcal for most US women, depending on age and activity level [3].

Vos disclosed that she is "author of and receives royalties from a book about childhood obesity" and is partly supported by a career award from the National Institute of Diabetes and Digestive and Kidney Diseases and the Children’s Digestive Health and Nutrition Foundation. The other coauthors had no disclosures.