High dietary intake of added sugars could increase the risk of coronary heart disease

By Dr. Chinta SidharthanReviewed by Lily Ramsey, LLMSep 6 2023

In a recent study published in The American Journal of Clinical Nutrition, researchers examined the associations between individual dietary sugar types and the risk of coronary heart disease.

Study: Associations of Dietary Sugar Types with Coronary Heart Disease Risk: A Prospective Cohort Study. Image Credit: Africa Studio/Shutterstock.com

Background

Research indicates that in the association between carbohydrate intake and the risk of coronary heart disease, the type of carbohydrate consumed seems to play a more significant role in increasing the risk of coronary heart disease than the amount of carbohydrates consumed.

Various studies have reported a link between consuming sugar-sweetened beverages and the increased risk of coronary heart disease. Furthermore, the Western diet typically comprises large quantities of sugars and starch, which have a more pronounced impact on blood glucose levels than foods with natural sugars, such as fruits.

Individual sugars are also processed differently in the body. Most di- and polysaccharides are broken down to the constituent monosaccharides, typically glucose and fructose, metabolized through different pathways.

Fructose, because of its ability to bypass many of the regulatory steps involved in glycolysis, is believed to play a role in the production of low-density lipoprotein (LDL), leading to an increase in the levels of LDL cholesterol and postprandial triglycerides.

While glucose is not reported to have such effects on LDL cholesterol and triglyceride levels, the evidence from prospective cohort studies has been limited.

About the study

In the present study, researchers examined whether different types of dietary sugars, especially the monosaccharides glucose and fructose, had a differential effect on the risk of coronary heart disease.

Dietary sugars were defined as those carbohydrate sources rapidly broken down into the constituent monosaccharides, and the impact of total fructose and total glucose from all the different sources of sugars in the diet was considered.

Two prospective cohorts were included in the study — one consisting of female nurses between 30 and 55 years of age enrolled in the Nurses’ Health Study, which began in 1976, and the other comprising male health professionals between the ages of 40 and 75, who were part of the Health Professionals Follow-up Study, which began in 1986.

Baseline data from the participants of both studies included a completed semiquantitative food frequency questionnaire, with follow-up questionnaires sent every two to four years to collect information on lifestyle, diet, medical history, and any new disease diagnoses.

From the data from the two prospective cohorts, the researchers excluded those participants with a history of cardiovascular disease, diabetes, or cancer or where implausible energy intakes based on sex were reported.

For the dietary assessment, detailed information on the types of foods and beverages consumed was extracted from the food frequency questionnaire responses, and the total energy and daily nutrient intakes were calculated.

Total fructose equivalents were calculated by accounting for the fructose consumed in the monosaccharide form and in the form of sucrose, as well as from whole vegetables, fruits, and fruit juice.

Total glucose equivalents were calculated based on the glucose consumed in the monosaccharide form and from starch, sucrose, lactose, and maltose.

The coronary heart disease endpoints considered during assessing coronary heart disease risk were non-fatal myocardial infarction and death due to coronary heart disease.

Covariates such as body mass index, smoking behavior, incidence of hypercholesterolemia or hypertension, menopausal status, alcohol intake, and physical activity levels were also considered in the analyses.

Results

The findings reported that the intake of total sugar, total glucose equivalents, and fructose from juice and added sugars were associated with an increased risk of coronary heart disease.

Still, the total fructose equivalents from whole vegetables, fruits, lactose, and sucrose were not significantly linked to a higher risk of coronary heart disease.

The researchers believe that the total glucose and fructose equivalents from juice and added sugar, substituted for total fat in an isocaloric manner, are linked to the increase in coronary heart disease risk.

The study also confirms the findings from previous studies that the quality of carbohydrates plays a more significant role in increasing the risk of coronary heart disease than the quantity, with added sugar and starch having a substantial impact on heart disease risk.

Furthermore, while meta-analyses of various prospective cohorts have reported a significant association between glycemic load, glycemic index, and a higher risk of coronary heart disease, the findings on the association between starch and coronary heart disease risk have been ambiguous.

The results from the present study show that starch intake is strongly linked to coronary heart disease risk, and it is important to consider the cumulative impact of glucose from all dietary sources, such as sucrose and starch, while assessing the risk of coronary heart disease.

Conclusions

Overall, the findings reported that total glucose and fructose equivalents from dietary components with added sugar increased the risk of coronary heart disease.

However, fructose intake as fructose or sucrose and from whole fruits and vegetables was not linked to increased risk of coronary heart disease.