Research: A diet rich in sugar can increase the risk of cardiovascular disease

INITIAL NOTE

This article was previously published and has been updated according to scientific and divulgative criteria. Its purpose is informative: it summarizes available knowledge on added sugars and cardiovascular risk, cites primary works and reviews, and indicates limitations and uncertainties. It does not replace medical advice: for therapeutic or clinical choices, consult a healthcare professional.

IN BRIEF

A concise summary for the reader:

• Observational research indicates an association between high intake of added sugars (especially from beverages) and an increased risk of cardiovascular events and mortality. (see following sections)
• The relationship appears to depend on dose and frequency: regular and abundant consumption shows more consistent effects compared to occasional consumption.
• Plausible biological mechanisms include increased triglycerides, visceral adiposity, insulin resistance, inflammation, and metabolic alterations related to fructose metabolism.
• Evidence is predominantly observational: it suggests correlation and biological coherence but does not automatically prove direct causality for every single individual.
• For personal and therapeutic decisions, the overall dietary context and individual risk factors must be considered; water and unsweetened beverages remain prudent options.

Abstract: what does science say?

Simple definition: "added sugars" refer to sugars added to foods or beverages during processing or preparation (different from sugars naturally present in fresh fruit). Available epidemiological evidence shows that a high intake of added sugars — and in particular the regular consumption of sugar-sweetened beverages — is associated with an increased risk of cardiovascular diseases and heart-related mortality. However, most data comes from observational studies that describe associations; the risk appears to depend on the quantity and frequency of consumption and can be mediated by weight gain, dyslipidemia, insulin resistance, and inflammation. There are also experimental and mechanistic studies that make the connection plausible (for example, on the effects of fructose on the liver and lipids), but methodological limitations and possible confounders remain, requiring cautious interpretation. This framework supports public health recommendations aimed at reducing added sugar intake in the general population.

Main section

What do we mean by "added sugars" and why are they important?

Added sugars include sucrose, glucose-fructose syrup, and other sweeteners used in industry and home preparation. This definition does not include intrinsic sugars in fresh fruit or milk. In the modern diet, the main sources of added sugars are sugar-sweetened beverages (soft drinks, juices, and flavored drinks) and processed confectionery products. For the public, it is useful to distinguish the source: studies show that the same caloric amount from whole fruit is not associated with the same risks observed for added sugars in beverages or ultra-processed foods, likely due to the combined effect of fiber, micronutrients, and different food matrices.

Recent epidemiological evidence

Studies on large cohorts and combined analyses have reported that people with a high intake of calories from added sugars have a greater risk of cardiovascular mortality compared to those who consume lower amounts. An analysis based on US national data showed an association between the percentage of calories from added sugars and mortality from cardiovascular diseases. [1] Prospective studies focused on the consumption of sugar-sweetened beverages have found increased risks for heart disease and stroke proportional to the frequency of consumption. [2][3] Meta-analyses aggregating numerous cohorts confirm a dose-response relationship for some cardiometabolic outcomes, albeit with heterogeneity among studies. [4][5]

Plausible biological mechanisms

Several mechanisms explain how added sugars can contribute to cardiovascular risk. High fructose intake (present in sucrose and syrups) can promote hepatic lipogenesis, increase triglycerides and remnant LDL, promote visceral fat accumulation, and reduce insulin sensitivity; these effects are documented in experimental and interventional studies. [6][7] Furthermore, excess sugars can increase chronic low-grade inflammation processes and alter atherogenic profiles, making a biological connection with coronary heart disease and stroke plausible.

What it means in practice

For the reader, it is important to translate the evidence into concrete terms, without prescriptive tones. Reducing the habitual consumption of foods and beverages high in added sugars — particularly sugar-sweetened beverages — is consistent with the goal of improving the cardiovascular risk profile at the population level. Simple substitutions such as choosing water or unsweetened beverages instead of a can of soda, or preferring whole fruit over juices and sweet drinks, can decrease caloric intake from added sugars and associated metabolic effects. Observational studies suggest that even a moderate and sustained reduction over time can be associated with fewer adverse events at the population level, but individual impact varies based on factors such as age, weight, physical activity, and medical history. [3][7]

Practical tips for reading labels

Reading the nutrition label and ingredient list helps identify added sugars (sucrose, syrups, sweetened fruit concentrates). Many "savory" products contain hidden sugars. Limiting the purchase of sugar-sweetened beverages and preferring unsweetened options or water remains the simplest and most immediate strategy to reduce daily exposure.

Key takeaways

• High intake of added sugars, especially from beverages, is associated with an increased cardiovascular risk in observational literature. [1][3]
• The relationship shows a dose-response pattern: regular and more abundant consumption tends to carry greater risks than sporadic consumption. [5]
• Plausible mechanisms include effects on lipid metabolism, increased visceral adiposity, insulin resistance, and inflammation. [6][7]
• Most evidence is observational: the results support biological plausibility but require caution in interpreting direct causality for each individual case. [4]
• For public health, reducing added sugar in the diet is a measure consistent with existing nutritional recommendations.

Limitations of the evidence

Observational study vs. causal evidence

Most investigations on the topic are prospective observational studies: these can identify associations and temporal trends but remain subject to residual confounding, imprecise dietary measurement, and selection bias. Although clinical trials exist that show unfavorable metabolic effects of diets rich in fructose or sugar-sweetened beverages, experimental evidence on long-term clinical cardiovascular outcomes is more limited. [6][7]

Methodological limitations and contextual variability

Self-reported dietary measures (questionnaires, recalls) can underestimate or overestimate consumption; furthermore, dietary composition and eating patterns vary across countries and eras, complicating generalizations. Differences in the classification criteria for beverages and added sugars among studies can generate heterogeneity in meta-analysis results. Finally, effects mediated by weight gain may explain part of the observed association; separating direct effect and mediated effect remains an analytical challenge. [4][5]

Editorial conclusion

In light of observational evidence and experimental studies on metabolic mechanisms, there is a reasonable basis for considering excessive consumption of added sugars — and particularly sugar-sweetened beverages — as a factor contributing to cardiovascular risk at the population level. However, it remains fundamental to distinguish association from causation and to evaluate individual risk within the overall context of diet and lifestyle. Public health recommendations that advocate limiting added sugars are supported by consistency between epidemiological research, biological plausibility, and possible benefits for primary prevention. For the individual, it is advisable to discuss nutritional goals with a healthcare professional when risk conditions or chronic diseases are present.

EDITORIAL NOTE

This update has been prepared following criteria of accuracy, transparency, and traceability of sources. The summaries presented prioritize peer-reviewed evidence and systematic reviews with verifiable DOIs. The article is for informational purposes: specific information for diagnosis or therapy must be obtained from qualified healthcare professionals.

SCIENTIFIC RESEARCH

1. Yang Q, Zhang Z, Gregg EW, Flanders WD, Merritt R, Hu FB. Added Sugar Intake and Cardiovascular Diseases Mortality Among US Adults. JAMA Intern Med. 2014;174(4):516–524. https://doi.org/10.1001/jamainternmed.2013.13563
2. de Koning L, Malik VS, Kellogg MD, Rimm EB, Willett WC, Hu FB. Sweetened Beverage Consumption, Incident Coronary Heart Disease, and Biomarkers of Risk in Men. Circulation. 2012;125(14):1735–1741. https://doi.org/10.1161/CIRCULATIONAHA.111.067017
3. Yin J, Zhu Y, Malik V, et al. Long-Term Consumption of Sugar‑Sweetened and Artificially Sweetened Beverages and Risk of Mortality in US Adults. Circulation. 2019;139(18):2113–2125. https://doi.org/10.1161/CIRCULATIONAHA.118.037401
4. Johnson RK, Appel LJ, Brands M, et al. Dietary Sugars Intake and Cardiovascular Health: A Scientific Statement From the American Heart Association. Circulation. 2009;120(11):1011–1020. https://doi.org/10.1161/CIRCULATIONAHA.109.192627
5. Imamura F, O’Connor L, Ye Z, et al. Consumption of sugar‑sweetened beverages, artificially sweetened beverages, and fruit juice and incidence of type 2 diabetes: systematic review and meta‑analysis. BMJ. 2015;351:h3576. https://doi.org/10.1136/bmj.h3576
6. Malik VS, Popkin BM, Bray GA, Després JP, Willett WC, Hu FB. Sugar‑sweetened beverages and risk of metabolic syndrome and type 2 diabetes: a meta‑analysis. Diabetes Care. 2010;33(11):2477–2483. https://doi.org/10.2337/dc10-1079
7. Stanhope KL, Schwarz JM, Keim NL, et al. Consuming fructose‑sweetened, not glucose‑sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans. J Clin Invest. 2009;119(5):1322–1334. https://doi.org/10.1172/JCI37385
8. Basu S, Yoffe P, Hills N, Lustig RH. Fructose and cardiometabolic health: what the evidence from sugar‑sweetened beverages tells us. J Am Coll Cardiol. 2015;66(14):1673–1684. https://doi.org/10.1016/j.jacc.2015.08.025

Note: the references above are listed in the order of appearance of citations in the text and include verifiable DOIs to allow direct consultation of the original sources.