What You’re Drinking With Your Meal: Sugar-Sweetened Beverages and Cancer Risk

Sugar-sweetened beverages (SSBs) — carbonated soft drinks, fruit-flavoured drinks, sweetened teas, and sports drinks — account for a substantial proportion of added sugar intake in many populations. Their role in obesity and metabolic syndrome is well-established. Less discussed, but increasingly well-supported by epidemiological and mechanistic evidence, is their association with cancer risk.

The Obesity Pathway: A Recognised Link

The most direct pathway connecting SSBs to cancer risk runs through adiposity. The World Cancer Research Fund (WCRF) has identified excess body fatness as a cause of at least 13 cancers, including colorectal, endometrial, post-menopausal breast, hepatocellular, pancreatic, kidney, and oesophageal adenocarcinoma. An IARC Working Group assessment confirmed this categorisation across multiple cancer sites and concluded that the evidence linking body fatness to cancer risk is sufficient to classify it as a causal relationship [1]. SSBs, as a major contributor to energy surplus and visceral adipose accumulation, sit early in this causal chain.

Visceral adipose tissue is metabolically active. It releases adipokines — including leptin and adiponectin — that modulate insulin sensitivity and inflammatory tone. Elevated leptin, reduced adiponectin, and chronic low-grade inflammation collectively create a hormonal and cytokine environment permissive to tumour initiation and progression.

Insulin, IGF-1, and Tumour Biology

The glycaemic impact of SSBs is rapid and substantial. High glycaemic load diets consistently increase postprandial insulin secretion and, over time, fasting insulin levels. A meta-analysis in Diabetes Care demonstrated that SSB consumption was significantly associated with metabolic syndrome and type 2 diabetes — conditions characterised by chronically elevated insulin and IGF-1 that sustain the PI3K/Akt/mTOR activation supporting tumour cell survival and proliferation [2].

This mechanism is particularly relevant for colorectal cancer. A prospective cohort analysis found that higher SSB consumption was significantly associated with increased risk of early-onset colorectal cancer — defined as onset before age 50 — with an odds ratio of 1.55 (95% CI: 1.23–1.95) comparing highest to lowest consumption quintiles [3]. Early-onset colorectal cancer has risen sharply in incidence over the past two decades, and dietary patterns including SSB consumption are among the most plausible explanatory variables. Further population-level evidence came from the NutriNet-Santé cohort, in which each 100 mL per day increase in sugary drink consumption was associated with an 18% increased risk of overall cancer and a 22% increased risk of breast cancer — after adjustment for BMI, suggesting pathways that extend beyond adiposity alone [4].

Artificial Sweeteners: A Separate Concern

The public health response to SSB-related harms has included a shift toward artificially sweetened beverages (ASBs). This substitution is not without its own biological questions. Several artificial sweeteners — particularly saccharin, aspartame, and sucralose — alter gut microbiome composition in ways consistent with dysbiosis: reducing commensal bacteria such as Lactobacillus and Bifidobacterium, promoting potentially pro-inflammatory taxa, and disrupting gut barrier integrity [5]. The clinical significance of these microbiome changes for cancer risk is not yet fully established, but the gut-cancer axis is an active area of mechanistic investigation. The microbiome modulates carcinogen metabolism, systemic immune tone, and bile acid composition — all of which have documented relevance to gastrointestinal carcinogenesis.

Fructose and Hepatic Lipogenesis

SSBs sweetened with high-fructose corn syrup (HFCS) present a metabolic challenge that extends beyond simple caloric excess. Fructose bypasses the rate-limiting step in hepatic glycolysis — phosphofructokinase regulation — and drives de novo lipogenesis directly. HFCS-driven fructose exposure promotes non-alcoholic fatty liver disease (NAFLD) through triglyceride accumulation and hepatic lipotoxicity, independent of total caloric intake [6]. NASH-associated cirrhosis carries an annual hepatocellular carcinoma (HCC) incidence of 1–2%, with cumulative risk reaching 10–15% over a decade in high-risk individuals [7]. Fructose metabolism also increases uric acid production as a byproduct, which inhibits nitric oxide synthesis and promotes endothelial dysfunction — creating systemic conditions that favour both mutagenesis and tumour survival.

The Paediatric Dimension

SSB consumption patterns are established early in life. Adolescent and childhood SSB intake predicts adult metabolic risk factors, and cohort data increasingly show that early-life dietary patterns have long latency relationships with adult cancer incidence. This is not a condition of adult excess alone — it is a developmental exposure with potentially long-term oncogenic consequences that the adult cancer epidemiology data will not fully capture for another generation.

The Evidence, Summarised

No single beverage causes cancer in isolation. But the sum of available evidence — epidemiological, metabolic, and microbiological — identifies SSB consumption as a modifiable contributor to cancer risk, particularly for colorectal, hepatocellular, and hormone-sensitive cancers. Reducing SSB intake is one of the most tractable dietary interventions available, with co-benefits across cardiometabolic risk reduction that compound the potential cancer risk reduction.

References

1. Lauby-Secretan B, Scoccianti C, Loomis D, Grosse Y, Bianchini F and Straif K (2016) Body fatness and cancer — viewpoint of the IARC Working Group. N Engl J Med 375:794–798. doi:10.1056/NEJMsr1606602.
2. Malik VS, Popkin BM, Bray GA, Despres JP, Willett WC and Hu FB (2010) Sugar-sweetened beverages and risk of metabolic syndrome and type 2 diabetes: a meta-analysis. Diabetes Care 33:2477–2483. doi:10.2337/dc10-1079.
3. Hua X, Feng J, Zhang X, Shan Z and Zheng H (2023) Sugar-sweetened beverage consumption and early-onset colorectal cancer risk: a prospective cohort study. Front Oncol 13:1132306. doi:10.3389/fonc.2023.1132306.
4. Chazelas E, Srour B, Deschasaux M, Kesse-Guyot E, Julia C, Alles B, Druesne-Pecollo N and Touvier M (2019) Sugary drink consumption and risk of cancer: results from NutriNet-Santé prospective cohort. BMJ 366:l2408. doi:10.1136/bmj.l2408.
5. Meenatchi P and Vellapandian C (2024) Artificial sweeteners, gut microbiota disruption, and cancer risk pathways: a narrative review. Cureus 16:e70043. doi:10.7759/cureus.70043.
6. Stanhope KL (2016) Sugar consumption, metabolic disease and obesity: the state of the controversy. Crit Rev Clin Lab Sci 53:52–67. doi:10.3109/10408363.2015.1084990.
7. Loomba R and Sanyal AJ (2013) The global NAFLD epidemic. Nat Rev Gastroenterol Hepatol 10:686–690. doi:10.1038/nrgastro.2013.171.