Does sugar feed cancer? What herbalists and doctors write about it

Aim of the study: To evaluate the quality of evidence, potential biases, and validity of all available studies on dietary sugar consumption and health outcomes.

Results: The search identified 73 meta-analyses and 83 health outcomes from 8601 unique articles, including 74 unique outcomes in meta-analyses of observational studies and nine unique outcomes in meta-analyses of randomised controlled trials. Significant harmful associations between dietary sugar consumption and 18 endocrine/metabolic outcomes, 10 cardiovascular outcomes, seven cancer outcomes, and 10 other outcomes (neuropsychiatric, dental, hepatic, osteal, and allergic) were detected. Moderate quality evidence suggested that the highest versus lowest dietary sugar consumption was associated with increased body weight (sugar sweetened beverages) (class IV evidence) and ectopic fatty accumulation (added sugars) (class IV evidence).

Aim of the study: The "first 1000 days" of life is a critical window for metabolic programming, while the long-term oncological consequences of nutritional exposures during this period remain understudied. We aimed to evaluate whether restricted sugar intake in utero and during early childhood reduces risk of early onset cancer diagnosis and mortality in adulthood, utilizing a natural experiment.

Results: Among 63,819 participants (56.3% female), 40,397 were exposed to rationing and 23,422 were unexposed. Early life sugar restriction significantly reduced early onset cancer risk (HR: 0.66; 95% confidence interval: 0.53, 0.81; P < 0.001). A dose-response relationship was observed, with peak protection in individuals exposed for ≤24 mo postnatally. This protection was observed systemically across solid tumors, independent of specific cancer sites. Specificity was corroborated by null associations with negative controls (herpes zoster and cataract). No significant difference was found for cancer-specific mortality. Restricting sugar intake during the first 1000 days is associated with a reduced risk of early onset cancer, extending the disease-free lifespan. The divergence between reduced incidence and unchanged mortality suggests early life metabolic environments primarily influence tumor latency rather than biological aggressiveness.

Aim of the study: Excess sugar consumption is implicated in multiple cancers through insulin resistance, chronic inflammation, and metabolic reprogramming, yet whether early-life sugar exposure causally shapes long-term cancer risk remains an open question. We exploit the abrupt end of United Kingdom sugar rationing in September 1953 as a natural experiment, analyzing 64,761 UK Biobank participants born 1951-1956.

Results: First, a behavioral pathway: Rationed cohorts consume less sugar, eat smaller quantities, and maintain healthier, more diverse diets five decades later, consistent with persistent taste preferences shaped during a critical developmental window. Second, a biological pathway: Rationed cohorts exhibit longer leukocyte telomere length ([Formula: see text]0.05 SD, approximately 2.2 fewer years of biological aging) and lower Granzyme B, indicating reduced chronic immune activation. These findings provide causal evidence linking early-life sugar intake to cancer and identify a behavioral pathway, consistent with persistent taste preferences, through which early nutritional environments may shape lifelong disease risk. The results carry direct implications for early-life nutrition and added-sugar policy.

Aim of the study: The consumption of sugar-sweetened beverages (SSB), of which Mexico is a large consumer, has been associated with the risk of breast cancer. We assessed the association between SSBs consumption and breast cancer risk in pre- and postmenopausal women.

Results: For premenopausal women, after adjusting for matching characteristics, total energy intake and all potential confounders, the odds of having breast cancer in women who drank one or more SSBs servings per day showed 1.78 times the odds of those who drank one or fewer SSBs servings per month [OR = 1.78; 95% confidence interval (CI), 1.06-3.01]. For postmenopausal women, the corresponding model was not statistically significant (OR = 1.38, 95% CI, 0.84-2.25). We also observed higher consumption of SSBs among pre- than in postmenopausal women (23.3% and 17.4%, respectively among controls in the highest consumption category (≥1 per day). Our results suggest that SSBs consumption increases the risk of developing breast cancer, particularly in premenopausal women.

Aim of the study: Sugar-sweetened beverage (SSB) consumption may be associated with cancer mortality independent of, or indirectly through, established influences on increased body adiposity.

Results: During follow-up, 135,093 CPS-II participants died from cancer. Consumption of ≥2 SSB drinks/day vs. never was not associated with all-cancer mortality, but was associated with increased risk of obesity-related cancers [HR, 1.05; 95% confidence intervals (CI), 1.01-1.08; Ptrend = 0.057], which became null after adjustment for BMI. SSBs were associated with increased mortality from colorectal (HR, 1.09; 95% CI, 1.02-1.17; Ptrend = 0.011), and kidney (HR, 1.17; 95% CI, 1.03-1.34; Ptrend = 0.056) cancers, which remained after BMI adjustment. A positive association of ASB consumption with obesity-related cancers (HR, 1.05; 95% CI, 1.01-1.08; Ptrend = 0.001) was null after controlling for BMI; however, an increased risk of pancreatic cancer was robust to BMI adjustment (HR, 1.11; 95% CI, 1.02-1.20; Ptrend &lt; 0.008). SSB consumption was associated with higher mortality from certain cancers, partially mediated through obesity.