Which Has More Harmful Effect: Salt or Sugar?
Both salt and sugar cause significant harm to health, but the evidence suggests that excessive sugar consumption—particularly from sugar-sweetened beverages—poses a broader range of serious health threats including cardiovascular disease, type 2 diabetes, obesity, cancer, and dental disease, making it arguably more harmful overall than salt. 1, 2
The Case Against Sugar
Cardiovascular and Metabolic Harm
The 2015 Dietary Guidelines Advisory Committee concluded with strong evidence that higher consumption of added sugars, particularly sugar-sweetened beverages, increases the risk of type 2 diabetes, and with moderate evidence that it increases risk of coronary heart disease, hypertension, elevated blood pressure, and stroke. 1
A comprehensive 2023 umbrella review of 73 meta-analyses found significant harmful associations between dietary sugar consumption and 45 different health outcomes, including 18 endocrine/metabolic outcomes, 10 cardiovascular outcomes, 7 cancer outcomes, and 10 other outcomes (neuropsychiatric, dental, hepatic, osteal, and allergic). 2
Low quality evidence indicates that each 250 mL/day increment of sugar-sweetened beverage consumption is associated with a 17% higher risk of coronary heart disease and 4% higher risk of all-cause mortality. 2
Each serving per week of sugar-sweetened beverages increases gout risk by 4%. 2
Cancer Risk
- Every 25 g/day increment of fructose consumption is associated with a 22% higher risk of pancreatic cancer (low quality evidence). 2
Obesity and Weight Gain
Sugar consumption, especially from beverages, strongly promotes weight gain and obesity. 1 The American Academy of Pediatrics specifically recognizes the detrimental effect of high sugar content on children's health and its propensity for promoting childhood obesity. 1
Dental Disease
Higher intakes of free sugars are linked to dental caries development in both children and adults (moderate evidence). 1
Gastrointestinal Effects
High sugar intake disrupts the intestinal barrier, increases gut permeability, causes profound gut microbiota dysbiosis, and disturbs mucosal immunity, enhancing infection susceptibility. 3
The Case Against Salt
Blood Pressure and Cardiovascular Disease
The 2015 Dietary Guidelines Advisory Committee concluded with moderate evidence that higher sodium intakes increase the risk of cardiovascular disease. 1
As salt intake increases, blood pressure rises in a dose-response relationship. 1
Reduced sodium intake can prevent hypertension in nonhypertensive individuals, lower blood pressure in those on antihypertensive medication, and facilitate hypertension control. 1
The effects of sodium reduction on blood pressure are greater in blacks, middle-aged and older persons, and individuals with hypertension, diabetes, or chronic kidney disease. 1
Reduced sodium intake is associated with a blunted age-related rise in systolic blood pressure and reduced risk of atherosclerotic cardiovascular events and congestive heart failure. 1
Comparative Analysis
Breadth of Harm
Sugar affects multiple organ systems with 45 documented harmful health associations, while salt's primary harm is mediated through blood pressure elevation and subsequent cardiovascular effects. 2, 1
Quality of Evidence
Both have moderate-quality evidence for cardiovascular harm, but sugar has strong evidence for type 2 diabetes risk, whereas salt's evidence is primarily moderate. 1
Recommended Limits
Sugar: Reduce added sugar intake to <10% of total calories daily, with further reduction to <5% suggested; limit sugar-sweetened beverages to <1 serving/week (approximately 200-355 mL/week); ideally consume <25 g/day (6 teaspoons/day) of free sugars. 1, 2
Salt: Reduce sodium intake to 2.3 g/day (100 mmol/day), with an ideal target of 1.5 g/day (65 mmol/day). 1
Clinical Pitfalls
Do not assume that replacing sugar with artificial sweeteners solves the problem—reformulation of fizzy drinks with intense sweeteners has had no effect on the rise in obesity, and people with obesity are more likely to buy diet drinks (reverse causality). 1
Avoid focusing solely on one nutrient—dietary patterns characterized by excess saturated fat, sodium, AND added sugars are associated with increased disease risk. 1
Remember that liquid sugars are worse than solid sugars—most evidence linking sugar to obesity focuses on sugar-sweetened beverages, while studies on sugars from solid foods yield null findings. 1, 4