A review of the evidence reveals diabetes, depression, obesity, and heart disease are among the 45 negative outcomes linked to excessive sugar consumption.

A comprehensive review of the evidence published by The BMJ recommends that individuals should aim to limit their consumption of added (“free”) sugars to approximately six teaspoons per day and restrict their intake of sugar-sweetened beverages to less than one serving per week.

The review’s experts discovered significant detrimental associations between sugar intake and 45 different outcomes, including asthma, diabetes, obesity, heart disease, certain cancers, and mortality.

The negative impacts of excessive sugar consumption on health are well-established, leading organizations such as the World Health Organization (WHO) to recommend that individuals limit their intake of free or added sugars to less than 10% of their total daily energy consumption. However, before implementing specific policies for sugar restriction, the quality of current evidence must be thoroughly assessed.

Consequently, a group of researchers in China and the United States conducted an umbrella review to evaluate the quality of evidence, possible biases, and validity of all existing studies examining the link between dietary sugar consumption and health outcomes.

Umbrella reviews consolidate prior meta-analyses and offer a comprehensive overview of research on a specific subject.

The aforementioned review comprised 73 meta-analyses (67 of observational studies and six randomized controlled trials) extracted from 8,601 articles that examined 83 health outcomes in both adults and children. The researchers evaluated the methodological quality of the studies included in the review and rated the evidence for each outcome as high, moderate, low, or very low quality to arrive at conclusions.

The review’s findings revealed significant negative correlations between dietary sugar consumption and 18 endocrine or metabolic outcomes, such as diabetes, gout, and obesity, as well as 10 cardiovascular outcomes, including high blood pressure, heart attack, and stroke. Additionally, seven cancer outcomes, including breast, prostate, and pancreatic cancer, and 10 other outcomes, such as asthma, tooth decay, depression, and mortality, were all associated with excessive sugar consumption.

Moderate quality evidence indicated that drinking sugar-sweetened beverages was substantially linked to higher body weight for those with the highest versus lowest consumption. At the same time, consuming any added sugar versus none was associated with elevated accumulation of fat in the liver and muscles.

According to low-quality evidence, consuming one additional serving of sugar-sweetened beverages per week was linked to a 4% increased risk of gout, while consuming 250 mL more of these drinks per day was associated with a 17% and 4% higher risk of coronary heart disease and mortality, respectively.

Low-quality evidence also suggested that a 25 g per day rise in fructose intake was related to a 22% higher risk of pancreatic cancer.

Overall, there is no trustworthy evidence indicating any beneficial relationships between dietary sugar consumption and any health outcomes, apart from glioma brain tumors, total cholesterol, type 2 diabetes, and cardiovascular disease mortality. However, the researchers caution that these favorable associations lack substantial evidence and should be interpreted carefully.

The researchers acknowledge that current evidence is primarily observational and of poor quality, and they emphasize that proof of an association between dietary sugar consumption and cancer remains limited but necessitates further research.

Despite these limitations, the researchers argue that these findings, when combined with recommendations from organizations such as the World Health Organization, World Cancer Research Fund, and American Institute for Cancer Research, suggest that individuals should aim to limit their intake of free or added sugars to less than 25 g per day (roughly six teaspoons) and restrict their consumption of sugar-sweetened beverages to less than one serving per week (approximately 200-355 mL/week).

They further assert that addressing patterns of sugar consumption, particularly among children and adolescents, requires a combination of widespread public health education and global policies.

Source: 10.1136/bmj-2022-071609

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