Controversies about sugars: results from systematic reviews and meta-analyses on obesity, cardiometabolic disease and diabetes

Abstract

Fructose-containing sugars are a focus of attention as a public health target for their putative role in obesity and cardiometabolic disease including diabetes. The fructose moiety is singled out to be the primary driver for the harms of sugars due to its unique endocrine signal and pathophysiological role. However, this is only supported by ecological studies, animal models of overfeeding and select human intervention studies with supraphysiological doses or lack of control for energy. The highest level of evidence from systematic reviews and meta-analyses of controlled trials has not shown that fructose-containing sugars behave any differently from other forms of digestible carbohydrates. Fructose-containing sugars can only lead to weight gain and other unintended harms on cardiometabolic risk factors insofar as the excess calories they provide. Prospective cohort studies, which provide the strongest observational evidence, have shown an association between fructose-containing sugars and cardiometabolic risk including weight gain, cardiovascular disease outcomes and diabetes only when restricted to sugar-sweetened beverages and not for sugars from other sources. In fact, sugar-sweetened beverages are a marker of an unhealthy lifestyle and their drinkers consume more calories, exercise less, smoke more and have a poor dietary pattern. The potential for overconsumption of sugars in the form of sugary foods and drinks makes targeting sugars, as a source of excess calories, a prudent strategy. However, sugar content should not be the sole determinant of a healthy diet. There are many other factors in the diet—some providing excess calories while others provide beneficial nutrients. Rather than just focusing on one energy source, we should consider the whole diet for health benefits.

Influences of added sugar consumption in adults with type 2 diabetes risk: A principle‐based concept analysis

“…HFCS is used to sweeten products like SSBs (eg, soda, sports drinks, fruit drinks) . Due to significant, global consumption of SSB products, HFCS's relationship to T2D risk has repeatedly been studied by researchers with some still questioning if HFCS actually increases an individual's risk of developing T2D . Results from a systematic review and meta‐analysis by Khan and Sievenpiper did not find evidence to support that fructose contributes to an increase in T2D risk and reported that no controlled trials exist to support the association.…”

“…Because added sugar is found in a variety of dietary foods and beverages, terms were often interchanged to describe added sugar or components of added sugar (eg, glucose and fructose). These examples include words like sugar, sucrose, free sugars, dietary sugars, nutritive sweeteners, sugar‐sweetened beverages (SSB), high glycemic carbohydrates, high‐fructose corn syrup (HFCS), fructose, and fructose‐containing sugars . Several publications studied SSB consumption which was not always portrayed as an exclusive “added sugar product”, but rather as a product containing HFCS .…”

“…Experimental research exploring a causal link between added sugar and T2D risk is inconsistent . Likewise, some scientists advocate that added sugar consumption is not causally linked with T2D but is instead mediated by excessive caloric intake and weight gain . Lack of a clear conceptual definition of added sugar, as well as inconsistent operationalization of added sugar across the literature, confounds the evidence by limiting generalizability and restricting between‐study comparisons.…”

Food Intake Characteristics during Early Pregnancy in Women with Gestational Diabetes Mellitus

“…Sugar-sweetened beverages are associated with an increased risk of DM [22], but sugar does not trigger DM [23]. The pathological condition of GDM is attributable to reduced insulin secretion secondary to reduced pancreatic beta cell function during pregnancy.…”

More pieces of the fructose puzzle

“…Four of these reviews detailed mechanisms by which dietary fructose may have direct deleterious effects on human health . The other four concluded that dietary fructose has no detrimental effects on health except those related to an increased chance of excessive energy intake and weight gain . This latter conclusion is contradicted by the work of Schwarz et al .…”