The metabolic and endocrine response and health implications of consuming sugar-sweetened beverages: findings from recent randomized controlled trials

Abstract

Fructose-containing sugars, including fructose itself, high fructose corn syrup (HFCS), and sucrose have engendered considerable controversy. The effects of HFCS and sucrose in sugar-sweetened beverages, in particular, have generated intense scientific debate that has spilled over to the public. This controversy is related to well-known differences in metabolism between fructose and glucose in the liver. In addition, research studies have often been conducted comparing pure fructose and pure glucose even though neither is consumed to any appreciable degree in isolation in the human diet. Other evidence has been drawn from animal studies and epidemiologic or cohort studies. Few randomized controlled trials (RCTs) have compared HFCS with sucrose (the 2 sugars most commonly consumed in the human diet) at dosage amounts within the normal human consumption range. This review compares results of recently concluded RCTs with other forms of evidence related to fructose, HFCS, and sucrose. We conclude that great caution must be used when suggesting adverse health effects of consuming these sugars in the normal way they are consumed and at the normal amounts in the human diet, because RCTs do not support adverse health consequences at these doses when employing these sugars.

FIGURE 1

Energy intakes from commodity groups, 1970–2010, demonstrating that added sugars comprise a small portion of increased caloric consumption and have been in decline since 1998. Reproduced from (2) with permission. From: USDA Economic Research Service Average Daily per Capita Energy from the US Food Availability, adjusted for loss.

FIGURE 2

Muscle fat determination (by MRI) on 68 participants who consumed either HFCS or sucrose to supply 8, 18, or 30% of energy in low-fat milk during a 10-wk, free-living trial. Reproduced from (69) with permission. (A) Gluteus maximus. (B) Vastus lateralis. HFCS, high fructose corn syrup.

FIGURE 3

Blood pressure response in 352 individuals who consumed either HFCS or sucrose to supply 8, 18, or 30% of calories in low-fat milk during a 10-wk, free-living trial. The white bars indicate baseline measurements and the black bars indicate measurements obtained following the 10-wk intervention. Adapted with permission from (75). (A) Diastolic blood pressure. (B) Systolic blood pressure. HFCS, high fructose corn syrup.

FIGURE 4

Metabolism of fructose and glucose in the liver. Although there are differences in metabolism, the pathways are interactive, as indicated in the figure. Reproduced from (22) with permission. ADP, adenosine diphosphate; AMP, adenosine monophosphate; ATP, adenosine-5'-triphosphate; CO₂, carbon dioxide; GLUT, glucose transporters.