There is no shortage of research showing the consumption of added sugars, especially those from sugar-sweetened beverages (SSB), to be detrimental to health. This of course hasn’t stopped Americans, with adults consuming ~14% and children consuming ~16% of their daily calories as added sugars. These average levels of intake correspond to an 18% increased risk of cardiovascular disease (CVD) mortality. But at what point does the CVD risk really take off? Is there a threshold of sugar consumption where detriments start to accumulate exponentially? To help answer these questions, Kimber Stanhope et al. from the University of California, Davis, investigated the effects of consuming different doses of added sugars from SSBs on CVD risk factors of young and otherwise healthy men and women.

In total, 85 normal and overweight subjects were assigned (double-blind) to consume beverages containing 0, 10, 17.5, or 25% of their estimated daily energy requirements as high-fructose corn syrup (HFCS) or aspartame (for the 0% group only) over the course of two weeks.

1. A 3.5-day inpatient baseline period during which subjects resided at the research center, consumed a standardized baseline diet without the beverages, and had baseline testing performed.
2. A 12-day outpatient period during which the subjects were provided their beverages and instructed to consume them alongside their regular diets.
3. A 3.5-day inpatient intervention period that matched the baseline period except for the inclusion of the intervention beverages.

The testing for phases 1 & 3 included both fasting and post-prandial (PP) blood-borne measurements. Since the subjects were living in the research center, collecting blood was easy, and on the last day of both inpatient phases three fasting blood samples were collected in the morning, followed by 29 PP blood samples that were collected every 30-60 minutes until the following morning. Thus, the PP blood samples represent what is going on over the course of a day as the participants eat their standardized meals.

The dose makes the poison

For the majority of the outcomes, there was a significant linear association with the amount of HFCS consumed. In other words, the more you consume, the worse off you are. This included both fasting and PP non-HDL-c, LDL-c, and ApoB, as well as PP triglycerides and ApoC_III, and fasting and 24-hour average uric acid concentrations. Moreover, these changes were independent of changes in body weight, which increased as HFCS consumption increased.

It is important to note that the absolute amount of sugar consumed was ridiculously high, which may have led to the seemingly deleterious results. In the 25% group, the amount of HFCS consumed was ~160g daily, which corresponds to about 1.5 liters or 50 ounces of soda pop. Of course drinking this much sugar is going to cause problems. Comparatively, the 10% HFCS group consumed ~60g of HFCS that can be obtained by drinking 18 ounces (1.5 cans) of soda pop daily. Nonetheless, even this small amount led to deleterious outcomes, raising the very important question of whether these effects occur with amounts below 10% of energy intake and if they occur with other sugars such as sucrose.