Connecting the dots

Just a few months ago we reported on a study that demonstrated a link between the amount of added sugars in a person's diet and their risk of death from heart disease (02/19/14), even after taking Body Mass Index into account.

It's one thing to look at people's risk of death from heart disease; it's another to find a link between sugar intake and poor cholesterol scores or poor blood pressure scores, both of which are risk factors for heart disease.

A team of researchers at University of Otago in New Zealand recently performed a meta-analysis (a look at the results of multiple studies) to see if sugar intake could be independently linked with cholesterol and blood pressure scores (Am J Clin Nutr 2014;100(1):65-79). Of the 40 different randomized controlled trials (the gold standard for reliable results in research) that they included in their review, all compared higher-sugar diets with lower-sugar diets. Thirty-nine of the studies reported on total cholesterol, triglycerides, LDL or HDL cholesterol, while 12 studies reported on blood pressures. A total of nearly 1,700 adult men and women participated in the 40 studies, and each study lasted for a minimum of 2 weeks and as long as 6 months.

They found that compared to lower sugar intake, higher levels of sugar intake were strongly associated with higher triglycerides, total as well as LDL cholesterol (the bad cholesterol, and blood pressure. Interestingly, this evidence was actually stronger in those studies where the participants maintained their weight: gaining or losing weight could not have accounted for the changes in blood pressure or cholesterol scores.

The researchers note that most of the studies they were looking at were concerned with sucrose (table sugar), as well as monosaccharides (like fructose or glucose), and other disaccharides (sucrose or starch), and not focusing exclusively on fructose or High Fructose Corn Syrup. This was an attempt to look at all "free sugars" as defined by the World Health Organization, and not to examine any particular subcategory of sugar.

What this means for you

The difference between the blood pressures or cholesterol scores for those on a high-sugar diet versus a low sugar diet was fairly small, but still clinically significant. That said, by no means should this be taken to mean that all sugars are bad; take this as a vote for caution in the amount of sugars of any kind you eat.

First posted: June 25, 2014