Last year I posted a review of a conference abstract looking at the sugar (carbohydrate) content of soft drinks. You can view the original post here. The abstract was a summary of work in progress with only preliminary findings. As such, there was no way to know how the full study would turn out. Recently, the authors completed and published the full study so now we can see how they compare.
The study centers around the sugar Fructose which is somewhat controversial. I discussed Fructose in detail previously, but the essence of the controversy is that Fructose is metabolized preferentially by the liver and as part of this process there is the potential, if conditions are right, for the sugar to more readily build fat. Fructose has been linked to obesity, fatty liver disease, and other health problems. It’s because of all this that many people are scrutinizing foods and drinks with high levels of fructose. And of course when foods with high fructose corn syrup (HFCS) are brought up, well, the name alone suggests a potential problem. Of course, what many people don’t realize is that most HFCS doesn’t have notably more fructose than glucose. Or does it? Since companies are not forced to list the final ratio of fructose to glucose on product labels, there is no way for the consumer to know. And so, the authors of Walker et al., 2014 wanted to find out for themselves.
The Takehome: The results of this full study supported the authors’ original conference abstract findings. Even using two additional independent methods, higher than expected levels of fructose in sweetened beverages were found. Specifically, the 5 most popular HFCS-sweetened beverages (Coca-Cola, Pepsi, Dr. Pepper, Mountain Dew, and Sprite, which comprise ~90% of the annual beverage market share) had fructose to glucose ratios of ~60:40 which means they contained 50% more fructose than glucose. Remember, sucrose (table sugar) has a ratio of 50:50 and HFCS-55 is 55:42. In addition, beverages had ingredient errors such as Mexican Coca-Cola having a high fructose content despite no source of free fructose being listed and Pepsi listed sucrose as an ingredient but none was found after analysis by the authors. There are many possible causes for all these discrepancies including production methods that allow for hydrolyzed syrups (loss of sucrose content), use of juice concentrates (which may have high fructose contents), and bleeding of HFCS-55 with higher syrups like HFCS-90. All of these methods are allowed in beverage production and do not have to be indicated on labels. Regardless of the sources of discrepancy, and regardless of whether or not manufacturers are intentionally creating products with sugar levels higher than claimed, the data suggest that sweetened beverage ingredients are not what they seem. Thus, according to the result of this study, estimates of society’s fructose intake are likely being underestimated.
- In addition to the original measurement data using liquid chromatography (LC), two different approaches were used to measure sugar content: 1) a metabolomics-type (MET) approach based on mass spectrometry combined with liquid and gas chromatography and 2) gas chromatography (GC) by itself.
- The different analyses were performed by separate companies and both companies were blinded as to the identity of the samples they were testing in order to prevent bias.
- 14 popular sodas/teas were analyzed (e.g., Dr. Pepper, Pepsi, Sprite, Mountain Dew, Coca-Cola) along with 19 juices/juice-like drinks (e.g., Minute Maid Apple Juice, Kool-Aid Jammers, V8 Splash Berry Blend).
- Product sugar measurements were compared against standards with known concentrations of glucose, fructose, sucrose, and maltose (and also galactose and lactose for the GC analysis).
- The amount of each sugar present in the tested sodas and juices was obtained from the NCC Food and Nutrient Database, USDA Nutrient Data Laboratory, data in the scientific literature, and food manufacturer’s information.
- Results were consistent across all three methodologies for % fructose, glucose, sucrose, and maltose. In addition, free fructose content was consistent across all the three methodologies.
- Mexican Coca-Cola consistently contained 49% of total sugar as free fructose even though neither HFCS nor fructose was listed on the label.
- Pepsi Throwback, Gatorade and Sierra Mist (none of which list HFCS or fructose as ingredients) contained fructose as 59, 40, and 8 percent of their total sugar, respectively.
- Beverages listing HFCS as an ingredient had a mean fructose to glucose ratio of 59 while those not listing HFCS had a mean ratio of about 50.
- Sprite, Dr. Pepper and Pepsi had free fructose accounting for 60% or more of total sugar.
- Pepsi listed sucrose as an ingredient, but no sucrose was detected as an ingredient using gas chromatography.
- Minute Maid and Juicy Juice 100% Apple Juices had the highest ratios of fructose to glucose of all the juices measured (67.1 and 67.3, respectively).
- Some values for sugar amount claimed/known to be in beverages were missing and a probable value had to be created using statistical procedures.
- A variety of sources were used to obtain the claimed/known amount of sugar in beverages and we do not know how the authors handled different values being reported in different sources (if any).
- This study would have been enhanced with a variety of control beverages such as those that are artificially sweetened and those with minimal ingredients and low sugar amounts (such as Honest Teas and Inkos Teas).