High Fructose Corn Syrup

HFCS comes out of the corn wet-milling industry. US refiners make it because corn subsidies and sugar import tariffs keep it cheaper than cane or beet sugar, and the syrup is pumped directly, with less labor.^2,3,5

1. 01 // Source Corn starch Starch separated from corn kernels, the same feedstock behind regular corn syrup.
2. 02 // Process Broken to glucose Two enzymes, alpha-amylase and then glucoamylase, cut the starch chains down to a glucose syrup.
3. 03 // Process Cleaned and isomerized Carbon and ion-exchange resins strip protein and minerals; an isomerase enzyme then turns glucose into about 42% fructose.
4. 04 // Process Enriched to 55 Chromatography pulls out a 90% fructose stream, which is blended back with the 42% syrup to make HFCS 55.
5. 05 // Output Liquid syrup A clear syrup of about 71 to 77% solids, sold in bulk and pumped into the mixer.

1. 01

   Keeps soft pieces from spoiling

   Dissolved sugar ties up water and lowers water activity, which helps keep molds and bacteria from growing in semi-moist food holding 15 to 50% moisture.¹¹

2. 02

   Sweetness dogs accept

   In two-bowl tests, puppies readily accepted fructose and sucrose and noticed both the type and the amount of sugar in a semi-moist recipe.⁶

3. 03

   Cheap, pumpable sugar

   In the US, corn subsidies and sugar import tariffs make HFCS cheaper than cane or beet sugar, and as a liquid it moves by pump with less labor.³

How much Published HFCS levels for dog food are not available; one semi-moist pet food patent puts total sugars at 6 to 30% of the recipe, 13 to 20% preferred.¹¹

1. Critics say

   It is just empty calories

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   By dry weight it is essentially all sugar: 42 to 55% fructose, the rest glucose and short glucose chains. That is energy and nothing else, since refining removes the protein and minerals.^3,4

2. Brands say

   Dogs love the sweet taste

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   In 1984 two-bowl choice tests, puppies accepted fructose and sucrose well and responded to the sugar type and amount in a semi-moist food. The data is old and from puppies, but the preference is real.⁶

3. Critics say

   Sugar in dog food causes diabetes

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Two dog trials, one feeding a combined high-fat/high-fructose diet and one comparing separate high-fat and high-fructose diets, found impaired liver glucose handling: after 4 weeks, hepatic glucose uptake was 0.8 mg/kg/min on the high-fructose diet versus 2.8 in controls. These diets differ from kibble, and the cited trials did not test for diabetes.^7,8

4. Critics say

   High fructose corn syrup contains mercury

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   A 2009 pilot test of syrup from 3 manufacturers found mercury from undetectable up to 0.57 micrograms per gram. The sample was small. The refiners' trade group said in 2009 that US plants had already gone mercury-free several years earlier.^3,9

5. Critics say

   HFCS is worse than regular sugar

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   A 2022 meta-analysis of 4 human trials and 767 people found no weight or BMI difference between HFCS and sucrose, only a small CRP rise of 0.27 mg/l. FDA sees no safety difference, and the cited studies did not test dogs.^1,4