Corn Glycemic Index (GI) - Is It High or Low?

by Victoria Mazmanyan | Last updated on August 21, 2024

Medically reviewed by Ani Harutyunyan

Corn is one of the world’s most popular cereal grains. It can be turned into an array of various food products with different qualities. That is why corn’s glycemic index has to be accounted for separately for each corn product, including a variance between origins.

Based on The International Tables of Glycemic Index study, corn granules from China have a glycemic index of 52±3.

The GI of cornflakes varies depending on the country. In one study, cornflakes from China have a GI of 74±3 and 79±4, based on the brand. Australian cornflakes have a lower GI of 77, while Canadian and British cornflakes show a higher glycemic index, 80±6 and 93±14, respectively.

Sweet corn’s GI has a wide range from 37 to 67. The “honey and pearl” type of sweet corn from New Zealand has the lowest GI of 37±12.

Boiled sweet corn on the cob from Australia has a GI of 48. The GI of sweet corn from China averages around 55±2, alongside a GI of 60 for sweet corn from the USA and 62±5 from South Africa.

Corn can also be made into gluten-free pasta. Australian corn pasta has a GI of 68±7 or 78±10, depending on other ingredients.

Corn syrup has a high GI of 90 but can change depending on the fructose and glucose ratio.

Corn chips from Australia have been noted to change positively over the years. Plain, salted corn chips from 1985 had a GI of 72, while the same corn chips in 1998 had a GI of 42±4.

Popcorn can also change qualities based on brand. One brand of microwave popcorn from Australia has a GI of 55±7, while the other has a GI of 89. The GI of popcorn from China ranges around 55±1. Corn hominy has a GI of 40±5.

A South American food called arepa, a cornbread cake made with cornflour, has a GI 72. Corn tortillas from Mexico have a GI of 52.

Baked sweet products naturally have a higher sugar concentration, making the GI of a low-amylose corn muffin 102, while the GI of a high-amylose corn muffin is 49. The GI of cornmeal porridge from Kenya is 109, whereas boiled cornmeal from Canada has a GI of 68.

The Queensland Government has classified corn flakes, corn pasta as having high GI, popcorn as medium GI, and sweet corn and corn chips as low GI foods (2).

One study has shown that regular consumption of corn and its derived whole grain products reduces the risk of developing type 2 diabetes due to its phytochemical content (3). In contrast, high-fructose corn syrup, due to its high glycemic index, is not recommended as a substitute for fructose for people with diabetes (4).