Question:
I like to eat canned sweetcorn and crackers made from corn but I’ve heard corn syrup is not good for our health. Does this mean corn crackers or sweetcorn contain the same sugars and that I should avoid eating them?
Answer:
At first glance, it seems logical to lump all corn products together – if corn syrup is unhealthy, does that also apply to all corn products? But although sweetcorn, cornmeal crackers and corn syrup all originate from maize, they’re not nutritional equivalents. The key difference lies in how they’re processed and what that means for your body.
Whole corn and corn-based products such as tinned corn that are minimally processed contain complex carbohydrates, dietary fibre, vitamins and beneficial plant compounds. They’re typically a nutritious option. Corn crackers are a mixed bag—some are ultra-processed, especially if created through mechanical extrusion and packed with added flavours, colours or processing aids. Others, however, can be a relatively nutritious choice, made simply from whole corn and few ingredients.
Corn syrup and particularly its cousin high-fructose corn syrup (HFCS), is a highly processed, concentrated source of sugar. It’s created by breaking down corn starch into glucose to create corn syrup, with some of that glucose converted into fructose to enhance sweetness.
This process is important, because not all sugars are equal in terms of their health effects.
The World Health Organisation recommends we limit our intake of free sugars – and that includes sugars added during food processing such as with corn syrup, as well as those naturally present in honey, syrups and fruit juice. These types of sugars are linked to poorer diet quality, tooth decay and chronic diseases.
By contrast, intrinsic sugars, naturally found in whole foods such as fruit or vegetables, are not a health concern. Corn on the cob or a few plain corn crackers don’t raise the same red flags.
When it comes to our health and corn syrup, a clearer picture has only recently emerged about HFCS. A 2022 review, published in Frontiers in Nutrition, found that consuming HFCS led to a significant rise in levels of C-reactive protein ‒ a marker of systemic inflammation ‒ as compared with consuming regular sucrose (table sugar). Elevated CRP levels have been linked to a higher risk of chronic conditions such as heart disease and type 2 diabetes.
Although this review didn’t assess long-term health outcomes, the rise in CRP suggests that even short-term consumption of HFCS can trigger low-grade inflammation in the body.
A 2021 review published in Cell Metabolism noted when people consume too much fructose through corn syrup-sweetened foods and beverages, the liver ends up processing more fructose than it can handle efficiently. This is now understood to be a significant factor in problems such as non-alcoholic fatty liver disease, type 2 diabetes, intestinal problems, cholesterol issues and cardiovascular and kidney diseases.
A consistent pattern emerges from research: it’s not that the sugar molecules in HFCS are inherently more dangerous, but their highly concentrated, easily consumed form in soft drinks and processed foods is problematic, especially when people consume them in large volumes.
HFCS is less common in New Zealand’s food supply than in other Western countries, but may appear in imported foods. So check the ingredients list on any imported soft drinks, juices, snack foods and confectionery. Whole corn, on the other hand, contains carbohydrates in the form of starch, which your body breaks down gradually. It also includes fibre that slows digestion and reduces blood sugar spikes.
Corn-based crackers are another example of context being important. On their own, plain varieties can be a good snack. But what you eat with them makes a difference ‒ hummus, nut butter or vegetables boosts their nutritional value. But if the ingredient list includes additives and sugars such as corn syrup, dextrose, maltodextrin or glucose syrup, they may be worth reconsidering, especially if they’re a regular part of your diet.
As with most nutrition advice, processing and the bigger dietary picture matter more than the ingredient alone.
