Let’s talk about corn. There is often confusion regarding this very common food and where it falls on the FODMAP scale. Corn is one of those tricky foods – fresh corn can easily be high FODMAP in moderate portions, while many processed corn-based products such as corn tortillas, corn chips, corn flakes, cornmeal, and popcorn are low FODMAP. And those little baby corn found in a can are also low FODMAP. Trust me, this is a little confusing even to a FODMAP trained dietitian.
Corn Varieties and FODMAP Content
There are six major types of corn: sweetcorn, flint corn, dent corn, flour corn, popcorn, and waxy corn.
Arguably the most common corn variety, sweetcorn is often referred to as corn on the cob and sometimes pole corn. Sweetcorn contains excessive amounts of polyols, specifically sorbitol, so it is important to limit your intake during the elimination phase.
This type of corn is well known for its natural sweetness thanks to the sorbitol content. Sweetcorn is harvested when the corn is still immature, which is known as the milk stage.
- Corn on the cob is considered high FODMAP in moderate and large serving sizes, however, it is low FODMAP at half an ear or 38 grams.
- Frozen corn is likely high FODMAP in portions similar to fresh corn as it is flash frozen soon after harvest.
- Canned corn serving size has recently been updated to a very generous serving size of one cup.
- Canned cream corn contains too many fructans resulting in a high FODMAP load in portions greater than ⅓ cup or 90 grams.
Dent corn is a type of field corn often used to manufacture food products like chips, tortillas, and taco shells. All of these corn-based products are low FODMAP aside from those containing high fructose corn syrup.
Unlike sweetcorn, dent corn’s mature, dried corn kernels must be milled before they are suitable for human consumption.
Flint corn, also called Indian or Calico corn, is a hard, dried, mature corn that is brightly colored. It contains a very hard outer shell and the sugar content is very low. Flint corn is used often in hominy, masa, grits, and polenta – all of which are low FODMAP.
Flour corn is a commonly used corn found in several corn products and sometimes consumed as intact kernels. Flour corn contains a soft starch that is very easy to grind into finer cornmeal than other corn varieties. This variety of corn is used to make fine corn meals, hominy for tamales, tortillas, hominy (whole kernels are used), and elotes. Canned and drained hominy is low FODMAP at ½ cup or 90 grams.
Popcorn, a scrumptious low FODMAP snack, is made from a different type of corn… you guessed it, popcorn. It is actually a type of flint corn but varies in size, shape, and higher levels of moisture allowing the kernels to “ pop” when heated. Popcorn is a perfect fiber rich snack that is low FODMAP up to seven cups.
Keep it simple with butter and salt or maybe top with nutritional yeast. Watch out for sweetened popcorns as they may contain high fructose corn syrup. Many of the cheese flavored options contain whey or dry milk protein making them too high in lactose.
Want more snacks? Check out our post: 10 New Low FODMAP Products to Spice Up Your Pantry
Waxy Corn is also a type of field corn. This contains no starch, only amylopectin (large branch of glucose units). Waxy corn is found in thickeners and maltodextrin – both low FODMAP ingredients.
Dent, flint, waxy, and flour corn are considered field corn which means they are actually considered grains or starches, not vegetables. Sorry to say, we can not justify those corn chips as eating our vegetables.
Starches are not considered FODMAPs, hence the reason for the FODMAP content variance.
How Field Corn is Processed
- Corn is inspected and cleaned.
- Corn is steeped in water for one to two days to break down the starch and protein bonds.
- Next, the corn is ground to separate the germ from the rest of the corn kernel. The germ is used to produce corn oil and livestock feed.
- The remaining slurry containing the fiber, starch, and protein is finely ground and filtered using a screen to separate the fiber from the starch and protein. The starch is then separated and dried. The remaining slurry can be converted to a syrup which is used to make a variety of sweeteners including high fructose corn syrup.
- Corn starch can also be made into several other products such as corn ethanol through a fermentation process. Corn ethanol can be used to make spirits or biofuels (gasoline alternatives).
Low FODMAP Corn Products
- Baby Corn – canned
- Tortilla Chips – watch out for seasoned ones as they may contain garlic or onion powder
- Corn Chips – watch out for seasoned ones as they may contain garlic or onion
- Cornflakes – watch out for those sweetened with fruit juice concentrates
- Corn flour
- Corn gluten
- Corn grits
- Corn meal
- Corn relish (in very small servings)
- Corn pasta
- Corn starch
- Corn Syrup
- Corn Thins such as Real Foods Corn Thins
- Corn tortillas
- Hominy – canned and drained
- Kellogg’s Corn Flakes are certified low FODMAP
- Polenta – found in a bag as dry corn grits or heat and eat style polenta
- Popcorners – Kettle and Sea Salt
- Rice and Corn Based Couscous – this grain is low FODMAP per Monash, however I have been unable to locate any gluten free couscous brands in the US.
You may be wondering what corn truffles or cuitlocoche are on the Monash App? Well despite the name this is actually a fungus that grows on corn and is considered a Mexican delicacy. Feel free to enjoy this low FODMAP food.
Label reading tips on corn, soy, milk, and other tricky FODMAPs.
High FODMAP Corn Products
- Sweetcorn or Corn on the Cob – in portions greater than ½ cob or 38 grams
- Canned Cream of Corn – in portions greater than ⅓ cup or 90 grams
- Frozen Corn – not been tested, but recommend limiting to sweetcorn portion
- Corn Bread – Monash gave corn bread the green light, however the majority of corn breads are made using wheat flour. Wheat flour is found in a few low FODMAP foods in small portions, however there are too many variables for me to be comfortable saying corn bread is low FODMAP. If you are craving corn bread stick with a gluten free variety as many of these are in fact low FODMAP.
- High Fructose Corn Syrup
Corn Products to Approach with Caution
This specific fiber has not been tested by Monash. There are some concerns that these isolated fiber sources can cause gut distress in some sensitive individuals. However, based on clinical experience, a little corn fiber in a gluten free bread or cereal appears to be well tolerated by most.
As a quick personal note, I was born and raised in Indiana with corn fields all around me. I absolutely love corn on the cob, specifically bicolor sweet corn. Polyols are one of my FODMAP triggers, and it is so hard for me to limit my intake of this delicious vegetable.
Pair corn with another sorbitol rich fruit such as watermelon (also high in sorbitol) and you have a polyol bomb and a pretty bad belly day if you too are sensitive to this FODMAP group.
- Limit your corn intake to half of a corn cob. Eat this yummy summertime food slow and really savor it to make it last.
- Skip the watermelon and swap with another FODMAP melon such as cantaloupe to keep that polyol bucket low.
- Think of corn as a garnish versus as a side entree.
- Enjoy processed corn products in moderation. See Monash App for appropriate low FODMAP serving sizes.
- It is also perfectly normal to see corn pass undigested, especially if you did not chew it up really well. This is a common side effect for everyone, IBS or not.