One of the biggest confusing things when on the FAILSAFE RPAH (Royal Prince Alfred Hospital) elimination diet is when corn flour is ok and when it needs to be avoided.
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CORN
Corn is high in salicylates and glutamates so needs to be avoided on the elimination diet.
Products made from corn such as polenta are also high in salicylates and glutamates.
Polenta is corn that has been roughly ground so still retains all the salicylates and glutamates from the original corn.
This means that polenta as well as other foods made from corn such as corn chips, corn thins and pop corn need to be avoided on the low or moderate FAILSAFE/ RPAH elimination diet.
CORN FLOUR (or MAIZE FLOUR) is high in salicylates and glutamate
Corn or polenta can be ground into corn flour which is still high in salicylates and glutamates so needs to be avoided.
Corn flour can also be called maize flour. So maize flour needs to be avoided.
Many foods can contain corn flour or maize flour, especially gluten free products so read the ingredient lists carefully.
Tip: corn flour tends to have a yellow colour for example yellow coloured gluten free pasta made from corn flour. This is different to corn starch which is white in colour.
CORN STARCH (OR MAIZE STARCH) is low in salicylates and glutamates
Corn flour (maize flour) can be further processed and washed which removes the protein portion and leaves the starchy part behind.
This corn starch (or maize starch) is a fine powder that is white in colour.
Corn starch is very low in salicylates and glutamates and so can be included in the elimination diet.
Although it is made from corn it is so highly processed tthat the salicylates and glutamates are processed out!
THE CONFUSION
Corn starch when used in food products can be labelled on the ingredient lists as cornflour although technically it is not corn flour, it is CORN STARCH!
For example- the cornflour you commonly see in Australian supermarkets (see below) is not actually corn flour or maize flour but is corn starch. For example White Ewings corn flour. Note: corn starch is white in colour.
To make things a bit more confusing... the picture on the right is actually called corn flour but has nothing to do with corn- it is actually just a wheat starch so is quite ok on the elimination diet if you are including wheat. NO corn in it at all!
HIGHLY PROCESSED CORN
Corn that is highly processed is fine, and all the following are ok to include in the elimination diet as the salicylates and glutamates have been processed out:
Dextrin/dextrose (from maize)
Modified starches or thickeners (from maize)
Glucose syrup (from maize)
Corn fructose syrup (from maize)
Caramel colour (from maize)
TAKE HOME MESSAGE
When you see corn flour or cornflour as an ingredient on a food label- you need to know if this means corn flour or corn starch.
- if it is yellow more likely is corn flour so avoid (eg some gluten free pasta for spaghetti such as Coles GF brand)
- if written as cornflour (one word) indicates it MAY be the starch- check the colour out
- if written as maize flour- avoid
- if written as maize starch- can include
- when in the form of the highly processed forms: dextrin/dextrose from maize | modified starches or thickeners from maize | caramel colour from maize is quite acceptable
If not sure- ask a specialist FOOD INTOLERANCE DIETITIAN!
UPDATED 17/8/23, Frances Walker
REFERENCES
1. RPAH elimination diet handbook: with food and shopping guide. Anne Swain, Velencia Soutter, Robert Loblay, 2019 (revised edition).
2. Monash University low FODMAP app. Version 3.0.3. Accessed 14/08/2019.