If you are on the low FODMAP diet, you will find soy confusing.
You will be thinking that soya milk is lactose free but then confused because some people say to avoid it.
You may also be thinking that you need to find gluten free Soya sauce, but this is not the case.
Having this confusion often leads to mistakes on the low FODMAP diet.
In this article I will cover different types of soy and explain to you whether they are low FODMAP or not AND why.
Table of Contents
Is Soy Sauce Low FODMAP?
Soy sauce is made using a fermentation process.
During this process, FODMAPs are destroyed. This makes soy sauce safe if you are on the low FODMAP diet.
Please note, soy sauce still contains gluten. This means that if you are coeliac or have a wheat allergy then you must opt for a gluten free soy sauce.
Soy Milk
Despite being lactose free, soya milk can be high in FODMAPs.
Soya milk is made from soy beans and so still contains too much GOS (1). This leads to IBS symptoms.
There is 1 way you could include soy milk into a low FODMAP diet. This is if it is made with just soy protein.
Soy protein contains no FODMAPs and so is low in FODMAPs.
Soya Beans
Soy beans are high in both GOS and fructans (Monash).
You must avoid soya beans if you are on the low FODMAP diet.
Soy Flour
This is made directly from grinding down soy beans. It is therefore high FODMAP and you should avoid it.
Tempeh
Tempeh is made with soy beans, so you may think it is high FODMAP.
However, it is low FODMAP. This is due to the process in which is has been made. In this process, soy beans are firstly soaked (reducing FODMAP content).
The soaked soy beans and then fermented using bacteria. Again, this process reduces the FODMAP content (2).
Tofu
You can enjoy tofu on a low FODMAP diet. BUT only the firm type!
Tofu is made by pressing soy beans. The longer this process takes, the less water there is in the tofu.
This process reduces the FODMAP content.
Edamame
It may surprise you to find that edamame beans contain less FODMAPs than soy beans despite being pretty much the same thing.
You can enjoy Edamame beans at a low FODMAP portion of 90g (1).
The reason that Edamame beans are low FODMAP is because they are harvested at a much younger age.
Summary
You can have soy in your low FODMAP diet. But, the type and amount is important. How soy is processed will determine how much FODMAPs it contains.
As with other foods, it is also important to check portion sizes.
References
1. https://www.monashfodmap.com/ibs-central/i-have-ibs/get-the-app/
2. https://www.bbcgoodfood.com/howto/guide/health-benefits-tempeh
Kirsten Jackson is a UK registered Consultant Gastroenterology Dietitian and founder of The Food Treatment Clinic. She has undergone many qualifications to get where she is today, including a UK BSc Honours Degree in Dietetics and Post-Graduate Certificate in Advanced Dietetics. In addition to this, she has FODMAP Training from Kings College London University. Kirsten set up The Food Treatment Clinic in 2015 after first experiencing digestive problems herself. She felt that the NHS was unable to provide the support individuals needed and went on to specialise in this area before opening a bespoke IBS service. Kirsten also participates in charity work as an Expert Advisor for the IBS Network. In addition, she can be seen in publications such as Cosmopolitan and The Telegraph discussing IBS as an Official Media Spokesperson to the IBS Network.
How about soy capsules and supplements? I’d like to try one to relieve hot flashes, but I’m worried about having a reaction to the FODMAPs
Sadly we are not experts in hot flashes so can not advise. It would depend on what part of the soy bean is being used for the FODMAP content.