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With Veganuary coming up (580,000 signed up for Veganuary in 20211 alone) and as we in the UK are recommended to reduce our overall intake of animal products,2 strict dietary protocols such as the low-FODMAP diet may become trickier to navigate for many people who decide to follow a plant-based diet.Low-Fodmap-diet-concept.-Low-fodmap-ingredients-on-black-background.-135293

A standard low-FODMAP diet can be difficult to adhere to and so it may not be the ideal time to trial the diet if the client or patient is also only just embarking on a plant-based diet. This can be discussed and low-FODMAP protocols adjusted where necessary. It could also be an excellent opportunity to work with clients to ensure that they’re getting what they need from a plant-based diet in general.

What does the term ‘plant-based’ cover?

There is not currently a universally accepted definition of ‘plant-based’; some people may choose to cut back on the amount of meat they’re eating and some cut out animal products altogether – needs should be assessed on an individual level. The list below is intended to provide a general overview of potential concerns.

Some nutrients that might be lacking in a plant-based Low FODMAP Diet:

1. Iodine: Our main sources of iodine in the UK come from dairy and fish3 and intakes may already be low in certain sub-groups.3,7 If your client is avoiding these foods altogether, you may wish to look at a suitable supplement.

2. Iron: Major plant-based sources of iron such as beans and pulses are severely restricted in the initial phases of a low-FODMAP Diet. Good sources of iron may, therefore, include:

  • Fortified low-FODMAP breakfast cereals
  • Leafy green vegetables
  • Tofu

You may wish to consider supplementation depending on overall intake of other iron-containing foods.4

3. B12: As our only reliable B12 sources come from animal products, look to ensure that clients are taking in at least three suitably sized portions of fortified products per day or are supplementing if they’re avoiding animal products altogether.5 These could include:

  • Low-FODMAP cereals
  • Fortified yeast extract / nutritional yeast
  • Low-FODMAP fortified plant milks, drinks and yoghurt alternatives

Detailed nutritional assessment can help to ascertain whether these can provide enough B12 over time. In my own clinical experience, many clients have assumed that a minimal amount of fortified foods will see them through and it has been important to address this.

4. Calcium: Aim to ensure that any low-FODMAP dairy replacements are fortified with calcium or that it’s adequately supplemented. Good sources of low-FODMAP calcium containing foods can include:

  • Fortified coconut milk / almond milk / rice milk
  • Calcium-set tofu (check the label)
  • Fortified coconut yoghurt6


It’s worth noting that organic foods aren’t fortified at this time in the UK and I’ve also found recently that clients may be making their own unfortified plant milks.

5 Zinc: In the UK, our main source of zinc tends to come from meat. Consider adding in some higher-zinc foods like mycoprotein mince such as Quorn (note that some Quorn products have added garlic and wheat), brazil nuts, pecans, peanuts and some seeds.8

6. Omega-3s: Plant-based sources include: some nuts, seeds and vegetable oils including rapeseed and linseed oil, and smaller amounts in soya-based foods like tofu and soya beans.9 There is not currently enough evidence to recommend supplementation for the general population, though you may wish to discuss the options.9

Overall, while it will require a lot more planning, label-reading and is very likely to involve more time spent cooking, it is possible to adjust the low-FODMAP diet for those who are following a plant-based diet. The initial restrictive phase of the low-FODMAP Diet is recommended to be carried out for around two to six weeks,10 but, as clients rechallenge foods, they may find that their tolerance for them is low and so will need suitable advice for continuing with this adjusted restricted diet.

With the likelihood being that more and more people will be following such a diet, it’s helpful to be aware of any key areas of concern to support patients and clients.

Jess English, RD

Jess is self-employed private practice dietitian with interests
in IBS, maternal and child health, public health.

Website: www.levelupnutrition.co.uk


  1. Veganuary - available from: https://veganuary.com/ [accessed 19th November 2021]
  2. National Food Strategy - report and recommendations available from: https://www.nationalfoodstrategy.org/the-report/ [accessed 20th November 2021]
  3. PHE - National Diet and Nutrition Survey results; years 9-11 - available from: https://www.gov.uk/government/statistics/ndns-results-from-years-9-to-11-2016-to-2017-and-2018-to-2019 [accessed 18th November 2021]
  4. BDA - Iron Food Fact Sheet - available from: https://www.bda.uk.com/resource/iron-rich-foods-iron-deficiency.html [accessed 18th November 2021]
  5. BDA - Practical Guide; Other Sources of vitamin B12 - available from: https://www.bda.uk.com/uploads/assets/5378b751-58bd-4e85-b15b360d8165a3f8/Practical-guide-other-sources-of-B12.pdf [accessed 18th November 2021]
  6. Monash University. Monash University FODMAP Diet Application (v 3.0.8) [Mobile app] [accessed 18th November 2021]
  7. BDA - Practical Guide; Other Sources of Iodine - available from: https://www.bda.uk.com/uploads/assets/265ece52-a20e-4b39-8e1c2f07056f6443/Practical-guide-other-sources-of-IODINE.pdf [accessed 18th November 2021]
  8. BDA - Practical Guide; Other Sources of Zinc - available from: https://www.bda.uk.com/uploads/assets/b8894b85-080a-4d36-84aa58d49eee5b2b/Practical-guide-other-sources-of-ZINC.pdf [accessed 18th November 2021)]
  9. BDA - Omega 3 Fact Sheet - available from: https://www.bda.uk.com/resource/omega-3.html [accessed 20th November 2021]
  10. Monash University, ‘Starting the FODMAP diet’ - available from: https://www.monashfodmap.com/ibs-central/i-have-ibs/starting-the-low-fodmap-diet/ [accessed 19th November 2021]



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