What Nutrients Are Missing on a Low FODMAP Plant-Based or Vegan Diet? | The PNW Clinic

June 16, 2023

Low FODMAP diets have gained popularity in recent years, particularly among individuals with irritable bowel syndrome (IBS) or other digestive issues. The low FODMAP diet aims to reduce the consumption of specific carbohydrates (FODMAPs) that can trigger digestive symptoms.

When on a plant-based diet, it can be common to miss certain nutrients while eating low FODMAP foods. This article will discuss what nutrients you may be missing out on and strategies to ensure you are meeting your requirements when following a low FODMAP plant-based diet.

Introduction to the FODMAP diet

The low FODMAP diet was created by Monash University as a therapeutic intervention to
help those suffering with irritable bowel syndrome (IBS)(1).


What are FODMAPs?

They are a diverse group of carbohydrates that can be poorly absorbed in the small intestine causing some people discomfort (2).

As these specific carbohydrates are not efficiently digested by the body, they instead accumulate in the large intestine resulting in one of two pathways:

  • Some FODMAPs attract water into the intestine, potentially leading to diarrhoea or increased pressure within the gut, resulting in bloating or discomfort (2).
  • FODMAPs can also be fermented by the bacteria living in our gut, generating gas as a by-product. While this process is considered normal, those with IBS may experience symptoms such as bloating, excessive gas, or discomfort.

FODMAPs stand for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols which can be found in various foods. They include:

  • Oligosaccharides (fructans and galacto-oligosaccharides (GOS)): wheat, rye, onions, garlic, legumes and nuts.
  • Disaccharides (lactose): dairy – milk, cheese, cream.
  • Monosaccharides (fructose): honey, certain fruits and vegetables – apples, pears, mango, sugar snap peas.
  • Polyols (sorbitol, mannitol and xylitol): artificial sweeteners, stone fruits, mushrooms (2)


lactose is a type of fodmap



How is the low FODMAP diet implemented?

After all first-line strategies have been investigated, it may be recommended for you to follow a low FODMAP diet. This diet is strongly recommended to be supervised by a qualified dietitian specialising in gut health due to its level of restriction.

Low FODMAP diets have three main stages:

  • Stage 1: Elimination stage- a 2-to-6-week period of restriction where high FODMAP foods are eliminated in the diet (3).
  • Stage 2: Re-introduction – FODMAPs are gradually reintroduced and challenged. This helps to identify which FODMAPs you are sensitive to (3).
  • Stage 3: Personalisation – Using the results from stage 2, your diet is personalised using a mix of low FODMAP and high FODMAP foods that don’t cause you symptoms (3).

As this diet restricts a number of foods, food choices can already feel quite limiting. On top of this, following a low FODMAP diet while maintaining a vegan or plant-based lifestyle can feel even more challenging.

While vegans omit all animal products, there can be a reliance on many high-FODMAP foods for many nutritional needs e.g. legumes for protein, wholegrains for carbohydrates, certain fruits and vegetables for key vitamins and minerals.

However, with careful planning and information of suitable alternatives, it is possible to maintain good vegan nutrition while on a low FODMAP diet.


Nutrients at risk on a low FODMAP diet

While a low FODMAP diet can be beneficial for symptom management, it’s important to be aware of potential nutrient deficiencies as a result of the restriction of certain foods.

Here are some nutrients that may be at risk on a low FODMAP diet:


Fibre is crucial for maintaining digestive health, regulating bowel movements, and supporting a healthy gut microbiome. FODMAPS are a type of fermentable fibre that can contribute to digestive symptoms.

By eliminating all high FODMAP foods, some people may unintentionally lower their overall fibre intake (4).



Iron is essential for oxygen transport and plays a vital role in energy production and immune function. As there is restriction of many iron-rich carbohydrates such as wholegrains and legumes, there are limited options and therefore increase risk of deficiency (5).


legumes are a great source of plant-based iron



Calcium is essential for bone health, muscle function and nerve transmission. As calcium is commonly found in dairy products that are high in FODMAPS, those following a low FODMAP diet may be at risk of calcium deficiency (4).



Zinc is essential for growth, development and immune health. Foods high in zinc include legumes, nuts and seeds. During stage 1 of the low FODMAP, many of these foods must be eliminated, meaning zinc can be harder to get enough of through the diet (6).


B Vitamins

Vitamin B1, B2, B3, B9, B12 are responsible for many parts of the body. These roles range from energy production, skin and eye health, cell production to red blood cell formation and nerve health. As these vitamins are found in many wholegrains, it can be
harder to meet the recommended requirements when on a low FODMAP diet (7).


Nutrients at risk on a plant-based/vegan diet

While there are increased risks of varying nutrients when on a low FODMAP diet, there are also nutrients to consider when following a plant-based diet. Here are some of the nutrients that may be at risk when on a vegan diet:


Omega-3 fatty acids

Omega-3 fatty acids are important for heart and brain health. There are plant-based sources of omega-3 fatty acids like flaxseeds, chia seeds, hemp seeds, and walnuts that provide alpha-linolenic acid (ALA).

However, conversion of ALA to the more bioavailable form EPA and DHA, is limited. This can in turn, make it harder for vegans to meet their omega-3 requirements.


walnuts contain plant-based omega 3


Vitamin B12

Vitamin B12 plays an important role in maintaining a healthy nervous system, supporting red blood cell production, and facilitating DNA synthesis. As vitamin B12 is primarily present in animal-based foods and not naturally occurring in any plant-based foods, it can be a concern for those following a vegan or plant-based diet.

While some plant-based foods are fortified with B12, it is common for many vegans to supplement this vitamin as they cannot meet their requirements with a food only approach (7).



As previously mentioned, iron is essential for transporting oxygen to tissues and cells.
Plant-based sources of iron (non-haeme) may be less readily absorbed by the body compared to the iron found in animal products (haeme).

For this reason, those following a plant-based diet need 1.8 times the recommended intake than those consuming animal-based foods like red meat making it more difficult to consume enough regularly (7).



Calcium is most readily available in dairy products. When following a plant-based diet, it can be harder to meet requirements from naturally occurring sources.

This can be a concern as calcium intake is already a struggle for many on a low FODMAP diet without the addition of a plant-based dietary approach.

Luckily, there are many fortified dairy alternatives for vegans to choose from. However as this is not an industry standard, it can be difficult to get enough calcium if not consuming fortified options (8).



If you follow a vegan or plant-based diet, you’ve probably heard that vegans may struggle to get enough protein. While it is entirely possible to consume adequate protein, it can still require some thought and planning (9).

When on a low FODMAP and vegan diet, many plant-based sources of protein aren’t an option. Foods such as legumes and beans are considered high FODMAP and shouldn’t be consumed in the elimination stage.

This can present a challenge for many vegans to meet their protein requirements.


tofu is low fodmap plant-based

Tips on following low-FODMAP diet on a plant-based or vegan diet

Following a low FODMAP plant-based diet can be challenging. As previously mentioned, it can be harder to meet all your nutrient requirements.

To get you started, here are our top tips on how to stay on top of your vegan nutrition when following a low FODMAP diet:


Identify your low FODMAP foods

Having a list of foods you know are low FODMAP can help you plan your meals and increase the diversity in your recipes.

Here is a summary of some low FODMAP plant-based foods as listed by Monash University:

  • Fruits- Pineapple, orange, mandarin, rockmelon, green kiwi fruits, firm banana
  • Vegetables – eggplant, green beans, bok choy, green capsicum, carrot, cucumber, lettuce, potato, zucchini.
  • Grains – oats, quinoa, rice, wheat/rye free breads, low FODMAP bread from Bakers Delight
  • Dairy alternatives – soy milk (made from soy protein), almond milk, rice milk, hemp milk
  • Protein sources – firm tofu, tempeh, edamame, canned lentils (1/4 cup)
  • Nuts and seeds – macadamias, peanuts, walnuts, pine nuts, pumpkin seeds.
  • Sugars and sweeteners- dark chocolate, maple syrup, rice malt syrup, table sugar (1)

For more information, you can download the Monash University FODMAP Diet app here for access to their database.

Prioritise protein

Protein is important for the maintenance of our tissues and our immune function.

When building a meal, ensure you’re including a good source of protein to help meet your requirements and to support muscle and immune health. This could include tofu, tempeh, edamame or low FODMAP nuts/seeds such as hemp seeds, peanuts and walnuts.


Eat enough fibre

As previously mentioned, fibre is important for a healthy digestive system. Include low FODMAP fruits, vegetables, seeds, and gluten-free wholegrains during mealtimes and snacks to ensure you’re meeting your requirements and supporting your gut


citrus fruit is low fodmap


Look for fortified low FODMAP plant-based alternatives

As it can be more challenging to meet all nutrition needs, opting for fortified options can be a practical way to boost
micronutrient intake. Fortified dairy alternatives such as soy milk or almond milk are an excellent source of calcium, vitamin D, and sometimes vitamin B12.

Additionally, fortified low FODMAP cereals like gluten-free Weetbix and gluten-free Special K offer a range of vitamins, including B1, B2, B3, folate, as well as essential minerals like potassium and magnesium (10).


Follow a low FODMAP diet for the recommended time

Going on a low FODMAP diet is only temporary and is not recommended to be followed long-term.

The diet is intended to help identify trigger foods and alleviate symptoms. Once these foods have been detected, it’s important to gradually reintroduce the non-triggering high FODMAP foods to avoid developing deficiencies and worsening your gut health.


Work with a health professional

Working with a dietitian specialising in gut health is highly recommended and can be extremely helpful when following a low FODMAP plant-based diet. We will discuss the range of benefits in detail below.

For more tips on following a low FODMAP plant-based diet, check out some of our other
posts related to this topic.



Why is it important to work with plant-based dietitian on a low FODMAP diet?

Working with a healthcare professional, such as an online dietitian from the PNW clinic while following a low FODMAP diet can be beneficial for several reasons. Some of these include:


Maintaining nutritional adequacy

A plant-based dietitian can help maintain a balanced and nutritionally adequate diet while following low FODMAP guidelines.
Dietitians can provide recommendations on how to replace high FODMAP foods with suitable alternatives to ensure you meet your nutrient requirements.


Food variety

Following a low FODMAP diet can be restrictive, particularly when combined with a plant-based or vegan diet. A plant-based dietitian can help expand food choices and suggest different foods and recipes to try.

This can help to overcome palette fatigue and increase satisfaction with meals.


Prevent nutrient deficiencies

As discussed, eliminating certain high FODMAP foods may lead to potential deficiencies in specific nutrients, vitamins, and minerals. A plant-based dietitian can monitor your intake and work with you to maintain a balanced diet while avoiding deficiencies.


prevent deficiencies by working with a low fodmap plant-based dietitian

Managing symptoms

A low FODMAP diet is primarily implemented to alleviate digestive symptoms (bloating, abdominal discomfort, flatulence etc). A dietitian who specialises in gut health can provide individualised advice to manage symptoms while adhering to low FODMAP guidelines.


Personalised approach

Each individual’s dietary needs and tolerances vary. A plant-based dietitian can help tailor the low FODMAP diet to your specific requirements.

Dietitians can take into account your plant-based preferences, potential trigger foods, intolerances, and other dietary considerations. There is also ongoing support with an ability to adjust the diet as needed based on progress and feedback.


Following a low FODMAP plant-based diet can be an effective intervention for managing symptoms associated with conditions like IBS. Working with a healthcare professional, like one of our online dietitians at the PNW clinic, can help you personalise and maintain a nutritionally balanced diet.

If you want to learn more, book in for a free 15-minute discovery call and see how we can help guide you through this journey to avoid nutrient deficiencies while on a low FODMAP diet.



Written by: Student dietitian Leanna Fyffe

Review by: PNW Dietitian Jade Wrigley

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