Vegetarianism and the Low FODMAP Diet (2024)

Today I have another guest post for you! Mikaela Horton is one of my nutrition student volunteers. She has written a wonderful and informative post about vegetarianism and the low FODMAP diet. The low FODMAP diet is already very restrictive, and combining it with a vegetarian or vegan diet can be tough, but it is possible to do in a healthy way. It is highly recommended to work with a dietitian when implementing the low FODMAP diet, especially when there are additional dietary restrictions. Keep reading to learn about vegetarianism and the low FODMAP diet, and key nutrients of concern!

Vegetarianism is one of the fastest growing dietary and lifestyle trends – nearly 12 million Canadians either identify as vegetarian or are making efforts to greatly reduce their meat intake.¹ This increase is reflected in our society in many ways. More veg-friendly options are offered at restaurants. Frequent news stories are encouraging us to reduce our intake of red and processed meats. Plus, there are veg-friendly meat and dairy alternatives popping up in grocery stores throughout the country.

There’s no denying that vegetarianism is growing, and with proper planning a vegetarian diet can be sustainable and beneficial. Combining vegetarianism and the low FODMAP diet is tricky, but it can be done.

Why Vegetarianism?

Choosing to follow a vegetarian diet is a personal choice, and the decision to switch can be motivated by any number of factors. Some of the more common reasons one may choose to adopt a vegetarian diet include:

To increase fruit and vegetable intake
To improve overall health
To lose weight
Ethical and/or moral concerns or beliefs regarding the treatment of animals
Religious, spiritual or cultural beliefs
Environmental concerns related to the resource-intensive process of producing animal-based foods

Types of Vegetarianism

Vegetarianism is largely known as a diet that excludes meat, and while this is generally true, classifying a vegetarian diet isn’t quite that simple. A vegetarian diet can come in many forms, from those that focus merely on reducing meat, to those that abstain from consuming any animal products. Check out the graphic below: it illustrates the basic classifications of a vegetarian diet, and which foods are included and excluded.

Nutrition on a Vegetarian Diet

Vegetarian diets are commonly labeled as being ‘deficient’ in certain nutrients, and while it is true that some nutrients are harder to obtain, a properly planned vegetarian diet can meet all your nutrient needs regardless of your age, gender or activity level. ² Some of the main nutrients of concern when transitioning to a vegetarian diet are discussed below.

It can be even trickier to meet all of your nutrient needs when also following the low FODMAP diet. Many commercial vegan meat-substitutes (veggie dogs, veggie burgers, vegan cheese, etc.) contain high FODMAP ingredients such as onion, garlic, cashews, soybeans, and more. Always read ingredients lists carefully before purchasing foods. All of the foods listed below are low FODMAP.

Protein

Protein is perhaps one of the most common issues brought up when someone is considering a vegetarian diet. It is a prominently held belief that eating meat is the only way that protein needs can be met. However, there are a number of plant-based foods that are high in protein and low in FODMAPs. Some examples include: ^{2, 8}

Tempeh
Firm tofu (avoid silken if low FODMAP)
Soy milk (made with soy protein, not soybeans)
Peanuts and peanut butter
Sesame and sunflower seeds
Quinoa
Almonds and almond butter (only low in GOS at serving size of 10 nuts/1 tbsp. or less)
Canned chickpeas (only low in GOS at serving size ¼ cup or less; rinse well before eating)
Canned lentils (only low in GOS at serving size ½ cup or less; rinse well before eating)

Vegetarians can also get protein from eggs and low-lactose/lactose-free dairy products.³ Hard cheeses are considered low in lactose. Regular milk and yogurt are high in lactose, but many stores carry lactose-free options which have added lactase enzyme to break down the lactose (making it low lactose).

Calcium

The first thing most of us think of when we hear the word ‘calcium’ is dairy. While dairy products like milk, cheese, yogurt and ice cream can certainly help those who choose to include them in their diet reach their calcium needs, there are other sources that can help those who are dairy-free. Some great plant-based and low FODMAP sources of calcium include:^{[2, 4, 8}

Plant-based milks that have been fortified with calcium (some low FODMAP examples include almond, hemp, soy (made from soy protein), and rice milks)
Firm tofu prepared with calcium sulfate
Tempeh
Sesame seeds
Bok choy
Okra
Collard greens
Turnip greens
Spinach

Why is Calcium Important? Calcium aids in the growth and maintenance of bones and teeth, and also plays a part in muscle contraction.² Inadequate calcium intake is linked to an increased risk for developing osteoporosis, where bones lose their density and become more prone to breaking. Including a variety of calcium-rich foods in your diet can contribute to stronger, healthier bones.⁵

Vitamin B12

Vitamin B12 is often touted as the one real “flaw” of a vegetarian diet – it appears to only be available in animal-based food products. However, vitamin B12 is actually derived from microorganisms.⁶Some veg- and low FODMAP-friendly sources of B12 include:^{2, 6, 8}

Fortified plant-based milks (such as those mentioned for Calcium)
Fortified nutritional yeast

Nutritional yeast was recently tested by Monash and found to be low in FODMAPs at the serving size of 1 tablespoon.⁸

Vegetarians can also get vitamin B12 from eggs and low-lactose/lactose-free dairy products.³Hard cheeses are considered low in lactose. Regular milk and yogurt are high in lactose, but many stores carry lactose-free options which have added lactase enzyme to break down the lactose (making it low lactose).

If you have trouble getting these foods into your diet, you may want to consult your doctor or dietitian about including a B12 supplement into your routine.⁶

Why is Vitamin B12 Important? Vitamin B12 helps to keep nerve cells healthy and aids in the production of red blood cells.²It also helps iron function better within the body.⁷

Iron

Iron is available in two different forms – one form comes from plants, and the other from animal sources. The iron that is found in plant foods is a little harder to absorb, so more iron-rich foods typically need to be included if daily needs are to be met. The recommended daily amount of iron is actually double for vegetarians,²which helps account for the malabsorption issue. However, combining vitamin C-rich foods with iron-rich foods can help to boost iron absorption.² Some FODMAP-friendly vegetarian iron-sources include:^{2, 8, 9}

Firm tofu
Tempeh
Fortified soy milk (made with soy protein)
Pumpkin seeds
Sesame seeds
Spinach
Kale
Potatoes (with the skin).

Examples of vitamin C-rich foods include oranges, lemons, limes, kiwis, cantaloupe, potatoes, bell peppers, kale, strawberries, bok choy, tomatoes, ripe guava, pineapple, blueberries, and raspberries.^{2, 8, 10}

Zinc

Zinc is usually a nutrient of concern when vegetarian diets come up – one of the highest sources of zinc is meat.¹¹ Luckily, there are a number of plant-based food sources that can help you to reach your daily recommended intake of zinc. Some low FODMAP examples include:^{2, 8, 11}

Soy milk (made with soy protein)
Tempeh
Firm tofu
Pecans
Peanuts and peanut butter
Pumpkin seeds
Sunflower seeds
Sesame seeds.

Vegetarians can also get zinc from eggs.³

Why is Zinc Important? Zinc is important for growth and maintenance, strengthening the immune system, and healing wounds. It also helps the body use the foods we provide it. ^{2, 11}

Vitamin D

Vitamin D is also known as the “sunshine” vitamin. Exposing your skin to the sun helps your body to produce vitamin D. However, too much sun exposure can damage the skin, and getting enough sunlight during the cold winter months here in Canada can be difficult. ¹²Some low FODMAP food sources of vitamin D include: ^{2, 8}

Plant-based milks that have been fortified with vitamin D (some low FODMAP examples include almond, hemp, soy (made from soy protein, not soy beans), and rice milks).

Vegetarians can also get vitamin D from eggs and low-lactose/lactose-free dairy products.^[3Hard cheeses are considered low in lactose. Regular milk and yogurt are high in lactose, but many stores carry lactose-free options which have added lactase enzyme to break down the lactose (making it low lactose).

Your geographical location, lifestyle, and other factors can impact the amount of sunlight you are exposed to. If you are concerned about getting enough vitamin D, consult your doctor or dietitian about including a vitamin D supplement into your routine.¹²

Why is Vitamin D Important? Vitamin D is important for the health of our bones – it helps our bodies to absorb the calcium and phosphorous that we take in.^{2, 12}

Omega-3 Fats

Omega-3 fatty acids include EPA, DHA, and ALA. Both EPA and DHA can be made by our bodies from the ALA that we consume, but this process is limited – ALA is converted to EPA quite efficiently, but more ALA is needed for it to be converted to a suitable amount of DHA. ^{13, 14}Including sources of EPA, DHA, and ALA in your diet can help you to meet your needs. Some examples of low FODMAP, ALA-rich sources include:^{2, 13, 14}

Winter squash (excluding butternut squash)
Fortified soy milk (made from soy protein)
Firm tofu
Chia seeds (2 tbsp.)
Flaxseeds
Pumpkin seeds
Pecans
Walnuts
Canola, soybean, flaxseed, and walnut oil

Grinding chia seeds and flaxseeds can increase the amount of ALA that is absorbed, as their hard shells can be difficult for our bodies to penetrate ¹³– flaxseeds can also be ground up and combined with water to serve as an egg replacement in baking!

Hemp seeds are another vegan source of ALA, but they have not yet been tested for FODMAP content. It is best to avoid hemp seeds during the elimination phase, and tolerance can be tested during reintroduction.⁸

Consult with your doctor or dietitian if you are considering DHA supplements to help ensure you are reaching your DHA needs, regardless of your bodies ability to convert ALA into a sufficient amount of DHA.

Why are Omega-3 Fatty Acids Important? Omega-3 fatty acids contribute to the health of our eyes, nervous system, and brain. There is also some evidence that suggests that omega-3s can reduce the risk of heart disease.^{2, 13, 14}

Where Do I Go from Here?

Please consult with your doctor or dietitian before making any dietary changes. As mentioned throughout this post, supplements may make a helpful addition to your diet, however, it is best to talk to a doctor or dietitian first before starting any form of supplementation.

The low FODMAP diet should be implemented with the help of a FODMAP registered dietitian, especially if the diet is being combined with a vegetarian/vegan diet. A dietitian can guide you properly through the diet and reintroduction, while helping ensure you are still eating a nutritious balanced diet.

If you are just making the switch to a vegetarian diet, remember to make changes at a pace that is sustainable and that works for you. While many people are able to change ‘overnight,’ it is important to not feel pressured or to stress about the strictness of the diet. Identify what becoming vegetarian or vegan means to you!

References:

About the Guest Author:

Mikaela is a nutrition student at the University of Guelph who aspires to become a Registered Dietitian and tohelp others live healthy, happy, and nutritious lives. Having followed a vegan lifestyle for over 6 years, Mikaelahas learned how to approach a vegetarian or vegan diet in a way that is sustainable, healthful and fun.Mikaela’s volunteer experiences include being a member of the Student Nutrition Awareness Program (SNAP),the Applied Human Nutrition Student Association (AHNSA), helping with an elementary school lunch program,and being the Dietitians of Canada (DC) Student Representative for the University of Guelph.

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