The global surge in people adopting a plant-based diet is making gastroenterologists like me very happy. We've known for decades that the Standard Western Diet, with its focus on animal products, dairy, and highly processed foods, has been responsible for soaring levels of serious digestive issues over the last 50 years. A healthy, whole food, plant-based diet ticks all the right boxes when it comes to preventing and even treating so many of the digestive diseases that we see every day in our clinics and on our hospital wards.
When it comes to avoiding conditions like Inflammatory Bowel Disease, diverticular disease, Irritable Bowel Syndrome, fatty liver disease and even bowel cancer, a healthy whole food plant-based diet gives you the best chance of maintaining a healthy gut. But there are a few common pitfalls that may provoke digestive symptoms on a plant-based diet. Here's how to avoid them.
Fill your plate 'whole foods'
As the food industry seeks to cater for increasing numbers of vegan customers, it is now possible to eat a plant-based diet based entirely on chocolate bars, donuts, rocky road ice-cream and vegan pepperoni pizza.
Although these foods can be a useful tool when initially making the transition to a plant-based diet, they cannot be considered gut-friendly options. These highly processed foods, as well as many protein shakes and supplements marketed to vegans, are often packed with artificial flavors, emulsifiers and preservatives.
Maltodextrin, polysorbate-80, carboxymethylcellulose and soy lecithin are just a few examples of the many hundreds of chemicals that are added to processed foods and are known to be bad news for gut health. It's no surprise that a 2018 study of 44,350 French adults found that the more highly processed foods they ate, the higher their risk of developing symptoms of Irritable Bowel Syndrome (1).
Reduce your risk of digestive problems by filling your plate with healthy whole-foods served up as close to their natural form as possible.
Build diversity into your plant-based diet
The key to maintaining good digestive health is keeping your gut microbiome happy. The trillions of microbes that inhabit our digestive tracts play a crucial role in digesting our food, maintaining a healthy gut lining, reducing inflammation, producing important nutrients and even regulating our appetite and caloric intake.
Last year, The American Gut Project published fascinating insights into the human gut microbiome (2). Having completed detailed microbiome analysis on over 11,000 volunteers, it concluded that the number one determinant of a healthy and functional gut microbiome is the variety of plants in your diet. Keep your gut microbiome happy by building diversity into your whole food plant-based diet. Enjoy a variety of fruits, vegetables, legumes, beans, greens, nuts and seeds each day.
Make sure your supplements are on point
A varied plant-based diet is rich in protein, fiber, phytonutrients, anti-oxidants, calcium, magnesium, potassium and many other vital substances. It ticks all the right boxes for gut health and multiple medical studies have shown that it is also an optimal diet to prevent and even treat heart disease, obesity, type 2 diabetes and many of the chronic diseases that have become so prevalent in populations that adhere to the 'Standard Western Diet' (3).
To maximise the overall health benefits of your plant-based diet, please make sure that your supplements are on point. Issues with vitamin B12, vitamin D3 and even trace nutrients like iodine and selenium can lead to feelings of fatigue, depression and poor concentration. Careful meal planning and regular exposure to sunshine can prevent most deficiencies but to eliminate the uncertainty I always advise taking vitamin B12 25mcg each day as a minimum.
To keep things simple and affordable, I recommend supplementing with 'VEG-1', available for global delivery from The Vegan Society. For less than 8 pence (10 cents) per day, this single pill provides your daily dose of vitamin B12 and vitamin D3 plus your recommended daily intake of iodine and selenium.
Top up your omega-3s
Multiple studies have shown that dietary omega-3 oils help to reduce intestinal inflammation and maintain good gut health (4). These healthy polyunsaturated fatty acids are divided into two types, 'short-chain omega-3s' and 'long-chain omega-3s'. Both types are made by plants.
Keep your short-chain omega-3s topped up by including a handful of walnuts or a tablespoon of flaxseeds (linseeds) or chia seeds in your diet each day. To ensure adequate levels of the long-chain omega-3s EPA and DHA, you should consider taking a daily supplement.
Plant-based or vegan omega-3 supplements are usually made by extracting the oil directly from algae which have been purpose-grown in clean, pollutant fee conditions. Capsules or oils can be obtained from reputable pharmacies and other suppliers. Aim for >250mg of EPA/DHA per day.
You might need to transition to plant-based gradually
Adequate fiber intake is essential to good gut health. Most people who eat the standard western diet do not get nearly enough dietary fiber, with the majority falling far short of the recommended minimum 30g per day. Not only do fiber-rich foods help prevent constipation and bloating, we have known for almost half a century that high fiber, plant-based diets play a crucial role in preventing obesity, type 2 diabetes, heart disease and numerous cancers (5).
Moving to a whole food plant-based diet will increase your fiber intake to a healthy 40-50g per day. Within just a week of making the change you will have induced favourable changes in your gut microbiome, helping to reduce your risk of developing serious digestive diseases including Inflammatory Bowel Disease, cancer and fatty liver disease (6-8).
However, an overnight conversion from standard western omnivore to healthy high-fiber herbivore can result in a period of bloating and digestive discomfort as your microbiome and digestive processes adjust.
Some people may need to take a step back and make the transition over a period of six weeks or so. We all eat about 21 main meals per week. Why not start by making all seven breakfasts 100 percent plant-based, and then gradually move on to lunch and dinner?
Watch out for excess FODMAPs
FODMAPs are short carbohydrates which are found in abundance in healthy plant-based foods. The acronym stands for 'fermentable oligo-saccharides, di-saccharides, mono-saccharides and polyols'. Overall FODMAPs are highly beneficial, acting as important 'pre-biotics', food for our healthy gut bugs which help us to build a rich and diverse microbiome.
However, high intake of FODMAP-rich foods can lead to excess fermentation, digestive gas and bloating. Many healthy plant-based foods such as avocado, cauliflower, beans, garlic and onions are also high in FODMAP content. You don’t need to eliminate these foods completely by any means, but it is possible to reduce your FODMAP intake while still maintaining a healthy and diverse plant-based diet. Any registered dietician should be happy to support you in this process.
To learn more about FODMAPs check out the 'Monash University Low FODMAP Diet App', or download the free 'Happy Gut Guide' here.
Final word: If you don't feel well, please see your doctor!
The medical evidence is overwhelming: when it comes to protecting your long-term gut health, a whole food plant-based diet ticks all the right boxes.. But it's worth remembering that no single diet or lifestyle change makes you 100 percent disease-proof. If you do develop digestive problems, fatigue, poor energy levels or any worrying symptoms please see your family doctor.
Discussing your problems and having routine blood work are important to make sure that a serious diagnosis has not been missed. There may even be a plant-based doctor your area. Search the global directory at www.plantbaseddoctors.org.
1. Torres MJ et al. Food consumption and dietary intakes in 36,448 adults and their association with irritable bowel syndrome: Nutrient-Sante Study. Therap Adv Gastroenterol 2018
2. McDonald et al.American Gut: an Open Platform for Citizen Science Microbiome Research MSystems 2018
3. Dinu M, et al. Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies. Crit Rev Food Sci Nutr. 2017
4. Barbalho et al. Inflammatory bowel disease: can omega-3 fatty acids rally help? Ann Gastroenterol 2016.
5. Burkitt D. Some diseases characteristic of modern Western civilization. BMJ 1973.
6. David LA, et al. Diet rapidly and reproducibly alters the gut microbiome. Nature 2014
7. O'Keefe, SJ et al. Fat, fibre and cancer risk in African Americans and rural Africans. Nat Commun 2015
8. Rietman et al. Association between dietary factors and markers of NAFLD in a general Dutch adult population. European Journal of Clinical Nutrition. 2018