Can Everyone Be Vegan? 13 Medical Conditions That May Prevent It

This is a huge frustration for ethical vegans: You’re trying to convince someone to go vegan… when they say they “can’t” for health reasons. It shuts down the conversation because you honestly don’t have the knowledge to refute it. But are these health claims legit?

No medical condition is known to absolutely prevent being vegan. However, conditions like herpes, kidney failure, food allergies, irritable bowel syndrome, and anemia may make it much harder to be vegan. In some cases, it may be unsafe for those with autism or eating disorders to be vegan, too.

There are several more “borderline” or “possible” conditions to mention, too. But all of these are nuanced topics. The details can vary, and they’re disputed in many cases. So please find the full explanations for each condition below!

Can Medical Conditions Prevent Being Vegan?

Can everyone go vegan? Here’s the conclusion reached by Ginny Messina, who is a registered dietitian (RD), author, and leading health authority in the vegan movement:

“With the exception of those who have extensive intolerances to numerous plant foods—leaving them with few plant food choices—I believe a vegan diet is a safe option for everyone. But, I can’t know that for an absolute fact because it’s something that is impossible to prove.”

– Ginny Messina, MPH, RD, in “Do Some People Need to Eat Meat?“

After researching this for quite a while myself, there are two points I’d emphasize. I think both are important to recognize to cover the subject honestly:

• 1. When someone says they “can’t” be vegan, it’s probably not 100% true. There’s nothing so unique about meat, dairy, or eggs that you can’t possibly get the same components from plants and supplements. There are many kinds of vegan diets, and you can combine “vegan” with mostly any other restriction that needs to be observed.

• 2. But some conditions make it much, much harder to be vegan. In some cases, the process of finding a specific vegan diet that “works” with a condition may take months or years of painful trial and error. The diet which results may also be so restrictive that it fails to meet some nutrient needs long-term or compliance becomes an issue.

The more diet restrictions you “stack” on top of each other, the fewer foods remain. And variety matters for a health diet. So you don’t want to be stuck eating the same 3 foods every day.

Some people also have social or material challenges that further “stack” difficulty onto being vegan in their situation. If you live in a food desert, for example, it may be harder to be a healthy vegan.

That said, many people who say they “can’t be vegan” don’t actually have restrictions that severe. And doctors who tell people they “can’t be vegan” aren’t always right, either. As I’ll cover below, most doctors receive shockingly little nutrition education in medical school.

But let’s get into the specific medical conditions a bit first.

Side Note: This is the best free video introduction I’ve found on adopting a plant-based diet—the right way. You’ll learn how to lower your risk of cancer, heart disease, type-2 diabetes, Alzheimer’s, and obesity—all with plants. Watch the free Masterclass here.

13 Conditions That May Make It Harder to Be Vegan

The following conditions do not necessarily prevent being vegan. But in most cases, they make it considerably harder and more complicated. In a few cases, a vegan diet may actually be totally okay or even preferable—but medical opinions vary, so I’ll explain that.

These were the conditions I saw being mentioned most often and by the more credible sources. But many other conditions may make veganism harder, too.

1. Herpes

Common advice for people with herpes is to eat foods high in lysine and low in arginine. Eating that way may limits outbreaks. But a vegan diet is naturally low in lysine and high in arginine—the opposite of what you want, as someone with herpes!

You can potentially still be vegan with herpes. Here’s an account from a committed ethical vegan with herpes. That person found that limiting arginine intake and supplementing with lysine daily helped a lot.

This Healthline post has a list of plant foods with a good lysine-to-arginine ratio for people with herpes, too. But a herpes diet and a vegan diet are not the easiest to mesh.

The dietitian Jack Norris wrote more about this issue here. He then posted a follow-up comment from another long-term vegan with herpes here.

2. Kidney Failure

With early kidney disease, a plant-based diet has actually been shown to be really helpful for some. But if you’re on dialysis, some of the dietary requirements can become trickier to fit with a vegan diet.

You often need your protein intake high to replace what’s lost from dialysis. You also need to keep your phosphorous and potassium lower. Many plant sources of protein, like beans and nuts, have too much phosphorous and potassium to be emphasized. And you have to watch sodium, too. (source)

You should still be able to do it with the help of the right dietitian and nephrologist. Phosphorous binders can be used to allow a bit higher phosphorous intake. And specific foods can be emphasized or cut.

In fact, there is limited data showing benefits from dialysis patients following a plant-based diet: lower blood pressure, better insulin sensitivity, higher antioxidant levels, and less protein loss in the urine. But diet planning comes with challenges.

Check out this page, this page, and this book for more about plant-based diets and kidney disease.

3. Allergies and Intolerances

This is a bit of an umbrella item. You could have all kinds of food allergies, intolerances, or sensitivities that could make it harder to be vegan.

Let’s look at a few common ones:

• Soy allergy: You can do well on a soy-free vegan diet, but a lot of plant protein sources like tofu, tempeh, and textured vegetable protein (TVP) are off-limits. Plus a lot of processed foods contain soy. So the restrictions can add up. See my posts on soy-free vegan burgers and soy-free vegan cheese for compliant options.

• Celiac Disease, Wheat Allergy, or Gluten Intolerance. If you need to avoid all wheat and gluten, that’s another big restriction. There are situations where the only gluten-free option isn’t vegan, and the only vegan option isn’t gluten-free. But still, it can be done. This post has some helpful tips for eating out as a gluten-free vegan.

• Tree Nut or Peanut Allergy. A nut allergy doesn’t just force you to cut out nuts themselves, but also almond milk, cashew cheese, and all those vegan snacks and cereals that include nuts, too. It can definitely be done, but it’s harder than a vegan diet without this restriction. See PETA’s guide to being a nut-free or peanut-free vegan.

• Fructose Malabsorption. This is kinda like lactose intolerance, but for fructose. It can lead to digestive issues like diarrhea and bloating after fructose consumption. Fructose is found in fruit, as well as many processed vegan foods. So this could add a layer of complexity to your vegan diet, for sure. Read this article for more info.

• Hereditary Fructose Intolerance. This is a more severe, rare kind of fructose intolerance. It’s genetic and often discovered as babies are weaned from breast milk. If it’s not identified, it can lead to organ failure and death. The list of allowed foods still contains vegan options, but there are some major restrictions.

There are many other allergens and intolerances, too, of course. In most cases, you can still be vegan. But if you have many intolerances, and if they’re for common foods like wheat, soy, and nuts… that’d be very restrictive, and adding veganism might kinda suck.

Here’s a helpful post on cooking vegan with allergies in general.

4. Anemia and Iron Absorption Issues

Some people, especially menstruating women, can find themselves with low iron stores on a vegan diet. A lot of the foods highest in iron are meats. Also the “heme iron” in meat is easier to absorb than the “non-heme” iron in plants.

Still, most people can fix their iron issues and stay vegan. First, you can eat more high-iron plant foods, especially legumes like beans, peas, lentils, and peanuts. Second, you can add high vitamin C foods to the same meals to aid iron absorption. (source)

Another kind of anemia—megaloblastic anemia—is not based on iron deficiency but on vitamin B12 deficiency. I’ll cover B12 issues below.

But even if you’re diagnosed as currently anemic, you can typically still stay vegan (or go vegan) with the right awareness of nutrients and supplementation. This article from Bustle includes tips from multiple dietitians on the specific steps to take.

5. Irritable Bowel Syndrome (IBS)

IBS is a term used to describe a cluster of digestive symptoms like diarrhea, constipation, gas, bloating, and abdominal pain. Treatment usually includes eating a “Low FODMAP” diet.

FODMAPs are specific types of fiber and carbs that ferment in your gut.

For example, beans generally have a ton of FODMAPs. Their fermentation is what gives many people gas after eating beans. But in IBS patients, this fermentation is more problematic.

So for IBS, you typically eat a Low FODMAP elimination diet first. Then you slowly add more FODMAPs back in, and you see which ones cause trouble for you. Then you avoid those foods long-term.

The problem for vegans is that many, many plant foods are high in FODMAPs. Aside from beans, there’s the fact that garlic and onions often must be completely avoided. Many other veggies, fruits, and grains are also problematic. (source)

But there are successful vegans with IBS. In fact, you can find whole websites like IBSvegan.com, and cookbooks like this one: “Low-FODMAP and Vegan: What to Eat When You Can’t Eat Anything.” So it can be done if you’re committed.

For more tips on IBS and plant-based diets, check out this interview with Kate Scarlata, a dietitian who is an expert on IBS.

6. Inflammatory Bowel Disease (IBD)

Often confused with IBS, inflammatory bowl disease (IBD) can be much more serious. But many of the symptoms are the same: diarrhea, constipation, gas, etc.

There are two specific kinds of IBD: Crohn’s Disease and Ulcerative Colitis.

Various diets have been recommended for IBD. Some of these—like the Low-FODMAP diet or the “Specific Carbohydrate Diet“—can be challenging on a vegan diet.

However, in the scientific literature, more evidence is stacking up to suggest that a plant-based diet (not necessarily fully vegan) can potentially be very beneficial for IBD, too. Plant-based diets have shown great remission rates for Crohn’s Disease, for example.

That said, this woman has Crohn’s Disease, tried a vegan diet, and deemed it worse for her. She says most healthy vegan foods are too high in fiber for her, and the raw foods upset her gut. She also felt tired, probably from not eating enough.

One story I like to mention is Andrew Perlot. He suffered from bad colitis on a plant-based diet that emphasized fibrous veggies like broccoli and grains… But then he switched to a more fruit-based raw vegan diet, and things cleared up entirely.

So, results may vary. My takeaway is that diet often has a big impact in IBD, and it seems like the exact triggers can vary. So while some researchers do recommend plant-based diets for IBD, that doesn’t mean a vegan diet will go well for all IBD patients.

7. Migraines

Many people who get migraines have “trigger foods” they try to avoid.

Most of these common trigger foods are meats, cheeses, and processed food. But some people also struggle with nuts, seeds, citrus fruit, bread, and even beans. (source)

So depending on your individual trigger foods, it could be harder to be vegan. But that doesn’t mean you “can’t be vegan” if you get migraines.

In fact, the National Headache Foundation found a balanced vegan diet can actually help with chronic migraines.

And the Physicians Committee for Responsible Medicine (PCRM) did a study that put migraine sufferers on a low-fat vegan diet and saw improvements.

There are also resources like PCRM’s “Plant-Based Migraine Diet.” They give caution about nuts, wheat, tomatoes, corn, onions, and some fruits… but they’ve marked other veggies, fruits, and grains to be safe.

If your triggers include nuts, beans, wheat, and corn, then that’d be a big restriction on a plant-based diet. But most people with migraines can still be vegan.

For more on headaches and a vegan diet, see my post on “Vegan Headache: Possible Causes and Cures.”

8. Eating Disorders

Some authorities worry that a vegan diet might not be safe while recovering from an eating disorder like anorexia. Why? A restrictive diet like veganism can potentially be an invitation or cover to keep restricting in an unhealthy way. (source)

For some people, this may be a legitimate concern. It makes sense that a mind obsessed with being thin would devise new ways to restrict food. It also makes sense that you could be “triggered” into old behaviors.

Another concern is that a vegan diet can make it harder to regain weight after becoming too skinny. (source)

But others have said going vegan was a key part of their successful eating disorder recovery. So it varies person to person.

Some people believe strict health eating itself is an eating disorder called “orthorexia nervosa.” But the use of this term “orthorexia” is in dispute. I personally ranted about it in my post, “No, Veganism Is Not an Eating Disorder.”

Still, a vegan diet can be a problem for some people while recovering from an eating disorder. This blog post offers some questions to ask yourself about your motivations for going vegan after an E.D. and whether it may be a good idea for you.

9. Akylosing Spondylitis

Ankylosing spondylitis (AS) is a type of inflammatory arthritis where the vertebrae in your back fuse together. You develop a hunched-forward posture over time. Many people with AS follow specific diet recommendations to help with the condition.

One of the common suggestions for people with AS is a low-starch diet. Some research suggests that it may help by starving the problematic Klebsiella bacteria in the gut, as well as decreasing inflammation.

But starches like grains, potatoes, and beans are usually the biggest source of calories for vegans. You can still eat fruits, veggies, nuts, seeds, and oils on a low-starch diet… But your options are cut way down from a normal vegan diet.

If you wanted to go the low-starch vegan way, this woman actually says a raw vegan diet actually cured her of AS… And her disease had progressed to the