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.
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.
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.
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.
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 point where she couldn’t even walk.
But is a low-starch diet really a necessity for AS patients? The Spondylitis Association of America doesn’t even mention it in their guide to diet and spondylitis.
And most of the diet recommendations for AS are ultimately based on reducing inflammation. Healthy plant-based diets have been shown to be great for reducing inflammation. There’s even data showing plant-based diets help with other kinds of arthritis.
So once again, it’s not that you can’t or definitely shouldn’t be vegan with AS. But it may be more complicated than going vegan for the average person.
Many people with Autism Spectrum Disorder (ASD) have strong emotional associations with food.
They may have intense preferences for food flavor, texture, smell, color, and even the type of plate used. (source)
Some people with autism only eat a small range of “safe foods.” For some, their diets may exclude fruits and vegetables almost entirely.
One study found that the majority of autistic children prefer bland foods, including processed chicken and grain products. Some reject “smooth” foods like mashed potatoes, while others reject “lumpy” dishes like oatmeal. (source)
The common aversion to vegetables is a shame, too, because certain veggies—especially broccoli—may hold significant benefit for children with autism.
Some sources actually recommend a dairy-free diet for autism. (Specifically, a gluten-free casein-free diet.) PETA has written about the possible link between autism and dairy products, too… But other sources say those claims are not well supported.
So a vegan diet might even help with autism by removing dairy… But if your range of “safe foods” is already small, then cutting it in half by going vegan could result in even more risk of a deficiency (and just a terribly small menu).
So it depends, and it’s complicated.
11. Burns and Injuries
These are temporary medical conditions, not life-long ones. But if you look up burn recovery diets, they need to be very high in protein and calories. And if you’re in a hospital, high-protein vegan options may be limited.
This CNN article tells the story of how Travis Barker, the vegan drummer from Blink 182, had severe burns after a plane crash. Barker had to eat a 6,000-calorie, high-protein diet during recovery.
In Barker’s case, he accepted the need to eat meat during this period, including “a lot of beef jerky.” He then resumed a vegan diet after leaving the hospital.
However, not everyone agrees that eating meat or dairy during recovery is necessary. That CNN article also cites Dr. Neal Barnard explaining how a plant-based diet can help reduce inflammation that can help with healing, too.
The documentary The Game Changers made claims about a vegan diet helping with injury recovery in athletes. All the antioxidants from the plant foods may aid in healing. But there are authorities who dispute these claims, too.
The takeaway? You may recover just fine from a burn or major injury as a vegan… but you’ll likely find that some authorities advise against it.
Especially in children with epilepsy, a ketogenic diet is sometimes prescribed.
And studies show about 50% of epilepsy patients see improvements from this very low-carb, high-fat diet. (source)
As I explained in my “Keto vs Vegan” post, the term “keto” has gotten distorted in popular usage. But it did originate as a medical diet, administered by clinicians—and epilepsy was its primary use case.
While it is possible to be vegan on a ketogenic diet, it’s very restrictive. A medical ketogenic diet requires keeping your carbs very low (lower than paleo and other “low-carb” diets). But vegan diets tend to be moderate or high in carbohydrates.
On keto, you can still eat green veggies, nuts, and seeds—but grains, beans, starches, and fruits are mostly off the menu. (Berries and some other low-sugar fruits may still be allowed in moderation.)
I’ve actually eaten a low-carb vegan diet myself because it seems to help with my acne. And it’s not easy. Social eating can be very difficult as a low-carb vegan.
Just think about it. Most of the “accidentally vegan” snacks, typical “vegan recipes,” and common “meatless products” are high in carbs. So you really have to plan ahead.
Vegan keto can be done—but I wouldn’t expect anyone to do it unless they’re truly committed to the ethics of veganism.
Side Note: If acne is something you struggle with, seriously, check out my big blog post on troubleshooting acne as a vegan. I have a ton to share about what I’ve learned over the years. I truly think I’ve made the best resource on the Internet for vegans with acne—and it’s right here.
13. Low Cholesterol
In the west today, high cholesterol is a drastically bigger problem than low cholesterol. But there are cases where low cholesterol may be an issue—including rare genetic disorders where your body doesn’t make enough functioning cholesterol on its own.
Some people are told to quit their vegan diet because their cholesterol levels are “too low.” This was part of the famous “eco-terrorist” Craig Rosebraugh’s story. He was vegan for years until he was “diagnosed with dangerously low cholesterol.”
This was also one of the reasons given by YouTuber Bonny Rebecca for why she quit being vegan. Her doctor said her cholesterol levels were too low.
There may be some rare conditions where this is a legitimate concern. But in most cases… probably not. As Mic the Vegan explains below, the data on low cholesterol and cancer risk was famously misinterpreted. And vegan hormone levels are shown to be healthy.
The most likely scenario, from what I can tell, is that vegans’ LDL cholesterol is just seen as crazy low compared to the norm—but it’s actually a good thing.
Even in cases where someone does have dangerously low cholesterol, that doesn’t necessarily mean dietary cholesterol from animal products would be needed. Eating more plant-based saturated fat from coconut oil or palm oil would also likely help.
A Few More Conditions (With Less Evidence)
I also found some talk of the following conditions not being ideal for a vegan diet. But the evidence was so thin or contradictory for these… I didn’t want to dedicate a full section to any of them:
- Dr. Amy Myers says lectins, phytates, and other “anti-nutrients” in many vegetarian foods led her to leaky gut that worsened her Graves Disease. Now she recommends eating meat for autoimmune thyroid diseases. However, some evidence tells a different story: Vegetarians have lower rates of hyperthyroidism. Indeed, some sources recommend a plant-based diet for Graves.
- Porphyria is a group of rare disorders where the hemoglobin in your red blood cells doesn’t work right. Some sources say high protein intake from meat is encouraged, while veganism is discouraged. But it’s hard to find good info on this. Other sources say a high-carb focus on raw foods is best. It may depend on the specific kind of porphyria.
- I’ve seen some people mention multiple sclerosis (MS)… but evidence for that seems to be completely lacking. If anything, a more plant-based diet may help with MS.
- Some mention autoimmune conditions like rheumatoid arthritis (RA). Jordan Peterson’s daughter Mikhaila famously cured hers with a ketogenic and then carnivorous diet. But there’s better evidence (from actual research) suggesting a plant-based diet for RA, too.
- If you have some kind of issue with zinc, vitamin D, B12, or omega-3 fat absorption, those could also be cases where a vegan diet may not be advised. But you could likely still fix the situation with supplements.
If Your Doctor Says You Can’t Be Vegan
I want to share a couple more things before closing.
But please don’t misunderstand what I’m about to say: I am not telling anyone to ignore the advice of their physician.
In the article “My Doctor Told Me I Can’t Be Vegan,” Neva Davis explains how as a child with a heart disorder (mitral valve prolapse), she was told by she must eat an egg and dairy products daily. She couldn’t be vegan.
She followed that advice for years. But eventually, after seeing her cousins die from their minor heart defects despite following doctors’ orders, she decided to just live life how she really wanted.
She took up a fully vegan diet, and she started running—another habit doctors advised against. And years later, doctors now say her heart defect has become so quiet, they can barely hear it.
The unfortunate truth today is that many doctors don’t known much about veganism and its benefits or risks. And it’s not necessarily their fault.
Medical schools in the U.S. only average 23.9 hours of nutrition training—with some offering almost none. Most people expect their doctors to know about nutrition. But a full 86% of internal medicine interns said they had insufficient training to counsel patients on nutrition. (source)
90% of cardiologists said their job requires providing nutrition information to patients… but 90% also received “little-to-no” nutrition training in their fellowship programs. (source)
Obviously, it’s dangerous to just ignore what your doctor tells you about nutrition. That’s not what I’m telling anyone to do. But what I’m saying is that, in many cases, it may be worth seeking a second opinion.
When a Vegan Diet Doesn’t Go Well…
Despite all my defense of vegan diets above, the fact is that some people do struggle with veganism. And it’s not always clear why.
I’ve heard many stories of ex-vegans who “immediately felt better” after eating eggs or fish again. In some cases, this could be a placebo effect. In other cases, there might be something to it.
As with any restrictive diet, a vegan diet can lead to deficiencies. The most well-known is vitamin B12. But iron, zinc, iodine, calcium, and other nutrients can sometimes cause issues, too.
I recommend following Dr. Michael Greger’s optimum nutrition recommendations for vegans. He recommends supplementing with vitamin B12, DHA/EPA (omega-3), and vitamin D3.
Personally, I get all three of those nutrients from the Future Kind Essential Vegan Multivitamin (read my review here).
If you’ve had trouble on a vegan diet and want to troubleshoot the situation, I recommend talking to a dietitian knowledgeable about vegan diets. More and more dietitians are familiar with it nowadays. You might also like my “Ex-Vegan’s Guide to Going Vegan Again.”
Two More Recommendations for Your Plant-Based Journey
1. This is the best free video training I’ve found on plant-based nutrition. You’ll learn how to reduce your risk of cancer, heart disease, type 2 diabetes, Alzheimer’s, and obesity—all with plant-based food. Watch the free “Food for Health Masterclass” here.
2. This is the best vegan multivitamin I’ve found in my 14 years of being vegan. It has vitamin B12, vitamin D, omega-3—and nothing else. Translation: It only has the nutrients vegans are actually low in. Read my full review of Future Kind’s multivitamin here (with 10% discount).