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Transitioning to vegan. Brain not working so well!

64 replies

Kind2027 · 04/11/2026 13:28

Hi,

New (almost) vegan here. Currently eating around 90% vegan for the last 2 months (pretty much did this over night). Over the last 2 weeks or so, I feel like my brain isn't working like it was before. I feel like I'm turning a bit "thick" for want of a better explanation & am struggling to focus a bit too. Struggling to process information as well & I've noticed my general awareness of what's going on around me isn't as good.

Has anyone else suffered from this? Any ideas what else I could do please? Or any idea of causes of this kind of brain fog?

I've been taking a cheap OTC multi-vit from ASDA which has b12, iron etc in it & have been pretty good at taking vit c with iron rich foods etc to maximise absorption. I am a male (hope it's ok to post on here)! I've also been having quite a bit of calcium & b12 enriched foods.

Any ideas what else I could do please? Or any idea of causes of this kind of brain fog?

I don't want this to affect my family so am still eating occasional animal products when they have cooked as I don't want them to have to bend to my requirements.

A bit of background:

I've just woken up to the cruelty & extreme suffering to animals in the food & dairy industries & am now trying to go vegan because of this. I love animals & am a very compassionate person & when I've come to realise the hidden realities of what actually happens within the industries to produce eggs, milk & meat, it has made me feel really strongly that it's something I need to move away from. I feel like I've woken up to a nightmarish horror film which is sadly real.

Thank you so much :)

OP posts:
Userregs · 04/11/2026 13:40

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BadTempeh · 04/11/2026 13:46

Well done on trying to be vegan! 🌱

I didn’t notice any negative differences, only positive and I’ve been vegan for a very long time.

What are you eating in a day? Have you checked you are getting enough calories, protein, iron? Are you taking a vegan source of omega 3?

Yesitsweird · 04/11/2026 13:51

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Hoppinggreen · 04/11/2026 13:55

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I am not Vegan (DD is ) and even I know that this is utter nonsense
DD has been veggie for years and DH is too, I do eat some meat but not regularly. The transition for her to be Veggie has been tricky and to be honest a bit limiting for us as a family but its important to her and I support it 100%
She has never been healthier as well and seems as sharp as ever. I think you might need to speak to your GP OP

MagicTape · 04/11/2026 13:56

It is extraordinarily unlikely that by being not-quite-vegan for a period of two months you are experiencing any sort of dietary deficiencies. Even if you had gone fully vegan, done it badly, and lived on nothing but fries and Oreos for eight weeks, you still haven't really had time to develop anything sinister. If you're experiencing concerning symptoms then go to the GP - it could be a pre-existing issue.

Minasama · 04/11/2026 13:56

Omega 3s like fish oil are important for brain health, is there a vegan version you can try?

Kind2027 · 04/11/2026 14:01

Wow, thank you for all your responses so far, I'm amazed & touched by how many of you have reached out 🙏

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Kind2027 · 04/11/2026 14:02

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I've not lost any weight & have worked really hard to make sure I'm getting enough protein, iron etc & pairing iron rich foods with vit c to increase absorption etc

OP posts:
BadTempeh · 04/11/2026 14:02

MagicTape · 04/11/2026 13:56

It is extraordinarily unlikely that by being not-quite-vegan for a period of two months you are experiencing any sort of dietary deficiencies. Even if you had gone fully vegan, done it badly, and lived on nothing but fries and Oreos for eight weeks, you still haven't really had time to develop anything sinister. If you're experiencing concerning symptoms then go to the GP - it could be a pre-existing issue.

Yes, good point. It doesn’t say much for a diet of meat and other animal products, if a couple of months of reducing those things, not even giving them up fully, leaves a person unable to think.

Userregs · 04/11/2026 14:04

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BadTempeh · 04/11/2026 14:04

Also, please remember this is the vegan board, not a place for pushing an animal based diet, even a ‘kind’ one…. lol.

BadTempeh · 04/11/2026 14:08

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I’ve been vegan for over 20 years and feel great. Any diet can be lacking.

Anyway, this is the VEGAN BOARD! Do we have to get mumsnet to do a reminder again. 🙄

Kind2027 · 04/11/2026 14:12

BadTempeh · 04/11/2026 13:46

Well done on trying to be vegan! 🌱

I didn’t notice any negative differences, only positive and I’ve been vegan for a very long time.

What are you eating in a day? Have you checked you are getting enough calories, protein, iron? Are you taking a vegan source of omega 3?

Breakfast is usually weetabix or shredded wheat with dried fruits & walnuts or pecans/other nuts. Having plenish almond or coconut milks generally. Sourdough toast with nuts/seeds with marmite/peanut butter etc, also often have fresh fruit too.

Lunch could be pasta, rice, stir frys, baked potatoes or tofu based dishes. Eating the rainbow of veggies, lots of mushrooms, making pasta sauces from lots of veg & cashews blended then put over the pasta etc. Sandwiches with the occasional bit of tuna. Soups with vegan cheese on toast....quite varied.

Dinner - bean casseroles or stews/curries. Occasional meat based bolognese/pasta dish where my wife cooks.

I rarely eat ready meals & most of what we eat is non-upf/whole foods cooked from scratch. I'd say I get a pretty well balanced diet (apart from suddenly cutting out meat & dairy that is😂)

OP posts:
Kind2027 · 04/11/2026 14:14

BadTempeh · 04/11/2026 13:46

Well done on trying to be vegan! 🌱

I didn’t notice any negative differences, only positive and I’ve been vegan for a very long time.

What are you eating in a day? Have you checked you are getting enough calories, protein, iron? Are you taking a vegan source of omega 3?

Not taking omega 3 supp yet but just ordered veg 1 from vegan society

OP posts:
Kind2027 · 04/11/2026 14:15

Kind2027 · 04/11/2026 14:14

Not taking omega 3 supp yet but just ordered veg 1 from vegan society

looks like will need omega 3 supp too as vit 1 doesn't contain this

do you have any better recommendations of supplements?

OP posts:
Noodge · 04/11/2026 14:18

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Where do you get this nonsense from?

If you do some (proper) research (as in not just googling with biased search terms) you will see that It's nonsense. 26 years vegan here, competitive bodybuilder, 44 years old, brain is more than fine and I could probably bench press everyone on this thread.

OP are you eating enough, period? That would be my first thing to look at. Other than that has anyting else gone on in your life to cause brain fog? Anything hormonal, any urine infections or stress etc?

Yesitsweird · 04/11/2026 14:20

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Ponderingwindow · 04/11/2026 14:20

It was nonstop headaches for me. I was focusing on a nutritious, protein rich diet, but I could not make the headaches stop. I tried and failed multiple times to go vegan. Then I tried just vegetarian. Always the unrelenting headaches.

BadTempeh · 04/11/2026 14:23

Kind2027 · 04/11/2026 14:14

Not taking omega 3 supp yet but just ordered veg 1 from vegan society

Good. You can just increase things like nuts and seeds but it’s not always converted well in your body. I actually had a test and my levels were fine from food but some peoples aren’t.

Things I eat regularly are tofu, tempeh, beans, lentils, nuts, seeds, nut butters, rice, quinoa, soya yogurts, oat and soya milk, obviously lots of fruit and veg, add nutritional yeast to meals.

I’ve actually taken part in a couple of studies of vegan diets over the years and have never been deficient in anything. Any diet can be bad!

HorseandHeron · 04/11/2026 14:26

Have you looked up how to create really good protein combinations? I remember years ago reading that peanut butter on proper wholemeal bread work together to make a protein almost equivalent to red meat.

Berries, leafy green veg and nuts and seeds are all good for combatting brain fog. I'd go for blurberry porridge with seeds and chopped walnuts in the morning, roast kale or steamed broccoli with sesame seeds as a veg at dinner and maybe humous topped with dukkah (spicy seed mix) at lunch time. Do that several times a week and see if there's any improvement.

As PP have said, if you are happy to occasionally eat eggs, you could get them from a free range local farm. A life-long vegan friend said she had issues which vanished when she agreed to her GP's recommendation of eating fish once or twice a week.

HorseandHeron · 04/11/2026 14:26

Ponderingwindow · 04/11/2026 14:20

It was nonstop headaches for me. I was focusing on a nutritious, protein rich diet, but I could not make the headaches stop. I tried and failed multiple times to go vegan. Then I tried just vegetarian. Always the unrelenting headaches.

What caused them? Did you ever find out?

Happylife32 · 04/11/2026 14:27

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Kind2027 · 04/11/2026 14:28

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I appreciate your thoughts & am a huge fan of open discussion so thank you :)

I'd completely agree with you that you have to work harder/become more nutrition aware to get the right nutrition as a vegan as we do live in a world where (due to a variety of factors) animal products are everywhere & so ingrained into our societies/diets.

The idea of having our own chickens for eggs is a nice one but a lot of work & a big tie & also does rely on getting female hens which have come from an industry that is horrifyingly cruel to the male babies.

For me even if an animal has lived a good free range life, the fear, cruelty & methods of how it is killed are unjustified especially that we have veganism as a viable option now. I didn't always feel that way but after doing some digging below the glossy surface, I've discovered an unimaginable level of cruelty towards animals that I wasn't aware of before. I thought I knew where my food was coming from but turns out I had no clue.

OP posts:
BadTempeh · 04/11/2026 14:29

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I’ve never had to supplement iron or vitamin d. If you eat well, absorb normally and spend time outdoors, you won’t need to.

Meat eaters used to get a lot more b12 from animal products because animals spent more time outside in the soil. Now, not so much with modern indoor farming. The animals are often given b12 vitamins now in their food, personally I’d rather take it myself than eat it via an animal being given it artificially in their diet anyway.

People also used to get more b12 when they weren’t so clean and scared of a bit of mud on a potato. Now they’re scrubbed clean.

Another reminder, it’s the vegan board. 😉

Noodge · 04/11/2026 14:29

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You don't.

B12 is to be monitored. I haven't taken it for a while as my levels are always fine when tested. Do you know the history of WHY B12 isn't available in plants? Research it.

The animals you eat are fed or injected with supplements of B12. It does not exist naturally in their food thus in them, either. I am not going to eat an animal to get B12 that the animal has been injected with, when I can just take the B12 myself. The rest of the nutrients you mention are readily available in plant-based sources. To be clear, so is B12 ifyou eat products fortified with it.Just like the Bovines/porcines you eat are.

What is the benefit of eating a fortified cow, over drinking a fortified drink, using fortified liquid on one's cereal, or taking a supplement? Unless you enjoy paying to torture those without a voice, I fail to see one.

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