AIBU to want to discourage my son from making his children vegan

[Esspee]

My DS and DIL have gone vegan in the last year. They are very well informed so I kept quiet about my reservations.

Tonight on FaceTime my elder grandchild explained that the shadows under her sister's eyes are caused by lack of iron and said something about her bruising and mentioned seeing the doctor. I said nothing as I don't want to cause a family rift but my darling granddaughters seem to be suffering because of their parents following a fad.
What can/should I do?

Well, I disagree with the majority of the posters here and think a grandparent is obliged to be concerned if they think their grandchildren are not being properly looked after.

If children were being beaten or starved, would it be none of the grandparent's business?

As for veganism, it probably is possible to bring up healthy children on that diet, but I remember, back in the day, before veganism became popular, most vegetarian children in Ireland had shadows under their eyes. And I am well aware that vegetarian children can eat healthily. The child of a very good friend of mine was very healthy, but a lot of people don't seem to have much of a clue about nutrition.

User Just one example is switching to low fat foods to lose weight.

If children were being beaten or starved, would it be none of the grandparent's business?

Of course it would be, but that’s not what’s happening.

I've got dark circles under my eyes and I'm not vegan. Dark circles can be caused by many things, but you're very quick to blame a vegan diet

It's very difficult to get enough iron from non-meat source. I would also be very concerned about
B12 which only comes from animal sources and a deficiency can cause significant and irreversible damage (in worst cases). Menstruating women are particularly prone to iron deficiency as are young girls. When my niece recently decided to be one vegan I just made sure both she and her parents were aware of the risks and suggested she consider supplementing.
And then I have left them to it. She is apparently doing lots of research and as they are aware assume they are keeping a close eye.
All you can do is kindly give them the information and not criticise a perfectly reasonable life choice. There are lots of good environmental and animal welfare reasons for choosing veganism but personally I would supplement b12 and iron.

“Dark circles can be caused by many things, but you're very quick to blame a vegan diet”

The doctor told them it was because of lack of iron in her diet. She says so. In the OP.

Caused by a lack of iron not by a vegan diet. You can get iron from non-meat sources Scrubs

Yes, I know, but the vegan diet as fed to these children so far seems not to have given them enough iron.
No doubt, now suitably aware, the parents will make adjustments.

Presumably they were not short of iron before they changed their diet, or the dark circles would have been investigated then.

Maybe her eye bags and bruises are a separate medical issue ? I think the whole
World should go vegan though so am maybe a bit biased

I agree with everyone saying to get them some iron rich vegan treats and a kids vegan cook book . Show support in the right way

Most meat eating fat people are lacking in something and actually are the most malnutritioned.

OP you seem to be getting a bit of a bashing about this. I’m with you re your concern and personally I think it’s a load of old bollocks (come and get me y’all) BUT at the end of day they ain’t your kids and sadly, it ain’t really your business