How to convince my wife's family to take B-12 supplements?

Sorry don't know.

Try googling this - 素食者B12 - or this - 嚴格素 B12

EDIT: Found this

http://cht.naturalnews.com/chtbuzz_buzz001033.html

You might check out the jacknorrisRD.com site or veganhealth.org. He's a vegan registered dietitian, but some of his articles have been translated into various languages. Or email him. He has a lot of contacts in the vegan world. He might be able to help you.

It seems like he has some research showing that vegan immigrants from other countries are more likely to develop b12 deficiencies. In many cases, apparently the more sanitary food and living conditions here in the US was a problem.

they don't need them. Mainstream health authorities recommend it as a precaution, but there are known risks of supplementing. Vitamin B12 is naturally-occurring in a range of foods - miso soup, fermented foods, almonds, organic produce, organic nuts, nutritional yeast, mushrooms, seaweeds of various kinds etc. I know they talk a fair bit about deactivated B12, but the reality is the foods also contain active B12 microbes. As long as they're not eating a lot of meat, eggs and dairy and not too much artificial sweetners the B12 microbes in their appendix's should be thriving anyway. Meateaters over 50 are far more likely to be deficient of B12 than vegans not supplementing, however instead of being tested and diagnosed they are instead diagnosed with dementia.

http://www.all-creatures.org/health/mcdougall-b12....

http://www.scribd.com/doc/76457405/CONFIRMED-YES-V...

http://www.ncbi.nlm.nih.gov/pubmed/667007

Have they been diagnosed as deficient in B12? It can take up to 30 years to become lacking in it. And since lots of foods are fortified, then it's not really a big problem.

You can get b12 from cereal and gatorade. Not that big of a deal.