Before we condemn vegan lida daidaihua slimming capsule diets, there are more things to consider. Apart from liver illnesses and poor digestive absorption, there are other factors which can cause B12 deficiency:
Contraceptives/Birth Control Pills
Antibiotics
Intoxicants (coffee, cigarettes, alcohol etc)
Stress (mental and physical)
Chronic illnesses
Can you see that 3X slimming capsule deficiency problems are not restricted to vegans only? Basically, anyone with an imbalanced lifestyle/diet can be at risk.
How - Solutions
The easiest way, and probably most used method is to take B12 supplements.
I personally do not take B12 supplements, but there is nothing wrong with adding a B12 supplement into a strict vegan diet, just to play safe.
A helpful note would be to know that B12 mal-absorption is mostly caused by gastric juices losing a mucoprotein enzyme (which makes B12 absorption efficient).