Substantial amounts of vitamin B12 were found in some edible algae (green and purple lavers, seaweed) and chlorella tablets. A study suggest that algal vitamin B12 is a bioavailable source for mammals.
Pseudovitamin B12 (an inactive corrinoid) predominated in the spirulina tablets, which are not suitable for use as a vitamin B12 source, especially for vegetarians.
A plant-based diet is a diet of any animal (including humans) based on foods derived from plants, including vegetables, whole grains, legumes and fruits, but with few or no animal products.
"Plant-based diet" has been used to refer to the following diets:
- Vegan diet - no food from animal sources.
- Fruitarian - consists primarily of fruit.
- Raw vegan - food is uncooked and sometimes dehydrated.
- Vegetarian - plant foods, may include eggs and dairy, but no meat.
- Ovo-lacto vegetarian - includes dairy and eggs.
- Ovo vegetarian - includes eggs but no dairy.
- Lacto vegetarian - includes dairy but no eggs.
- Pescatarian - diet with eggs, dairy and seafood.
- Semi-vegetarian - with occasional inclusion of meat.