I'm vegan so I know the difference. The Adventists are often cited in nutrition studies and the vegan subgroup of Adventists is the healthiest.
Quoting directly from the link I provided:
If you think the Mediterranean diet looks a little low on dairy foods, you're right. It's certainly lower in dairy than is currently advised in the National Dietary Guidelines
...But traditional Greek Mediterranean populations got calcium from other sources: sardines and other small fish which were eaten with their bones, and from leafy greens (which contain only a little calcium but the large volume of the greens eaten meant the amount added up).