Nutritionist and author Jonny Bowden has created several lists of healthful foods people should be eating but aren’t. But some of his favorites, like purslane, guava and goji berries, aren’t always available at regular grocery stores. I asked Dr. Bowden, author of “The 150 Healthiest Foods on Earth,” to update his list with some favorite foods that are easy to find but don’t always find their way into our shopping carts. Here’s his advice.