Question about homecooking

Brodi isn't getting any better with his poop problem and seems like he only has normal poops when on boiled chicken and rice. I have decided to start home cooking and if everything goes okay eventually switch him to raw cause dog food doesn't seem to agree with him. I'm trying a recipie from BML's website but I have no idea where to purchase nutritional (tortula) yeast , lecithin granules , kelp powder and bone meal??  Also I have read that he needs Vit C but also read ascorbic acid, sodium ascorbate, calcium ascorbate or ascorbal palmitate) can cause damage to the liver and kidneys?? Help! I'm so confused lol