Healthy Powder for Cats 
2 cups brewer's or nutritional yeast 
1 cup lecithin granules 
1/4 cup kelp powder 
1/4 teaspoon ascorbate powder, vitamin C crystals or a 1,000mg tablet, crushed 
1 to 4 teaspoons unsalted garlic powder (optional)

Mix all ingredients together in a container. Cover and refrigerate. Add 1 to 2 teaspoons to commercial cat food, daily.

*To make eggshell powder, wash eggshells out right after cracking the egg. Bake in a 300° (F) oven for about 10 minutes to remove mineral oil coating and make them dry and brittle. Grind them in to a fine powder using a blender, a nut and seed grinder, or a mortar and pestle.  Grind well enough so that there are no sharp, gritty pieces. One whole eggshell makes about 1 teaspoon  of powder.

From Rodale's Book of Practical Formulas

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