Natural cat health is all about looking to nature to provide the answers to your questions. Nature has perfected every aspect of health care. Wild cats are healthy and never suffer from the crippling diseases their domestic cousins do. They can suffer from a lack of food, from injuries and territorial squabbles, but debilitating disease is definitely not on nature's agenda.
With this firmly in mind, it indicates there are at least three possible areas that cause your cat's ill health.
diet
health care
environmental issues
One of the most effective and fastest ways to turn your cat's health around is to feed her a diet similar to that of her wild cousins. Now, you may not be interested in going out to catch mice, especially if you're out at work all day. But the diet doesn't have to be identical, just similar.
Take the essential points out, and compromise in other, less important areas. For example, a wild cats diet is essentially quality raw meat and bones. Mostly from animals their own size or smaller.
So by feeding your cat quality, human grade food from lamb, chicken and rabbit, you're not far off the mark. Even beef is OK as long as it's quality meat and raw.
However, the bones do need to be the small ones found in chicken necks or chicken wings. Bigger bones may chip their teeth.
Natural health care is all about keeping a strong immune system. This is not achieved by drugs and vaccines. This can only be achieved by good food and a happy, healthy environment.
Try to use only those modalities of health care which support your cat's immune system, rather than depress it. Homeopathy, probably one of the most effective and affordable health care systems, works by doing just that.
A healthy environment is essential to cat health, whether natural or not. This includes access to the sun, stimulating play, a happy household, a toxic free house and garden, ability to get away from the family when necessary and access to healthy water.