I don't think it's abnormal, but I would have vet check out your cat's teeth b/c bad teeth can cause other health problems.
Is it normal that a cat lose his teeth when he gets older?
How old is older? If we're talking an 18 year old cat, it is not unusual. But tooth loss is not inevitable, either.
However, many cats do suffer from dental problems. and as the other answer said that can be bad not only for dental health. Dental infection can get into the blood and affect the cat's health in other ways.
If your cat has not had a dental prophylaxis recently (or ever), you should get that done. The vet will use anaesthesia so he/she can check and clean the cat's teeth, and extract any if they are rotten. Unless your cat is in very weak health, it is best to have it done ASAP to stop any problems from getting worse.
Reply:Uh, a cat can't be 18 years old...
7 yr old cat is very old.
It isn't abnormal between 9-12 years of life, but take it to a vet.