Siamese cats, like all cats, have specific nutritional requirements to maintain their health. While a balanced and complete diet can provide most of the nutrients they need, sometimes additional supplements can be beneficial. Here are some vitamins and supplements that can be given to Siamese cats:

1. Vitamin B Complex: This group of vitamins is essential for cats and helps support healthy skin, coat, and nervous system.
2. Vitamin E: This antioxidant helps support a healthy immune system and promotes healthy skin and coat.
3. Omega-3 fatty acids: Omega-3 fatty acids can help reduce inflammation and promote healthy skin and coat.
4. Taurine: Taurine is an amino acid that is essential for cats and helps support healthy vision and heart function.
5. Glucosamine: Glucosamine can help support joint health and mobility, especially for older cats.
6. Probiotics: Probiotics help maintain a healthy balance of gut bacteria and can support digestive health.
7. Multivitamins: A multivitamin supplement can help ensure that your cat is getting all of the vitamins and minerals they need, especially if they have a picky appetite.

It’s important to remember that not all supplements are created equal and it’s best to consult with a veterinarian before starting your cat on any new supplement regimen. Over-supplementation can be harmful to cats, so it’s important to follow the recommended dosages and use high-quality products. In addition, some supplements may interact with other medications your cat is taking, so it’s important to discuss your plans with your vet.

In general, it’s best to provide vitamins and supplements as part of a balanced and complete diet, rather than relying on them as the sole source of nutrition. A healthy diet and regular veterinary check-ups are the most important components of maintaining your cat’s health.