Slowing the progression?

My mum has had Parkinsons for 18 years. Having lived through that, I have a potential taste of the future. I am not diagnosed but have seen a Neurologist as I suspect some of my symptoms could be related. Next appointment is in November.

I just am interested to know your theories (however alternative they may be), on slowing the decline.

I know that diet and exercise are important in trying to stay healthy and fit. I am 50. I swim, like to walk and have just started taking vitamin D.

Do you take supplements? I know that there are connections between Parkinsons and the gut. Would love to hear all your wild and wonderful theories. Thank you