I remember as a child getting a strange feeling in my stomach after running long and hard, sort of like hunger pangs, but apparently something having to do with lack of oxygen. Now I have that feeling to a small extent most of the day. It feels almost like there is an acid build up.
It seems many if not most cases of PD begin in the gut and stomach where 500 million neurons make up the enteric nervous system. Other cases start in the nose and heart. The Lewy-bodies caused by a-syn misfolding travel up to the brain over the course of years. These neurons are only 0.5% of your total neurons, but they produce 50% of the dopamine. But it seems the ghrelin they produce is more relevant to PD. PD patients produce less of it which causes PD to worsen more quickly and worsen anxiety, depression, memory, and lack of sleep. It also increases dopamine in the SN and protects the SN from future damage. Prolonged fasting produces more ghrelin and calorie restriction has been shown to slow PD progression. Marijuana increases ghrelin which might be why it often causes hunger and sleep. Not giving in to that crave will repair damaged neurons and slow PD progression. Green tea extract also increases it. Chin-shin oolong tea is a special tea that a researcher noticed had similar effects as ghrelin as it is reputed to relieve constipation and something else I can't remember. So they tested it and it has a ghrelin-like compound that appears to activate the needed receptor, so it might work as well, so I spent the $64 on amazon to get 10 oz. It does not decrease as much if you consume fats instead of proteins or carbs. It appears that you could take it orally (if you can find it). More likely to be easily available (since ghrelin is natural and therefore not patentable) are similar synthetic compounds that are more likely to not work right and be toxic.
"As ghrelin circulates naturally, it is possible to pharmacologically increase the plasma concentration with minimal adverse effects. Patients who have been diagnosed with PD already exhibit reduced levels of circulating ghrelin as well as a reduced postprandial ghrelin response [Unger et al. 2011]. Ghrelin may also help to minimize nonmotor effects of PD such as gastrointestinal dysfunction, weight loss and depression, as well as learning and memory deficits [Diano et al. 2006; Edwards et al. 1992; Starkstein et al. 1991]. Nearly all patients diagnosed with PD suffer from selective cognitive impairments, including problems with attention, concentration and memory [Zgaljardic et al. 2004] and studies have shown that ghrelin enhances both learning and memory via an increase in synaptic plasticity in the hippocampus [Diano et al. 2006]. To date, ghrelin agonists have been successful for the treatment of cachexia to increase food intake and decrease energy expenditure in cancer patients [Neary et al. 2004]. These studies indicate that the ghrelin system is a potential therapeutic target to reduce multiple nonmotor symptoms of PD, as well as playing an active role in reducing further neurodegeneration."
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Peripheral neuropathy : numbness, tingling, discomfort. What should I do? 
Have you heard of this doctor?
what do you do when you’re “off”
