Does anyone have any experience with this? Especially middle-aged onset with weight loss or a change in diet?

I first noticed this winter that my boots weren't keeping my toes as warm as they had in the past. Then in the last couple of weeks I've had several instances of my hands being cold, fingertips turning white and going numb. I recognized Reynaud's symptoms right away because the teenaged daughter of a friend of mine has it.

Reading about it on the web has me a little freaked out. Low potassium, magnesium, vitamin D, omega-3 and low carbs have all been implicated, but apparently it can also be the first symptom for a number of serious autoimmune diseases. My daily carb intake is 100-150g so it's not like I'm VLC. I suppose other nutrients could be off. I haven't had my thyroid tested in about 5 yrs, but I've had pretty good success with weight loss and my energy levels are the best they've been in at least 10 yrs.