I also vote for malabsorption. I have a similar experience to stannarads and I think there is a correlation between the digestive problems and the nail ridges. Andreas just informed me that all the good (read -expensive) fats I've been guzzling likely aren't being absorbed well because of insufficient bile, so it's time for me to do another liver flush. You might want to try a Liver Flush and/or bowel cleanse. Good luck!
Stannarad - Thank you so much for posting this!! I had chalked up my fingernail ridges to age, which is what I've always read. I do believe you're right though and I'm eager to see if my ridges go away once I get the digestive problems under control. Last year after vigorous cleansing they were gone but now they're back and so is the absorption problem. Coincidence? We shall see :)