https://pubmed.ncbi.nlm.nih.gov/8882373/

“Fermentation increased potassium (11.6 percent), soluble fiber (18.9 percent), and some amino acids but decreased fatty acids (linoleic: 13.5 percent; linolenic: 19.9 percent), soluble sugar (75.2 percent) and vitamin (riboflavin: 41.0 percent; niacin: 24.5 percent) contents in common beans.”

I ferment mine with a 2% salt brine like you would a sauerkraut or pickle. I have never had any gas or bloating from them.