Comment by hilbert42

"Folate is an essential water-soluble B vitamin found in foods, including dark-green leafy vegetables and legumes."

The above quote from that Springer reference reminds me of plant toxins in common foods especially in dark-green leafy ones, spinach, rhubarb, etc. Oxalic acid is one of the main ones but there are many others.

If you worry about what you eat you ought to be concerned about these. It's understandable that these toxins exist in these plants as they use them as protection against insects etc. Incidentally, I use oxalic acid industrially and I'm very careful how I handle it.