A deficiency of riboflavin can be primary - poor vitamin sources in one's daily diet - or secondary, which may be a result of conditions that affect absorption in the intestine, the body not being able to use the vitamin, or an increase in the excretion of the vitamin from the body.
Substantial evidence means more than a mere scintilla. It means such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.. Richardson v. Perales, 402 U.S. 389, 401 (1971).
Admissible Evidence. Evidence that is formally presented before the trier of fact (i.e., the judge or jury) to consider in deciding the case. The trial court judge determines whether or not the evidence may be proffered. To be admissible in court, the evidence must be relevant (i.e., material and having probative value) and not outweighed by countervailing considerations (e.g., the evidence is unfairly prejudicial, confusing, a waste of time, privileged, or based on hearsay).