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).
C. Methods of Authentication: Generally, any evidence that tends to establish genuineness may be used to authenticate a writing. Evidence may be authenticated by either direct evidence or circumstantial evidence. Examples of evidence sufficient to support the authenticity of evidence are included in FRE 901(b).