Document Type



Doctor of Philosophy (PhD)


Dietetics and Nutrition

First Advisor's Name

Adriana Campa

First Advisor's Committee Title

Committee Chair (Major Professor)

Second Advisor's Name

Evelyn Enrione

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Vijaya Narayanan

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Tan Li

Fourth Advisor's Committee Title

Committee Member


Vitamin B6, Pyridoxal 5'-Phosphate, Polyunsaturated Fatty Acids, EPA, DHA, AA, NHANES, Gender Differences, Liver Fibrosis, Inflammation

Date of Defense



Vitamin B6-restricted diets and low plasma pyridoxal 5'-phosphate (PLP) status altered plasma polyunsaturated fatty acids (PUFA) compositions. The relationship of aging with vitamin B6 status and PUFA metabolism is poorly understood. This dissertation explored the association between vitamin B6 intake and status and plasma PUFA in US young/middle-aged adults and in older adults from NHANES 2003-2004. Future research plans will examine the relationships among vitamin B6, PUFA, inflammatory diseases, including chronic liver diseases; however, there is a gap in plasma PLP data in the Miami Adult Studies in HIV (MASH) cohort data on these relationships. Thus, the relationship between substance use and liver disease progression was assessed using the MASH cohort participants.

In 864 participants aged 20−59 y (484 men, 380 women), there were significant interactions between gender and plasma PLP on plasma PUFA, whereas no interaction between gender and B6 intake existed. In men, PLP was positively associated with EPA (β=0.138, PP=0.005), EPA/AA (β =0.144, PP=0.005). However, no associations between PLP and PUFA existed in women. Further, among 467 participants aged ≥60 y, PLP was directly associated with EPA (β=0.176, P=0.002), DHA (β=0.109, P=0.004), EPA+DHA (β=0.137, P=0.002), EPA/AA (β=0.169, P=0.009). Odds of having plasma EPA/AA and (EPA+DHA)/AA above the median were greater in those with adequate vitamin B6 compared with those who were deficient (aOR: 1.32, 95% CI: 0.8−2.17; aOR: 2.08, 95% CI: 1.0−4.33 each). Among 317 PLWH participants, opioid use in PLWH smokers was associated with higher odds of moderate to advanced liver fibrosis compared with opioid nonusers in PLWH smokers (aOR: 3.75, 95% CI: 1.44-9.97). In contrast, opioid use in nonsmokers in PLWH was not associated with liver fibrosis.

In conclusion, gender differences were found in the relationships between PLP and EPA, DHA, EPA+DHA, EPA/AA, and (EPA+DHA)/AA, with significant direct associations only in men among young/middle-aged adults. In older adults, adequate B6 status was associated with having above the median EPA/AA and (EPA+DHA)/AA. Future research regarding the relationships between vitamin B6, PUFA, and chronic inflammatory conditions, such as chronic liver diseases and cardiovascular diseases, needs to be conducted.




Previously Published In

Kim H, Enrione EB, Narayanan V, Li T, Campa A. Gender Differences in the Associations of Plasma Pyridoxal 5'-Phosphate with Plasma Polyunsaturated Fatty Acids among US Young and Middle-Aged Adults: NHANES 2003-2004. Nutrients. 2021 Jan 31;13(2):477.



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