The rapidly growing plant-based diet trend is promoted, in part, by evidence on health risks associated with the consumption of red meat.While vegetarians may have lower risks for ischemic heart disease, diabetes, total cancer, and eye cataract, the supply of certain nutrients in these diets is questioned.
Meat and fish are good sources of vitamin B6 and there is evidence to suggest reduced bioavailability as well as digestibility of vitamin B6 from plant foods. However, previous studies on the vitamin B6 status among vegetarians are inconsistent and this may be because biomarkers of the vitamin B6 status, especially PLP, but also 4-pyridoxic acid (4-PA), are influenced by a range of potential confounders, such as obesity, smoking or inflammation.
In the present study, the vitamin B6 status of vegetarians, pescatarians, flexitarians, and meat-eaters was compared in the population-based NHANES. Making use of the unique availability of comprehensive data on lifestyle factors and biomarkers in NHANES, the specific aim was to account for known determinants of the vitamin B6 status beyond diet (e.g., obesity, smoking, alcohol intake, but also kidney function and inflammation) in multivariable analyses on the vitamin B6 status according to the type of diet.
The data showed that despite the slightly lower dietary vitamin B6 intake among vegetarians, no differences in biomarkers of the vitamin B6 status (serum PLP, 4-PA, and their ratio, i.e., 4-PA/PLP) were found between vegetarians, pescatarians, flexitarians, and meat-eaters.
The report concludes: "Overall, the use of vitamin B6 supplements was the strongest predictor of the vitamin B6 status, followed by the dietary vitamin B6 intake. Interestingly, several other covariates were significantly associated with vitamin B6 biomarker levels, particularly serum albumin, creatinine and alkaline phosphatase, and should be considered when assessing the vitamin B6 status. In summary, our findings suggest that a vegetarian diet does not pose a risk for vitamin B6 deficiency."
This is the first large-scale epidemiological study showing a wide range of lifestyle factors, prevalent medical conditions, medications, and biochemical indicators are associated with both PLP and 4-PA concentrations.
NHANES is a study program conducted by the Centers for Disease Control and Prevention’s (CDC) National Center for Health Statistics (NCHS). The data collection comprises interviews and physical examinations in order to to analyse lifestyle factors, socio-economic and demographic characteristics, dietary habits, medical conditions, and physiological measures.The present study incorporated the public use files of the two NHANES cycles 2007–2008 and 2009–2010.
The vitamin B6 status was examined on the basis of the serum concentrations of PLP (nmol/L) and 4-PA (nmol/L), as well as their ratio 4-PA/PLP. Both biomarkers were measured by high-performance liquid chromatographic (HPLC) analysis.
The data analysis suggested no differences in biomarkers of the vitamin B6 status (serum PLP, 4-PA, and their ratio, i.e., 4-PA/PLP) between vegetarians, pescatarians, flexitarians, and meat-eaters in the NHANES, despite the slightly lower dietary vitamin B6 intake among vegetarians.
The majority of study participants across all groups reached the recommended dietary allowance (RDA) values for vitamin B6 intake of 1.3 mg/d and 1.5 mg/d for women aged 19–50 years and >51 years, respectively, and 1.3 mg/d and 1.7 mg/d for men aged 19–50 years and >51 years.
The report concludes: "These data are important as they provide evidence that a vegetarian diet does not pose a risk for vitamin B6 deficiency. In addition to supplemental vitamin B6 intake and dietary vitamin B6 intake, several lifestyle factors (including age, sex, ethnicity) and biochemical parameters (particularly creatinine, albumin, alkaline phosphatase) were significantly associated with the vitamin B6 status."
Schorgg, P.; Bärnighausen, T.; Rohrmann, S.; Cassidy, A.; Karavasiloglou, N.; Kühn, T.
Vitamin B6 Status among Vegetarians: Findings from a Population-Based Survey
https://doi.org/10.3390/nu13051627 (registering DOI)