The Origins of Salivary Vitamin A, Vitamin B12 and Vitamin D-Binding Proteins

Higher circulating vitamin B12 is associated with lower levels of inflammatory markers in individuals at high cardiovascular risk and in naturally aged mice

BACKGROUND

Vitamin B12 is an essential nutrient that is involved in numerous physiological processes, and its deficiency can lead to various complications, including neurological and haematological disorders. Some studies have suggested that vitamin B12 may have anti-inflammatory effects, but the mechanisms underlying this relationship are not yet fully understood. We investigated the relationship between circulating vitamin B12 and inflammatory markers interleukin (IL)-6 and C-reactive protein (CRP). The association of peripheral levels of vitamin B12 with IL-6 and CRP was assessed in 136 human samples from a high cardiovascular risk population. To corroborate the results from the human trial, the analysis was replicated in naturally aged mice.

RESULTS

Individuals with higher serum levels of vitamin B12 showed lower concentrations of IL-6 and CRP after adjustment for potential confounders, and an inverse association was also found between serum IL-6 and vitamin B12 levels in naturally aged mice.

CONCLUSION

Circulating vitamin B12 was inversely associated with IL-6 and CRP in humans and with IL-6 in mice, suggesting that it may exert an anti-inflammatory effect through modulation of these pro-inflammatory molecules. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Proteins involved in fat-soluble vitamin and carotenoid transport across the intestinal cells: New insights from the past decade

It is now well established that vitamins D, E, and K and carotenoids are not absorbed solely through passive diffusion. Broad-specificity membrane transporters such as SR-BI (scavenger receptor class B type I), CD36 (CD36 molecule), NPC1L1 (Niemann Pick C1-like 1) or ABCA1 (ATP-binding cassette A1) are involved in the uptake of these micronutrients from the lumen to the enterocyte cytosol and in their secretion into the bloodstream. Recently, the existence of efflux pathways from the enterocyte back to the lumen or from the bloodstream to the lumen, involving ABCB1 (P-glycoprotein/MDR1) or the ABCG5/ABCG8 complex, has also been evidenced for vitamins D and K. Surprisingly, no membrane proteins have been involved in dietary vitamin A uptake so far. After an overview of the metabolism of fat-soluble vitamins and carotenoids along the gastrointestinal tract (from the mouth to the colon where interactions with microbiota may occur), a focus is placed on the identified and candidate proteins participating in the apical uptake, intracellular transport, basolateral secretion and efflux back to the lumen of fat-soluble vitamins and carotenoids in enterocytes. This review also highlights the mechanisms that remain to be identified to fully unravel the pathways involved in fat-soluble vitamin and carotenoid intestinal absorption.

[Vitamins and Immune System Health]

Keeping the immune system healthy forms an effective way to fight infections. Past experience has shown that, in addition to effective interventions including vaccination, drug therapy, and non-pharmaceutical intervention (NPI), dietary nutrition and mental health are also key factors in maintaining immune system health and combating emerging and sudden outbreaks of infections. As the main dietary nutrients, vitamins are active regulators of the immune response and exert a critical impact on the immunity of the human body. Vitamin deficiency causes increased levels of inflammation and decreased immunity, which usually starts in the oral tissues. Appropriate vitamin supplementation can help the body optimize immune function, enhance oral immunity, and reduce the negative impact of pathogen infection on the human body, which makes it a feasible, effective, and universally applicable anti-infection solution. This review focuses on the immunomodulatory effects of vitamin A, B, C, D, and E and proposes that an omics-based new systemic approach will lead to a breakthrough of the limitations in traditional single-factor single-pathway research and provide the direction for the basic and applied research of vitamin immune regulation and anti-infection in all aspects.

Serum, saliva, and gingival tissue human β-defensin levels in relation to retinoic acid use

BACKGROUND

Retinoic acid is an active derivative of vitamin A and regulates the differentiation, proliferation, and antimicrobial peptide expression profiles of human cells. The aim of the present study was to analyze the effect of systemic retinoic acid use on serum, saliva, and gingival tissue levels of human β-defensin (hBD)-1, hBD-2, and hBD-3.

METHODS

A total of 69 participants (34 systemic retinoic acid users and 35 healthy controls) were enrolled in this study. Plaque index, probing pocket depth, bleeding on probing (BOP), and clinical attachment loss were measured. Saliva and serum hBD-1, hBD-2, and hBD-3 levels were quantified by enzyme-linked immunosorbent assay. Gingival tissue hBD-1, hBD-2, and hBD-3 levels were determined by immunohistochemistry. A univariate general linear model was used in adjusted comparisons of hBD1, hBD-2, and hBD-3. P values of < 0.05 were considered statistically significant.

RESULTS

Reduced salivary levels of hBD-2 (P = 0.042), but not hBD-1 or hBD-3, were detected in systemic retinoic acid users compared to non-user controls. There was a significant difference in the adjusted (for BOP%) salivary hBD-2 concentrations between retinoic acid and control groups (P = 0.031). No difference was observed in serum or tissue levels of hBD-1, hBD-2, or hBD-3 between the two study groups.

CONCLUSION

Systemic retinoic acid use was associated with suppressed salivary hBD-2 level, which was independent of gingival inflammation.

KEY FINDINGS

Systemic retinoic acid use associates with suppressed salivary hBD-2 levels.

Vitamin E: A potential preventive approach against dental erosion-an in vitro short-term erosive study

OBJECTIVES

This study evaluated the in vitro effect of different components of palm oil on enamel in a short-term erosive challenge.

METHODS

The acquired enamel pellicle (AEP) was previously formed in situ for 2 h. Subsequently, the bovine enamel blocks were treated in vitro according to following solutions: G1-palm oil; G2-85% tocotrienol solution; G3-oily vitamin E; G4-oily vitamin A; G5-deionized water (negative control); G6-stannous-containing solution (Elmex® Erosion Protection Dental Rinse) (positive control). After application of the treatment solutions (500 µl, 30 s), the blocks were immersed in 0.5% citric acid (pH 2.4) during 30 s (initial erosion). The response variable was the percentage of surface hardness loss. Data were analyzed by one-way ANOVA and Fisher's Test (p < 0.05).

RESULTS

The positive control (G6), palm oil (G1) and oily vitamin E (G3) groups presented the lowest percentage of surface hardness loss, and were statistically different from the negative group (G5) (p < 0.05), and no differences were found between these three groups. The 85% tocotrienol solution (G2) and oily vitamin A groups (G4) were not different to the negative control group.

CONCLUSIONS

Stannous-containing positive control (Elmex® Erosion Protection), palm oil and oily Vitamin E were able to protect enamel against the erosive challenge performed in this in vitro study. In addition, vitamin E is probably the key ingredient of palm oil responsible for preventing enamel erosion.

CLINICAL SIGNIFICANCE

Vitamin E presented similar preventive effect to a commercial mouthwash stannous-containing solution (Elmex® Erosion Protection) against initial erosion and, it can be considered as a promising natural alternative for the formulations of solutions aiming to prevent erosive tooth wear.