Simulation of Food Folate Digestion and Bioavailability of an Oxidation Product of 5-Methyltetrahydrofolate

Generating bioavailability data from in vivo studies is time-consuming and expensive. In vitro simulation can help to investigate factors influencing bioavailability or facilitate quantifying the impact of such factors. For folates, an efficient deconjugation of polyglutamates to the corresponding monoglutamates is crucial for bioavailability and highly dependent on the food matrix. Therefore, the bioaccessibility of folates of different foodstuffs was examined using a simulated digestion model with respect to folate stability and the efficiency of deconjugation. For realistic simulated deconjugation, porcine brush border membrane was used during the phase of the simulated digestion in the small intestine. For a better understanding of folate behaviour during digestion, single folate monoglutamates were also investigated with this in vitro digestion model. The results for bioaccessibility were compared with data from a human bioavailability study. They support the idea that both stability and deconjugation have an influence on bioaccessibility and thus on bioavailability. Tetrahydrofolate is probably lost completely or at least to a high extent and the stability of 5-methyltetrahydrofolate depends on the food matrix. Additionally, 5-methyltetrahydrofolate can be oxidised to a pyrazino-s-triazine (MeFox), whose absorption in the human intestinal tract was shown tentatively.

The impact of folate intake on the risk of head and neck cancer in the prostate, lung, colorectal, and ovarian cancer screening trial (PLCO) cohort

BACKGROUND

Although low levels of folate leads to disturbances in DNA replication, DNA methylation and DNA repair, the association between dietary folate intake and head and neck cancer (HNC) risk remains unclear.

METHODS

We evaluated the association between folate intake and HNC risk using prospective cohort data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial. This study included 101 700 participants and 186 cases with confirmed incident HNC. The median follow-up was 12.5 years. We estimated hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) using Cox proportional hazard model including age, sex, body mass index, education, race, tobacco smoking, alcohol drinking and total fruit and vegetable intake.

RESULTS

Higher intake of food folate and fortified folic acid in foods was associated with a decreasing HNC risk in a dose-response manner. The HRs of highest vs the lowest quartile of intake were 0.35 (95%CI: 0.18-0.67) for food folate, and 0.49 (95%CI: 0.30-0.82) for fortified folic acid. Intakes of total folate, natural folate and supplemental folic acid were not associated with the risk of HNC and its subsites. We did not detect any interaction between smoking, drinking and food folate intake on HNC risk.

CONCLUSIONS

These findings provide evidence of the protective role of dietary folate intake on HNC risk.

Association of food folate with asthma in US children and adolescents: a cross-sectional study

BACKGROUND

Asthma is a chronic inflammatory disease. Currently, contradictory findings exist regarding the association between food folate and asthma. Therefore, we hypothesize a positive correlation between food folate and asthma.

PURPOSE

To investigate the possible relationship between food folate intake and the development of asthma in children and adolescents in the United States.

METHODS

Data from the U.S. National Health and Nutrition Examination Survey (NHANES) from 2009 to 2018 were analyzed cross-sectionally by covariate adjustment using multivariate logistic regression, restricted triple spline curves, threshold effects, and stratified analyses.

RESULTS

There were 8,821 participants, of whom 1,697 (19.2%) self-reported having received a diagnosis of asthma from a physician or other health professional. After accounting for potential confounders, the adjusted odds ratios (ORs) for asthma in the second (T2, 111-178 µg/day) and third (T3, >178 µg/day) groups were 1.15 (1-1.33) and 1.23 (1.04-1.46), respectively, compared with the group with the lowest food folate intake (T1, <111 µg/day). In addition, the association between food folate intake and asthma showed an inverse L-shaped curve (non-linear relationship, p = 0.003), and stratified analysis further validated the robustness of the results. The OR of asthma in subjects with food folate intake less than 263.9 µg/day was 1.002 (1.001-1.004).

CONCLUSION

In children and adolescents in the United States, there is a non-linear association (inverted "L" shape) between food folate intake and asthma, with an inflection point at 263.9 micrograms per day.