Moderate cryptoxanthin intake correlates with maintenance of a proper PINT index in a general Japanese population.

Introduction: Small fibre neuropathy (SFN) is an early manifestation of diabetic polyneuropathy. Although oxidative stress, inflammation and change of intestinal bacterial population are assumed to be their pathogenesis, the effects of dietary nutrition have not been evaluated. The relationship between dietary nutrition intake and pain sensation was evaluated in the Japanese population.

Methods: We conducted the Iwaki project, a population-based study recruiting 1,028 individuals, in 2018. The relationships between the pain threshold from intraepidermal electrical stimulation (PINT) and the amount of dietary nutrition evaluated by a brief-type self-administered diet history questionnaire were examined. The odds ratio was further explored after categorizing subjects based on low (< 63.7 μg/day), intermediate (63.7-159.2 μg/day), and high cryptoxanthin levels (> 159.2 μg/day).

Results: Univariate linear regression analyses showed significant correlations between PINT and cryptoxanthin intake even after adjustments for other nutritional intakes (ß = 0.107, p < 0.01). Multivariate logistic regression analysis revealed low and high cryptoxanthin intake as significant risk factors for abnormal PINT (≥ 0.20 mA). Multivariate linear regression analyses showed significant correlations between PINT and cryptoxanthin intake levels after adjustment for other clinically PINT-related factors (ß = 0.09, p < 0.01).

Conclusions: Adequate intake of cryptoxanthin is recommended to maintain the pain threshold in the Japanese population.