SUE MCKAY*, ANNICK MERCENIER, RUUD ALBERS
*Corresponding author
NutriLeads, Wageningen, Netherlands

Abstract

Good nutrition is vital for maintaining health and supporting optimal immune function. Several essential micronutrients are known to contribute to normal functioning of the immune system and may carry health claims on products when they contain meaningful amounts. Certain dietary fibers, for example pectic polysaccharides from carrot that are rich in rhamnogalacturonan-I (cRG-I), have also been shown to play an important role as they can educate, regulate, and modulate immune cell responsiveness. The aim of this paper is to provide an overview of the scientific evidence supporting the immunomodulatory role of RG-I via nutrition.

INTRODUCTION
A healthy immune system is a resilient system that manages daily challenges while maintaining responsiveness within a normal range and minimizing the notable impact of infections (1). Factors that can negatively impact the resilience of the immune system include ageing, an unhealthy diet and lifestyle, malnutrition, (chronic) illness, and medication (e.g., antibiotics). Good nutrition is one of the key factors that can positively influence the immune system. A nutritious diet provides a balanced supply of (micro)nutrients and is essential for maintaining health. While vitamins A, B6, B12, C, D, E, folate and zinc, copper, selenium, and iron support the normal function of the immune system (2–15), other food components and especially specific (non-digestible) dietary fibers can play an important role in the education and regulation of immune responses, both locally in the gut and beyond the gut in the rest of the body (16–18). Everything that is eaten is sampled by immune cells located in and around the small intestine, recognition of specific ‘patterns’ can result in priming or training and subsequent modulation of immune responsivene ...