Impact of food structure on lipophilic micronutrients bioavailability: a human study
Résumé
A major challenge in the next years will consist in producing healthy and sustainable foods with optimized nutritional quality. Whereas the prevalence of overweight and obesity is still increasing in Western countries, micronutrient deficiencies continue to rise in developing countries. In particular, regardless of vitamin D crucial role for health and its major involvement in many biological functions, vitamin D deficiency still affects 50% of the world's population. Similarly, age-related macular degeneration is the first cause of visual handicap over 50 years old, while it was recently confirmed that xanthophyll supplementation decreases the risk of progression of this pathology.
Food fortification to increase micronutrient intakes is a strategy currently used to overcome these (sub)deficiencies. Since the structural characteristics of food influence disintegration process during digestion, it appears relevant to assess the impact of food structure on micronutrients bioavailability.
To address this issue, a clinical trial has been set up, using four model foods enriched in both lutein and vitamin D. These products were designed with identical composition (on dry matter) but with different structures and textures (custard, pudding, sponge cake and biscuit) obtained by modulating the production process. A multiscale characterization of these products was carried out by confocal microscopy and texture analysis. Twelve healthy male subjects were recruited for this monocentric, controlled and randomized study, in a cross experimental design. After an overnight fast, kinetics of micronutrient responses in plasma were recorded for 8 hours following each product consumption. Vit D and lutein were measured in chylomicrons.
Preliminary results suggest that food structure modulate the kinetics of micronutrient appearance in plasma, opening the way for the concept of « fast vs slow micronutrients ». If this concept is confirmed, further studies using an in vitro digestion model will aim to determine which food characteristics can influence micronutrient bioavailability.