Impact of Food Structure on Micronutrient Bioavailability in Human

The nutritional quality of foods strongly depends on the structure / texture of foods, because of the impact on food disintegration, and then on digestion process and nutrient utilization by the human body. However, this relationship between food structure and nutrient bioavailability is still widely unknown.

MicroNut project aims at demonstrating and evaluating in humans the impact of structure / texture changes on micronutrient bioavailability. In order to do this, four complex food matrices, with constant composition but different structures / textures, and as close as possible to real foods have been designed and are evaluated in the present study. A mixture of egg and plant proteins is the basis of these lipoprotein matrices in which four micronutrients will be followed up : two lipophilic (vitamin D and lutein) and 2 hydrophilic (vitamins B9 and B12).

The main objective consists in understanding how food structure / texture impacts on micronutrient bioavailability. The second objective consists in studying food disintegration at oral phase (in the mouth) and the consequences on the bioaccessibility of hydrophilic vitamins in saliva.

The clinical study is open, monocentric, controled and randomized, in a cross experimental design.

The included volunteers (n=12) will participate in the whole two protocols. The first protocol is related to the study of vitamins B9, B12, D and lutein bioavailability during 8h kinetics, after ingestion of a food matrix (custard, biscuit, flan or sponge cake). The second protocol is related to the study of hydrophilic vitamin release during mastication of two of these matrices (biscuit and sponge cake).

The study is not performed in a double blind way. However, the measure bias will be limited because of the standardized and objective characteristic of the main criteria. Moreover, biological samples will be analysed by the same partners of the project. Each subject will be his own control, so that confusion factors related to individual variability will be eliminated.

The monocentric characteristic of the study, the low number of subjects and the expertise of the involved staff will enable to limit the number of missing data.

The randomization (latin square) has been established by a bio-statistician of the project before the study started. A document describing the randomization proceeding is confidentially kept.

Eligibility Criteria:
Inclusion Criteria:

* no smoking since 6 months at least
* no pathology and no medical treatment
* no history of calcium lithiasis
* BMI \>=20 and \<=30 kg/m²
* normal biological status
* no dislike for the food tested
* good dental health, no pain, no treatment in progress, no orthodontics since 3 years

Exclusion Criteria:

* hypercalcemia (\>2.52 mmol/L), hyperphosphoremia (\>1.58 mmol/L)
* known pathology
* allergy or intolerance to one of the food matrix components (egg, vitamins B12, B9, D, lutein, pea, gluten)
* intake of food supplements and/or UVdose for the 3 months before the study, except enriched foods
* exposure to UV during the 2 weeks before the study and all along the study
* vitamin D \< 80µg/L