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Approximately 0.1% is the average genetic difference between two individuals. This small percentage is responsible for the variations of certain physical traits, such as eyes, hair, and height, but also for differences in our susceptibility to certain diseases and capacity to absorb vitamins and phytomicronutrients (carotenoids, polyphenols, etc.), involved in the prevention of chronic disease.
Based on the study of genetic interindividual variability, researchers from INRA and Aix-Marseille University examined personalize nutritional recommendations to optimize nutrient, micronutrient, and phytomicronutrient by consideringgenetic differences between individuals. Previous studies have shown that the capacity to absorb some vitamins varies considerably between individuals, for example, by a factor of 34 in the case of vitamin D.
Researchers have compiled current knowledge about genetic interindividual variability in regard to the absorption of micronutrients, especially fat-soluble vitamins (A, D, and E), carotenoids (plant pigments such as beta-carotene, lycopene, and lutein), and phytosterols (plant-derived sterols). Given the fact that human body cannot produce them and that they are either essential for it to function well (vitamins) or capable of enhancing the beneficial effects of fruits and vegetables (certain phytomicronutrients), human beings must obtain these micronutrients through the diet.
Adequate intake of vitamins and phytochemicals like carotenoids or polyphenols is essential to prevent cancer, cardiovascular, neurodegenerative and ocular diseases. Interindividual variability in the bioavailability of certain micronutrients is modulated by single nuclotide polymorphisms (SNPs)2 The identified SNPs are located in genes involved in the intestinal uptake and transport of these compounds.
The effect of each SNP is usually low, but a combination of SNPs can explain a significant part of interindividual variability. For example, the researchers discovered that the interindividual variability in the bioavailability of vitamin E is modulated, at least to some extent, by a combination of 28 SNPs in 11 genes.
Other types of genetic variations could be involved in the bioavailability of these micronutrients, for instance, copy number of certain genes associated with micronutrient absorption and metabolism. Factors other than genetic could be involved as well. One example is the microbiota, which has been proven to participate in the regulation and absorption of certain micronutrients.