575
25.3 Nutrient Enhancers and Inhibitors
Interaction of nutrients with one another and with other dietary components at the
site of absorption, affects their overall bioavailability. Addition of nutrient enhancers or inhibitors can therefore enhance, reduce or neutralize these activities. Nutrient
enhancers increase the bioavaibility of nutrients by keeping a nutrient soluble and
protect it from their interaction with the inhibitors. For example, carotenoids are
fat–soluble, and addition of small quantities of fat or oil to the meal improves the
bioavailability of carotenoids. Similarly, meat, fish, and poultry, while containing
highly bioavailable iron, are also known to enhance the absorption of iron from
other foods ingested at the same time. Although this meat factor has yet to be identified, it has been suggested that muscle protein may exert an influence. Nutrient
inhibitors, on the other hand, reduce bioavailability by binding the nutrient in a form
that is not recognized by uptake systems on the surface of intestinal cells, rendering
the nutrient insoluble and, thus, unavailable for absorption. For example, phytic
acid is abundant in certain plant foods (e.g. pulses, whole grain cereals, seeds, and
nuts) and strongly binds minerals such as calcium, iron, and zinc in soluble or insoluble complexes, which are unavailable for absorption. The undesired phytic acid
content of foods can be reduced by fermentation or by soaking and germination of
pulses. The inhibitory effect of food constituents can also be used advantageously to
provide health benefits. For example, phytosterols extracted from certain plant
foods can be added in higher doses to a variety of other foods (e.g., spreads and
fermented milk drinks) to reduce the absorption of cholesterol either from dietary
sources or produced in the human body (Gibney et al. 2009; Gylling and Simonen
2015; Schönfeldt et al. 2016).
25.4 Nutrient Deficiency and Gut Health
Deficiency of micronutrients such as iron, zinc, vitamin A and folate is the main
cause of hidden hunger across the world (Bailey et al. 2015) Nutrients–rich diet
significantly modulates the metabolic activities of the gut microbiota (Le Chatelier
et al. 2013) which uses micronutrients as substrates for the several physiological
processes (Lozupone et al. 2012). Their deficiency may cause disruption in gut
microbiota eubiosis balance leading to the development of colon cancer, allergy,
cardiovascular diseases, obesity, and gastrointestinal disorder (Clemente et al.
2012). Acute deficiency of vitamin A has significant effect on microbiota composition and meta transcriptome, and enhances the population of Bacteroides vulgates
(Hibberd et al. 2017) responsible for inflammatory bowel diseases, ulcerative colitis
and Crohn’s disease (CuÝv et al. 2017). Zinc deficiency is associated with reduction
in gut microbiota diversity and production of short chain fatty acids (SCFAs) such
as acetate and butyrate in the broiler chicken model (Reed et al. 2015). Likewise,
deficiency of vitamin C and E leads to the depletion of microbiota of phyla
25 Bioavailability of Nutrients and Safety Measurements
25.3 Nutrient Enhancers and Inhibitors
Interaction of nutrients with one another and with other dietary components at the
site of absorption, affects their overall bioavailability. Addition of nutrient enhancers or inhibitors can therefore enhance, reduce or neutralize these activities. Nutrient
enhancers increase the bioavaibility of nutrients by keeping a nutrient soluble and
protect it from their interaction with the inhibitors. For example, carotenoids are
fat–soluble, and addition of small quantities of fat or oil to the meal improves the
bioavailability of carotenoids. Similarly, meat, fish, and poultry, while containing
highly bioavailable iron, are also known to enhance the absorption of iron from
other foods ingested at the same time. Although this meat factor has yet to be identified, it has been suggested that muscle protein may exert an influence. Nutrient
inhibitors, on the other hand, reduce bioavailability by binding the nutrient in a form
that is not recognized by uptake systems on the surface of intestinal cells, rendering
the nutrient insoluble and, thus, unavailable for absorption. For example, phytic
acid is abundant in certain plant foods (e.g. pulses, whole grain cereals, seeds, and
nuts) and strongly binds minerals such as calcium, iron, and zinc in soluble or insoluble complexes, which are unavailable for absorption. The undesired phytic acid
content of foods can be reduced by fermentation or by soaking and germination of
pulses. The inhibitory effect of food constituents can also be used advantageously to
provide health benefits. For example, phytosterols extracted from certain plant
foods can be added in higher doses to a variety of other foods (e.g., spreads and
fermented milk drinks) to reduce the absorption of cholesterol either from dietary
sources or produced in the human body (Gibney et al. 2009; Gylling and Simonen
2015; Schönfeldt et al. 2016).
25.4 Nutrient Deficiency and Gut Health
Deficiency of micronutrients such as iron, zinc, vitamin A and folate is the main
cause of hidden hunger across the world (Bailey et al. 2015) Nutrients–rich diet
significantly modulates the metabolic activities of the gut microbiota (Le Chatelier
et al. 2013) which uses micronutrients as substrates for the several physiological
processes (Lozupone et al. 2012). Their deficiency may cause disruption in gut
microbiota eubiosis balance leading to the development of colon cancer, allergy,
cardiovascular diseases, obesity, and gastrointestinal disorder (Clemente et al.
2012). Acute deficiency of vitamin A has significant effect on microbiota composition and meta transcriptome, and enhances the population of Bacteroides vulgates
(Hibberd et al. 2017) responsible for inflammatory bowel diseases, ulcerative colitis
and Crohn’s disease (CuÝv et al. 2017). Zinc deficiency is associated with reduction
in gut microbiota diversity and production of short chain fatty acids (SCFAs) such
as acetate and butyrate in the broiler chicken model (Reed et al. 2015). Likewise,
deficiency of vitamin C and E leads to the depletion of microbiota of phyla
25 Bioavailability of Nutrients and Safety Measurements