By Satya S. Jonnalagadda, PhD, MBA, RDN, Vice President, Scientific and Clinical Affairs, Medifast Inc.
Nutrient Intake and Bioaccessibility/Bioavailability
“We are what we eat.” Our bodies transform and are transformed by the components in the food, beverages and dietary supplements we consume. As the field of pre-, pro-, syn-, post-biotics and gut microbiome continues to advance, our understanding of the relationship between these “-biotics” and health will evolve to help us maximize the benefits of what we consume. This blog will briefly highlight the role of these “-biotics” in nutrient bioaccessibility and bioavailability. Briefly, nutrient bioaccessibility is the proportion of an ingested nutrient that is available for absorption in the gut, whereas nutrient bioavailability is the proportion of the absorbed nutrients that enters the systemic circulation and exerts its biological effect at its specific site of action.
Prebiotics and Nutrient Absorption
Existing evidence suggests that certain non-digestible, fermentable oligosaccharides, i.e., prebiotics, selectively promote the growth and activity of beneficial bacteria in the gut, such as Bifidobacterium and Lactobacillus, Roseburia, Eubacterium or Faecalibacterium species (Gibson et al., 2017). Prebiotics such as inulin, fructooligosaccharides (FOS), galactooligosaccharides (GOS), and resistant starch are found in foods we consume – leeks, asparagus, onions, wheat, garlic, chicory, oats, soybeans, Jerusalem artichokes, and milk. Prebiotics are fermented in the colon by gut bacteria, producing short-chain fatty acids (SCFAs) that play a role in nutrient and phytonutrient absorption (Gibson et al., 2017). Although the existing evidence is equivocal, studies in humans and animals suggest certain prebiotics may have a positive effect on the bioaccessiblity of select minerals (e.g., calcium, magnesium), contributing to physiological benefits, such as improving bone mineral composition and bone architecture (Markowiak et al., 2017; Zakrzewska et al., 2022). The SCFAs produced in the colon, especially butyrate, may play an important role in nutrient bioaccessibility, by producing an osmotic effect, by enlarging the gut absorption surface area, and by decreasing the pH of the intestinal lumen, thereby increasing mineral solubility (Gibson et al., 2017; Markowiak et al., 2017; Zakrzewska et al., 2022). The SCFAs may also promote production and secretion of pancreatic lipase, which helps break down dietary fats. Prebiotics have also been shown to enhance the gut barrier function, which helps regulate the passage of nutrients through the intestinal lining, while also blocking the absorption of harmful substances such as toxins and pathogens. Prebiotics promote the production of mucus in the gut, which serves as a protective barrier and helps prevent damage to the intestinal lining. Overall, prebiotics can affect gut health and improve nutrient bioaccessibility.
Probiotics and Nutrient Absorption
Probiotics are live microorganisms that provide various health benefits to the host when consumed in adequate amounts. Probiotics are commonly consumed either in foods, such as yogurt, or as dietary supplements. While probiotics are most associated with improving gut health, they also play a role in nutrient bioaccesiblity in humans, and the effect of probiotics on nutrient absorption is dependent on the probiotic species and strain (Markowiak et al., 2017). Probiotics can enhance the production of SCFAs, improve gut lining, decrease inflammation, and increase production of certain digestive enzymes, which can help improve bioaccessibility of certain nutrients and phytonutrients. Probiotics can also help maintain the integrity of the intestinal barrier, which is also essential for proper nutrient absorption. Proteolytic activity of certain Lactobacillus spp. contributes to the production of smaller bioactive soluble peptides that are better absorbed than the native protein, which can contribute to improving the nutritional value of certain proteins (Manus et al., 2021; Wang et a., 2019). Fermentation of plant proteins with certain Lactobacillius species has been shown to have a positive effect on the protein absorption by decreasing antinutritional compounds like trypsin inhibitor, tannins, and phytate (Manus et al., 2021; Walden et al., 2022; Wang et al., 2019). Fermentation can help lower the pH, reduce the trypsin inhibitor activity and the amount of phytates and tannins in pulses (Jager et al., 2020). In addition to absorption, certain probiotics play an important role in the production of certain B-vitamins, such as thiamin, B12 and folate, in the gut (Hill, 1997). Although probiotics can play an important role in improving nutrient and phytonutrient bioaccessibility in humans, it is important to acknowledge that the efficacy of probiotics depends on the species and strain of bacteria, the dosage, and the individual’s health status.
Gut Microbiome and Nutrient Absorption
The gut microbiota evolves with human evolution and are in a constant, dynamic interaction with the host’s gastrointestinal microenvironment. The microbiome is known to convert fibers, polyphenols, fats, and nucleic acids to SCFAs, modified polyphenols, conjugated fatty acids, B vitamins and other metabolites (Barone et al., 2022; Gibrayel et al., 2022). The gut microbiome plays a crucial role in nutrient absorption by breaking down complex food molecules that bypass the human digestive system (Uebanso et al., 2020). Gut bacteria have the necessary enzymes to break down these molecules and release nutrients and metabolites, such as glucose and SCFAs. The gut microbiome is also involved in the metabolism of amino acids, lipids, and other nutrients, producing metabolites that can affect nutrient absorption and utilization. For example, gut bacteria can produce bile acids, which help to emulsify fats and aid in their absorption; they can also synthesize vitamin K, and vitamin B12 (Uebanso et al., 2020). In addition to their direct involvement in nutrient metabolism, gut bacteria can also influence nutrient absorption through their effects on gut barrier function and immune system regulation. The gut microbiome can help maintain the integrity of the gut barrier by producing mucus and other protective compounds, and by modulating the immune response to lower inflammation and damage (Barone et al., 2022; Gibrayel et al., 2022; Uebanso et al., 2020). Overall, the gut microbiome plays an important role in nutrient absorption by breaking down complex food molecules, synthesizing vitamins and other nutrients, and regulating gut barrier function and immune system activity. Imbalances in the gut microbiome, such as dysbiosis, can lead to nutrient malabsorption and contribute to poor health outcomes.
Ensuring adequate intake of prebiotics, probiotics to maintain healthy gut, microbiome has benefits beyond just the gut. Incorporating fermented foods and other food and dietary supplement sources of these pre- and pro-biotics can help support healthy digestive health, gut microbiome activity and overall nutritional status.
- Barone M, D’Amico F, Brigidi P, Turroni S. Gut microbiome-micronutrient interaction: The key to controlling the bioavailability of minerals and vitamins? Biofactors. 2022;48(2):307-314. doi: 10.1002/biof.1835.
- Gebrayel P, Nicco C, Al Khodor S, Bilinski J, Caselli E, Comelli EM, Egert M, Giaroni C, Karpinski TM, Loniewski I, Mulak A, Reygner J, Samczuk P, Serino M, Sikora M, Terranegra A, Ufnal M, Villeger R, Pichon C, Konturek P, Edeas M. Microbiota medicine: towards clinical revolution. J Transl Med. 2022;20(1):111. doi: 10.1186/s12967-022-03296-9.
- Gibson, G., Hutkins, R., Sanders, M. et al. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol. 2017;14, 491–502. https://doi.org/10.1038/nrgastro.2017.75
- Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev. 1997; 6 Suppl 1:S43-5. doi: 10.1097/00008469-199703001-00009.
- Jäger R, Zaragoza J, Purpura M, Iametti S, Marengo M, Tinsley GM, Anzalone AJ, Oliver JM, Fiore W, Biffi A, Urbina S, Taylor L. Probiotic administration increases amino acid absorption from plant protein: a placebo-controlled, randomized, double-blind, multicenter, crossover study. Probiotics Antimicrob Proteins. 2020;12(4):1330-1339. doi: 10.1007/s12602-020-09656-5.
- Manus J, Millette M, Uscanga BRA, Salmieri S, Maherani B, Lacroix M. In vitro protein digestibility and physico-chemical properties of lactic acid bacteria fermented beverages enriched with plant proteins. J Food Sci. 2021;86(9):4172-4182. doi: 10.1111/1750-3841.15859.
- Markowiak P, Śliżewska K. Effects of probiotics, prebiotics, and synbiotics on human health. Nutrients. 2017;9(9):1021. doi: 10.3390/nu9091021.
- Uebanso T, Shimohata T, Mawatari K, Takahashi A. Functional Roles of B-Vitamins in the Gut and Gut Microbiome. Mol Nutr Food Res. 2020;64:e2000426. doi: 10.1002/mnfr.202000426.
- Walden KE, Hagele AM, Orr LS, Gross KN, Krieger JM, Jäger R, Kerksick CM. Probiotic BC30 improves amino acid absorption from plant protein concentrate in older women. Probiotics Antimicrob Proteins. 2022; doi: 10.1007/s12602-022-10028-4.
- Wang J, Ji H. Influence of probiotics on dietary protein digestion and utilization in the gastrointestinal tract. Curr Protein Pept Sci. 2019;20(2):125-131. doi: 10.2174/1389203719666180517100339.
- Zakrzewska Z, Zawartka A, Schab M, Martyniak A, Skoczeń S, Tomasik PJ, Wędrychowicz A. Prebiotics, probiotics, and postbiotics in the prevention and treatment of anemia. Microorganisms. 2022;10(7):1330. doi: 10.3390/microorganisms10071330.