This presentation explains the digestion and absorption of protein, vitamin A and vitamin B2 found in eggs.

1. Digestion, Absorption and
Metabolism of Eggs
KIERA SEABROOK
ID: 110271952
11 August 2019

2. Nutrition Panel
Nutrient Per medium sized
egg (58g)
Nutrient Per medium sized
egg (58g)
Protein (g) 6.4 Vitamin D (μg) 1.6
Total Fat (g) 4.6 Riboflavin; B2 (mg) 0.25
SFA (g) 1.3 Vitamin B12 (μg) 1.4
MUFA (g) 1.7 Folate; B9 (μg) 24
PUFA (g) 0.7 Phosphorus (mg) 91
N-3 PUFA (g) 0.1 Sodium (mg) 78
N-6 PUFA (g) 0.7 Iodine (μg) 25
Vitamin A (μg) 64 Selenium (μg) 12
Figure 1: Ovalbumin (protein
found in egg white) [2]
Figure 2: Vitamin A (Retinol) [3] Figure 3: Vitamin B2 (Riboflavin)[4]
Table 1: Adapted from [1]

3. Mastication [5]
• Teeth, tongue, masticatory
muscles and temporomandibular
joint [5]
• Mechanoreceptors activate [5]
Mechanical Digestion [5]
Salvia secretion [5]
• Mucins (Glycoproteins) &
Water [6]
Chemical Digestion [5]
• Saliva enzymes [5] Figure 4: [7]

4. The Oesophagus
Figure 5: Peristalsis [8]
Peristalsis [6]
• Constrictor muscles [6]
• Moves bolus into oesophagus [6]
• Upper oesophagus [6]
• Active reflex [6]
• Lower oesophagus [6]
• Enteric nervous system [6]

5. • Peristalsis: Antrum and pylorus are subjected
to peristaltic waves [10]
• Bolus is churned into chyme [11]
TheStomach
Chemical Digestion Mechanical Digestion
Figure 6: [9]
Figure 7: [12]:

6. Small Intestine - Digestion
Duodenum
• Chyme enters through pyloric
sphincter [10]
• Pancreatic proteases released [13]
• Stomach acids neutralised [13]
• Absorption preparation [13]
Figure 8: [14]

7. Figure 9: [14]

8. Small Intestine - Digestion
Jejunum
• Microbiota [16]
• Brush border enzymes [16]
• Muscle contractions [16]
• Digested proteins arrive [2]
Ileum
• Digested proteins arrive [2]
Figure 10: 17

9. Small Intestine - Absorption
• Amino acids and
oligopeptides transport
into enterocyte [13]
• Sodium-amino
transporters [18]
• PepT1 transporter [19]
Figure 11: Adapted from [20]

10. Large Intestine
• Absorbs water [6]
• Remaining intact
proteins [21]
• Digestion [21]
• Fermentation [10]
• Microbiota [21]

11. Vitamin A (Retinol)
Digestion Absorption
• Gastric acid and proteolytic enzymes
[22]
• Mechanical churning aggregate and
solubilize [22]
• Fat globules enter duodenum [22]
• Bile acids and pancreatic juices
emulsify fat globules [23]
• Bile salts secreted from gall bladder [23]
• Micelles = amphipathic molecules [23]
• Brush border of enterocyte [23]
• Simple diffusion [23]
• Proximal Jejunum [23]
• Reliance on lipid intake [25]
Figure 13: [3]
Figure 14: [26]

12. Vitamin B2 (Riboflavin)
• Free-form vitamin [27]
• Coenzyme form:
• flavin adenine dinucleotide (FAD) [27]
• flavin mononucleotide (FMN) [27]
• HCl denatures protein bound riboflavin [27]
• FAD pyrophosphatase cleaves FAD to FMN
[27]
• FMN phosphatase cleaves FMN to free
riboflavin [27]
Digestion Absorption
• Occurs in free-form [27]
• Riboflavin transporter 2 (RFT2) [27]
• Na+ dependent ATPase activity
transport [27]
• High amounts = simple diffusion [27]
• FAD remnants in large intestine [27]
Figure 15: [4]

13. Protein
Transportation
and storage of
nutrients[28]
Support
immune
system[29]
Enzymes[29]
Growth and
Maintenance
[29]
Messenger[29]
Structure[29]
Acid-Base
Balance[28]
Fluid
Balance[28]
Energy[28]

14. Vitamin AImmune response [30]
Vision[30]
Cell differentiation
and proliferation [30]
Intercellular
communication
[30]
Reproduction [30]

15. Vitamin B2
(Riboflavin)
Energy
metabolism[31]
Antioxidant[31]
Red blood cell
production and
growth[31]
Skin and mucous
membrane[31]

16. Figure 16: Krebs Cycle [32]

17. Summary
• Protein, Vitamin A & B2
• Mechanical digestion
• Chemical digestion
• Nutrient functions
• Protein = non preferred energy
source

18. 1. Griffin, BA 2016, ‘Eggs: good or bad?’, vol. 75, no. 3, pp. 259–264.
2. Wikimedia Commons contributors, Ovalbumin 1OVA 2016, Wikimedia Commons, the free media repository, viewed 17 August
2019, <https://commons.wikimedia.org/w/index.php?title=File:Ovalbumin_1OVA.png&oldid=190803832>.
3. Wikimedia Commons contributors, Retinol 3D balls 2014, Wikimedia Commons, the free media repository, viewed 17 August 2019,
<https://commons.wikimedia.org/wiki/File:Retinol_3D_balls.png#filelinks>.
4. Wikimedia Commons contributors, Riboflavin 3D balls 2018, Wikimedia Commons, the free media repository, viewed 17 August 2019,<
https://en.wikipedia.org/wiki/File:Riboflavin-3d-balls.png>.
5. Pedersen, A, Bardow, A, Jensen, SB & Nauntofte, B 2002, ‘Saliva and gastrointestinal functions of taste, mastication, swallowing and digestion’, Oral
Diseases, vol. 8, no. 3, pp. 117–129.
6. Campbell, I 2011,‘The mouth, stomach and intestines’, Anaesthesia & Intensive Care Medicine, vol. 13, no. 2, pp. 56–58.
7. Quain, J 1840, ’Anatomy of the mouth’, The viscera of the human body, viewed 17 August 2019
<https://www.flickr.com/photos/liverpoolhls/10825831536>.
8. Wikimedia Commons contributors 2017, 2404 PeristalsisN, Wikimedia Commons, the free media repository, viewed 17 August 2019,
<https://commons.wikimedia.org/wiki/File:2404_PeristalsisN.jpg>.
9. Physiologymodels n.d., Protein Digestion and Absorption, viewed 17 August 2019, <http://www.physiologymodels.info/digestion/proteins.htm>.
10.Boland, M 2016, ‘Human digestion – a processing perspective’, Journal of the Science of Food and Agriculture, vol. 96, no. 7, pp. 2275–2283.
11.Medicine LibreTexts 2019, 5.4: PROTEIN DIGESTION, ABSORPTION AND METABOLISM, viewed 17 August 2019
<https://med.libretexts.org/Courses/American_Public_University/APUS%3A_An_Introduction_to_Nutrition_(Byerley)>.
12.Wikimedia Commons contributors 2018, Regions of the Stomach, Wikimedia Commons, the free media repository, viewed 17 August 2019,
<https://commons.wikimedia.org/wiki/File:Regions_of_stomach.svg>.
13.OpenStax 2016,’ Protein Metabolism’, Anatomy and Physiology, OpenStax CNX, viewed 17 August 2019, <https://courses.lumenlearning.com/suny-
ap2/chapter/protein-metabolism/>.
14. Authors own image 2019 (unpublished)
15.Hammiverse.com, n.d., 41.1 Digestion in Humans - Overview and Protein Digestion, viewed 17 August 2019,
<http://www.hammiverse.com/lectures/41/1.html>.
References

19. References
16. Jochems, PGM, Garssen, J, van Keulen, AM, Masereeuw, R & Jeurink, PV 2018, ‘Evaluating Human Intestinal Cell Lines for Studying Dietary Protein
Absorption’, Nutrients, vol. 10, no. 3.
17. Authors own image 2019 (unpublished).
18. Vivo.colostate.edu, n.d., Absorption of Amino Acids and Peptides, viewed 17 August 2019
<http://www.vivo.colostate.edu/hbooks/pathphys/digestion/smallgut/absorb_aacids.html>.
19. Goodman, BE 2010, ‘Insights into digestion and absorption of major nutrients in humans.’, Advances in Physiology Education, vol. 34, no. 2, pp. 44–53.
20. Wikimedia Commons contributors 2017, Absorption of proteins in small intestine, Wikimedia Commons, the free media repository, viewed 17 August
2019 <https://commons.wikimedia.org/wiki/File:Absorption_of_proteins_in_small_intestine.png>.
21. Van der Wielen, N, Moughan, PJ & Mensink, M 2017, ‘Amino Acid Absorption in the Large Intestine of Humans and Porcine Models’, The Journal of
Nutrition, vol. 147, no. 8, pp. 1493–1498.
22. Basu & Donaldson 2003, ‘Intestinal absorption in health and disease: micronutrients’, Best Practice & Research Clinical Gastroenterology, vol. 17, no.
6, pp. 957–979.
23. Campbell, I 2011, ‘Digestion and absorption’, Anaesthesia & Intensive Care Medicine, vol. 13, no. 2, pp. 62–63.
24. Reboul, E 2013, ‘Absorption of Vitamin A and Carotenoids by the Enterocyte: Focus on Transport Proteins’, Nutrients, vol. 5, no. 9, pp. 3563–3581.
25. Bauer, E, Jakob, S & Mosenthin, R 2005 ’Principles of Physiology of Lipid Digestion’, Asian-Australasian Journal of Animal Sciences, vol. 18, no. 2, pp. 282-
295.
26. Authors own image 2019 (unpublished).
27. Nutrition Factors 2019, Vitamin B2 Riboflavin Absorption and Digestion, Nutrition Factors, viewed 13 August 2019,
<https://www.nutritionfactors.com/library/detail/vitamin-b2-riboflavin-absorption-and-digestion-1>.
28. Loomis, H 1999, ‘Protein’, Chiropractic Journal, vol. 13, no. 8, p. 41.
29. Van De Walle, G 2018, 9 Important Functions of Protein in Your Body, Healthline, viewed 17 August 2019
<https://www.healthline.com/nutrition/functions-of-protein>.
30. Debelo, H, Novotny, JA & Ferruzzi, MG 2017, ‘Vitamin A’, Advances in Nutrition, vol. 8, no. 6, pp. 992–994.
31. Goldstein, MC, & Goldstein, MA 2018, Vitamins and Minerals: Fact Versus Fiction, ABC-CLIO, LLC, 2018 ProQuest Ebook Central,
<https://ebookcentral.proquest.com/lib/unisa/detail.action?docID=5351444>.
32. OpenStax 2016, ’24.4 Protein Metabolism’, Anatomy & Physiology, OpenStax CNX, viewed 15 August 2019, <http://cnx.org/contents/14fb4ad7-39a1-
4eee-ab6e-3ef2482e3e22@8.25>.