Vitamin C

Ascorbic acid structure.png

Ingredient name: Vitamin C / L-Ascorbic Acid

Chemical Formula: C6H8O6

Quantity of Vitamin C in one pouch of Soylent: 60 mg

Food and Drug Administration Recommended Daily Value: 60 mg/day

Nutrition role

Vitamin C's role in the body is centered on its function as an antioxidant - a substance that can quickly donate an electron to stop a damaging oxidation reaction.[1] Vitamin C not only stops oxidation reactions, but can also "recharge" other antioxidants such as vitamin E.[2]

In one example of some of its biochemical functions, Vitamin C couples with enzymes as what is termed a "cofactor". The electron-donating ability of the vitamin, in conjunction with the structure and function of the associated enzyme, play a role in the synthesis of a wide variety of compounds.

Some examples of vitamin C-cofactor-synthesized compounds include the neurotransmitter norepinephrine,[3] as well as  collagen,[4] the most abundant protein in the body[5] and a major structural component of connective tissue.

Prophylactic effects

The immune system is one of the regions of high vitamin C levels in the body. Specifically, vitamin C is highly concentrated in neutrophils - a type of leukocyte, or white blood cell (a major component of the body's immune system). While research suggests that a vitamin C deficiency might reduce leukocyte efficacy,[6] there isn't yet a clear correlation between consumption of vitamin C in amounts greater than levels necessary to prevent deficiency and improved immune response or recovery rates to the common cold.[7],[8],[9] 

There is, however, conclusive data which shows that, under normal physiological conditions, vitamin C absorption into the body drops drastically at consumption levels greater than one gram.[10]

In some studies, intake of vitamin C has been loosely correlated with reducing long-term risks for certain types of cancer.[11] However, the data produced isn't able to attribute with certainty that the reduced risks of cancer are due to vitamin C and not, for example, the overall healthier lifestyle that one who consumes adequate quantities of vitamin C might have.[12]

Further research is needed in order to better understand the mechanisms by which vitamin C affects cancer risk as well as its roles in immune system function. However, vitamin C's critical antioxidant functions in reducing oxidative stress in the body is well-documented.

Absorption mechanism

Vitamin C is absorbed via the villi in the small intestine. After absorption, vitamin C travels through veins to the liver. A small amount of vitamin C stays in liver cells, but the majority - along with many other absorbed nutrients - is filtered by the liver (to remove toxins and regulate concentrations of nutrients in the blood[13])  and passes through into the general circulatory system, where the water-soluble vitamin is distributed throughout the body.[14]

The FDA's daily value of 60 mg is designed to provide a complete body pool of 900 to 1,500 mg of vitamin C - a quantity deemed sufficient to act as a buffer for times of low intake and physiologic stresses.[15]

Reason this form chosen:

Ascorbic acid is equally bioavailable in natural and synthetic forms, which are indistinguishable.[16] 

[1] In an oxidation reaction, a free radical with a high electronegativity (often an oxygen- or nitrogen-based compound) "pulls" electrons from other molecules, which can cause the molecule to weaken or break apart. Free radicals are continuously generated as a bi-product of many normal chemical reactions in the body, which is why it is important to maintain adequate levels of antioxidants such as vitamins C and E in order keep the total number of free radicals low.

[2] Vitamin C recharges (scientific term is "reduction") antioxidants by giving those that have already donated their electron a replacement electron. Because vitamin C only has 1 electron available to donate, it must be regenerated (reduced) itself, where it receives an electron from an antioxidant called glutathione)

[3] Erdman, John W., Ian MacDonald, and Steven H. Zeisel. "Vitamin C." In Present Knowledge in Nutrition, 251. Washington, DC: International Life Sciences Institute, 2012.

[4] Myllylä, R., K. Majamaa, V. Günzler, H. M. Hanauske-Abel, and K. I. Kivirikko. "Ascorbate Is Consumed Stoichiometrically in the Uncoupled Reactions Catalyzed by Prolyl 4-Hydroxylase and Lysyl Hydroxylase." The Journal of Biological Chemistry 259, no. 9 (1984): 5403-405. 

[5] Di Lullo, G. A., S. M. Sweeney, J. Körkkö, L. Ala-Kokko, and J. D. San Antonio. "Mapping the Ligand-binding Sites and Disease-associated Mutations on the Most Abundant Protein in the Human, Type I Collagen." The Journal of Biological Chemistry 277, no. 6 (2001): 4223-4231. 

[7] Pauling, L. "The Significance of the Evidence about Ascorbic Acid and the Common Cold." Proceedings of the National Academies of Sciences of the United States of America 68, no. 11 (1971): 2678-2681. 

[8] Jacob, R. A., Sotoudeh, G. "Vitamin C Function and Status in Chronic Disease." Nutrition in Clinical Care 5, no. 2 (2002): 66-74. 

[9] Sasazuki, S., Sasaki, S., Tsubono, Y., Okubo, S., Hayashi, M., Tsugane, S. "Effect of Vitamin C on Common Cold: Randomized Controlled Trial. European Journal of Clinical Nutrition 60, no. 1 (2006): 9-17. 

[10] See footnote 8.

[11] Cho, E., Hunter, D. J., Spiegelman, D., Albanes, D., Beeson, W. L., van den Brandt, P. A., Colditz, G. A., Feskanich, D., Folsom, A. R., Fraser, G. E., Freudenheim, J. L., Giovannucci, E., Goldbohm, R. A., Graham, S., Miller, A. B., Rohan, T. E., Sellers, T.A., Virtamo, J., Willett, W. C., Smith-Warner, S. A. "Intakes of Vitamins A, C and E and Folate and Multivitamins and Lung Cancer: A Pooled Analysis of 8 Prospective Studies." International Journal of Cancer 118, no. 4 (2006): 970-978. 

[12] See footnote 8.

[13] Reece, Jane B., Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, and Robert B. Jackson. "Animal Nutrition." In Campbell Biology, 888. Ninth Edition, Global ed. San Francisco, CA: Pearson, 2011.

[14] Stipanuk, Martha H., and Marie A. Caudill. "Vitamin C." In Biochemical, Physiological, and Molecular Aspects of Human Nutrition, 630. Third Edition ed. St. Louis: Elsevier, 2013.

[15] See footnote 8.

[16] Stipanuk, Martha H., and Marie A. Caudill. "Vitamin C." In Biochemical, Physiological, and Molecular Aspects of Human Nutrition, 629. Third Edition ed. St. Louis: Elsevier, 2013.