For as long as vitamin C has been known as the "antiscorbutic factor" (preventing or curing scurvy, a symptom of vitamin C deficiency), most scientific evidence has suggested that humans cannot produce vitamin C and must get it from food.

However, tantalizing evidence suggests that some humans might be able to produce vitamin C and that there might be a way to induce vitamin C production in all or most of us.

And I'm pretty sure this woman is confident that she produces vitamin C ...

If you would like to know how your body might be able to produce its own vitamin C, read on.

This is the fourth article in a series about vitamin C. You can access the first three articles at the links below:

1. Vitamin C: Superpowers, Ordinary Powers, and Common Questions
2. How To Stop Vitamin C From Forming Oxalates
3. What Is The "Real" Vitamin C?

Why We (Usually) Cannot Produce Vitamin C (Ascorbic Acid)

By the way, if you doubt that vitamin C and ascorbic acid are one and the same thing, at least in mammals, including humans, read the previous article, What Is The "Real" Vitamin C?.

In mammals that can produce ascorbic acid, glucose is converted to ascorbic acid via a four-step process. The last step in the process is catalyzed by an enzyme called L-gulonolactone oxygenase (GULO). In humans, the GULO gene that codes for the GULO enzyme appears to contain an extensive number of mutations compared to the GULO gene in species that can produce ascorbic acid. (1)

Do Some Humans Actually Produce Ascorbic Acid?

However, very young humans possess levels of ascorbic acid that suggest the possiblity that humans might produce ascorbic acid early in life and then lose that capacity.

For example, in the forebrain of the human fetus between 4 and 11 weeks gestational age, ascorbic acid levels are four to eleven times as high as in an adult forebrain, and the ascorbic acid concentration in umbilical cord blood is four times as high as in maternal blood. (2) But this could simply be due to processes in the fetus that concentrate ascorbic acid to support development. 

In other research, breast-fed babies showed two times higher blood levels of ascorbic acid, and this was relatively independent of the ascorbic acid concentration of the mother's breast milk. (3) But this could simpbly be due to the infants' ability to upregulate endogenous antioxidant enzymes like gluthathione to recycle vitamin C.

The infants of Bantu communities in South Africa never present with scurvy or vitamin C deficiency, despite very minimal vitamin C intake (3 to 8 mg/day), leading the investigators to conclude that "the only alternative is to postulate an endogenous production of the vitamin". (4) It is harder to explain this away by an upregulation of glutathione for recycling of vitamin C.

Some adults might also be able to produce their own ascorbic acid. In one study, a woman maintained high blood levels of ascorbic acid as her intake decreased. Another woman went 149 days without any significant dietary vitamin C intake, without developing deficiency symptoms. (5) Could the blood levels of vitamin C in these two women have been maintained from storage sites in the body, like the adrenal glands? Not likely at all, and probably impossible, because the body's capacity to store vitamin C is too limited.

Can Some Guinea Pigs Produce Ascorbic Acid?

More striking evidence of ascorbic acid production in a species generally known to be incapable of ascorbic acid production has been observed in female guinea pigs deprived of exogenous ascorbic acid for long periods. After 8 months of ascorbic acid deprivation, one animal was observed to have an ascorbic acid concentration in its liver that was twice as high as that in other guinea pigs that were on a daily intake of 10 mg ascorbic acid. The authors concluded, "It is evident that certain guinea pigs are capable to synthesize ascorbic acid that fully covers the needs of the organism." (6) 

Since humans and guinea pigs have lost the ability to produce ascorbic acid, at least in most cases, the fact that some guinea pigs still produce ascrobic acid lends weight to the possibility that some humans might also be able to produce ascorbic acid.

How Might Some Humans Produce Ascorbic Acid?

So if some guinea pigs, and perhaps some humans as well, at least early in life, might be able produce ascorbic acid, how could this be so? The answer may lie in what type(s) of DNA mutations impair our ascorbic acid production.

DNA provides the "code" for producing substances in the body, mainly proteins. DNA is transcribed into a mirror image molecule called messenger RNA (mRNA) that travels to cellular structures called ribosomes that read the mRNA as an instructional template for stringing together amino acids to form a target protein. The ribosome starts readsing the mRNA from a short sequence called a "start codon" and stops reading the mRNA at a short sequence called a "stop codon".

Several types of mutations in DNA cause a target protein (e.g. an enzyme like GULO) to be dysfunctional. One type of mutation codes for the substitution of one amino acid for another amino acid, which causes varying degrees of alteration in the function of the protein. Genes with multiple mutations of this kind are more likely to generate completely non-functional proteins. This type of mutation cannot be overcome except by correcting the DNA sequence.

Another type of genetic mutation results in a stop codon being placed prematurely in the mRNA sequence, interrupting the construction of the target protein's amino acid sequence before it is complete. However, certain substances have been shown to enable the ribosome to skip over the stop codon and continue producing the complete protein. This is called "readthrough". 

For example, resveratrol and other compounds have been shown to enable readthrough of mRNA to produce functional hemoglobin in the disease beta-halassemia, a genetic disorder in which hemoglobin production is severly impaired. (7)

If the typical absence of ascorbic acid production in humans has anything to do with a premature stop codon in the mRNA for producing the GULO enzyme, might there be a compound that could promote readthrough that skips over the stop codon to produce the whole (and possibly functional) GULO enzyme, thereby enabling ascorbic acid production in humans?

In a human study of 14 individuals taking 45mg daily of hydroxytyrosol, a polyphenol found in olives, the level of ascorbic acid in blood doubled. (8) However, this could have been due to upregulation of endogenous antioxidant enzymes like glutathione, which recycles ascorbic acid.

Nevertheless, these results raise the intriguing possibility that hydroxytyrosol might promote readthrough of a premature stop codon in the mRNA sequence for the GULO enzyme, potentially restoring ascorbic acid production in humans. Obviously, more research is certainly needed to clarify whether this is indeed happening.

Don't Let Polyphenol Intolerance Block Your Potential Ascorbic Acid Production

As promising as hydroxytyrosol might be as a readthrough agent for GULO transcription and ascorbic acid production, people who have low tolerance of phenols might be blocked from obtaining this potential benefit of hydroxytyrosol consumption if they cannot tolerate taking hydroxytyrosol. 

Phenol intolerance is often undiagnosed in people experiencing it because not many practitioners are looking for it, and the symptoms can look like many other conditions. Phenol intolerance is generally due to nutrient deficiencies and genetic mutations affecting a person's sulfation capacity, and it can be due a certain type of intestinal dysbiosis.

I have had one client that reacted negatively to olive oil (a source of hydroxytyrosol) due to an apparent phenol intolerance that seemed to be caused by dysbiosis and a genetically impaired ability to produce sulfate for the sulfation of phenols. 

If you want support with a health issue, whether or not it relates to dysbiosis, intolerances, or nutrient deficiencies, feel free to schedule a time to chat about whether I might be able to help. To do that, schedule a 15-minute conversation or first learn more about my approach by downloading the Bio-Individual Blueprint Roadmap and watching the walkthrough video.