Vitamin C is the queen of vitamins, of which we constantly seem to fall short. The established recommendations just might not quite cut it – an issue that is not unknown in the scientific community and has long been taught by advocates of natural health and nutritional supplements.
However, supplements are not always the optimal way to go, and in the case of vitamin C, there is an important root cause that needs to be addressed: Humans need a diet much higher in fruits and vitamin C than we previously thought, and there is quite an astonishing evolutionary and dietary reason for that!
In this article, we take the bigger biological perspective and calculate the amount of vitamin C that mammals usually get in nature. Recognizing our unique vitamin C condition also helps to – finally – understand what a natural and regenerative diet of humans looks like!
For quick readers:
When comparing humans to other omnivorous mammals, including chimpanzees, it is apparent that we need around 2000-3000 mg of vitamin C daily and a diet high in fruits. The pattern found in animals is in alignment with long-term proponents of high-vitamin C intake and scientific research on the benefit of high-dosage vitamin C therapies.
Humans are unique: we don’t produce our own vitamin C!
Humans need to get vitamin C via diet, while most other mammals do not. But why? Because humans, and other animals with a high-fruit diet, have lost their vitamin C production during the course of evolution. That humans have dysfunctional vitamin C genes has far-reaching implications for the human diet:
Our ancestors had a high-fruit diet, and we still need a lot of vitamin C for optimal health!
How much fruit and vitamin C we really need, is what we explore below in this article.
It’s simple – but important: All apes, most primates, and other frugivorous mammalian species do not produce vitamin C, because they get the compound in abundance via their natural diet. To understand our own diet and the role of fruits, we can learn from chimpanzees, but also other mammals in a comparative approach.
Not convinced yet that we are high-fruit beings? We have an in-depth article on the adaptive characteristics of frugivorous primates and humans!
Vitamin C intake recommendations are too low!
And here is why: The common recommendation for Vitamin C is much lower than the amount of vitamin C mammals get and need in nature, whether from their diet or internal production. The Recommended Dietary Allowance (RDA) for humans is around 75-90 mg.
The average of vitamin C in 100 g of fruit is around 25-30 mg, with a range of around 5-60 mg for most fruits (with some exceptions that have a very high content). To reach the RDA, we need to eat around 200-300 grams of fruits daily. But, is this really enough for optimal health?
Let’s look at our closest relatives, the chimpanzees:
Chimpanzees eat around 3-6 kg of fruit daily, equaling approximately 1000 – 2000 mg of vitamin C (body weight between 30-60 kg). This is around 25 times more than the RDA for humans, for the corresponding body weight.
Chimpanzees and humans are both species that do not produce vitamin C internally and, generally, are very similar physiologically. To illustrate this: In zoos, the RDAs for humans are used to establish the dietary guidelines for chimpanzees in captivity.
But maybe, the chimpanzee diet is just high in fruits, which happens to be high in vitamin C as a “side effect”? Or do they actually need that much of the essential compound?
To answer this, we can compare the vitamin C intake of the fruit-loving omnivorous apes to non-frugivorous omnivores. Dogs, for example, is a species that still have functional vitamin C genes and, thus, do not depend on external sources. And after calculating, we find that they have around the same amount of vitamin C per kg body weight as chimpanzees!
Comparing Vitamin C requirement of humans with other mammals
Body weight 30 kg:
| Species | Vit C-source | Vit C per kg body weight (mg) | Daily vit C (mg) |
|---|---|---|---|
| Dog | internal | 36 | 1080 |
| Chimpanzee | diet | 33 | 1000 |
| Human | diet | 1.2 | 35 |
| Goat | internal | 200 | 6000 |
Body weight 60 kg:
| Species | Vit C-source | Vit C per kg body weight (mg) | Daily vit C (mg) |
|---|---|---|---|
| Dog | internal | 36 | 2160 |
| Chimpanzee | diet | 33 | 2000 |
| Human | diet | 1.3 | 75 |
| Goat | internal | 200 | 12000 |
Dogs produce around 36 mg of vitamin C per kg body weight. So a 30-kg dog produces around 1000 mg (corresponds to a small-sized chimpanzee in body weight and vitamin C intake), while a 60-kg dog produces around 2000 mg (corresponds to a large-sized chimpanzee in body weight and vitamin C intake).
The amount of natural vitamin C is very similar in a frugivorous and non-frugivorous omnivore species in this example. So why should this be markedly different in humans? The thing is, it is probably not!
The high vitamin C intake of chimpanzees counters the possible argument that frugivores (including humans) need less vitamin C than other species due to their compensatory mechanisms: Humans and other frugivores make up for their broken vitamin C production by recycling vitamin C. This adaptation is not present in species with intact vitamin C genes. Read more here.
How much vitamin C is optimal for humans?
Taking the RDA of vitamin C can prevent a severe deficiency like scurvy, but it is not nearly enough to reach optimal levels. Naturally, mammals seem to need around 36 mg of vitamin C per kg body weight.
This equals around 2000 mg of vitamin C for an adult woman and 3000 mg for an adult man. And while these values are based on calculations and theory, they are in accordance with many proponents of “high-dosage” vitamin C therapies and research.
Humans are still biological frugivores and need a high-fruit diet to obtain optimal vitamin C intake of around 2000 – 3000 mg of vitamin C per day.
What does scientific research say about high dosages of vitamin C?
Overdosing vitamin C from whole food sources is not known. And even taking high dosage-supplements up to 3000 mg, which contain isolated, synthetic vitamin C, are nontoxic. More than these amounts can cause some side effects limited to gastrointestinal disturbances and an extra burden on the excretion organs of people with pre-conditions.
Linus Pauling, a Nobel-Prize-winning chemist, already proposed over 50 years ago, that vitamin C is therapeutic when given in very high dosages short time, but also safe and effective in higher dosages than the common recommendations if taken long term (source). Today, scientific literature points towards IV infusions of vitamin C in high dosages (ca. 10 grams daily) being more effective as therapeutic for serious conditions than oral administration. Oral vitamin C intake may take longer to unfold its benefits than infusions – comparable to iron infusion versus oral intake. High-dose IV vitamin C protocols have been tested over and over in scientific research (see a few amazing examples here, here and here.).
Not having optimal levels of vitamin C has impacts on health and even on other nutrients! Having optimal vitamin C intake is thus crucial to balance our nutrients:
How to get enough vitamin C?
Eat a diet high in fruits, especially tropical fruits. Additionally, you can take natural supplements with vitamin C superfruits, like camu camu.
In times of “war against sugar” this recommendation might seem odd, but adopting a diet high in fruits is the way to go if you aim to stick closely to the natural human diet. We come from a highly frugivorous ancestry and still carry the typical adaptations for eating fruit. In science, it is a consensus that fruits are highly beneficial for health. However, most are not aware that we actually have evolved with high-fruit diets. To put this into perspective, our closest relatives, the chimpanzees, have a diet that consists of around 70% fruits!
You can integrate as many ripe, high-quality fruits into your diet as you can, as in this regard, we can trust our natural instincts -because we are tropical frugivores! This is also the reason why tropical fruits have a special role in the human diet. For more in-depth on the natural human diet, check out our guide!
Optimal vitamin C intake can substitute many other nutritional supplements
Because we cannot get enough Vitamin C in a modern diet (as we are adapted to a very high-fruit diet), most of us do not get an optimal amount of this key nutrient! The vital substance is involved in the metabolism of many other biochemical molecules. If we do not address the underlying shortcoming of Vitamin C, we are only treating the symptoms by taking in the lacking components!
Vitamin C is vital and essential for our organism and is required (here and here) in many important metabolic processes:
- as the most abundant water-soluble antioxidant (electron donor)
- for iron uptake, by forming a chelate with iron and lowering hepcidin (protein build by the body to block iron uptake)
- in regenerating (recycling) vitamin E by reducing the radicalized form of vitamin E after its done its action.
- in collagen synthesis (skin and cartilage health)
- in the synthesis of carnitine
- in neurotransmitter synthesis
- in metabolic processes, directly or indirectly
- in stabilizing folate (preventing its oxidation), enhancing folate status
- in amino acid metabolism
The far-reaching functions and vital role of vitamin C indicate that obtaining optimal levels of vitamin C through diet – which is only possible on a high-fruit diet – would positively impact other nutrients (directly or indirectly) and might substitute taking many nutritional supplements, rendering them unnecessary!
For example, carnitine and collagen are two popular supplements believed to be necessary, especially on a plant-based diet. However, the body produces them when vitamin C is present to do so. Folic acid and iron are other nutrients that are often said to be in short supply, while sub-optimal vitamin C intake is likely an underlying cause for deficiencies!
Our condition as tropical frugivores being limited in our natural food intake (mainly tropical fruits) and the consequent shortfall in vitamin C certainly has the potential to answer some fundamental questions regarding the need of many nutritional supplements.
Conclusion: Getting higher vitamin C levels is a game changer in nutrition!
Frugivores – including humans – do not synthesize vitamin C, because their species-specific diet contains high amounts naturally. Therefore, vitamin C is an essential micronutrient they need to obtain from the diet in large quantities! Humans, however, do not obtain nearly enough of it in most modern diets, which are “deficient” in fruit!
This is why vitamin C is such a huge deal in health – and why only a high-fruit diet can really address the root cause! Learn more about the human species-appropriate high-fruit diet here:
If you are new to this, visit this overview about frugivores and frugivory here!
Go to How to do the Frugivore Diet
References
- By the way, doctor: What’s the right amount of vitamin C for me? (2023) Harvard Health. Available at: https://www.health.harvard.edu/staying-healthy/by-the-way-doctor-whats-the-right-amount-of-vitamin-c-for-me (Accessed: 28 July 2023).
- Vitamin C recommendations may be too low, according to New Analysis (no date) Medical News Today. Available at: https://www.medicalnewstoday.com/articles/vitamin-c-revisiting-controversial-study-may-change-recommendations (Accessed: 28 July 2023).
- Gantt, E. (2023) Vitamin C for dogs: Functions, recommended intake, and more, Wag! Available at: https://wagwalking.com/wellness/vitamin-c-for-dogs# (Accessed: 31 July 2023).
- CellPressNews (2008) How humans make up for an ‘inborn’ vitamin C deficiency, EurekAlert! Available at: https://www.eurekalert.org/news-releases/900561 (Accessed: 31 July 2023).
- How humans make up for an ‘inborn’ vitamin C deficiency (2008) ScienceDaily. Available at: https://www.sciencedaily.com/releases/2008/03/080320120726.htm (Accessed: 31 July 2023).
- Pauling, L. (1971) ‘Vitamin C and common cold’, JAMA: The Journal of the American Medical Association, 216(2), p. 332. doi:10.1001/jama.1971.03180280086025.
- Kashiouris, M.G. et al. (2020) ‘The emerging role of Vitamin C as a treatment for sepsis’, Nutrients, 12(2), p. 292. doi:10.3390/nu12020292.
- Huang, L. et al. (2021) ‘High-dose vitamin C intravenous infusion in the treatment of patients with covid-19’, Medicine, 100(19). doi:10.1097/md.0000000000025876. Böttger, F. et al. (2021) ‘High-dose intravenous vitamin C, a promising multi-targeting agent in the treatment of cancer’, Journal of Experimental & Clinical Cancer Research, 40(1). doi:10.1186/s13046-021-02134-y. Kashiouris, M.G. et al. (2020) ‘The emerging role of Vitamin C as a treatment for sepsis’, Nutrients, 12(2), p. 292. doi:10.3390/nu12020292.
- Langley, P.C. et al. (2015) ‘Antioxidant and associated capacities of camu camu (myrciaria dubia): A systematic review’, The Journal of Alternative and Complementary Medicine, 21(1), pp. 8–14. doi:10.1089/acm.2014.0130.
- G. Drouin, J.-R. Godin, B. Page, The genetics of vitamin C loss in vertebrates. Current Genomics. 12, 371–378 (2011), doi:10.2174/138920211796429736.
- S. Chambial, S. Dwivedi, K. K. Shukla, P. J. John, P. Sharma, Vitamin C in disease prevention and cure: An overview. Indian Journal of Clinical Biochemistry. 28, 314–328 (2013), doi:10.1007/s12291-013-0375-3.
- Lynch, S.R. and Cook, J.D. (1980) ‘Interaction of vitamin C and iron’, Annals of the New York Academy of Sciences, 355(1 Micronutrient), pp. 32–44. doi:10.1111/j.1749-6632.1980.tb21325.x.
- Chiu, P.-F., Ko, S.-Y. and Chang, C.-C. (2012) ‘Vitamin C affects the expression of hepcidin and erythropoietin receptor in hepg2 cells’, Journal of Renal Nutrition, 22(3), pp. 373–376. doi:10.1053/j.jrn.2011.09.007.
- Deshmukh, A.R. and Kim, B.S. (2019) ‘Chitosan-vitamin C nanoparticles’, KSBB Journal, 34(4), pp. 221–232. doi:10.7841/ksbbj.2019.34.4.221.
- Paladugula, N. et al. (2019) ‘Serum folate forms are stable during repeated analysis in the presence of ascorbic acid and during frozen sample storage’, The Journal of Applied Laboratory Medicine, 3(6), pp. 993–1002. doi:10.1373/jalm.2018.027102.
- Alcazar Magana, A. et al. (2020a) ‘Vitamin C activates the folate-mediated one-carbon cycle in C2C12 myoblasts’, Antioxidants, 9(3), p. 217. doi:10.3390/antiox9030217.
Could you be more precise on the role of vitamin C
in catabolic processes
in the folic acid metabolism
in the amino acid metabolism, which amino acid? or multiple.
thanks
JS
Thank you for your questions. The most prominent functions of vitamin C are as a potent antioxidant, and as a co-factor for enzymes, and histone demethylation – all of which plays a role in metabolic function, directly and indirectly. Vitamin C is directly involved in the hydroxylation of proline and lysine (find a list here). For more in-depth information on the other functions that I mentioned (including the link to folic acid), kindly visit the original source of the text here. I corrected catabolic into metabolic functions. Thanks for improving the article!