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Why We Need More Vitamin C than We Think. Recommendations From a Natural Perspective.

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 that of non-frugivorous omnivores. Dogs, for example, are 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 the vitamin C requirement of humans with other mammals

Mammals that are able to synthesize vitamin C in the liver get approximately the same amounts as frugivores, which get vitamin C from their diet. The only animals that fall out of the range are humans: humans get way less if we follow the standard recommendation of around 75-90 mg! And this is without even considering that animals increase vitamin C production during stress! For example, guinea pigs, which are highly frugivorous, need around 30 mg of vitamin C from their diet per day (they weigh about 1 kg). Pregnant or nursing guinea pigs need around double this amount (preciselypets.com).

Whether from diet or internal production, the amount of vitamin C that mammals get in nature is much higher than what is recommended for humans. So why are humans so markedly different in their vitamin C requirements than other animals? The thing is, we are probably not! Most of us do not get nearly enough vitamin C as we should optimally get in nature! So how much should we get? See below…

Here is a table that compares different species and how much vitamin C they get, either from diet or from internal production. Humans get much less vitamin C than all other mammals if they follow the official recommendations!

Species (body weight)Vit C-sourceDaily Vit CVit C per kg body weight
Human (60 kg)diet75 mg1-2 mg
Chimpanzee (60kg)diet2000 mg33 mg
Guinea Pig (1 kg)diet30 mg30 mg
Dog (30 kg)internal1080 mg36 mg
Goat (60 kg)internal12000 mg200 mg
Comparison of the vitamin C requirement in different mammalian species. Frugivorous species obtain vitamin C from diet.
Diet of the species listed are 1. humans (fruit-eating omnivores); 2. chimpanzees (fruit-eating omnivores); 3. guinea pigs (frugivorous herbivores); 4. dogs (meat-eating omnivores); 5. goats (herbivores). All values are calculated approximations. While there is variation between species, humans have an exceptionally low vitamin C intake, when taking the RDA (Recommended Dietary Allowance) as the value.

Do species with broken vitamin C genes (frugivores) need as much vitamin C as other species? Humans and other frugivores compensate 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). However, the high dietary vitamin C intake of chimpanzees and guinea pigs in nature counters the argument that frugivores (including humans) need less vitamin C than those species that produce their vitamin C internally.

How much vitamin C is optimal for humans?

Taking the RDA of vitamin C can prevent severe deficiency like scurvy, but it is not nearly enough to reach optimal levels. Naturally, mammals seem to need a minimum of around 30-35 mg of vitamin C per kg body weight, either from diet or internal production.

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. Even the officially recommended “upper limit” for adults is 2,000 mg a day. The Mayo Clinic states: “The upper limit for all adults is 2,000 mg a day. Although too much dietary vitamin C is unlikely to be harmful, large doses of vitamin C supplements might cause: Diarrhea.” (K. Zeratsky)

The human biology is that of a frugivore. We need a high-fruit diet to obtain an optimal vitamin C intake of around 2000 – 3000 mg daily. We should consider natural supplements if we cannot get this via diet.

Humans obviously can survive on much lower vitamin C than 2000-3000 mg per day, and the officially recommended amount of 75-90 mg prevents scurvy (severe vitamin C deficiency symptoms). But, we do not nearly get the optimal amount of vitamin C, which is our body’s key antioxidant. This might explain why antioxidant polyphenol-rich foods are so healthy for us – because we constantly fall short of vitamin C and need more anti-oxidant power!

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 biologically appropriate diet naturally contains high amounts of the essential compound. Humans, however, do not obtain nearly enough of it in most modern diets, which are “deficient” in fruit!

This is why increasing vitamin C is such a huge deal for recovery and improving health in general. It is also the reason why only a high-fruit diet can really address the root cause! Learn more about the human species-appropriate high-fruit diet here:


  1. Hooper, M.H., Carr, A. and Marik, P.E. (2019) ‘The adrenal-vitamin C axis: From fish to guinea pigs and primates’, Critical Care, 23(1). doi:10.1186/s13054-019-2332-x. 
  2. Jenna (2023) 17 foods for guinea pigs that are high in Vitamin C, Precisely Pets. Available at: https://preciselypets.com/foods-for-guinea-pigs-high-in-vitamin-c/ (Accessed: 22 November 2023). 
  3. 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). 
  4. Katherine Zeratsky, R.D. (2022) How much vitamin C is too much?Mayo Clinic. Available at: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/vitamin-c/faq-20058030#:~:text=The%20upper%20limit%20for%20all,Diarrhea (Accessed: 22 November 2023). 
  5. 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). 
  6. Gantt, E. (2023) Vitamin C for dogs: Functions, recommended intake, and moreWag! Available at: https://wagwalking.com/wellness/vitamin-c-for-dogs# (Accessed: 31 July 2023). 
  7. CellPressNews (2008) How humans make up for an ‘inborn’ vitamin C deficiencyEurekAlert! Available at: https://www.eurekalert.org/news-releases/900561 (Accessed: 31 July 2023). 
  8. 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). 
  9. 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. 
  10. 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. 
  11. 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. 
  12. 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. 
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  • 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.

    • 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!

  • Hi Martina,

    I came across your website (which is excellent!), and I immediately thought you would be very interested in a novel theory of human evolution/devolution, created and refined over 25 years by a friend named Tony Wright.

    Rather than try to explain it to you, I will give you several links so you can see for yourself:

    Book: Left In The Dark – https://www.unwelcomeguests.net/archive/652/Left%20in%20the%20Dark.pdf

    Website: https://childrenoftheforest.info/

    Videos: https://youtu.be/jXwwsJUMoQg?t=183



    After you get familiar with the theory, you will clearly see how important a frugivorous diet was and is for the human animal throughout its history. I realize you already know that, but Tony’s theory elevates the importance of fruit diet several steps higher than ever considered before. Indeed, over the past 10’s of thousands of years, humanity has been rapidly devolving, and our brain degenerating, precisely because of our exit from our tropical forest home, and the plethora of fruit it contains.

    If you do find this interesting, please let me know, and we can discuss further if you like.

    All The Best To You!


    • Hi Robert,

      thank you so much for your comment and the links! I will study them and get back to you soon.

      I am working on a book on truth in the human diet, which I would love to become a great work joined by enthusiasts of the field. I have been contacted by many interesting, knowledgable people over the last year, who I will all ask to contribute or join once I am ready. I think it’s about time we unite and speak up. Especially now that shadow-banning of this infos is an increasing problem.

      I see you left your email address here, so I will contact you there. Thanks again!

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Martina Spaeni Lima, MSc

"We are frugivores - specialized fruit-eaters!" It was passion at first sight when I came across the intriguing concept that humans are adapted to a high-fruit diet, similar to chimpanzees...

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