Does Vitamin C Come From Animals? Understanding Ascorbic Acid Sources

December 26, 2025 •

4 min read

An estimated 5.9% of the U.S. population suffers from vitamin C deficiency, and it’s a critical nutrient for human health. This raises the question for many: does vitamin C come from animals, or must we rely exclusively on plant-based foods to meet our daily needs?

Quick Summary

Most animals can produce their own vitamin C internally, while humans must obtain it from food. Some raw animal products contain small amounts, but fruits and vegetables are the most reliable and abundant sources for a balanced diet.

Key Points

Animal Synthesis: Most animal species produce their own vitamin C internally and do not need to consume it in their diet.
Human Dependency: Due to a genetic mutation, humans and a few other species cannot produce vitamin C and must obtain it from external dietary sources.
Trace Amounts in Meat: Only trace amounts of vitamin C are found in raw muscle meat, and this is completely destroyed during cooking.
Organ Meat Exception: Raw organ meats, such as liver and spleen, contain a higher concentration of vitamin C compared to muscle meat, but still less than most fruits and vegetables.
Plant Sources are King: Fruits and vegetables are the most reliable, practical, and abundant sources of vitamin C for humans.
Carnivore Diet Theory: In the absence of dietary carbohydrates, some believe the body's need for vitamin C is reduced, allowing smaller amounts from raw animal foods to be sufficient.
Scurvy's Cause: The disease scurvy, a historical plague among sailors, is a direct result of chronic vitamin C deficiency from a lack of fresh plant foods.

The Surprising Truth: Most Animals Make Their Own Vitamin C

In a fascinating quirk of evolution, the majority of animal species on Earth do not need to consume vitamin C in their diet because their bodies produce it automatically. This is thanks to a functioning gene that synthesizes the necessary enzyme, L-gulonolactone oxidase, which converts glucose into ascorbic acid. In these species, such as dogs, cats, goats, and many mammals, vitamin C is not technically a 'vitamin' at all, as a vitamin is, by definition, a nutrient that cannot be synthesized by the body and must be obtained from the diet.

The Evolutionary Gap: Why Humans Cannot Produce Vitamin C

Humans belong to a small group of animals that cannot produce their own vitamin C. This includes other primates (apes, monkeys, tarsiers), guinea pigs, and certain bats. Our ancestors experienced a genetic mutation in the L-gulonolactone oxidase gene that deactivated it. Because early primates had a diet rich in vitamin C from fruits and plants, there was no evolutionary pressure to maintain the gene's function. The mutation was not lethal and was passed down, leading to our current dependence on external sources.

Animal-Based Sources of Vitamin C: Minimal and Unreliable

While animals create vitamin C internally, the levels found in the muscle meat commonly consumed by humans are minimal. Any trace amounts are highly sensitive to heat and are largely destroyed during cooking. However, there are some exceptions that hold a small amount of the vitamin:

Organ Meats: Raw organ meats, particularly liver, spleen, and brain, contain higher levels of vitamin C than muscle meat. For instance, raw beef liver can contain a small amount of vitamin C, though still significantly less than many fruits.
Fish Roe: This animal-based product is another source that contains some vitamin C.
Raw vs. Cooked: The distinction between raw and cooked animal products is critical. Cooking destroys vitamin C, meaning that a well-cooked steak offers virtually none of the nutrient, even if the raw meat had a trace amount.

Plant-Based vs. Animal-Based Vitamin C Content

For a clear picture, consider the comparative levels of vitamin C in different foods. This comparison highlights why plant-based sources are considered the standard for human dietary intake.


Food Source	Vitamin C per 100g (approx.)	Notes
Plant-Based Sources
Kakadu Plum	1000–5300 mg	Extremely high concentration.
Camu Camu	2800 mg	Extremely high concentration.
Acerola Cherry	1677 mg	Very high concentration.
Bell Peppers (Yellow)	183 mg	Excellent source.
Kale	120 mg	Good source.
Broccoli	90 mg	Good source.
Orange	53 mg	Well-known source.
Animal-Based Sources (Raw)
Beef Spleen	~45.5 mg	A concentrated but raw source.
Beef Liver	~31 mg	Small amount in raw form.
Oysters	~30 mg	Raw seafood source.
Human Milk	~5 mg	Amount can vary.
Cow's Milk (Raw)	~1 mg	Pasteurized milk has virtually none.

The Carnivore Diet: A Unique Nutritional Perspective

For those on a restrictive carnivore diet, the question of vitamin C intake is often debated. Proponents argue that the body's need for vitamin C is lower in the absence of glucose (sugar). Glucose and vitamin C have similar molecular structures and compete for the same absorption pathways into cells. When dietary carbohydrates are eliminated, there is less competition, allowing the body to absorb and use the smaller quantities of vitamin C found in fresh or raw animal products more efficiently.

Advocates typically recommend incorporating nose-to-tail eating, focusing on organ meats like liver, kidney, and spleen to meet vitamin C requirements. Historically, arctic explorers like Vilhjalmur Stefansson proved that an all-meat diet (including raw organ meat) could prevent scurvy, a disease caused by vitamin C deficiency.

The Importance of Variety for Most Diets

While the carnivore approach presents an interesting case study, it is not the standard nutritional advice for the general population. For the vast majority of people following a standard diet that includes carbohydrates, relying on animal sources for vitamin C is impractical and could lead to deficiency. The most practical and reliable way to ensure adequate intake is to consume a variety of fruits and vegetables daily. Many of the best plant-based sources are rich not only in vitamin C but also in other beneficial vitamins, minerals, and antioxidants.

Conclusion: The Essential Plant Connection

To conclude, the answer to "does vitamin C come from animals?" is complex. While most animals do synthesize their own vitamin C, humans do not. Therefore, for most people, animal products are not a reliable or practical source for this essential nutrient, with only trace amounts surviving in certain raw cuts and organs. The standard recommendation for healthy vitamin C intake remains a diet rich in fruits and vegetables, which provide the nutrient in abundance and stability. The carnivore diet provides a unique counterpoint, but it relies on specific, and for many, unpalatable, dietary habits to function without deficiency. For comprehensive information on dietary recommendations, see the NIH's Vitamin C Fact Sheet.

Further Functions of Vitamin C

Vitamin C's role goes far beyond preventing scurvy. It is a critical component for numerous bodily functions:

Antioxidant Protection: It protects the body's cells from damage caused by free radicals.
Collagen Synthesis: It is a vital cofactor for enzymes that produce collagen, a protein essential for healthy skin, bones, joints, and other connective tissues.
Immune System Support: It supports the function of various immune cells and helps maintain the integrity of physical barriers against pathogens.
Iron Absorption: It significantly enhances the absorption of non-heme iron from plant-based foods.

NIH Vitamin C Fact Sheet

Frequently Asked Questions

No, most animals can synthesize their own, but exceptions include humans, other primates, guinea pigs, and some bats, which lack a specific enzyme.

Raw muscle meat contains only trace amounts of vitamin C. Organ meats like raw liver and spleen have higher concentrations, but cooking destroys the vitamin.

Humans cannot produce vitamin C internally due to a genetic mutation that renders the L-gulonolactone oxidase enzyme non-functional, making dietary intake essential.

Vitamin C is water-soluble and heat-sensitive, meaning cooking methods like boiling can significantly reduce or eliminate its content in both plant and animal foods.

Proponents suggest that on a zero-carbohydrate diet, the body requires significantly less vitamin C. The trace amounts from fresh meat and higher levels in raw offal are believed to be sufficient when glucose isn't competing for absorption.

Fruits like oranges, kiwis, and berries, and vegetables such as bell peppers, broccoli, and kale are excellent and reliable sources of vitamin C.

Yes, at a molecular level, synthetic ascorbic acid is chemically identical to natural vitamin C found in foods. The body cannot distinguish between the two, and both are biologically active.

Vitamin C is essential for many bodily functions, most notably acting as a co-factor for enzymes involved in the synthesis of collagen, which is critical for skin, bone, and connective tissue health.