Which Vitamin is Totally Absent in Milk? The Surprising Truth

November 21, 2025 •

3 min read

While milk is famously rich in calcium, protein, and B vitamins, it is naturally deficient in or entirely lacks one key nutrient: Vitamin C. This article explains which vitamin is totally absent in milk and explores the scientific reasons behind this nutritional quirk.

Quick Summary

Milk is missing Vitamin C (ascorbic acid) because cows produce their own internally and don't need to consume it, unlike humans who must get it from food.

Key Points

Absent Vitamin: Vitamin C (ascorbic acid) is the essential nutrient that is naturally absent or present in negligible amounts in cow's milk.
Animal Synthesis: Cows and most other mammals can synthesize their own Vitamin C and do not require it in their diet, so they do not pass significant amounts into their milk.
Pasteurization Impact: The process of pasteurization further reduces any trace amounts of Vitamin C due to its heat-sensitive nature.
For Humans: As primates, humans cannot produce their own Vitamin C and must obtain it through their diet, primarily from fruits and vegetables.
Diversify Your Diet: To get the Vitamin C milk lacks, a balanced diet should include other nutrient-rich foods such as citrus, berries, and green vegetables.
Not a 'Complete' Food: While milk contains many important nutrients like calcium and protein, its lack of Vitamin C means it cannot be considered a 'complete' food for human nutrition.

The Missing Nutrient: Vitamin C (Ascorbic Acid)

Despite its reputation as a highly nutritious food, milk is not a complete source of all essential nutrients for human consumption. Specifically, Vitamin C, or ascorbic acid, is either completely absent from milk or present in only negligible trace amounts. While human breast milk contains sufficient Vitamin C for a developing infant, cow's milk does not, which is a critical distinction for dietetics. The primary reason for this absence lies in a key biological difference between humans and most other mammals.

Why Vitamin C Is Not in Milk

Most animals, including cows, possess the ability to synthesize their own Vitamin C within their bodies. For them, it is not a dietary essential that must be consumed from external sources. The cow's liver can produce the necessary ascorbic acid, so there is no biological imperative for it to be secreted in the milk for its calf. Humans and other primates, on the other hand, lost this gene for synthesizing Vitamin C millions of years ago, making it a critical nutrient we must obtain from our diet.

The Impact of Processing

Even if small amounts of Vitamin C were initially present in raw milk, the pasteurization process would destroy it. Vitamin C is a water-soluble vitamin that is highly sensitive to heat, light, and oxygen, making it unstable during the pasteurization process where milk is heated to kill harmful bacteria. As a result, commercially available pasteurized milk is not a reliable source of this vital antioxidant, and relying on it for your Vitamin C needs would be ineffective.

Milk's Nutritional Powerhouse (Minus One)

While milk lacks Vitamin C, it remains an excellent source of many other important nutrients. Its nutrient profile includes high-quality protein, calcium, and several B vitamins. It is also commonly fortified with Vitamin D in many countries, making it a vital dietary source for bone health. The combination of these nutrients is crucial for overall health, bone density, and muscle growth.

Sources of Vitamin C to Complement Milk

To ensure a balanced diet, it's essential to include foods rich in Vitamin C, such as fruits and vegetables. These should complement your milk intake, not be replaced by it. Some of the best natural sources of Vitamin C include:

Citrus fruits (oranges, lemons, grapefruits)
Berries (strawberries, blueberries)
Bell peppers
Broccoli and leafy greens
Kiwi fruit

By diversifying your food choices, you can easily obtain all the necessary vitamins and minerals for optimal health.

Comparative Nutritional Profile: Milk vs. Vitamin C Sources


Feature	Cow's Milk	Citrus Fruits & Vegetables
Vitamin C Content	Absent / Negligible	High
Calcium Content	High	Low to Moderate
Vitamin D Content	Often fortified	Very low to none
B Vitamin Content	High (especially B2 & B12)	Varies, not a primary source
Antioxidant Properties	Not from Vitamin C	Strong due to Vitamin C
Primary Function	Bone strength, muscle growth	Immune support, collagen synthesis

Conclusion

In summary, the vitamin that is totally absent in milk is Vitamin C, or ascorbic acid. This is because cows, unlike humans, can produce this nutrient internally. The pasteurization process further ensures that commercially available milk contains no significant amount of Vitamin C. To achieve a truly balanced diet, milk should be valued for its rich supply of calcium, protein, and other vitamins, but it should always be complemented by fruits and vegetables to meet the body's essential Vitamin C requirements. Making informed dietary choices ensures you get a full spectrum of nutrients for optimal health. You can read more about vitamin C from reputable sources like the National Institutes of Health.

Frequently Asked Questions

No, milk is not a complete food for humans, as it is naturally deficient in Vitamin C and iron, which are essential nutrients we must get from other dietary sources.

Vitamin C is not in cow's milk because cows can synthesize their own ascorbic acid in their liver, so it is not a necessary component of their milk for their calves.

Yes, Vitamin C is highly sensitive to heat, and both boiling and pasteurizing will destroy any minuscule amount that might have been present in raw milk.

Relying solely on cow's milk for nutrition would lead to a Vitamin C deficiency, which can cause health issues like scurvy, in addition to other potential deficiencies.

You can complement a milk-based meal with Vitamin C-rich foods like citrus fruits (e.g., in a smoothie), strawberries on cereal, or vegetables like bell peppers.

Yes, Vitamin C is present in human breast milk because, unlike cows, humans cannot synthesize it internally, and human babies need to consume it.

Besides Vitamin C, cow's milk is also a poor source of iron and Vitamin K, although it does contain a wide range of other vitamins and minerals.