Can You Get Vitamins From Animals? A Guide to Animal-Sourced Nutrients

December 28, 2025 •

4 min read

Certain essential vitamins, including B12, are found almost exclusively in animal products naturally, as they are produced by bacteria. So, can you get vitamins from animals? The answer is a resounding yes, and for many crucial nutrients, it is often the most efficient source due to enhanced bioavailability and unique nutrient forms.

Quick Summary

Animal-sourced foods are primary sources for several crucial vitamins, offering highly bioavailable forms of nutrients like B12, preformed vitamin A, and D3. These are vital for overall health.

Key Points

Vitamin B12: Sourced almost exclusively from animal products naturally, as it is produced by bacteria and stored in animal tissues.
Preformed Vitamin A: Found in animal liver, eggs, and dairy, this retinol form is more bioavailable than plant-based beta-carotene.
Vitamin D3: The most biologically active form, D3, is found in fatty fish and egg yolks, distinct from plant-derived D2.
Enhanced Bioavailability: Vitamins from animal sources are often in forms that are more easily absorbed and utilized by the human body compared to their plant-based counterparts.
Balanced Nutrition: For many, an omnivorous diet that includes a variety of animal and plant products is the most reliable way to obtain all essential vitamins and minerals.
Dietary Deficiencies: Individuals following strict plant-based diets must plan carefully and often supplement to avoid deficiencies in nutrients like B12, which are difficult to obtain otherwise.

The Unique Role of Animal-Sourced Vitamins

For many people, a balanced diet includes both plant and animal-based foods. While fruits, vegetables, and grains are foundational for many micronutrients, animal products offer a distinct nutritional profile that is difficult to replicate. The primary reasons for this difference lie in the type and bioavailability of the vitamins they contain. Animal-sourced foods are recognized for their nutrient density, meaning they provide a high concentration of essential vitamins and minerals for relatively few calories. This makes them particularly important for vulnerable populations, such as infants and the elderly, who require concentrated nutrients for growth and maintaining muscle mass. A shift away from a diet including animal-sourced foods without careful nutritional planning can lead to deficiencies in several key vitamins.

Bioavailability and Nutrient Form

One of the most significant advantages of obtaining vitamins from animal sources is their superior bioavailability. This refers to the proportion of a nutrient that is absorbed from the diet and used by the body. Many plant-based foods contain compounds known as 'anti-nutrients,' such as phytates, which can inhibit the absorption of minerals and some vitamins. Conversely, vitamins from animal sources are often in a more readily usable form for the human body. A comprehensive review of vitamin bioavailability confirmed that, in general, vitamins from animal sources are more bioavailable than those from plants.

Key Vitamins Found in Animal Products

Animal-sourced foods are the almost exclusive natural sources for several critical vitamins. Here is a breakdown of some of the most important:

Vitamin B12 (Cobalamin): This is perhaps the most well-known example. B12 is synthesized by bacteria and archaea, not by animals or plants directly. Ruminant animals, like cattle, acquire B12 from bacteria in their stomachs, which is then stored in their tissues. Humans, therefore, obtain natural B12 almost exclusively by eating animal products like meat, fish, eggs, and dairy. Without these sources, a supplement is necessary to prevent deficiency.
Preformed Vitamin A (Retinol): Animal products contain preformed vitamin A, or retinol, which is the active form of the vitamin. Our bodies can use this form directly. Plants, by contrast, contain provitamin A carotenoids, such as beta-carotene, which must first be converted into retinol in the body. The conversion rate is highly inefficient, making animal sources a much more reliable way to obtain this vital nutrient for vision, immune function, and cell growth. Key sources include beef liver, egg yolks, and fortified dairy.
Vitamin D3 (Cholecalciferol): While some plants and fungi produce vitamin D2 when exposed to UV light, the more biologically active and potent form for humans, vitamin D3, is primarily obtained from animal sources. Fatty fish like salmon and herring, as well as eggs, are good dietary sources of D3. Humans can also produce D3 in their skin from sunlight, but dietary intake is essential for those with limited sun exposure.
Other B Vitamins: Many other B vitamins, including riboflavin, niacin, and vitamin B6, are abundant in animal products. These water-soluble vitamins are crucial for energy metabolism and nerve function.

Comparison: Animal vs. Plant-Sourced Vitamins


Vitamin	Primary Animal Sources	Primary Plant Sources	Key Differences & Bioavailability
Vitamin B12	Meat, poultry, fish, eggs, dairy	Fortified foods (cereals, milks), nutritional yeast	Exclusively from animal sources naturally; vegans require supplementation or fortified foods.
Vitamin A	Retinol in liver, eggs, dairy	Beta-carotene in orange vegetables, dark leafy greens	Retinol is preformed and highly bioavailable. Beta-carotene must be converted, which is inefficient.
Vitamin D	D3 in fatty fish, egg yolks	D2 in some fungi, fortified foods	D3 is significantly more biologically active than plant-derived D2.
Vitamin K	K2 in certain animal products, fermented foods	K1 in leafy green vegetables	K1 is less bioavailable than K2; K2 has distinct functions in bone and heart health. Bioavailability needs more study.
Iron	Heme iron in red meat, poultry, fish	Non-heme iron in legumes, leafy greens	Heme iron from animals is much more readily absorbed than non-heme iron from plants.

The Importance of a Balanced Diet

For most people, relying on a diverse diet that includes both animal and plant-based foods is the most straightforward way to meet all nutritional requirements. This approach ensures a wide spectrum of vitamins, minerals, and other nutrients, leveraging the strengths of both food categories. Animal products provide high-quality, complete proteins, along with key vitamins like B12, D3, and preformed A, and minerals like iron and zinc in highly bioavailable forms. Meanwhile, plant foods are rich in fiber, vitamin C, and many antioxidants that are not found in animal products.

For those following vegetarian or vegan diets, careful planning and supplementation are critical to avoid deficiencies in nutrients like vitamin B12. Fortified plant-based milks and cereals, as well as nutritional yeast, are important sources for these individuals. However, without deliberate attention, relying solely on plant sources can leave nutrient gaps, particularly in terms of bioavailability.

Ultimately, nutritional strategies should be personalized based on individual needs, health status, and ethical considerations. Consulting a healthcare professional or a registered dietitian is always recommended to ensure nutritional requirements are met, regardless of dietary choices.

Conclusion

Yes, you can and do get essential vitamins from animals, and for certain nutrients, it is the most natural and efficient source. Animal products provide highly bioavailable forms of critical vitamins, including B12, preformed vitamin A (retinol), and vitamin D3. While plant-based diets offer a host of health benefits, they require meticulous planning to ensure all nutritional needs are met, often relying on fortified foods or supplements to compensate for nutrients predominantly found in animal tissues. By understanding the unique contributions of both animal and plant sources, individuals can make informed decisions to build a truly balanced and healthy diet. For more in-depth information on nutrition and dietary guidelines, refer to resources from authoritative sources like the National Institutes of Health.

Frequently Asked Questions

Yes, vegetarians and especially vegans must pay close attention to their nutritional intake to avoid deficiencies, particularly for vitamin B12, which is naturally found almost exclusively in animal products. Fortified foods or supplements are necessary.

Animal sources provide preformed vitamin A (retinol), which is immediately active in the body. Plant sources contain provitamin A carotenoids, like beta-carotene, that the body must convert to retinol, a much less efficient process.

While plants provide many vitamins, some, like B12, are naturally absent. Obtaining all essential nutrients, especially in their most bioavailable forms, can be challenging on a strictly plant-based diet without fortification or supplementation.

Organ meats like liver are excellent sources of retinol and B vitamins. Fatty fish such as salmon and herring are rich in vitamin D3. Eggs and dairy products also provide B12 and other nutrients.

Dogs and cats, unlike some other mammals, cannot synthesize enough vitamin D from sun exposure and must get it from their diet. Many livestock also require dietary vitamin D supplementation for optimal health.

Vitamins in animal products are often in forms that are more easily absorbed by the human body. For example, heme iron from meat is more absorbable than non-heme iron from plants, and preformed retinol is more directly usable than beta-carotene.

No, humans, along with some other animals like primates and guinea pigs, have lost the ability to synthesize vitamin C and must obtain it from their diet.

Relying exclusively on plants can lead to potential deficiencies, particularly in B12. Additionally, certain plant compounds (anti-nutrients) can inhibit mineral and vitamin absorption, and some vitamin forms are less bioavailable than their animal-sourced counterparts.