What Vitamins Can't You Get From Food (or Easily)?

January 3, 2026 •

4 min read

Globally, nearly 50% of people have a Vitamin D deficiency, highlighting that food alone cannot provide all essential nutrients. Several critical vitamins are notoriously difficult or impossible to obtain in sufficient quantities from dietary sources alone, making supplementation or alternative methods necessary for optimal health, and answering the question: what vitamins can't you get from food?

Quick Summary

This guide covers essential vitamins that are difficult or impossible to obtain from food alone, such as Vitamin D, Vitamin B12, and Vitamin K2, explaining why they are not sufficiently available through diet and outlining alternative sources like sun exposure, supplements, and fortified foods.

Key Points

Vitamin D is hard to get from food: Despite its presence in some foods like fatty fish and eggs, sunlight is the primary source, and dietary intake is often insufficient for most people.
Vegans and older adults need Vitamin B12 supplements: As B12 is almost exclusively found in animal products and absorption declines with age, supplementation is critical for these populations.
Vitamin K2 is rare in modern diets: This crucial vitamin for bone and heart health is found in fermented foods like natto and grass-fed animal products, which are not staples in many modern diets.
Fortified foods can help but aren't a complete solution: While items like milk and cereal are fortified with vitamins like D and B12, they may not provide optimal levels and are no substitute for a varied diet or targeted supplementation.
Sun exposure and supplementation are key: For Vitamins D and B12 respectively, non-food methods are the most reliable ways to achieve and maintain adequate levels.
Gut bacteria produce some Vitamin K2: The gut microbiome can produce a small amount of Vitamin K2, but relying on this for sufficient intake is not recommended.

Introduction to Hard-to-Obtain Vitamins

While a balanced diet is the cornerstone of good nutrition, it is a common misconception that all essential vitamins can be acquired solely through food. In reality, several key vitamins are not readily available in nature, or their primary sources are not universally consumed, leading to widespread deficiencies. This article explores the specific vitamins that are challenging to obtain from food, detailing the reasons why and providing practical solutions to ensure your body gets the nutrients it needs.

Vitamin D: The Sunshine Vitamin

Vitamin D is a fat-soluble vitamin crucial for calcium absorption, bone health, and immune function. The human body can synthesize it when skin is exposed to sunlight, but dietary sources are limited. Few foods naturally contain significant amounts of Vitamin D. While fatty fish and eggs contain some, it is not enough to meet daily requirements for many individuals, especially those with limited sun exposure.

Why food is an unreliable source of Vitamin D

Limited natural sources: The number of foods that naturally contain Vitamin D is very small, primarily limited to a few types of fatty fish and eggs.
Geographical location: People living far from the equator receive less intense sunlight, especially during winter months, hindering natural synthesis.
Lifestyle: Modern indoor lifestyles, sunscreen use, and protective clothing significantly reduce sun exposure.
Fortified foods: While many foods are fortified with Vitamin D (like milk, cereal, and orange juice), relying on them can still be insufficient and may introduce unwanted additives like sugar.

Vitamin B12: A Crucial Nutrient for Vegans and Older Adults

Vitamin B12, or cobalamin, is vital for red blood cell formation, nerve function, and DNA synthesis. It is a water-soluble vitamin that is produced by bacteria and is found almost exclusively in animal-sourced products. Vegans and strict vegetarians are at high risk of deficiency because plant foods do not naturally contain bioactive Vitamin B12. Furthermore, as people age, their ability to absorb B12 from food decreases, regardless of diet.

Why Vitamin B12 is often missed in diet

Animal-based source: The primary dietary sources are meat, dairy, eggs, and fish, making it a critical nutrient to monitor for those following a plant-based diet.
Absorption issues: The body's ability to absorb B12 is complex and declines with age due to decreased stomach acid production.
Unreliable plant sources: While some algae and fermented products may contain trace amounts, they are not considered reliable or sufficient sources.

Vitamin K2: The Overlooked Co-factor

Vitamin K2, specifically the MK-4 and MK-7 forms, is a fat-soluble vitamin important for bone health and cardiovascular function, specifically by regulating where calcium is deposited in the body. Unlike its counterpart, Vitamin K1, which is abundant in leafy greens, Vitamin K2 is found in a more limited range of foods and is often difficult to acquire in optimal amounts through a typical Western diet.

Why Vitamin K2 is hard to get from food

Limited dietary sources: The best food sources of K2 include natto (fermented soybeans), goose liver, certain fermented cheeses like Gouda, and pasture-raised animal products.
Modern farming: The prevalence of grain-fed rather than grass-fed animal products in modern agriculture has reduced the K2 content in meat, eggs, and dairy compared to historical levels.
Acquired taste: The highest food source, natto, is a traditional Japanese food with a strong, acquired taste that is not widely consumed globally.

Comparison of Hard-to-Obtain Vitamins


Feature	Vitamin D	Vitamin B12	Vitamin K2
Primary Source (Dietary)	Fatty fish, eggs, fortified foods	Animal products (meat, dairy, eggs)	Fermented foods (natto), grass-fed animal products, certain cheeses
Primary Source (Non-Dietary)	Sunlight exposure	Supplements, fortified foods	Gut bacteria synthesis, supplements
High-Risk Groups for Deficiency	People with limited sun exposure, darker skin, older adults	Vegans, strict vegetarians, older adults, individuals with absorption issues	Individuals on modern Western diets, those who avoid natto and certain animal products
Recommended Solution	Sun exposure, supplementation, fortified foods	Supplementation (oral or injections), fortified foods	Targeted food choices, supplementation

Strategies to Acquire Sufficient Vitamin Intake

For the vitamins that can't you get from food alone, or only with great difficulty, proactive steps are essential.

For Vitamin D:

Safe sun exposure: Aim for 5 to 30 minutes of midday sun exposure several times a week, ensuring to protect yourself from overexposure.
Supplements: Vitamin D supplements, particularly D3, are an effective way to maintain adequate levels. Consult a healthcare provider for the right dosage.
Fortified foods: Incorporate fortified foods like certain cereals, milk, and orange juice into your diet.

For Vitamin B12:

Supplements: Oral B12 supplements are a reliable way for vegans and older adults to get their daily needs.
Fortified foods: Many cereals, nutritional yeasts, and plant-based milks are fortified with B12.
Monitoring: Regular check-ups are important, especially for those at risk of deficiency, as B12 injections may be necessary for severe cases.

For Vitamin K2:

Targeted food choices: Incorporating natto, fermented dairy from grass-fed animals, and organ meats into your diet can boost K2 intake.
Supplements: A high-quality K2 supplement (ideally MK-7) can ensure consistent intake, particularly for those who do not eat K2-rich foods.

Conclusion

While a well-rounded diet is the foundation of health, relying on food alone for every essential vitamin is not always feasible or realistic. Vitamins D, B12, and K2 are prime examples of nutrients that are difficult or impossible to obtain in sufficient amounts through diet alone due to specific dietary choices, modern food processing, or physiological limitations. Recognizing these limitations and utilizing strategies such as safe sun exposure, supplementation, and consuming fortified foods is crucial for preventing deficiencies and supporting overall health. By being proactive and informed, you can ensure your body receives the complete spectrum of vitamins it needs to thrive, even those that food sources cannot reliably deliver.

Optional Link Example: Vitamin B12 - Health Professional Fact Sheet

Frequently Asked Questions

No vitamins are impossible to get from food entirely, but obtaining sufficient Vitamin D from diet alone is extremely difficult, and Vitamin B12 is not naturally found in plants. Vitamin K2 is also scarce in many modern diets.

While fortified foods like cereals and milks can help increase intake of vitamins like B12 and D, they should not be your only source. A varied diet, along with targeted supplements where necessary, is a more reliable approach.

Sun exposure is the primary way the body produces Vitamin D, but it's not always enough. Factors like geography, season, skin pigmentation, and lifestyle can affect production, making supplements often necessary.

Vitamin B12 is produced by bacteria and primarily accumulates in animal tissues. While some plant-based products like fortified nutritional yeast contain it, plants themselves do not naturally produce bioactive B12.

Vitamin K1 is mainly found in leafy green vegetables like kale and spinach. Vitamin K2 is primarily found in fermented foods (natto) and grass-fed animal products, and is far less common in the average diet.

Even with a healthy diet, supplementation for specific vitamins may be necessary, especially for Vitamin D (due to lack of sun) and B12 (especially for vegans and older adults). Consulting a healthcare provider is recommended.

To increase Vitamin K2, incorporate fermented foods like natto or high-quality cheeses into your diet. Choose grass-fed animal products over grain-fed ones, or consider a K2 (MK-7) supplement.