Understanding the different types of vitamin D
Vitamin D is a fat-soluble vitamin essential for regulating calcium and phosphorus, supporting immune function, and maintaining bone density. While the body can produce vitamin D when skin is exposed to sunlight, dietary sources are also critical. For vegetarians and vegans, understanding the two primary forms of this vitamin is key.
Vitamin D2 (Ergocalciferol)
This form is produced by plants and yeast when exposed to ultraviolet (UV) light. For vegetarians, this is a readily available plant-based form of the vitamin. It is commonly used to fortify foods and is found naturally in certain mushrooms.
Vitamin D3 (Cholecalciferol)
Traditionally, D3 is derived from animal sources, such as lanolin from sheep's wool, but a plant-based D3 is now widely available. This vegan D3 is extracted from lichen, a symbiotic organism combining algae and fungi. Some research suggests that D3 may be more effective than D2 at raising and maintaining vitamin D levels in the blood, though both can address deficiency.
Vegetarian and vegan food sources of vitamin D
Since animal products like fatty fish and cod liver oil are high in vitamin D, vegetarians and vegans must rely on other sources. Fortunately, many options exist to help meet daily requirements.
- UV-Exposed Mushrooms: The only natural, non-animal food source of significant vitamin D are mushrooms that have been exposed to ultraviolet light. This process converts ergosterol in the mushrooms into vitamin D2. The vitamin D content can vary, but some UV-exposed mushrooms offer significant amounts.
- Fortified Plant-Based Milks: Many plant milks, including soy, almond, oat, and rice milks, are fortified with vitamin D. A single cup can provide a notable portion of the daily recommended intake.
- Fortified Cereals: A large number of popular breakfast cereals and oatmeal brands are fortified with vitamin D, making them an easy way to boost intake, especially when paired with fortified plant milk.
- Fortified Orange Juice: Some brands of orange juice add vitamin D and calcium, providing a convenient way to supplement your diet. Always check the label, as not all brands fortify their juice.
- Fortified Tofu: Certain tofu products are fortified with vitamin D and other nutrients like calcium and vitamin B12, offering a versatile and nutrient-dense option.
- Dairy Products (for lacto-vegetarians): For vegetarians who consume dairy, some cheeses (like cheddar and ricotta) contain small amounts of vitamin D. Fortified cow's milk and yogurts are more reliable sources.
- Eggs (for ovo-vegetarians): The yolk of eggs, especially those from chickens raised with outdoor access, provides a small amount of vitamin D.
Sunlight: A primary source for everyone
Regardless of dietary choices, sun exposure is a crucial factor for vitamin D synthesis. The body creates its own vitamin D3 when skin is exposed to UVB radiation from the sun.
- Timing: A short period of mid-day sun exposure (10-30 minutes for most people) several times a week can significantly boost vitamin D levels.
- Factors Affecting Production: Sunscreen use, geographic location, time of day, season, and skin pigmentation all influence how much vitamin D your body can produce. Individuals with darker skin tones, those in higher latitudes during winter, or those who spend most of their time indoors may need to prioritize other sources.
Supplementation strategies
For many vegetarians and vegans, relying solely on food and sunlight is insufficient to meet their vitamin D needs, especially during winter months. Supplementation is a reliable strategy for preventing deficiency.
- Vitamin D2 Supplements: Derived from UV-irradiated yeast, these are a straightforward plant-based supplement option.
- Vegan Vitamin D3 Supplements: These are sourced from lichen and are becoming more widely available. Given the potential for D3 to be more effective at maintaining levels, vegan D3 is often recommended.
- Absorption: Taking vitamin D supplements with a meal containing healthy fats, such as avocado or nuts, can significantly enhance absorption.
Comparing vegetarian vitamin D sources
| Source | Vitamin D Type | How to Get It | Notes |
|---|---|---|---|
| Sunlight | D3 (Cholecalciferol) | Short, regular exposure to UVB rays | Best natural source, but efficiency varies seasonally and by location and skin type. |
| UV-Exposed Mushrooms | D2 (Ergocalciferol) | Buy specially-grown mushrooms or expose them to sunlight yourself | The only natural plant food source, varies in potency. |
| Fortified Plant Milks | D2 or D3 | Look for 'fortified with vitamin D' on the label | Convenient way to boost intake, but read labels carefully for type and amount. |
| Fortified Cereals | D2 or D3 | Check nutrition labels; often paired with plant milk | Content varies by brand, useful as part of a balanced breakfast. |
| Vegan D3 Supplements | D3 (Cholecalciferol) | Purchase supplements derived from lichen | May be more effective than D2 for raising blood levels over time. |
| D2 Supplements | D2 (Ergocalciferol) | Purchase plant-based D2 supplements | A reliable and guaranteed vegan source, effective for treating deficiency. |
Conclusion
Yes, there is vegetarian vitamin D, and a variety of options exist to ensure those on a plant-based diet can meet their nutritional needs. While natural, unfortified vegetarian food sources are limited primarily to UV-exposed mushrooms, the market is rich with fortified products like plant-based milks, cereals, and orange juice. Additionally, reliable supplements are available in both D2 and vegan D3 (from lichen) forms. By combining safe sun exposure, a balanced diet including fortified foods, and potentially a supplement, vegetarians and vegans can effectively manage their vitamin D levels for optimal bone health and immune function.
For more information on recommended daily allowances and safety guidelines, consult the National Institutes of Health Office of Dietary Supplements.
