No, flaxseed oil does not contain vitamin D.
Flaxseed oil contains the following nutrients in meaningful quantities, and is regularly tested for them:
- The omega-3 fatty acid ALA (alpha-linolenic acid).
- Various omega-6 fatty acids.
- Various omega-9 fatty acids.
Flaxseed oil should contain varying amounts of other nutrients, but they are not usually tested for. Depending on various factors such as sourcing and processing, these nutrients should be found in flaxseed oil, but in small and unknown quantities:
- Important minerals including magnesium, zinc and potassium.
- Vitamin K, various vitamin B complexes and vitamin E.
- Various phenolic compounds. These have been shown to have a large number of benefits, although relatively little is still known about them.
Despite the lack of vitamin D in flaxseed oil, there is no doubt that flaxseed oil is a health supplement worth taking. However, there are some important drawbacks to flaxseed oil. The most important omega-3 fatty acids to humans are EPA and DHA. Flaxseed oil doesn’t provide any of these fatty acids, instead it provides ALA. ALA can be converted to EPA and DHA, but this conversion is very poor. Furthermore, the conversion is inhibited by omega-6 fatty acids, which are found in large quantities in flaxseed oil. Omega-6 fatty acids are also abundant in a typical western diet, and so this would make the conversion of ALA to EPA and DHA extremely poor.
The best source of the fatty acids EPA and DHA is cod liver oil. Different brands contain different amounts of EPA and DHA, and this depends on various processing and sourcing methods. Dropi cod liver oil for example contains 70mg EPA and 90mg DHA per gram, and about 2µg of vitamin D. However, cod liver oil has its own short comings too. For a detailed comparison of cod liver oil and flaxseed oil, have a read of this article.
On the whole, if you are looking for an omega-3 supplement that also contains vitamin D, then cod liver oil is the better supplement, but this obviously does depends on personal circumstances and requirements.