Updated: Aug 28
Heat, light, and oxygen stability parameters are provided below.
***How does vitamin D degrade with light? Isn't it increased in the sunshine?
Vitamin D is often referred to as the "sunshine vitamin" because our skin can produce it when exposed to sunlight. However, when we talk about the light stability of vitamin D, we're typically referring to its stability in food sources, supplements, and storage conditions, not its synthesis in the skin.
Vitamin D in food is sensitive to ultraviolet (UV) light. When foods containing vitamin D are exposed to light, it can lead to a degradation of the vitamin.
Vitamin D synthesis in the skin, as you mentioned, is a natural process that occurs when our skin is exposed to UVB rays from sunlight. This is a separate process from the degradation that can happen to vitamin D in certain storage conditions. So, while vitamin D is indeed increased through sunlight exposure, its stability in foods and supplements can be affected by light, especially UV light.
With that being said, it is important to remember that the overall vitamin D that we can get from food is very little and that it is always better for a person to get their vitamin D from the actual sun, rather than from foods or supplements.
Please note that the "N/A" values for certain RDIs indicate that the specific values may vary or may not be applicable in some cases. Also, remember that this table provides a general overview, and individual needs can vary based on age, gender, and health status. Consult with Matt or your trusted healthcare provider if you have specific questions.
Vitamin heat, light, and oxygen stability.
Heat Stability: Heat stability refers to how well a vitamin retains its potency and function when exposed to high temperatures, typically during cooking. Vitamins that are sensitive to heat can degrade and break down into inactive forms or even be destroyed at elevated temperatures. The extent of degradation depends on factors such as the specific vitamin, cooking time, temperature, and cooking method.
Matt’s Note: Heat-sensitive vitamins can be tricky and a common deficiency for many. I have seen quite a few individuals benefit immensely from supplementing with Vitamin B1 (thiamin), Vitamin C, and vitamin B6 specifically. Vitamin A and Vitamin B9 (Folate) seem to be less problematic (but that’s my personal experience with clients). Heat-sensitive vitamins really supports the argument for consuming fermented or raw foods since there's no heat involved to destroy these vitamins. Vitamin B1, B6, and B12 are all rich in red meat but are destroyed if the meat is cooked all the way through, so having a quick sear on each side may be beneficial, but the best option would be to (safely) prepare steak tartar. Keep in mind that raw meat consumption happens around the world. Also, it may seem taboo to have raw meat, but raw fish is widely consumed as sushi. Talking to a butcher, or looking it up online, should help you bridge that potential gap. The Nourishing Traditions book has content on preparing raw meat dishes for those who are interested.
Light Stability: Light stability indicates a vitamin's ability to resist degradation when exposed to light, particularly sunlight or artificial light sources. Some vitamins, especially those sensitive to ultraviolet (UV) light, can break down and become less effective when exposed to light over time. Light stability is especially important for foods that are stored in clear containers or are exposed to sunlight during storage.
Matt’s Note: keep in mind that the inside of a food that is ‘hidden’ from light will protect light-sensitive vitamins. For example, the skin on a peach will protect the vitamin C inside the peach.
Oxygen Stability: Oxygen stability relates to how well a vitamin maintains its integrity when exposed to oxygen, which is present in the air. Some vitamins are prone to oxidation, a chemical reaction that can lead to the breakdown of the vitamin's molecular structure. Oxygen stability becomes more critical for vitamins that contain sensitive compounds like double bonds or reactive groups that can be affected by oxidation.
Matt’s Note: like light stability, oxygen-sensitive vitamins are protected in the inner parts of a food. This is often why we will cut off the ‘dried out’ part of a fruit or vegetable that’s been sitting in the fridge. This is also why the surface of red meats will get a brownish color