If you’ve been on a raw food diet for some time, you will probably come across the issue of vitamin D. However, vitamin D deficiency is a worldwide problem, even having an official day devoted to vitamin D awareness.
Vitamin D is synthesized when ultraviolet rays from the sun hit the skin and transform cholesterol into vitamin D3 (see image below). It then undergoes further transformation in the liver and kidneys in order to be transformed into vitamin D2.
Of course, as depicted by the image above, D3 can also come from food sources or supplementation. But as you are probably also aware, vitamin D3 food sources are often of animal origin and not available on a raw food plant-based diet. It is out of the scope of this article to go into why these foods should be avoided in terms of their detrimental effects on health, however, some of the diseases that have been linked to the consumption of animal products can be found here, here, here, here, here, here, here, and I will stop there (for now)! So, for the sake of this article, we will focus on obtaining our vitamin D from exogenous sources (ie. sun and supplements).
(As an aside note, vitamin D2 can be found in some plant sources, such as mushrooms.)
Sun exposure is arguably the most natural way to obtain your vitamin D requirements. For primates, sun exposure is the primary way they fabricate this nutrient, through the mechanisms located in the skin. Humans, like primates, have adaptive preferences for tropical conditions. Our temperature preferences reflect those of a tropical climate, causing our muscles to be less effective in cooler temperatures. And of course the issue of hypothermia in temperatures less than -1oC when sitting still without clothing.
If we look at the following map, we can see that obtaining our vitamin D from the sun in the more northern countries (such as mine, here in beautiful Canada!) can range from possible to not likely depending on the month of the year as well as several other factors. (For a very thorough vitamin D calculator, which takes into account the majority of the factors that can affect absorption, see this site.)
As you can see, the countries at or around the equator receive moderate to intense sunshine all year round. This would have provided all the sunshine a person would need in order to produce adequate vitamin D all year. And looking to the northern countries, it becomes apparent that sunshine was most likely not largely derived from sunshine as we migrated north.
We may have migrated away from our tropical past, but we took the warm climate with us, making use of clothing and climate controlled spaces to allow us to be comfortable all year round. We managed to survive in these climates, likely taking advantage of what few resources we had, which likely included some animal products. But as this paper suggests, our nutrient needs were not likely affected by these vastly different diets that our ancestors followed. In fact, our nutrient needs were likely developed long before we became humans and there is little evidence of much adaptation physiologically or nutritionally. So, although we may have derived our vitamin D from food sources during times of low sunshine, it is not likely the way we have adapted to obtaining it.
It is likely that we are still best suited to obtaining our vitamin D from the sun, as there are also many other benefits of moderate sun exposure, including: “the release of nitric oxide in the body which can serve to widen the blood vessels and decrease blood pressure, and the production of beta-endorphin resulting in an increased feeling of well-being, boosting the immune system, aiding wound healing, and advancing the production of melatonin and serotonin, both vital for circadian rhythm control.” More sunshine exposure resulting in elevated vitamin D status can also have an impact on treating some types of cancer, the risk for type 1 diabetes as well as several other disease related to vitamin D deficiencies in pregnant women. Another study found that sunshine exposure is related to benefits including various types of cancer, cardiovascular disease, Alzheimer disease, myopia and macular degeneration, diabetes and multiple sclerosis. In fact, many nutritional advisory groups are calling for new guidelines pertaining to non-burning sun exposure, now suggesting that sun exposure is essential to human health.
Do we need to move to the tropics?
Luckily scientific progress has now made it possible to get our UVB rays while living up north, making moving to a tropical climate unnecessary (although it does sound like a whole lot of fun!).
Several companies have been coming out with at home lamps that have been FDA approved and independently studied, showing elevations in serum vitamin D3 levels after the recommended exposure of the product. I am in no way an affiliate for the Sperti lamp, just a proud owner. I use my lamp for slightly longer durations of time as I’ve found that I respond better to more UVB exposure, and the manual for the lamp is vague as to how much vitamin D you will make during their recommended length of time.
It is also possible to find a tanning bed in your local area that could help to elevate your vitamin D concentrations, as this study has found. Just to repeat the point from above, it is essential that the skin does not get burned, as this can put you in higher risk of skin cancer and other problems associated with too much sun exposure.
If you would prefer to take a supplement during months of low sun exposure, there are a few things to consider. The amount of vitamin D currently recommended may not yield enough of the vitamin to achieve adequate serum D levels. This study found that the recommended daily allowance of 200 IU is enough to prevent osteomalacia, but is insufficient to prevent osteoporosis and secondary hyperparathyroidism.
Depending on who you ask, many different health councils recommend different intake levels of vitamin D and toxicity levels. The Endocrine Society‘s recommendations tend to be much higher (adult 1500-2000 IU/day) than those recommended by the Food and Nutrition Board and the National Institutes of Health (adult 600-800 IU/day). The Vitamin D Council‘s recommendations err on the high side (adult 5000 IU/day) as their consensus is that lower amounts do not yield adequate intakes. In regards to the upper limit, they state that, “vitamin D toxicity, where vitamin D can be harmful, usually happens if you take 40,000 IU a day for a couple of months or longer.”
Vitamin D3 supplements are often not vegan, being derived from lanolin (although there are some D3 supplements that are plant-derived). Vitamin D2 is the form of D found in plants. Most supplements are in the vitamin D3 form and is often the form recommended, however, it appears that most studies find that D2 and D3 raise blood D levels equivalently.
Here’s to more good times in the sun!