Switching from solar to dietary Vitamin D
Vitamin D recycling meets Autumn meal-planning at it’s finest
Here comes the transition from early Fall to late Fall.
Soon, the sun will be low in the sky all day.
Life seems to slow down, and yet, remain busy at the same time.
Autumn Sunshine
This time of year, the sun in here Oregon begins to feel watery. It takes much longer outside to feel it penetrating the deeper layers of the body. Part of this is because soon, the sun will no longer be rising high enough above the horizon for skin to generate significant Vitamin D. In total, we have 80 days of this darkness at this latitude, beginning in early November.
You can find out for your latitude using the UV index, or, you can use the app Dminder. Here’s what the chart from the Dminder app showing the changes in solar noon across the year looks like (this one is for Southern Oregon where I am):
The good news is Vitamin D from solar exposure can last through the whole winter.
The upper limit to the body's ability to recycle Vitamin D is still unknown, but depending on genes, may be months.
(I’m assuming those still pushing irradiated lanolin and lichen pills haven’t read this research.)
But it is true: Vitamin D deficiency isn't from the long winter—it's from a sun-blocking lifestyle.
Case in point: rickets is still a problem in communities (even equatorial ones) that use the burqa1.
Vitamin D in Polar climates
Polar-living indigenous peoples ate large amounts of vitamin D rich seafood to survive the dark months.
Should you do the same?
As usual, there is no one-size-fits all answer.
For example, the Eskimo Inuit have a trait that allows them to digest quantities of dietary vitamin D that would be toxic to everyone else.
Interestingly, and the mechanism isn’t known, but in pregnancy, women’s Vitamin D levels can reach levels that would kill a non-pregnant person due to Vitamin D’s effect on calcium2. This Vitamin D seems to be synthesized in her kidneys because the effect starts right away at implantation, but in time as the placenta and baby’s kidneys grow, they also start producing Vitamin D.
For all humans, vitamin D goes through separate pathways in the body depending on it’s origin (endogenous vs exogenous):
The two pathways work with chemically identical Vitamin D, but it’s travelling in different pathways with different transport mechanisms.
Very large doses (like 10k IUs and higher) of dietary Vitamin D can even cause the body to dump its solar reserves and at the same time become less sensitized to Vitamin D! So be mindful of that if trying to catch up quickly.
Smaller and more consistent sources of Vitamin D over time are safer and more effective than mega-doses through the exogenous pathway3.
Local Oregon Foods Available in Novemner
Here in Oregon, we have a variety of natural dietary sources of Vitamin D.
Lingcod, Rockfish, Sole, Flounder, and Blackcod are all in season on the coast right now.
Farmed oysters are also available fresh.
We also have a unique source of vitamin D: wild mushrooms4.
Deer season just closed (game and other meats can also contain Vitamin D, especially if you eat the organs like liver and kidney5).
For other in-season foods, we are the second largest global producer of hazelnuts (also called filberts), which, according to legend, are a cure for the common cold—a welcome and tasty remedy for this time of year:
[The filbert] cures chronic coughing if pounded filbert is eaten with honey. Cooked filbert mixed with black pepper cures the cold.
Credited to the Greek physician Dioscorides, author of De materia medica
Root crops and winter squash are also abundant, and orchard crops and dried herbs.
Ingredients Available for the Original Thanksgiving
What I have shared in this post so far (seafood, mushrooms, game, nuts and freshly harvested orchard and field crops)… this is starting to sound much like the originally documented Thanksgiving-season feast.
The pilgrims didn't have potatoes, but a letter from the time helps paint the picture of their abundance. This is from William Hilton, passenger on the Fortune (November of 1621).
Loving Cousin,
At our arrival in New Plymouth, in New England, we found all our friends and planters in good health, though they were left sick and weak, with very small means; the Indians round about us peaceable and friendly; the country very pleasant and temperate, yielding naturally, of itself, great store of fruits, as vines of divers sorts in great abundance. There is likewise walnuts, chestnuts, small nuts and plums, with much variety of flowers, roots and herbs, no less pleasant than wholesome and profitable. No place hath more gooseberrries and strawberries, nor better. Timber of all sorts you have in England doth cover the land, that affords beasts of divers sorts, and great flocks of turkey, quails, pigeons and partridges; many great lakes abounding with fish, fowl, beavers, and otters. The sea affords us great plenty of all excellent sorts of sea-fish, as the rivers and isles doth variety of wild fowl of most useful sorts. Mines we find, to our thinking; but neither the goodness nor quality we know. Better grain cannot be than the Indian corn, if we will plant it upon as good ground as a man need desire. We are all freeholders; the rent-day doth not trouble us; and all those good blessings we have, of which and what we list in their seasons for taking.
Our company are, for most part, very religious, honest people; the word of God sincerely taught us every Sabbath; so that I know not any thing a contented mind can here want. I desire your friendly care to send my wife and children to me, where I wish all the friends I have in England; and so I rest
Your loving kinsman,
William Hilton
Source: Alexander Young's Chronicles of the Pilgrim Fathers (1841)
While researching this post, I found out the establishment of Thanksgiving is disputed. All but one of the claimants is along the coast.
This leads me to think Thanksgiving is best celebrated with seafood as well as the land harvest!
Eating seafood regularly is a great way to nudge Vitamin D levels up through the dark winter6.
Winter Dairy
Speaking of changes, for those that eat dairy, did you know the color of butter matters?
Summer butter with it's golden hue has a higher nutritional value than winter butter7.
When I learned this, I was reminded of Little House in the Big Woods, by Laura Ingalls Wilder. She recounts how her mother would color the white winter butter with carrot juice to make it pretty!
In times past, dairy helped many Northerners survive long winters. Nowadays, it seems like many adults can't handle dairy. One key may be the A2 beta-casein vs A1 beta-casein proteins. Sheep, goats, buffalo and humans all produce A2 beta-casein milk. But most cows in commercial dairies now produce an additional protein called A1, which is implicated in diabetes and autoimmune/allergic issues8.
In years past, I bought cheaper butter for the sake of more pies. After learning about the differences between A2 and A1 proteins, I became more cautious, especially when feeding youngsters.
There are a growing number of dairies that keep cow breeds that only produce A2 cows, such as Jersey cows, if you prefer it over the alternative dairy milks (goat, sheep, etc). Alexandre Family Farms is one here on the Northwest Coast. And you may be able to find a raw A2 dairy at realmilk.com if you can take part in a herdshare.
If you can handle dairy, it’s documented you are also more likely to have a higher wintertime Vitamin D status! I shared about this, and the herdshare I participate in, here.
Oregon’s Local Autumn Foods Shopping List
So, to put it all together, here's my local Northwest shopping list for eating seasonally and keeping Vitamin D levels high through the incoming winter:
Seafood
Wild game (or at least pastured meat, and preferably some organ meat)
Wild mushrooms
Naturally sweet foods such as squashes, root vegetables, orchard fruits, and dried berries
Frost-resistant bitter greens (like chard, kale, arugula and cabbage)
Lots of dried herbs
Herbal teas
Local honey
Hazelnuts
Popcorn
High-quality A2 dairy
And this will be my guiding plan for the rest of this season.
Speaking of planning, next year I’m excited that I’ll be using Danielle LaPorte’s heart-centered—paper!—planner! It’s an agenda meets gratitude journal with nervous system + relationship check-ins. There’s nothing out there like this. Here’s where you can check it out and see if it would be a good fit for you or someone you would like to gift it to. With my code, NIKKOLOVE10, you get 10% off your order and worldwide expedited shipping (plus a special bonus):
Hollis, B. W., & Wagner, C. L. (2022). Substantial Vitamin D Supplementation Is Required during the Prenatal Period to Improve Birth Outcomes. Nutrients, 14(4), 899. https://doi.org/10.3390/nu14040899
I wish I was local bc this info is so so so cool. Definitely inspired to make my own list for my location! You’re so lucky to be close to the coast. We are landlocked but our region used to have many healthy rivers overflowing with fish, sadly they are all pretty polluted now. I’m not sure if the benefits of local fish outweigh the risks of pollutants in that case? Something to consider.
I am curious about how much reserves I have and to know for how long it will last. I also plan to take more trips to the equator this winter until I can make a permanent move.