The Last Good Month
Small Hinges No. 01 · October 2026 · Real change you can feel, one small hinge at a time.
Why “Small Hinges”?
hinge (noun): a determining factor; a turning point. (Merriam-Webster)
A hinge is a small part that lets a big door swing open. Every month, you'll get a few small changes worth making, each one backed by science. Each takes only a few minutes. Keep what works, and by the end of the year they add up to a real change in your health.
You turned on a light today.
Around half past four you reached over and switched on a lamp. In July you would not have needed it. You probably did not even think about it. Your hand just did it.
That small move is the only warning most people get.
Why October is different
It is more than the days getting shorter. The sun is also sitting lower in the sky.
When the sun sits low, its light has to pass through much more air to reach you. One part of that light gets used up on the way down. It is called UVB.
UVB is the only light that makes vitamin D in your skin. No UVB, no vitamin D.
So you can stand outside on a bright, sunny day and make none at all.
Scientists tested this directly. They put samples of skin out in the sun in two cities. In Boston, it made no vitamin D from November through February. In Edmonton, further north, it made none from October through March.
Toronto is further north than Boston. So are Halifax, Montreal, Ottawa, Winnipeg, Vancouver and Calgary. For most of Canada, the months with no vitamin D from the sun start sooner than they do in Boston.
So this is not really an article about pills. It is a note about a deadline. October is the last month when going outside still does what you think it does.
What that looks like across Canada
Statistics Canada measures vitamin D in the blood of thousands of Canadians. In their survey from 2016 to 2019, 13 percent of people were low on vitamin D from November to March. From April to October, it was 5 percent.
That is more than twice as many people running low in winter. Same people, same country. The only thing that changed was the sun.
Who runs short first
Older skin. Skin makes less vitamin D as we age. In one lab study, skin from people aged 77 to 82 made less than half as much as skin from young people, under the same light.
Darker skin. The same pigment that protects skin from the sun also slows down how much vitamin D it makes. Darker skin needs more time in the sun to make the same amount.
People who are mostly inside. If most of your daylight comes through a window or a windshield, you are making little or none. More on that below.
Health Canada's own advice is that adults over 50 take a daily vitamin D supplement of 400 IU. If you are not sure what is right for you, ask your pharmacist or doctor.
01 · Bank it while it still works
Get outside for ten to fifteen minutes a day, as early in the day as you can.
Two things happen out there at once.
One is vitamin D, while the sun is still high enough to make it.
The other has nothing to do with vitamin D. Daylight in your eyes sets the timer that decides when you get sleepy tonight. That timer works all winter, long after the UVB is gone. But it needs you outside. Indoor light is far too dim to count.
In a study of more than 400,000 adults in Britain, people who spent more time outdoors had an easier time in the morning. For every extra hour outside, the odds of finding it easy to get up went up by about half. The odds of feeling tired often went down by about a fifth. The odds of low mood went down by about an eighth.
That kind of study shows a link. It cannot prove that the time outside caused the change, and it is worth saying so.
How: eat lunch outside. Park at the far end. Take a call while you walk. It does not have to be exercise, and it does not have to be sunny. A grey day outside still has many times more light than a bright room.
02 · The window does not count
Sitting in a sunny window is not the same as being outside. The door has to open.
Window glass blocks UVB. It still lets in light and heat, and that is what makes it so convincing. It feels like sun. It is warm and bright on your face.
It makes no vitamin D. None.
This is why people who sit all day in a bright, sunny office can still run low. It catches them by surprise.
The window does less for your body clock too. Even with the blinds up, you get a small slice of the light that is outside.
How: if your ten minutes happen behind glass, they did not happen. Same in the car. The windshield is glass too.
03 · Send it in with fat
When you do go to the bottle, take it with the fattiest thing you eat that day.
Vitamin D needs fat to get in. It rides in with the fat from your food. With no fat, some of what you swallow never gets in.
This was tested. Fifty adults over fifty took the same dose of vitamin D3. Half took it with a breakfast that had fat in it, half with a fat-free one. Twelve hours later, the fat group had 32 percent more in their blood.
That was one big dose, not a daily one. The researchers said so themselves, so treat 32 percent as the direction, not a promise.
How: take it with a meal that has real fat. Eggs. Salmon. Olive oil. Avocado. Cheese. Yogurt. Nuts. Not with black coffee on the way out the door, which is when most people take it.
One more thing. The time of day does not matter. The fat does.
You may see a bigger number online: that taking vitamin D with your biggest meal raises levels by 57 percent. That figure came from 17 people, with no group to compare them to. We use the smaller number because it comes from a better test.
Quick answers
Does a cloudy day count? For your body clock, yes. Even a grey day outside is far brighter than indoors. For vitamin D, clouds cut the UVB, so you make less.
Morning or noon? Morning light does the most for your body clock. The middle of the day does the most for vitamin D, because that is when the sun is highest. If you can only pick one, go out when you can. Any time outside beats none.
Can I just sit by the window? No. Glass blocks the light that makes vitamin D. The door has to open.
Does it matter when I take my vitamin D? Not the time of day. What matters is taking it with food that has fat in it.
What you get
Do the ten minutes and you get two things at once. Vitamin D while the sun still works, and the light signal that keeps your sleep from sliding later as winter comes in.
Fix the fat and the vitamin D you already pay for goes further.
None of this is hard. That is the point.
Watch
Light & Your Body Clock, about 2 minutes. Why the darker months throw your sleep out, and the two simple habits that set it right again.
More short videos are on the LeafSource videos page.
The research behind this issue
- Boston and Edmonton: Webb AR, Kline L, Holick MF. Influence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin. Journal of Clinical Endocrinology & Metabolism. 1988;67(2):373-378. PMID 2839537. Boston (42°N): none November to February. Edmonton: none October to March. The study did not measure Toronto; we say only that Toronto is further north than Boston, which it is.
- Canada, winter vs summer: Statistics Canada, Canadian Health Measures Survey, 2016-2019 (10,761 people). Vitamin D below 30 nmol/L: 13% November to March, 5% April to October.
- Older skin: MacLaughlin J, Holick MF. Aging decreases the capacity of human skin to produce vitamin D3. Journal of Clinical Investigation. 1985;76(4):1536-1538. PMID 2997282. Skin from people aged 77 to 82 compared with ages 8 to 18: more than a twofold drop.
- Darker skin: Clemens TL, Adams JS, Henderson SL, Holick MF. Increased skin pigment reduces the capacity of skin to synthesise vitamin D3. The Lancet. 1982;1(8263):74-76.
- Health Canada advice: Applying Canada's Dietary Guidelines: Advice on vitamin and mineral supplementation. Health Canada, 2026. "Adults 51 years of age and older should be advised to take a daily supplement of 400 IU (10 mcg) of vitamin D."
- Time outdoors: Burns AC, et al. Time spent in outdoor light is associated with mood, sleep, and circadian rhythm-related outcomes: a cross-sectional and longitudinal study in over 400,000 UK Biobank participants. Journal of Affective Disorders. 2021. PMID 34488088. Per extra hour outdoors: ease of getting up OR 1.47, tiredness OR 0.81, low mood OR 0.88. Observational: it shows a link, not a cause.
- Window glass: Tuchinda C, Srivannaboon S, Lim HW. Photoprotection by window glass, automobile glass, and sunglasses. Journal of the American Academy of Dermatology. 2006;54(5):845-854. PMID 16635665.
- Vitamin D with fat: Dawson-Hughes B, et al. Dietary fat increases vitamin D-3 absorption. Journal of the Academy of Nutrition and Dietetics. 2015;115(2):225-230. PMID 25441954. Randomized, 50 adults aged 50+, a single 50,000 IU dose. Peak blood D3 32% higher with the fat-containing meal.
- The 57 percent figure (not used): Mulligan GB, Licata A. Taking vitamin D with the largest meal improves absorption and results in higher serum levels of 25-hydroxyvitamin D. Journal of Bone and Mineral Research. 2010;25(4):928-930. PMID 20200983. 17 people, no control group.
This article is for education. It is not medical advice.