The sun was already gone when I checked the time. We’ve all been there. Five o’clock. Somewhere else, or “back home”, that would still have been the afternoon, the hour when people are wrapping up work but the day feels unfinished. In Charlottetown, however, it was already evening.
We all know Canada as being cold. But winter can start to wear thin by the time the calendar reaches January. The novelty is gone. The holidays have passed. Clouds cover the sun almost daily, and when it does appear, it doesn’t really warm anything. For many people, especially those who grew up in warmer climates, the body begins to push back.
Sleep changes. Energy thins out. People get sick more often. Moods flatten, sometimes quietly, sometimes all at once. And sooner or later, often without much explanation, someone suggests taking vitamins.
For many people who move to Canada from warmer climates, especially those of us who are Black, Indigenous, or people of colour, winter is introduced as a logistical challenge. Buy a good coat. Get proper boots. Learn how to drive in snow. What’s rarely discussed is the biological adjustment: the way months without sunlight affect the nervous system, the immune system and the quiet chemistry of the body.
Winter, it turns out, is not just a season. It is a condition the body has to learn to survive.
1. Vitamin D: When sunlight disappears, the body notices
Vitamin D is often described as a vitamin, but it behaves more like a hormone. It helps regulate immune responses, supports bone and muscle health, and plays a role in mood and inflammation. Most importantly, the body is designed to produce it through direct exposure to sunlight.
In much of Canada, that process essentially shuts down between late fall and early spring. The sun may be visible, but the angle is too low for the skin to synthesize vitamin D. Covering up for warmth only compounds the issue. By January and February, many people are running on reserves.
For people with darker skin, this effect is magnified. Melanin reduces the skin’s ability to produce vitamin D, which means racialized communities are statistically more likely to be deficient in northern climates. This isn’t widely discussed in public health messaging, but it is well established in medical research.
Food can help, fatty fish, eggs, fortified milk or plant-based milks, but diet alone rarely provides enough during winter months. That’s why vitamin D supplementation is so commonly recommended in Canada.
How it’s taken matters. Vitamin D is fat-soluble, meaning it needs dietary fat to be absorbed properly. Taken with a meal that includes oil, dairy, eggs, nuts or fish, it is far more effective than when taken on an empty stomach. Some people also find it mildly stimulating, which is why many clinicians suggest taking it earlier in the day rather than at night.
2. Vitamin B12: Winter fatigue isn’t just about sleep
If vitamin D is about light, vitamin B12 is about energy.
B12 helps the body convert food into usable energy and keeps the nervous system functioning properly. When levels are low, symptoms can be subtle at first: persistent fatigue, brain fog, low mood, or a sense that rest never quite restores you.
B12 is found naturally in animal products such as meat, fish, eggs and dairy, as well as in fortified foods like some plant-based milks and nutritional yeast (labels matter here). People who eat little or no animal products are at higher risk of deficiency, but diet is not the only factor. Absorption depends on stomach acid and gut health, both of which can be disrupted by chronic stress, something winter is very good at amplifying.
Unlike vitamin D, B12 is water-soluble and doesn’t require fat for absorption. Many people take it in the morning, as it can feel energizing. Taken later in the day, it may interfere with sleep. This is one reason multivitamins, which combine stimulating nutrients like B12 with calming ones like magnesium, often work against the body’s natural rhythms.
3. Magnesium: The nervous system nutrient
Magnesium rarely gets the attention it deserves, but it plays a quiet, foundational role in the body. It helps muscles relax, regulates nerve signals, supports sleep and assists in managing stress responses.
Winter increases the body’s demand for magnesium in several ways at once. Cold temperatures cause muscles to tense. Short days disrupt circadian rhythms. Psychological stress rises. At the same time, people often eat fewer magnesium-rich foods, as winter diets are shaped by cost, energy and access rather than intention.
Magnesium exists in several forms, and they are not interchangeable. Magnesium glycinate, bound to the amino acid glycine, is often recommended because it is well absorbed and gentle on the digestive system. Other forms, such as magnesium citrate, are more likely to cause diarrhea and are typically used for constipation rather than nervous system support.
Glycine itself has calming properties, which is why magnesium glycinate is commonly taken in the evening. For many people, it supports deeper sleep and reduces the physical tension that builds up during long, dark months.
Food sources include beans, lentils, nuts, seeds, whole grains, leafy greens and dark chocolate.
4. Omega-3s: Feeding the brain
Omega-3 fatty acids are structural components of brain cells and play a role in regulating inflammation and mood. In winter, when people eat less fresh fish and experience higher levels of stress and seasonal depression, omega-3 intake often drops.
Fatty fish such as salmon, sardines and mackerel are the most efficient sources. Plant-based options like flax, chia and walnuts contain omega-3s as well, but in a form the body must convert, a relatively inefficient process.
Supplementing with omega-3s can help bridge that gap, particularly for people who don’t eat fish regularly. Taken with meals, they are generally well tolerated and can support both physical and mental health during the winter months.
5. Iron: Important, but not something to guess about
Iron supports oxygen transport in the blood and plays a central role in energy levels. When iron is low, people may feel weak, dizzy or chronically exhausted. But iron supplementation should never be automatic.
Too much iron can be harmful, and symptoms of deficiency overlap with many other conditions. People who menstruate, particularly those with heavy periods, are at higher risk of low iron, as are some racialized communities due to dietary patterns and unequal access to health care.
Iron from plant sources is absorbed less efficiently than iron from meat, but absorption improves significantly when consumed with vitamin C. Coffee and tea, on the other hand, inhibit iron absorption.
Before assuming iron supplementation is necessary, blood work is recommended to assess iron levels.
6. Vitamin C and zinc: Support, not armour
Vitamin C and zinc are often marketed as immune shields, but their role is more modest. They support normal immune function and tissue repair and can be helpful during periods of stress or illness.
Frozen fruits and vegetables, often dismissed unfairly, are excellent winter sources of vitamin C and retain most of their nutritional value. Seeds, legumes and whole grains provide zinc. Supplements can be useful in the short term, but they are not meant to be taken in high doses indefinitely.
Do I need to buy all of this? And how do I even know what I need?
At this point, the question becomes unavoidable: does surviving a Canadian winter mean walking into a pharmacy and leaving with a bag full of supplements?
The short answer is no. For many people, that assumption is exactly what makes vitamin advice feel alienating, classed or unrealistic.
Supplements are meant to fill gaps, not replace food, culture or common sense. They work best when they are targeted, not when they are taken all at once in the hope that something will stick. This is where many people get discouraged: they try a multivitamin, feel no different, and assume either that vitamins “don’t work” or that something is wrong with them.
A better starting point is to notice patterns rather than isolated symptoms. Are you tired even when you’re sleeping? Is your mood lower than usual every winter? Do you get sick more often once the light disappears? These aren’t diagnoses, but they are signals. Vitamin D deficiency, for example, rarely announces itself dramatically. It shows up as a general sense that winter is harder than it should be.
Food comes first, as much as possible. Fatty fish once or twice a week does more than a low-dose omega-3 capsule taken inconsistently. Beans, lentils, seeds, greens and whole grains provide magnesium, iron and zinc in forms the body recognizes. Frozen fruits and vegetables, often cheaper and easier to access, are nutritionally solid winter choices.
Cultural foods matter here, too. Stews, soups, slow-cooked meals and fermented foods aren’t just comfort; they are adaptive strategies humans have used in cold climates for generations.
Supplements become useful when food alone can’t reasonably meet the body’s needs. This is also where multivitamins tend to fall short. They promise coverage but rarely deliver it. Doses are often too low to correct deficiencies, and combinations ignore timing and absorption. A multivitamin may contain vitamin D, but not enough for winter needs. It may include B12 and magnesium together, even though one can be stimulating and the other calming.
For many people, this results in no noticeable change, not because their bodies are unresponsive, but because the approach is unfocused.
It’s also important to be honest about expectations. Vitamins don’t make winter joyful. They don’t fix structural loneliness, racism, housing insecurity or the exhaustion of migration. What they can do, when used thoughtfully, is take the edge off. They can make sleep a little deeper, energy a little steadier, illness a little less frequent. They support the body so that coping requires slightly less effort.
The deeper issue is not whether people “should” take vitamins, but why so many are never taught how winter actually affects the body. For newcomers, racialized communities and people navigating poverty or chronic stress, the cost of that knowledge gap is real. Fatigue becomes normalized. Low mood is internalized and structural conditions are framed as personal shortcomings.
Supplements are not a moral issue. People are not “better” because they don’t need them, nor is supplementation “a woman’s thing.” Frozen food is not inferior. Cultural food counts.
Learning how to care for your body in a northern climate is not indulgence, it is adaptation.