Vitamin D deficiency symptoms, and getting through a Manitoba winter

Vitamin D deficiency symptoms tend to be vague, which is why low levels often go unnoticed until someone checks. Your body needs vitamin D to absorb calcium and phosphorus, the building blocks of bones. Your skin makes it from sunlight, but in Southern Manitoba that source largely shuts off for half the year.

Here is what low vitamin D can feel like, why Canadians run short, how much Health Canada recommends, where it comes from in food, and when a test makes sense.

Vitamin D deficiency symptoms: what to look for

Low vitamin D doesn’t always announce itself. When symptoms do appear, they can include:

• muscle aches and weakness
• bone pain or tenderness, especially in the spine, pelvis and legs
• in severe, long-standing cases, softened bones (osteomalacia) in adults and rickets in children
• over time, lower bone density (osteoporosis) and a higher risk of fractures

Tiredness and low mood can be associated with low vitamin D, but they have many potential causes. If you’re worn out, look at the bigger picture: see why am I always tired?

Why is vitamin D deficiency common in Canada?

Latitude is the main reason. In a classic study, skin exposed to sunshine in Boston (42°N) made no vitamin D from November through February, and in Edmonton (52°N) that gap ran from October through March. Steinbach sits near 49.5°N, much closer to Edmonton, so expect a long “vitamin D winter” here. Even in summer, sunscreen, clothing, cloud cover and time indoors cut how much you make.

The numbers reflect it. In Statistics Canada’s national survey (2009 to 2011), about 32% of Canadians had blood levels below the cut-off considered sufficient for bone health, rising to about 40% in winter compared with 25% in summer. Among people who took a vitamin D supplement, 85% were above the cut-off, versus 59% of those who didn’t.

You’re more likely to run low if you:

• have darker skin, which takes longer to make vitamin D from sunlight
• are an older adult
• spend most daylight hours indoors, or keep most of your skin covered outdoors
• have a condition that affects absorption, such as celiac disease or cystic fibrosis, or have had small-bowel surgery
• take certain long-term medicines that affect how your body handles vitamin D (your pharmacist can tell you whether yours is one)

Why vitamin D matters

Cardiovascular disease. Cardiovascular disease is listed as the first and second most common cause of death in the USA and Canada, respectively. Vitamin D has been found to impact many areas of the body, far beyond bone health. A retrospective study by Wang et al. looked at almost 2,000 participants and found that individuals with low vitamin D were 62% more likely to have a cardiovascular event when compared to people with normal vitamin D levels. They found this effect even more pronounced among people with hypertension (high blood pressure): this group was twice (200%) as likely to have a cardiovascular event with low vitamin D than with normal levels.

Cancer. Statistics Canada ranks cancer as the leading cause of death, and breast cancer is the most common cancer impacting women. A systematic review and meta-analysis found that women with low vitamin D were 91% more likely to develop breast cancer than their vitamin D sufficient counterparts. The same study notes the anti-proliferative (anti-spreading) and pro-apoptotic (cancer cell killing) actions vitamin D may have on malignant cells, but as always, more research is needed.

Mood. Evidence suggests that low vitamin D plays a role in some depression cases.

Vitamin D has a wide-reaching effect in the human body and is worth taking note of. If you want to have your vitamin D tested, book in with Dr. Esau, ND and start the conversation.

How much vitamin D should I take in winter in Canada?

Health Canada sets a Recommended Dietary Allowance (RDA), the daily amount that meets the needs of nearly all healthy people, and a Tolerable Upper Intake Level (UL), the highest daily amount unlikely to cause harm. Both count food and supplements together.

Health Canada also advises adults over 50 to take a daily supplement containing 400 IU (10 mcg) of vitamin D. Infants have separate guidance, so ask your public health nurse or family doctor about babies under one.

Since January 1, 2026, Canadian cow’s milk carries 200 IU per 250 mL cup, double the old level, and plant-based drinks are fortified to match; yogurt and kefir may now be fortified too. Two cups of milk gives you 400 IU, still short of the 600 IU RDA, so many people also look at a supplement from fall to spring. If you do, check the amount against the table above.

Food sources of vitamin D

Health Canada lists these as food sources of vitamin D:

• fatty fish, such as salmon, arctic char and rainbow trout
• egg yolks
• soft margarine
• unsweetened lower-fat milk
• unsweetened fortified plant-based beverages

How to read a vitamin D label

Supplements list vitamin D in international units (IU), micrograms (mcg or µg), or both. One microgram equals 40 IU, so 400 IU is 10 mcg and 1,000 IU is 25 mcg. Add up every source you take, including multivitamins and calcium-plus-D products, and compare the total with the upper limit in the table.

More isn’t better. Over time, too much vitamin D can raise the calcium in your blood (hypercalcemia), which can harm the kidneys and heart. The best way is to test and dose accordingly.

How is vitamin D tested?

It is a blood test that NDs commonly run, and in some cases a medical doctor would run. Routine screening of healthy people isn’t recommended: the St. Boniface Hospital laboratory manual in Winnipeg states that screening healthy people for vitamin D deficiency is not recommended. The blood test (25-hydroxy vitamin D) is meant for situations such as osteoporosis or repeated fractures, abnormal calcium levels, kidney or liver disease, malabsorption, certain long-term medicines, or signs of too much vitamin D while taking high doses.

If you do test, know that labs label results differently. The St. Boniface lab calls 75 nmol/L and up sufficient, while Statistics Canada uses 50 nmol/L as the level sufficient for bone health for most people. Lab testing ordered by a naturopathic doctor isn’t covered by Manitoba Health, so you pay the lab. Prices vary widely depending on what’s tested, but generally start around $75. Our guide to lab testing with a naturopathic doctor in Manitoba explains how it works.

Before a test, it’s worth asking:

• Is there a specific reason to test me, and will the result change what I do?
• Which cut-off does this lab use for “sufficient”?
• Should the test be done at a particular time of year?

Also tell your practitioner how much vitamin D you already take, from every supplement.

Seeing a naturopathic doctor at Natura

At Natura Integrative Care Clinic in Steinbach, a first naturopathic visit is 60 minutes, 30 with a registered nurse and 30 with the ND. Your ND goes through your diet, time outdoors, supplements and medications, may do a physical exam, and may order testing when there’s a reason to. You then discuss a plan together, including how vitamin D fits with calcium, diet and any medications you take.

Dr. Erin Esau, ND sees patients in person in Steinbach, and visits can also be booked by secure video. Osteoporosis is among the areas of focus for Lindsay Porter, CSEP-CEP, Natura’s clinical exercise physiologist; see exercise for osteoporosis. Natura serves Steinbach and Southern Manitoba, including Niverville, Blumenort, Mitchell and La Broquerie.