Summary
Supplements are popular in Canada, but more isn’t always better. Overdosing on vitamins, minerals, or herbal remedies can cause serious health issues, from nausea and kidney stones to bleeding risks and liver strain. This guide reviews the top 15 supplements—including vitamin D, calcium, omega-3s, probiotics, and turmeric—covering what they do, who might need them, safe dosages, upper limits, and potential risks, helping Canadians make informed, safe choices.
Supplements are everywhere these days. Whether it’s vitamin D to make up for our long winters, a daily multivitamin “just in case,” probiotics for gut health, or turmeric to fight inflammation, supplements are so prevalent that almost half of Canadians add them to their health routines. It feels like an easy way to stay healthy—but here’s the catch: more doesn’t always mean better.
In fact, taking too much of certain supplements can backfire. Some can build up in your body to toxic levels, others can interfere with prescription medications, and many of us don’t realize that we’re already getting plenty through our food. Without guidance, it’s surprisingly easy to go overboard.
That’s why we’ve pulled together a guide to the fifteen most popular supplements Canadians take. You’ll find safe dosage ranges, situations where you should only take them under a doctor’s advice, and what can happen if you overdo it. Because when it comes to supplements, the smartest choice is the safe one.
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Vitamin D | Calcium | Omega-3 (EPA + DHA) | Vitamin C | Magnesium | Probiotics | Vitamin B12 | Iron | Zinc | Multivitamins | Echinacea | Turmeric / Curcumin | Ginger | Garlic | Ginseng
1. Vitamin D
What it does:
Vitamin D helps the body absorb calcium and phosphorus, making it essential for strong bones and teeth. It also supports immune function and has been linked to mood regulation.
Recommended intake (RDA/AI):
The amount of vitamin D you need each day depends on your age and any medical conditions that require higher doses of the vitamin such as osteoporosis. Generally, adults 19–70 years require 600 IU (15 mcg) per day and adults 71+ require 800 IU (20 mcg) per day
Safe upper limit (UL):
Unless prescribed by your doctor, people over the age of 9 should ingest maximum 2,000 IU (50 mcg) per day from all sources (diet, supplements, fortified foods).
Who might need it:
People in northern climates with limited sun exposure during seasons such as winter should know their levels and supplement accordingly under supervision from their doctor. Additionally, older adults, and people with darker skin tones may benefit from supplementation since natural vitamin D production through sunlight can be insufficient.
Caution:
People with kidney disease, certain parathyroid disorders, or high calcium levels should only take vitamin D under medical supervision.
Risks of too much:
Consistently exceeding the upper limit can cause hypercalcemia (too much calcium in the blood), which may lead to kidney stones, heart rhythm problems, nausea, or even permanent kidney damage.
2. Calcium
What it does:
Calcium is the most abundant mineral in the body, crucial for strong bones and teeth, muscle contraction, nerve signaling, and blood clotting.
Recommended total intake from food and supplement sources:
- Adults 19–50 years: 1,000 mg/day
- Women 51+ and men 71+: 1,200 mg/day
Safe upper limit (UL):
2,000–2,500 mg/day (depending on age). This includes food, fortified beverages, and supplements combined.
Who might need it:
Postmenopausal women, older adults, people suffering from osteoporosis, and people with lactose intolerance or limited dairy intake may require supplementation to meet daily needs.
Caution:
People with a history of kidney stones, cardiovascular disease risk factors, or chronic kidney disease should be careful with supplementation. Large doses of calcium are best avoided unless directed by a healthcare provider.
Risks of too much:
Excess calcium can lead to kidney stones, constipation, and reduced absorption of other minerals like iron and zinc. Some studies have suggested a possible link between very high calcium intake and cardiovascular risk, though the evidence is mixed.
3. Omega-3 (EPA + DHA)
What it does: Promotes heart and brain health, reduces inflammation, and supports eye health.
Recommended intake: There’s no official RDA for omega-3s in Canada, but expert groups like the World Health Organization and Heart and Stroke Foundation recommend about 250–500 mg of combined EPA and DHA daily for general health from both food and supplement sources. People with heart disease may be advised to take higher doses under medical guidance.
Safe upper limit (UL):
Health Canada has not set a formal UL for omega-3, but intakes above 3,000 mg/day from supplements may increase risks and should only be used under medical supervision.
Who might need it: People who rarely eat fatty fish, individuals with heart disease risk, or anyone looking for anti-inflammatory support.
Caution:
People on blood thinners (like warfarin) or those with bleeding disorders, since omega-3s can reduce blood clotting. Patients preparing for surgery should typically stop high-dose omega-3s at least a week before.
Risks of too much: Some people report that taking Omega 3 supplements is unpleasant because they taste bad and leave a nasty taste in the mouth or cause bad breath. On a more serious note, people taking antiplatelet or anticoagulant medications should take under supervision of their doctor due to the antiplatelet effect. Finally, gastrointestinal issues such as nausea and diarrhea may arise when taking Omega 3’s.
4. Vitamin C
What it does: Acts as an antioxidant, supports immune function, and aids in collagen production.
Recommended intake:
- Women: 75 mg/day
- Men: 90 mg/day
- Pregnant women need 85mg/day, breastfeeding women need 120mg/day and smokers may need an additional 35 mg/day
Safe upper limit (UL):
2,000 mg/day for adults.
Who might need it:
People with low fruit and vegetable intake, pregnant and breastfeeding women, people recovering from surgery, smokers, or individuals under high oxidative stress.
Caution:
People with a history of kidney stones or chronic kidney disease, hemochromatosis and Individuals taking certain medications (e.g., chemotherapy drugs or blood thinners) should check with their healthcare provider.
Risks of too much:
- Gastrointestinal upset such as diarrhea or nausea.
- People with kidney conditions who also take vitamin C may also take in more aluminum from medicines that have aluminum, such as phosphate binders, which can be harmful
- Potential increased risk of kidney stones in susceptible individuals.
- Possible Increase in estrogen levels with birth control pills or hormone replacement therapy might
- Taking vitamin C with statins and niacin
- may prevent them from working as well as expected.
5. Magnesium
What it does: Supports muscle and nerve function, heart health, bone health, and energy production.
Recommended intake:
- Women: 310–320 mg/day. Pregnant women require about 350-360 mg daily and breastfeeding women, 310-320 mg.
- Men: 400–420 mg/day
Safe upper limit (UL):
350 mg/day from supplements only (magnesium from food is not counted toward the UL).
Who might need it: People with poor dietary intake, older adults, or those experiencing muscle cramps or high stress.
Caution:
– People with kidney disease, diabetes, heart disease should consult with their healthcare provider before taking the supplement.
– Those taking diuretics, heart medications, bisphosphonates, thyroid medications, HIV medications or antibiotics should discuss taking magnesium supplements with their doctor as it may not be safe or may change the efficacy of the medication.
Risks of too much:
- Diarrhea, nausea, and abdominal cramping are common at high doses.
- Magnesium toxicity can cause irregular heartbeat or low blood pressure, confusion, slowed breathing and even cardiac arrest in severe cases.
6. Probiotics
What it does: Supports gut microbiome balance, digestion, and immune health.
Recommended intake:
- There is no official RDA for probiotics.
- Typical supplement doses range from 1–10 billion CFU/day (colony-forming units).
Safe upper limit (UL):
No established UL, as probiotics are generally considered safe for healthy adults.
Who might need it:
People with digestive issues (like IBS, diarrhea, or constipation), those who have taken or are taking antibiotics, or anyone looking to support gut health.
Caution:
Immunocompromised individuals or those with serious underlying health conditions should only take probiotics under medical guidance. People with central venous catheters or severe illness may be at higher risk of infection.
Risks of too much:
- Usually mild in healthy adults, such as bloating, gas, or mild digestive upset.
- Rarely, probiotics can cause infections in vulnerable populations.
7. Vitamin B12
What it does: Essential for red blood cell formation, brain and nerve function, and DNA synthesis.
Recommended intake:
- Adults: 2.4 mcg/day
Safe upper limit (UL):
No established UL, as vitamin B12 has a very low toxicity risk.
Who might need it:
Vegans, vegetarians, adults 65+, or individuals with malabsorption issues.
Caution:
Generally safe for most people, but individuals on certain medications like metformin or proton pump inhibitors may need higher doses or monitoring. Adults 65+, vegans, and vegetarians are at higher risk of deficiency and may require supplementation.
Risks of too much:
- Vitamin B12 is generally well-tolerated, even at high doses.
- Rarely, very high supplemental doses may cause acne-like skin eruptions, tingling in the hands and feet or mild gastrointestinal symptoms.
8. Iron
What it does: Helps carry oxygen via hemoglobin in red blood cells and myoglobin in muscle cells, maintains healthy immune function, produces energy, and supports overall growth and development. Lack of iron in the blood is called anemia and it is the most common nutritional deficiency worldwide.
Recommended intake from food sources:
Iron supplements are generally not recommended for everyone and should only be taken when a healthcare provider advises it. Most people can get the iron they need from food sources, however some groups who may need supplements include pregnant women, infants, women living with heavy menstrual bleeding, frequent blood donors, endurance athletes, people with certain gastrointestinal disorders, and vegetarians/vegans. Self-treating can be dangerous.
- Children – between 7to 11mg daily, depending on age
- Women 19–50 years: 18 mg/day, 27 mg for pregnant women
- Men and women 51+: 8 mg/day
Safe upper limit (UL):
40 mg/day for adults and adolescents aged 14 and over, including lactating and pregnant women.
Who might need it:
Premenopausal women, pregnant women, people with blood loss, or those with diagnosed iron-deficiency anemia.
Caution:
After menopause, a woman’s recommended dietary allowance (RDA) for iron decreases from 18 mg to 8 mg per day, the same as for adult men. Most healthy people can meet this requirement through diet alone, making supplementation unnecessary unless prescribed by a doctor. Anyone with hemochromatosis should avoid iron supplements. Pregnant women and individuals with diagnosed iron-deficiency anemia may require higher, supervised doses.
Risks of too much:
- Short-term: nausea, vomiting, constipation, diarrhea
- Long-term or severe overdose: organ damage (liver, heart)
- Particularly dangerous for children, where accidental overdose can be life-threatening
9. Zinc
What it does: Maintains the sense of taste and smell, contributes to fertility, bone health, skin health, and eye health. Supports immune function, wound healing, and DNA synthesis. Most people, including vegetarians, can get their daily zinc requirements through a balanced diet. Always consult your healthcare provider before taking zinc supplements, especially if you have a medical condition.
Recommended intake:
- Women: 8 mg/day, 11mg/day needed during pregnancy and 12 mg/day while breastfeeding
- Men: 11 mg/day
Safe upper limit (UL):
40 mg/day for adults
Who might need it:
People with poor dietary intake, vegetarians, or individuals with wounds, immune challenges, or slow healing.
Caution:
Individuals with copper deficiency risk should be cautious, as high doses of zinc can interfere with copper absorption.
Risks of too much:
Taking too much zinc can cause nausea, vomiting, and abdominal pain. In the long-term, excessive intake can lead to copper deficiency, which may cause neurological issues such as numbness and weakness. Other risks of chronic zinc overdose include reduced immune function, lower HDL (good) cholesterol levels, and potential interference with magnesium absorption.
10. Multivitamins
What it does: Provides a broad mix of vitamins and minerals to help fill nutritional gaps in the diet. They’re usually formulated to cover roughly 100% of daily requirements for most nutrients.
Recommended intake:
- Follow the label, typically one tablet or capsule per day.
Safe upper limit (UL):
Depends on the individual nutrients included (especially fat-soluble vitamins A, D, E, K, and iron).
Who might need it:
People who generally don’t get enough essential vitamins and minerals from their diet or people on medications that affect appetite, digestion, and nutrient absorption. Anyone with Crohn’s disease, ulcerative colitis, celiac disease or gastric bypass surgery should also speak to their doctor before taking a multivitamin. All pregnant women should take a daily multivitamin containing 0.4 mg of folic acid and 16 – 20 mg of iron.
Caution:
People taking additional single-nutrient supplements should avoid “doubling up,” which can exceed safe limits.
Risks of too much:
There is potential for vitamin toxicity (especially vitamins A, D, E, K) and Iron-containing multivitamins can be dangerous for children if accidentally ingested. Vitamins may cause nausea, constipation, or gastrointestinal upset in some individuals.
11. Echinacea
What it does: Primarily used to support the immune system and manage symptoms of the common cold.
Recommended intake:
- Dry powdered extract: 300–500 mg, 3 times daily
- Liquid extract (tincture): Up to 10 mL per day, divided into 2.5 mL doses taken 3 times daily.
Safe upper limit (UL):
No established UL; however, long-term use beyond 8 weeks is not recommended.
Who might need it:
People who frequently get colds or want immune system support during seasonal transitions.
Caution:
Individuals with autoimmune disorders (e.g., lupus, rheumatoid arthritis) should consult a healthcare provider before use.
Risks of too much:
Echinacea can cause minor side effects such as an upset stomach, nausea, and dizziness. It can also worsen asthma symptoms. Serious side effects include allergic reactions such as rash, swelling, and difficulty breathing. Talk to your doctor right away about any side effects you are having.
Some people are allergic to plants in the daisy family. These could include daisies, ragweed, marigolds, or chrysanthemums. This may put you at more risk of having an allergic reaction to echinacea.
Generally well-tolerated; excessive use may cause mild gastrointestinal upset.
12. Turmeric / Curcumin
What it does: Acts as an anti-inflammatory and antioxidant, and may support joint health.
Recommended intake:
- Curcumin extract: 500–1,000 mg per day, often combined with black pepper extract (piperine) to enhance absorption.
Safe upper limit (UL):
While turmeric is generally considered safe, high doses (above 8,000 mg per day) may cause gastrointestinal issues and liver stress.
Who might need it:
Individuals with joint pain, arthritis, or those seeking general anti-inflammatory support.
Caution:
Pregnant women, anyone undergoing surgery, people on blood thinners, those with gallbladder problems, bleeding disorders, diabetes, gastroesophageal reflux disease (GERD), infertility, iron deficiency, liver disease, hormone-sensitive conditions, and arrhythmia should consult with their doctor before taking turmeric supplements.
Risks of too much:
High doses can interfere with iron absorption so anyone with iron deficiency should be cautious. Similarly, those with liver disease should also be cautious as there is some concern that turmeric may damage the liver in rare cases. Overconsumption can also lead to nausea, diarrhea and dizziness.
13. Ginger
What it does: Supports digestion, reduces nausea, and may have anti-inflammatory and antioxidant effects.
Recommended intake:
- Dried ginger powder or supplement: 1–2 grams per day
- Maximum 1 gram for pregnant women
- Fresh ginger root: 2–5 grams per day
Safe upper limit (UL):
No established UL; however, excessive intake above 4 to 6 grams may cause gastrointestinal discomfort and lead to dangerous interactions with certain medications.
Who might need it:
People looking to reduce nausea from motion sickness, morning sickness, chemotherapy and those with inflammation-related discomfort such as osteoarthritis.
Caution:
Individuals on blood thinners should be cautious. The research isn’t conclusive, but anti-coagulants such as warfarin, aspirin and others may be impacted by taking ginger supplements. Those with gallstones, heart conditions, or diabetes should consult a healthcare provider before use. Same if you are pregnant or breastfeeding, or are scheduled for surgery,
Risks of too much:
- High doses may lead to digestive problems, a higher risk of bleeding, and potentially dangerous interactions with certain medications.
14. Garlic
What it does: May support heart health, immune function, and healthy blood pressure.
Recommended intake:
- Garlic powder: 600–1,200 mg per day, divided into 1–3 doses
- Fresh garlic: 1–2 cloves per day
Safe upper limit (UL):
No established UL; however, excessive intake may cause body odor and gastrointestinal discomfort.
Who might need it:
Individuals looking for cardiovascular support or immune system support, or those with high cholesterol or blood pressure risk.
Caution:
People who should not take garlic supplements include those who are allergic to garlic, have a bleeding disorder, are pregnant or breastfeeding, or will undergo surgery soon. Individuals taking blood thinners, high blood pressure, HIV or diabetes medications should be cautious and consult a healthcare provider, as garlic can interfere with these drugs. Those with digestive problems like acid reflux or a fructan intolerance may experience symptoms such as bloating, gas, and stomach upset.
Risks of too much:
The risks of consuming too many garlic supplements include gastrointestinal issues like heartburn, nausea, and gas, increased bleeding risk, and potential allergic reactions. Bad breath and body odour are also of concern while excessive consumption may also lead to low blood pressure and can interact with negatively with certain medications as discussed above.
15. Ginseng (Panax ginseng)
What it does: May boost energy, support cognitive function, and reduce stress.
Recommended intake:
- Standardized extract: 200–400 mg per day
Safe upper limit (UL):
No established UL; however, prolonged use beyond 3 months is not recommended.
Who might need it:
People experiencing fatigue, low energy, or cognitive decline, or anyone seeking stress support.
Caution:
Children, individuals with autoimmune diseases, hypertension, bleeding disorders, hormone-sensitive conditions, heart conditions or pregnant or breastfeeding women should consult a healthcare provider before use.
Risks of too much:
Taking too much ginseng can lead to nervousness, insomnia, headaches, stomach upset, and skin reactions. It may also cause high blood pressure, liver damage, and severe allergic reactions. Women may experience menstrual irregularities and breast tenderness. Ginseng is not recommended for children, pregnant or breastfeeding women, or people with autoimmune conditions, bleeding disorders, or hormone-sensitive conditions.
Making Smart Choices with Supplements
Supplements and herbal remedies can support health, but they’re not a substitute for a balanced diet. The key takeaway: more isn’t always better. Even nutrients your body needs can be harmful in excess.
Tips for safe supplementation:
- Check your diet first. You may already meet your needs through food.
- Know safe limits. Each nutrient or herb has recommended intakes and upper limits.
- Consider your personal health. Age, medications, and health conditions matter.
- Consult a healthcare professional. They can guide you on safe dosages and prevent interactions.
When used thoughtfully, supplements can complement your health—but taking too much can create risks instead of benefits.
~ Read more from The Health Insider ~
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- Medication Adherence: The Challenges, Risks and SolutionsYour medication routine matters. Here’s how to overcome some of the barriers that impact 25% of the population.
- Ozempic Now Approved to Treat Kidney Disease in Patients with Type 2 DiabetesA major international study called The FLOW trial has resulted in approval for Ozempic from Health Canada to help treat CKD in people with type 2 diabetes.
The information provided on TheHealthInsider.ca is for educational purposes only and does not substitute for professional medical advice. TheHealthInsider.ca advises consulting a medical professional or healthcare provider when seeking medical advice, diagnoses, or treatment. To read about our editorial process, click here.
