Many people take vitamins and supplements hoping to boost immunity, prevent illness, or improve overall health. The most commonly used products include multivitamins, vitamin D, omega 3s, probiotics, and antioxidants. While some supplements are important in specific situations, everyday use is not always necessary and, in some cases, may cause harm. 

Do I need a daily multivitamin? 

For most people, a balanced diet provides all the vitamins and minerals needed to maintain good health. Fruits, vegetables, whole grains, lean proteins, and healthy fats usually meet daily nutritional requirements without supplementation. When deciding whether to take a vitamin or supplement, it may be helpful to ask: 

• Why do I need it? 

• Does it work for me? 

• What harm may occur if I take it, including possible interactions with prescription medications? 

A daily multivitamin may be appropriate for people who: 

• Have limited access to a variety of foods. 

• Have medical conditions that affect nutrient absorption. 

• Are pregnant or planning pregnancy. 

• Have dietary restrictions (for example, vegan or vegetarian diets). 

However, taking a multivitamin “just in case” has not been shown to significantly reduce the risk of chronic disease or improve overall health in otherwise healthy individuals. 

What about individual supplements? 

Single‑nutrient supplements, such as vitamin C, vitamin D, iron, or calcium, are often marketed with strong health claims. In reality, evidence supporting routine supplementation varies, and needs differ from person to person. 

Should I take vitamin C to prevent getting sick? 

Vitamin C is an essential vitamin that supports many bodily functions, including the immune system. The body cannot produce vitamin C, but it is readily available from food sources such as citrus fruits, peppers, tomatoes, and leafy green vegetables. 

Vitamin C deficiency is uncommon for most people who have access to fruits and vegetables. It is more likely in individuals with restricted diets or medical conditions that affect nutrient absorption. 

Medical benefits and common claims 

Vitamin C is often associated with many health claims. However, evidence from clinical studies has been inconsistent, and the overall quality of evidence varies. Claims that vitamin C supplementation reduces the risk of cardiovascular disease, cancer, dementia, or other chronic conditions are inconclusive due to conflicting results and limitations in study design. 

At this time, there is no strong evidence to support routine vitamin C supplementation for the prevention of chronic disease in otherwise healthy individuals. 

Does vitamin C help prevent colds or infections? 

Vitamin C is often associated with preventing or treating respiratory infections, especially during cold and flu season. While vitamin C plays a role in immune function, research has not shown meaningful benefits for preventing or treating pneumonia. 

For the common cold, studies show that vitamin C does not prevent colds in the general population. Some evidence suggests it may slightly reduce the duration and severity of symptoms (by about one day) in people under extreme physical stress, such as endurance athletes or military personnel in training. 

For most people, vitamin C supplements do not provide a significant reduction in how often they get sick. 

How much vitamin C do I need? 

To maintain adequate vitamin C levels, most people need about 200 mg per day, which can usually be met through diet alone. 

Vitamin C is water‑soluble and stored minimally in the body. Excess amounts are excreted by the kidneys. Regular intake above 500 mg per day does not provide additional health benefits, and doses exceeding 2,000 mg per day have been linked to side effects such as stomach upset and an increased risk of kidney stones in some individuals. 

Bottom line 

Most people do not need a daily multivitamin or vitamin C supplement if they eat a balanced diet. 

• Vitamin C is essential, but routine supplementation is unlikely to meaningfully prevent colds or other infections in the general population. 

• High‑dose vitamin C may cause harm if taken regularly. 

• Supplements should not replace a healthy diet. 

Before starting any vitamin or supplement, it is a good idea to speak with a pharmacist or family physician to determine what, if anything, is appropriate for your individual needs. 

The information provided in this article is for personal use, reference, and education only. ASEBP does not provide medical advice. Before starting any medication or product, you should always consult with your pharmacist, health care provider, or call Alberta Health Link at 811.