Supplements, Do You Need Them? Pt. 2

Welcome to the second blog post in the “Vitamin Supplements, Do You Need Them?” series. In the last post, we talked about the importance of eating a balanced diet. We also talked about natural health products and some supplements that may provide benefits. This time, we will discuss some considerations for using supplements safely.

Step 1: Determine the need for vitamin supplementation

You should always make sure that you need to take a supplement before you take anything! The first blog mentioned vitamin D as one supplement that may benefit most people. Supplements may also be needed if your healthcare provider identifies a nutrient deficiency or a nutrient at risk. For instance, if you follow a vegan or vegetarian diet, you may need to take vitamin B12. In other cases, you may have increased nutrient needs. For example, if you are pregnant, a prenatal multivitamin is recommended throughout the pregnancy. Before using any vitamin supplement, consult your doctor, pharmacist, or dietitian.

Step 2: Read the ingredients

Next, you should look at the ingredient list of any product you will be consuming. Check that the supplement contains no allergens or ingredients you may be sensitive or allergic to.

Step 3: Look for the DIN or NPN

Supplements that are legal to sell in Canada have a Natural Health Product Number (NHN) or Drug Identification Number (DIN) (5). NPNs and DINs give consumers confidence in the product’s quality, safety, and regulatory compliance. Remember, natural health products are less regulated than pharmaceutical drugs. This means that some untested supplements can still enter the market.

Step 4: Take the right dose

After determining the need for supplements, you should make sure that you look at the labels. The labels on supplements state the dose and provide directions for taking them. Brands offer the same nutrient in different dosage units, which can make it difficult for you to choose which to buy. Talking to your doctor, dietitian or pharmacist about your supplements can help you determine how much you need to take and how often.

Dietary reference intakes (DRIs) can help you decide what kind of dose is reasonable. DRIs are a set of guidelines developed by scientific experts (1). They provide daily nutrition recommendations based on age and gender. You can find dietary reference tables for vitamins and minerals on the Health Canada website (2,3).

One common DRI is the Recommended Daily Allowance (RDA).  The RDA is the daily amount of nutrients needed to meet the needs of almost every person (97-98%)(4). It also separates nutrient needs by age and gender(e.g. adult women between 19-30).

Note that the DRIs encompass all sources of vitamins and minerals, including food and supplements. So, remember to consider the nutrients you are getting from food!

So, is a higher dose better? 

No! You might think taking a vitamin supplement with a higher dose is better for you, but it could be dangerous. This is why another DRI, the Tolerable Upper Limit (UL), is established. It helps you identify the maximum safe nutrient intake level (1). When you take vitamins and minerals beyond the UL, you risk toxicity. This is especially true of micronutrients like iron or fat-soluble vitamins like vitamin A.

Step 5: Consider interactions with medications or food

Taking some supplements with your food or medicine can make them less effective or cause side effects. For example, iron supplements lose some of their effectiveness when taken with calcium foods or supplements. Be sure to tell your healthcare professional about anything you are taking. They can identify potential interactions and guide you on safe supplement use.


We discussed some considerations for using supplements in this post. Talk to your doctor, pharmacist or dietitian for information about the need for supplements, dosage and potential interactions with food or medications. You should also always read the ingredient list and look for the DIN or NPN on any products you want to buy.


  1. Health Canada. Dietary reference intakes and their development. Version current 7 February 2023. Internet:  (accessed 14 July 2023). 
  2. Health Canada. Dietary reference intake tables – Table 1 reference values for vitamins. Version current 29 November 2010. Internet: 
  3. Health Canada. Dietary reference intake tables –  reference values for elements. Version current 29 June 2006. Internet: 
  4. Health Canada. Dietary reference intakes tables. Version current 29 September 2022. Internet: (accessed 13 July 2023).
  5. Health Canada. About Natural Health Product Regulation in Canada. Version current 6 July 2022. Internet: (accessed 14 July 2023).

Written By Jessica Odyjewski. Edited by Emma Wiwchar and Doug Klein. Image by wirestock on Freepik.

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