How to Pick a Good Olive Oil (and Not Get Fooled by the Label)

Two bottles can both say "extra virgin olive oil" and be completely different products. One is fresh, peppery and full of the compounds that make olive oil worth eating. The other is old, flat, or not even fully olive oil.

The good news: you don't need to be a sommelier to tell them apart. You need to know what to look for on the label, and you don't have to pay a fortune.

Why olive oil is worth getting right

Strong evidence

In the PREDIMED trial, about 7,400 adults in Spain at high risk of heart disease were randomly assigned to different diets. One group ate a Mediterranean diet with a generous weekly supply of extra virgin olive oil. Over about five years, that group had roughly 30% fewer heart attacks, strokes and heart-related deaths than the group told to follow a lower-fat diet.

That's a randomized trial, the strongest kind of evidence in nutrition. (It was re-analysed and republished in 2018 after problems with how some people were assigned to groups. The result held up.)

A Harvard study that followed more than 92,000 American adults for 28 years found something similar in everyday life. People who had more than half a tablespoon of olive oil a day had a 19% lower risk of dying from heart disease than people who rarely used it. Swapping butter, margarine or mayonnaise for olive oil was linked to lower risk too. That one is observational, so it shows a link, not proof.

What makes "the good stuff" good

Promising evidence

Extra virgin olive oil is just pressed olive juice, never heated or chemically refined. That keeps in its polyphenols, natural plant compounds that act as antioxidants. Refined and "light" olive oils lose most of them.

In Europe, an olive oil is only allowed to claim that its polyphenols help protect blood fats from damage if it contains at least 5 mg of a specific group of them per 20 grams of oil (about 1.5 tablespoons). Plenty of oils on the shelf don't reach that.

Here's the easy test: a fresh, high-polyphenol oil tastes a little bitter and leaves a peppery sting at the back of your throat. That sting comes from a compound called oleocanthal, which researchers found works on the same pathway as ibuprofen. If your oil tastes like nothing at all, it's probably old or low quality.

Why so many bottles aren't what they say

Strong evidence

Olive oil is one of the most commonly faked foods. When CBC Marketplace obtained ten years of results from the Canadian Food Inspection Agency's olive oil testing, about one in three samples (from 44 of 140 brands) didn't meet the standard. Problems included oils cut with cheaper vegetable oils, oils sold as extra virgin that weren't, and oils that were simply stale.

It's not just a Canadian problem. In a September 2026 test of 11 popular olive oils by the independent lab ConsumerLab, three failed to qualify as extra virgin because of taste defects like rancidity, even though they passed the chemical tests. And the price didn't predict quality: the cheapest oil was among the best, and the most expensive was among the worst.

How to read the label in 30 seconds

• "Extra virgin" only. "Olive oil", "pure", "light" and "pomace" are refined. They're fine for frying, but most of the polyphenols are gone. "Light" means lighter flavour, not fewer calories.
• A harvest date. This is the best sign of a serious producer. Look for the most recent harvest, and use the oil within about a year of it. A "best before" date alone tells you much less.
• Dark glass or a tin. Light and air break olive oil down. Clear bottles, and plastic, which lets air through slowly, are a step down.
• A specific origin. One country, or better, one region or estate. "Packed in Italy" or "a blend of EU and non-EU oils" can mean oil from anywhere.
• A quality seal, if there is one. A PDO or PGI seal (a protected-origin stamp from the European Union), or a seal from a group that tests every batch, such as the California Olive Oil Council, is a good extra sign.
• Ignore "cold pressed". All real extra virgin oil is made without heat. It's marketing, not a quality mark.

What it costs in Canada (bang for your buck)

We checked online prices in Vancouver on October 13, 2026. Prices change, and warehouse prices can differ from online ones.

Two things jump out. First, decent extra virgin oil starts around $11 a litre, so you don't need a $60 bottle. Second, watch for look-alikes in the same aisle: "Kirkland Signature Olive Oil" (not extra virgin) and blends made with olive pomace oil sit right next to the real thing.

A price tag doesn't tell you how fresh an oil is or how many polyphenols it has. Use the label checklist above, then trust your throat: buy a bottle, taste it on its own, and keep buying the one that has some bite.

How TK does it: shops Costco first, checks the bottle for a harvest date and what it's packed in before it goes in the cart, and does a straight-from-the-spoon taste test at home.

Can you cook with it?

Promising evidence

Yes. The old advice that extra virgin olive oil "can't take the heat" doesn't hold up well. In a 2018 lab study that heated ten common cooking oils, extra virgin olive oil produced the fewest harmful breakdown compounds, fewer than canola, sunflower, grapeseed and even avocado oil. The researchers found smoke point was a poor predictor of how an oil behaves when heated.

A practical approach: cook with your everyday extra virgin oil, and save a fancier, punchier bottle for drizzling on finished food, where you'll taste the difference.

How to store it

• Away from the stove. Heat speeds up the damage. A cupboard is better than the counter next to the burners.
• Cap on, out of the light. If you buy a big tin, decant a small amount into a dark glass bottle for daily use and keep the rest sealed.
• Use it up. Once opened, try to finish it within a couple of months. A big bottle is only good value if you'll use it while it's fresh.

One thing this week

Pull out the olive oil you already have. Check whether it says extra virgin, whether it has a harvest date, and what it's packed in. Then taste a spoonful on its own. No bite? Next time, try a different bottle.

Sources

1. Estruch R, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. New England Journal of Medicine, 2018;378:e34. Link
2. Guasch-Ferré M, et al. Consumption of Olive Oil and Risk of Total and Cause-Specific Mortality Among U.S. Adults. Journal of the American College of Cardiology, 2022;79(2):101-112. Link
3. EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on health claims related to polyphenols in olive. EFSA Journal, 2011;9(4):2033. Link
4. Beauchamp GK, et al. Ibuprofen-like activity in extra-virgin olive oil. Nature, 2005;437:45-46. Link
5. Olive Oil Times. One-third of olive oils sold in Canada don't meet quality standards (CFIA testing reported by CBC Marketplace), 2017. Link
6. ConsumerLab. Extra virgin olive oil review, September 2026. Link
7. De Alzaa F, Guillaume C, Ravetti L. Evaluation of Chemical and Physical Changes in Different Commercial Oils during Heating. Acta Scientific Nutritional Health, 2018. Link