A Dietitian's Guide to Olive Oil

Olive oil is rich in important nutrients like monounsaturated fats and antioxidants, so it's no wonder it has numerous health benefits. In one recent study, researchers found that two tablespoons of extra virgin olive oil (EVOO) daily can improve blood pressure and cholesterol levels within three weeks and help manage weight loss.

Another recent study showed that consuming 7 grams or more of olive oil daily lowered the risk of dementia-related deaths by 28%.

However, there are many different types of olive oil in your local supermarket, and they all have different characteristics. So, we spoke with Sally Dorfzaun, MS, RD, CDN, a registered dietician at Columbia, to give us an overview.

Can you help us understand the different types of olive oil?

According to the USDA, "Olive oil is the oil obtained solely from the fruit of the olive tree" without additives, other oils, or any other ingredients mixed in. Furthermore, there are three main categories of olive oil: virgin olive oil, olive oil (also known as pure olive oil), and refined olive oil.

Virgin olive oil includes a sub-category: extra virgin olive oil (EVOO), considered the purest form of olive oil and deserves the most attention. It is produced by mechanically crushing the olives and extracting the oil without using any chemical treatments (just washing, decantation, centrifugation, and filtration). EVOO has a distinct aroma. To me, it's also the best tasting, and ideal for salad dressings, drizzling over dishes, and low-heat cooking.

Virgin olive oil is also made by mechanically crushing olives and extracting the oil without using chemicals. However, this oil is of a lower quality than EVOO, has a higher acidity level, and has a milder taste. Virgin olive oil is still a healthy choice; it contains antioxidants and has anti-inflammatory properties. It is good for cooking, baking, and sautéing.

Refined olive oil, as the word states, is made by certain methods of refining virgin olive oils. It is flavorless and odorless.

Olive oil (pure olive oil) is a blend of virgin and refined olive oil.  

So, which olive oil is healthiest?

Always look for the "extra virgin" or "virgin" label to ensure you get the healthiest option.

The most recommended is EVOO. It is rich in more than 200 antioxidants and anti-inflammatory plant compounds, including polyphenols, which may reduce inflammation that can contribute to heart disease, diabetes, and possibly dementia.

A 2022 study suggests that virgin olive oil reduces mortality risks from heart disease.

All olive oil is high in monounsaturated fats, which can lower harmful cholesterol levels and reduce the risk of heart disease.

What is the best way to store olive oil?

Ideally, keep the oil in a cool, dark place, away from heat sources. Also, try to buy it in dark containers to avoid sunlight and degradation.