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What’s the healthiest oil for salad dressings?


Question: What's the healthiest oil for tossing salads?

Answer: There are a few different types of cooking oil I recommend for salad dressings. When it comes to nutrition, the healthiest oils are those rich in monounsaturated fat, phytochemicals, and alpha linolenic acid.

Cooking oils contain predominantly polyunsaturated or monounsaturated fa t. Both are considered heart healthy unsaturated fats. Excellent sources of monounsaturated fat include olive, canola, peanut, avocado and almond oils. Olive oil is the richest source of monounsaturated fat – 77 per cent of its total fat is derived from this type of fat.

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Olive oil has received the most attention by scientists. Its monounsaturated fat helps lower blood pressure and LDL (bad) cholesterol and raise HDL (good) cholesterol. Olive oil also contains phytochemicals thought to help dilate blood vessels, prevent blood clots, and decrease inflammation in the body.

If you decided to use olive oil for salad dressing, choose extra virgin and virgin olive oil. These are "cold pressed" from olives using minimal heat and no chemicals. As a result they retain the highest amount of phytochemicals and nutrients compared to "pure olive oil", "olive oil" or "light olive oil", which have been refined.

Cooking oils high in polyunsaturated fat include sunflower, safflower, soybean, corn, grapeseed, hemp, flaxseed, and walnut. These oils provide essential fatty acids called linoleic acid and alpha linolenic acid (ALA). They're essential because your body can't make them on its own; they must be supplied by your diet.

Most of us already get plenty of linoleic acid, an omega-6 fatty acid that's widespread in processed foods made with soybean and corn oils. We don't, however, consume enough ALA, an omega-3 fatty acid found in flax, walnut, canola and hemp oils that may help lower the risk of heart disease.

Some cooking oils are also good sources of vitamin E, an antioxidant that protects cells from the harmful effects of unstable oxygen molecules (free radicals). Best oils for vitamin E content include grapeseed oil, almond oil, and avocado oil.

I told you earlier that I recommend oils rich in monounsaturated fat, phytochemicals, and alpha linolenic acid for salad dressings. These include extra virgin olive, canola, peanut, flaxseed, walnut, hemp, avocado, and almond oils. I would also add grapeseed oil to my recommended list because it's such a good source of vitamin E. (Canola and peanut oils are also good choices for sautéing and stir-frying.)

Nut oils such as walnut, almond, hazelnut, and flaxseed have a distinctive rich taste. I like to use them in combination with another oil in dressings. One of my favourite dressings for arugula is three parts extra virgin olive oil and one part walnut oil. It's got a great nutty flavour and it's an excellent source of monounsaturated fat and alpha linolenic acid.

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Send dietitian Leslie Beck your questions at He will answer select questions, which could appear in The Globe and Mail and/or on The Globe and Mail website. Your name will not be published if your question is chosen.

The content provided in The Globe and Mail's Ask a Health Expert centre is for information purposes only and is neither intended to be relied upon nor to be a substitute for professional medical advice, diagnosis or treatment.

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