An interesting article published in the journal Vascular Pharmacology by Chun-Yi NG et al (2014) looking at the relationship between heating (and reheating) vegetable oils and cardiovascular disease risk factors.

Specifically, the article details the changes in chemical composition of cooking oils when exposed to heat. These chemical changes result in the degradation of the cooking oils, which become toxic to health. Furthermore, prolonging the exposure of cooking oil to heat (e.g. oil in a deep fryer that is heated for several days in a row), results in further degradation, increasing the amount of harmful compounds in the oil.

There are many health effects, including:

• Increased vascular inflammation
• Increased deposition of fatty plaques on the walls of arteries
• Increased levels of low density lipoproteins (LDL – bad cholesterol) and lower levels of high density lipoproteins (HDL – good cholesterol)
• Formation of trans fatty acids (a type of fatty acid that greatly increases the risk of atherosclerosis)
• Hardening of blood vessels,
• Increased blood pressure

These health effects can lead to

• Increased risk of heart attack and stroke.

To summarize, heating vegetable oils alter their chemical composition resulting in the formation of multiple harmful chemicals. Deep frying further increases the presence of the harmful chemicals by exposing vegetable oils to high heat for extended (and repeated) periods of time. So the next time you are considering eating deep fried foods – stop, think, and give your cardiovascular system a break.

Graham Beaton“>Graham Beaton is a naturopathic doctor practicing in downtown Ottawa. For an appointment or for more information on how naturopathic medicine can help you, please call 613-290-6115.

Tags: blood pressure, Cardiovascular, Deep Fried Foods, Fried Foods, Healthy Eating, Heart disease, High blood pressure, High Cholesterol, Meal Choices