Frying up: Antioxidants assessed
- Published: Nov 15, 2012
- Channels: Chemometrics & Informatics
Counting on fat
A cheminformatics study of chromatographic data on different kinds of vegetable oils and their potential antioxidant effects reveals that for obese individuals who enjoy a classic fried breakfast - colloquially known as the Full English Breakfast - they might experience greater health benefits if they fry with olive oil rather than sunflower oil.
Carlos Ferreiro-Vera, Feliciano Priego-Capote, José Mata-Granados and María Luque de Castro of the University of Córdoba, Spain, have looked at blood serum levels of eicosanoids in individuals before and after intake of different types of breakfast using univariate descriptive analysis and multivariate analysis to uncover statistical differences based on data from solid-phase extraction coupled to liquid chromatography-mass spectrometry.
The team could readily distinguish between those who partook of a "fry-up" and those who did not and within the former group discern who had eaten food cooked with sunflower oil or olive oil. They saw "significant increase in the concentration of hydroxyoctadecadienoic acid (HODE) metabolites, indicative markers of the intake of fried oils," the team explains. The researchers add that HODE metabolite concentrations were lower if natural antioxidants from extra virgin olive oil had been consumed but higher with sunflower oil.
Dietary fat and oils are an essential component of balanced nutrition, despite extreme health claims that we should attempt to eradicate these substances from our food. Dietary fats provide energy about 40 kilojoules per gram as opposed to about 15 kJ/g from carbohydrates or protein. They are also the most common source of essential fatty acids (EFAs). Linoleic acid from vegetable oils, including sunflower oil, accounts for about 85-90% of the n-6 fatty acids in our diet. The remainder is made up by arachidonic acid and gamma-linolenic acids.
The main n-3 EFA is alpha-linolenic acid but this makes up less than 1% of common vegetable oils. EFAs are important constituents of the cell membrane and act as precursors for the eicosanoids, including the prostaglandins, thromboxanes and leukotrienes, which are involved the inflammatory and immune responses, blood vessel dilation and constriction and blood clotting.
The dilemma regarding fat in the diet arises because EFAs are made via two enzymatic routes and give rise to two groups of eicosanoids with opposing actions. N-6 fatty acids, such as arachidonic acid from vegetable oil, are converted into those biomolecules that have pro-inflammatory, pro-aggregating, vasoconstricting action and immunosuppressive properties. By contrast the N-3 fatty acids are used to make the eicosanoids with the opposite, apparently more beneficial actions, anti-inflammatory, blood thinning, vasodilation (lowering blood pressure) and immune-boosting properties. Needless, to say, there is thus an imbalance if the main foods in your diet use vegetable oils rich in arachidonic acid rather than oils containing n-3 EFAs, such as olive oil.
Opting for olive
"This study supports both the accepted high-value of extra virgin olive oil as base fat source from a clinical and nutritional point of view, and also the proposal of addition of natural antioxidants as a promising alternative to improve the nutritional properties of other edible oils," the researchers conclude.
Food Chem, 2013, 136, 576-584: "Short-term comparative study of the influence of fried edible oils intake on the metabolism of essential fatty acids in obese individuals"
Article by David Bradley
The views represented in this article are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd.