Most of us are familiar with the potential benefits of using olive oil in the diet. Fresh olive oil, a natural source of beneficial polyphenols, appears to reduce risk of heart disease, metabolic syndrome, cancer, high blood pressure, blood clots and more. So what's the problem?
A recent article from Live Science.com cites sources from the USDA and UC Davis, indicating that the beneficial polyphenol compounds simply aren't present in most commercially available olive oils. And it's the polyphenols, not the oil itself, that confers health benefits.
Several factors appear to be responsible:
1 - Shelf Life- Poyphenols decline with age. Maximum shelf life is 2 years but that's much too long.
2 - Harvest methods- Rough handling of fruit exposes polyphenols to the elements.
3 - Older Trees- Polyphenol content is significantly higher in fruit from older trees.
4 - Over Processing- "Extra virgin" oil is pressed only once and is best.
5 - Cooking and Storage Methods- Exposure to light, air, or any use of heat (including cooking) will reduce polyphenol content.
6 - Dilution of Olive Oils with Canola and other products.
Look for harvest dates (many bottlers only give "sell by" dates which are typically 2 years after harvest). Try to use within a few months of harvest.
US growers are now producing high quality oils which may be fresher than European products.
Use only oils in dark or opaque bottles to prevent light damage. Store oils in a cool dark place at home.
Avoid cooking with high heat...instead drizzle oils on salads etc for maximum benefit.