Many components naturally present in vegetable oils have been shown to have beneficial properties. Once isolated and concentrated, a number of these compounds have proven effective in treating a wide range of conditions ranging from irritable bowel syndrome to chronic liver disease (1). Similarly, many of the fatty acids and other compounds present in vegetable oils have long been known to benefit our health. There is clearly great potential for developing functional vegetable oils.
The active ingredients
The number of active ingredients so far identified in oil seeds is impressive. Many of these compounds make it through to the final salad or cooking oil whilst others may be partially or wholly removed during the oil refining process.
Vitamin E is a powerful antioxidant and vegetable oils are a major dietary source of this vitamin. Each fatty acid also has its own specific properties (2). Linoleic acid is a polyunsaturated fatty acid with cholesterol-lowering properties and a-linolenic acid is also linked to heart health. Ricinoleic acid is the active ingredient in castor oil and is a powerful stimulant laxative, whilst ?-linolenic acid provides the main benefits of evening primrose oil, used among other things, to treat breast pain and atopic eczema.
Phytosterols are found in vegetable oils, particularly germ oils. Margarines fortified with sterols have recently hit the headlines because their cholesterol lowering capacity is as effective as many drugs (3). It is now also suggested that natural levels of phytosterols found in many vegetable oils (maize oil: 968mg/100g, wheat germ oil: 553mg/100g and olive oil: 221mg/100g)* may also make a significant contribution to cholesterol lowering (4).
Plenty of other beneficial compounds are also extracted and concentrated from by-products of the refining process including;