Grapeseed oil can lower heart disease, diabetes risk

The results showed that men and women with higher linoleic acid levels -- which contains omega-6 fatty acid -- are less prone to heart disease and inflammation and also possess more lean body mass.

Higher linoleic acid levels also means lower likelihood of insulin resistance, which is a precursor to diabetes.

“This finding could have obvious implications in preventing heart disease and diabetes, but also could be important for older adults because higher lean body mass can contribute to a longer life with more independence,” said Martha Belury, professor at Ohio State University.

Grapeseed oil for now remains an excellent source of linoleic acid, which constitutes about 80 percent of its fatty acids. Corn oil also remains a decent source, the researchers noted.

However, the general consumption of linoleic acid is declining because of genetic modification of plants for food manufacturers seeking oils higher in oleic acid. The industry's push against trans fats can be one possible reason.

"Vegetable oils have changed. They're no longer high in linoleic acid," Belury pointed out.

When linoleic acid gets solid (hydrogenated) for processed foods, it is more likely to convert to trans fat than its oleic cousin.

So oils, notably safflower, sunflower and soybean, now routinely contain less linoleic acid - it often makes up less than 20 percent of the fatty acids in commonly purchased oils, based on food labels and confirmed by testing in her lab, Belury explained.

The study, published in the journal Molecular Nutrition & Food Research, is the first to examine linoleic acid alongside body composition and other health markers in people who hadn't been given supplements or prescriptive diets, the researchers noted.