A major supplier of soy-based oils has criticised a study that questioned whether supposedly better-for-you trans-fats alternatives were, in fact, any healthier than their demonised hydrogenated cousins.
The study, published in Nutrition & Metabolism by researchers hired by the Malaysian Palm Oil Board — a long-time competitor to the soy-based oils industry — found interesterified oils widely used as trans-fats alternatives not only raise LDL cholesterol, but also cause a significant spike in blood-sugar levels by changing the body's levels of insulin — just as trans fats do.
ADM defended its soy oils and criticised the terms of the study. "ADM interesterified shortenings have demonstrated functionality in a variety of food applications where solid fat is needed. The fats evaluated in this study were used as cooking fats, not as ingredients in food products," said Graham Keen, vice president of corporate marketing at ADM, which manufactures an interesterified fat called Novalipid.
"ADM believes soy-based interesterified shortenings provide a functional low-trans alternative to that of partially hydrogenated vegetable oils," he said.
The study authors said more research was required, "before interesterification is disseminated as the process of choice for replacing partial hydrogenation as a primary means for hardening vegetable oils for use in foods."
Trans fats are known to raise LDL cholesterol levels, and were originally thought to be superior to LDL-hiking saturated fats such as tropical oils and animal fats. But ingredient technology improvements have brought a swathe of trans-fat alternatives — Novalipid and others from companies such as Cargill and Loders Croklaan — to market as scrutiny has increased on the use of trans fats. Measures have been taken by governments in many countries to restrict or prohibit trans-fats use even as groups like the American Heart Association have questioned whether trans fats are actually worse than any other form of fat.
Some of the world's biggest food companies such as Kraft, ConAgra Foods, McDonalds, Burger King, PepsiCo and General Mills have removed trans fats, or committed to replacing them with healthier oils in recent years. Even Girl Guide biscuits have been reformulated without them.
In the Nutrition & Metabolism study, a natural saturated fat, palm olein, was compared to two forms of modified replacement fats, one containing trans fatty acids, the other interesterified. Both modified fats adversely altered metabolism of plasma lipoproteins and blood glucose in humans. In 30 humans, the surge was 20 per cent greater for saturated fats, in only four weeks' time.