Interest + terrified = interesterified fat?
Barely have consumers - and health authorities - woken up to the dangers of trans fats when we are now told of a new, possibly greater threat. The new substance to watch out for is interesterified fat.
Huh? What's this?
First, let me tell you how I remember the spelling of this word - combine together “interest” and “terrified” but spell “terrified” with only one “r”. Actually, it is made up of the words “inter” and the chemical term “esterified”, meaning “formed into ester”.
Basically, it is an attempt by food scientists to produce oils with “no trans fats”.
What they do is hydrogenate the oils fully. The oils become fully saturated and there are no trans fats left. But fully hydrogenated oil is hard and inedible. So the smart aleck scientists mix it with liquid oils and put it through other chemical processes to create a semi-solid grease like margarine and vegetable shortening.
Enough of the chemistry.
The bottom line is this… Early scientific reports -- one of which was released in mid-January 2007 by joint-researchers from Malaysia and the UK -- suggest that interesterified fat is far more harmful than trans fats.
Interesterified fat was found to depress the level of HDL (good cholesterol) more than trans fat.
In addition, interesterified fat raised blood glucose levels and depressed the level of insulin. This strongly suggests that interesterified fat could lead to diabetes.
So be extra careful of products labelled “No Trans Fat” especially when they contain fully hydrogenated oils.
The research on interesterified fat -- which is gaining popularity as food producers try to meet the criteria of having “No Trans Fat” -- was conducted in Malaysia and at Brandeis University, UK.
Biologist and nutritionist K.C. Hayes, from Brandels University, collaborated on the research with Dr. Kalyana Sundram, Nutrition Director for palm oil research at the Malaysian Palm Oil Board in Kuala Lampur.
Both Hayes and Sundram are experts on human lipid metabolism and were instrumental in the development of Smart Balance® Buttery Spreads, a blend of vegetable oils that improves the cholesterol ratio.
The study compared trans-rich and interesterified fats with an unmodified saturated fat, palm olein, for their relative impact on blood lipids and plasma glucose.
Thirty human volunteers participated in the study, which strictly controlled total fat and fatty acid composition in the subjects' diet. Each subject consumed all three diets in random rotation during four-week diet periods.
This study further confirmed previous studies in animals and humans, indicating once again that trans fats negatively affect LDL and HDL cholesterol.
The interesterified fat had a similar, though weaker impact on cholesterol. However, the effect of interestified fat on blood glucose was stronger than that of trans fat, raising blood glucose levels by 20 percent within a month.
Interesterified fat is rich in stearic acid, which is the type of saturated fat found in cocoa butter as well as in beef.
Stearic acid, together with palmitic acid (from palm oil) are said to be the "preferred food for the heart", providing energy for the heart to work. Some studies also suggest that stearic acid helps lower cholesterol levels.
Incidentally, the properties of stearic acid also makes it beneficial for the manufacture of candle, soap, plastic, oil pastel, cosmetics etc. It is also used for softening rubber.BUT... the stearic acid in interesterified fat is not quite the same as naturally occurring stearic acid. Because the processs of creating interesterified fat unnaturally rearranges the position of individual fatty acids on the fat molecule.
Dr Hayes said the research:
"One of the most interesting aspects of these findings is the implication that our time-honored focus on fat saturation may tell only part of the story.
"Now it appears that the actual structure of the individual fat molecule is critical, that is, the specific location of individual fatty acids, particularly saturated fatty acids, on the glycerol molecule as consumed seems to make a difference on downstream metabolism of fat and glucose.”
Added Dr Kalyana Sundram:
“This is the first human study to examine simultaneously the metabolic effects of the two most common replacement fats for a natural saturated fat widely incorporated in foods. As such, it is somewhat alarming that both modified fats failed to pass the sniff test for metabolic performance relative to palm olein itself.”
Dr Kalyana Sundram said further studies were needed as “the apparent adverse impact on insulin metabolism is a troubling finding."
Interesterified fat - what should consumers do?
Scientists working for the food industry keep coming up with strange, weird and terrifying stuffs. As consumers, we need to keep abreast of these developments and watch out for the dangers.
Otherwise, just stick to traditional foods that humans have been eating for thousands of years, and we will be all ok. In the case of oils and fats, just stick to:
Note also that:
One product to be careful about is peanut butter, some of which are now made with fully hydrogenated oils. These could well be interesterified fat. If you want a healthy peanut butter, look for those that contain just one or two ingredients, either only peanuts, or peanuts and salt.