Trans Fatty Acids - Adverse

BLUF:  In the following abstract, a very select population was tested for outcomes after comparing 'high' intake of industrial TFA (trans fatty acids) to a control group eating increased saturated fats.  The TFA group fared worse on all measures except for measures of abdominal and liver fat (for which both groups fared the same).  Seems like a good reason to be afraid of these 'frankenfats', which are so new to the food chain we've barely had time to become fearful of them.

Background:

Intake of industrially produced trans fatty acids (TFAs) is, according to observational studies, associated with an increased risk of cardiovascular disease, but the causal mechanisms have not been fully elucidated. Besides inducing dyslipidemia, TFA intake is suspected to promote abdominal and liver fat deposition.

Objective:

We examined the effect of a high intake of TFA as part of an isocaloric diet on whole-body, abdominal and hepatic fat deposition, and blood lipids in postmenopausal women.

Methods:

In a 16-week double-blind parallel intervention study, 52 healthy overweight postmenopausal women were randomized to receive either partially hydrogenated soybean oil providing 15.7 g day⁻¹ of TFA or a control oil with mainly oleic and palmitic acid. Before and after the intervention, body composition was assessed by dual-energy X-ray absorptiometry, abdominal fat by magnetic resonance (MR) imaging, and liver fat by ¹H MR spectroscopy

Results:
Compared with the control fat, TFA intake decreased plasma high-density lipoprotein (HDL)-cholesterol by 10%, increased low-density lipoprotein (LDL)-cholesterol by 18% and resulted in an increased LDL/HDL-cholesterol ratio (baseline adjusted mean (95% CI) difference between diet groups 0.41 (0.22; 0.60); P=0.001). TFA tended to increase the body fat (0.46 (−0.20; 1.17) kg; P=0.16) and waist circumference (1.1 (−0.1; 2.4) cm; P=0.08) more than the control fat, whereas neither abdominal nor liver fat deposition was affected by TFA.  

Conclusion:
The adverse effect of dietary TFA on cardiovascular disease risk involves induction of dyslipidemia, and perhaps body fat, whereas weight gain-independent accumulation of ectopic fat could not be identified as a contributory factor during short-term intake.  http://www.nature.com/nutd/journal/v1/n1/full/nutd20104a.html

Humorous Study Disection

While I doubt that disecting studies will ever become a truly mass media event, this one's pretty funny for a geek like me.  Hyper Lipid's hyper-dissection of this study does a nice job of showing how a "study" and its "conclusions" are supposed to be picked over and picked apart.  Along the way, we can learn a little bit about the finer points of the study of fat metabolism and in particular its relationship to diabetes. 
BLUF:  Don't eat trans-fats unless you like being sick, and don't feed it to mice unless you want to confound your test results.

Also, a nice clarification in the post - what is the difference between partially hydrogenated and hydrogenated?

Cited Study Text:
The present study used hydrogenated corn oil for dietary fat sources since it has less harmful effect on diabetes than lard, even though it contained trans fat.27 
Hyper Lipid Translation: This study did not use hydrogenated corn oil.  It used PARTIALLY hydrogenated corn oil, full hydrogenation would eliminate all trans fats.  Bollocks statement number two is that trans fats have a less harmful effect on diabetes than lard.