Leading CLA researchers and suppliers have slammed product claims that safflower oil is superior to CLA (conjugated linoleic acid) for reducing 'belly' fat, as the CLA community unites to set the record straight on the science.
Safflower oil is a rich source of linoleic acid, but only contains minimal amounts of CLA (about 0.7 mg CLA/g fat). Both main CLA brands on the market (Tonalin from BASF and Clarinol from Stepan Lipid Nutrition) are derived from safflower oil using proprietary processes.
Interest in safflower oil and its potential role in ‘busting belly fat’ boomed following a very high profile segment on the Dr Oz show under the title Safflower Oil to Bust Your Belly, where Montel Williams promoted the effects of the Safslim safflower oil product . Williams is a paid spokesperson for Safslim.
The Safslim website quotes one study to support its claims of 'superiority' - a study with 35 morbidly obese diabetic women (average BMI of 35.7 kg/m2), led by Martha Belury from Ohio State University and published in the American Journal of Clinical Nutrition (2009, Vol. 90, pp. 468–476).
“As demonstrated in the Ohio State University study, safflower oil is superior in attacking belly fat... Safflower oil has been shown in a major university study to help reduce belly fat by up to 9.4%, or 6 times more than the leading omega oil, in only 16 weeks without diet or exercise,” states the Safslim site. Safslim was contacted on June 11 for comment by NutraIngredients-USA, but no response had been received prior to publication.
On another website, the product description is : “Looking for something even better than CLA? Try SAFActive78 high-linoleic safflower oil. A major 16-week university study at Ohio State found that SAF outperformed CLA with a 6.3% reduction of belly fat and a 20.3% increase in adiponectin, an important belly fat hormone that regulates sugars and fat stores.”
Such claims have attracted criticism from leading CLA researchers: Dr Michael Pariza, widely recognized as the founder of the modern field of CLA research, told us: “The claim that SafSlim is superior to CLA is not factual and certainly not supported by the study referenced. The study authors do not claim that safflower oil is superior to CLA, only that it might be synergistic when you take 8 g per day (CLA is effective in clinical trials at 3 grams per day or less). CLA reduced BMI and total adipose tissue, whereas the safflower oil had no effect.
“The data showed that CLA actually reduced body fat, whereas the best you could say for safflower oil is that it appeared to 'rearrange' body fat, so that the subjects had less around the waist (but likely more somewhere else, since their total body fat did not drop.)
“In our studies, we always used linoleic acid, the major fatty acid in safflower oil, as a control, so clearly safflower oil is not 'superior' to CLA.”
‘An exceedingly small effect relative to CLA’
Fellow CLA researcher, Dr Mark Cook from The University of Wisconsin told NutraIngredients-USA that safflower, sunflower, and corn oil are vegetable oils high in linoleic acid (80, 60, and 50%, respectively).
“In all of our studies, where we have shown reduced fat accumulation, and decreased acute or chronic inflammation, these oils served as a negative control. Replacing approximately 5 to 10% of these vegetable oils with CLA was effective in markedly reducing fat accumulation and inflammation.
“Key in the study by the Belury group was that CLA dropped BMI, whereas Safflower oil did not affect BMI. In our experiments, if safflower oil had any effects on body composition it would have been exceedingly small relative to CLA.” added Dr Cook.
Where’s the placebo?
Dr. Hiskias Keizer from Stepan Lipid Nutrition, which supplies the Clarinol-branded CLA ingredient, told NutraIngredients-USA that the company agrees with the comments from the scientists at the University of Wisconsin.
“In addition, other arguments could be made that had not been mentioned yet is that CLA reduces fat loss in placebo controlled trials and the subjects where morbidly obese and diabetic. The Belury study was not placebo controlled. We have no idea what a placebo would have done.
Dr Keizer added that the study participants were diabetics (who changed medication during the study), and were also morbidly obese. "CLA works best on overweight and slightly obese people (BMI 25-32)," he said. "Morbidly obese people are likely to have abnormal physiology.
“This study therefore says little about the effect of Safflower oil in a healthy but overweight population. Science wise, safflower oil is not a serious alternative to CLA for improved body composition.”
One study vs a meta-analysis
Marianne Heer, Global Scientific Marketing Manager for BASF Nutrition & Health, suppliers of leading CLA ingredient Tonalin, said that BASF’s ingredient has been clinically proven to reduce body fat mass in 18 clinical studies, including a meta-analysis (Whighamet al. 2007), whereas the company is aware of only one study (the Belury study in AJCN, 2009) documenting the effects of high linoleic safflower oil on trunk fat mass.
“Accordingly, comparing the benefits of safflower oil to CLA is like comparing one, small observational study to a meta-analysis,” she said.
Heer echoed Dr Keizer’s comments about the very specific population studied (obese, postmenopausal women), and said that it cannot be concluded that SAF’s effect on trunk fat mass would be observed in other populations as well.
“In contrast, the effectiveness of CLA on body fat mass has been confirmed in different populations,” she said.
“The following questions remain unanswered with respect to the effectiveness of safflower oil on reducing body fat mass:
(a) Does the product reduce trunk fat or does it only shift the trunk fat to other portions of the body? and
(b) Can trunk fat be translated directly into abdominal (belly) fat as described on the SafSlim homepage?
“Furthermore, because safflower oil did not change other measures of abdominal fat, such as waist circumference and sagittal abdominal diameter, it has not been conclusively determined that safflower oil reduces “belly” fat.
“To conclude, the overall efficacy of an ingredient cannot be determined based on a single study of a specific population. Before any ingredient can be recommended for a stated purpose, additional studies are required to confirm the effectiveness of such ingredient in achieving the stated purpose," said Heer.