Sunflower oil compared with CLA in exercising adults
What it found
In a 12-week trial in 62 regularly exercising adults, high-oleic acid sunflower oil was used as the comparison.
The authors report that CLA, not sunflower oil, lowered insulin after a glucose drink in women.
What they found
Studies in people
Insulin after glucose
In women taking CLA, average insulin levels after a glucose drink were lower after 12 weeks. In women taking sunflower oil, insulin levels were higher after 12 weeks.
Free fatty acids
After the glucose drink, free fatty acid levels in the blood were lower in both men and women taking CLA compared with those taking sunflower oil.
Body composition
CLA did not change body weight, body fat or fat distribution compared with sunflower oil. There were also no changes in waist or hip measurements.
Energy use and appetite
Resting energy use, fuel burning at rest and during exercise, and appetite ratings were similar in both groups. No differences were found between CLA and sunflower oil.
Blood fats
Total cholesterol and LDL cholesterol fell in both groups over 12 weeks. HDL cholesterol fell in women in both groups. These changes were not specific to CLA.
What the authors conclude
“In conclusion, mixed-isomer CLA supplementation had a favourable effect on serum insulin and NEFA response to oral glucose in non-obese, regularly exercising women, but there were no CLA-specific effects on body composition, energy expenditure or appetite.”
Also in their conclusions
- They conclude that mixed-isomer CLA supplementation had a favourable effect on serum insulin and NEFA response to oral glucose in non-obese, regularly exercising women.
- They state that there were no CLA-specific effects on body composition, energy expenditure or appetite.
- They call for more studies to understand the mechanisms and the possible role of gender, fitness and body fat levels.
How it was done
The authors wanted to test whether CLA supplements change body composition, energy use, blood fats, insulin sensitivity and appetite in people who exercise regularly. They used high-oleic acid sunflower oil as the control because it is similar in fat content to CLA.
They gave 62 non-obese, regularly exercising men and women either 3.9 g per day of CLA or 3.9 g per day of high-oleic acid sunflower oil for 12 weeks. Before and after, they measured body composition, resting energy use, blood fats, glucose tolerance and appetite.
What it can’t tell you
- This trial was in non-obese, regularly exercising adults, so the results may not apply to other groups.
- The trial lasted 12 weeks, so it cannot show what happens over longer periods.
- The sunflower oil was the comparison, not the main treatment, so the findings are mainly about how CLA differed from it.
Who paid
- Authors work at
- University of Cape Town, South Africa
The paper
- Title
- Conjugated linoleic acid versus high-oleic acid sunflower oil: effects on energy metabolism, glucose tolerance, blood lipids, appetite and body composition in regularly exercising individuals
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Lambert EV, Goedecke JH, Bluett K, et al (2007). Conjugated linoleic acid versus high-oleic acid sunflower oil: effects on energy metabolism, glucose tolerance, blood lipids, appetite and body composition in regularly exercising individuals. The British journal of nutrition. doi:10.1017/S0007114507172822Free full textPubMed 17381964DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error