Randomised trial · Clinical nutrition (Edinburgh, Scotland) · 2011Conflicts declared

Safflower oil and metabolic health in women with diabetes

Asp ML, Collene AL, Norris LE, et al · Free full text

In 35 post-menopausal women with type 2 diabetes, taking 8 grams of safflower oil daily for 16 weeks improved blood sugar control, inflammation, and HDL cholesterol.

CLA, a different oil, did not change these measures.

What they found

Studies in people

Blood sugar control

Safflower oil lowered HbA1c by 0.64% and fasting glucose after 16 weeks. CLA did not change HbA1c or fasting glucose.

Insulin sensitivity

Safflower oil improved insulin sensitivity (measured by QUICKI) after 16 weeks. CLA had no effect.

Inflammation

Safflower oil lowered C-reactive protein (CRP) by 13.6 mg/L after 16 weeks. CLA did not change CRP. Neither oil changed interleukin-6.

Blood lipids

Safflower oil raised HDL cholesterol by 0.12 mmol/L after 12 weeks. Neither oil changed total cholesterol, LDL cholesterol, or triglycerides.

Fatty acids in blood

Linoleic acid in the blood rose with safflower oil, and CLA isomers rose with CLA, each within 4 weeks. These increases came before the metabolic changes.

What the authors conclude

“We conclude that 8 g of SAF daily improved glycemia, inflammation, and blood lipids, indicating that small changes in dietary fat quality may augment diabetes treatments to improve risk factors for diabetes-related complications.”

Asp ML, Collene AL, Norris LE, et al, 2011

Also in their conclusions

They conclude that 8 grams of safflower oil daily improved glycemia, inflammation, and blood lipids.
They say that small changes in dietary fat quality may augment diabetes treatments to improve risk factors for diabetes-related complications.
They suggest that including a small amount of safflower oil in the diet may have meaningful effects on risk factors in diabetes management.

How it was done

The authors wanted to see whether safflower oil or CLA could improve blood sugar, blood fats, and inflammation in people with type 2 diabetes, and how long any effects might take.

They studied 55 post-menopausal, obese women with type 2 diabetes, of whom 35 completed the study. Each woman took 8 grams of safflower oil and 8 grams of CLA daily for 16 weeks each, in a random order, with a 4-week break in between.

What it can’t tell you

This study cannot show whether the improvements in risk factors lead to fewer heart attacks or other diabetes complications over time.
It cannot tell whether safflower oil as a whole or just the linoleic acid in it caused the effects.
It cannot show what happens in men, younger women, or people without type 2 diabetes.

Who paid

Funding: Funded by NCRR NIH HHS; NCCIH NIH HHS (from the PubMed record).
Conflicts: Conflict of Interest Statement . There are no conflicts of interest declared by any of the authors.
Authors work at: The Ohio State University, USA

The paper

Title: Time-dependent effects of safflower oil to improve glycemia, inflammation and blood lipids in obese, post-menopausal women with type 2 diabetes: a randomized, double-masked, crossover study
Type: Randomised controlled trial
Evidence: Studies in people
Summarised from: Full text
Cite: Asp ML, Collene AL, Norris LE, et al (2011). Time-dependent effects of safflower oil to improve glycemia, inflammation and blood lipids in obese, post-menopausal women with type 2 diabetes: a randomized, double-masked, crossover study. Clinical nutrition (Edinburgh, Scotland). doi:10.1016/j.clnu.2011.01.001Free full text PubMed 21295383 DOI

Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error