A study found that benefits of consuming good unsaturated fats can disappear when the person has had a stressful day. Published Tuesday in the journal Molecular Psychiatry, the study was led by researchers at the Ohio State University.

Stress and diet can affect inflammation in the body, and chronic inflammation is linked to several diseases including diabetes, heart disease and rheumatoid arthritis. Researchers were looking to study the interaction between stress, diet and inflammatory markers which they can measure in the bloodstream.

They observed 58 women, of which 38 were breast cancer survivors. The women were assigned either of two meals at random. One of the two breakfasts had less-healthy saturated fat from palm oil and the other had the healthier unsaturated fat from sunflower oil, which is high in oleic acid.

Participants were also questioned about their activities from the previous day. Researchers used the Daily Inventory of Stressful Events to figure out if the women were under stress or not. Based on the responses to the questionnaire, researchers determined that 31 women experienced at least one recent stressor before one of the two sessions while 21 experienced stress before both sessions. Six women experienced no significant stressor before both sessions.

Researchers looked for two markers of inflammation, C-reactive protein and serum amyloid A, in the blood samples collected from the participants. They also analyzed the blood samples for two markers called cell adhesion molecules. Cell adhesion molecules can predict the likelihood of plaque formation in the arteries.

The levels of all four markers were higher in women who consumed saturated fat, researchers found after adjusting results for factors like age, blood pressure before meals, age difference, abdominal fat and physical activity.

Researchers also found that among women who had experienced stress, the positive effects of the unsaturated fat vanished. However, stress did not affect the high levels of the markers in women who consumed saturated fat.

“We know that a less-healthy meal is going to have adverse effects on markers of inflammation, but we wanted to look at this meal type with different types of fat,” co-author of the study Martha Belury said in a statement.