ISLAMABAD: New research, however, suggests that low-fat dairy may benefit mental health, too.
Prof. Nagatomi and colleagues note that previous studies have associated dairy intake with depression, though whether the effect is positive or negative has been inconclusive.
For their study, the researchers set out to investigate how the consumption of certain low-fat and high-fat dairy products individually impact the risk of developing symptoms of depression.
Participants disclosed how often they consumed low-fat and whole-fat milk and yogurt in a dietary questionnaire. The intake of cheese, butter, and other dairy products was not reported.
Symptoms of depression were assessed using the 20-item self-rating depression scale.
The team identified depressive symptoms among 31.2 percent of men and 31.7 percent of women.
Compared with adults who reported no consumption of low-fat dairy products, those who consumed low-fat milk and yogurt between one and four times weekly were less likely to have symptoms of depression.
These results remained after accounting for a number of possible confounding factors, such as age, sex, overall diet and lifestyle, and health status.
Commenting on what their findings show, the researchers say.
"The current results indicate that a higher frequency of low-fat dairy consumption may be associated with a lower prevalence of depressive symptoms."
No link was identified between the consumption of whole-fat dairy products and depression. The researchers hypothesize that this may be because the trans-fatty acids in whole-fat milk - which are associated with depression - were offset by an amino acid in milk, called tryptophan.
The team concludes that further studies are needed to pinpoint the mechanisms underlying the link between low-fat dairy intake and a lower risk of depression.