Principal investigator Dr. Carol Shively, a professor of pathology at Wake Forest University School of Medicine, and her research team explained that in previous work with monkeys they showed significant links between stress and abdominal fat. More specifically, social stress and the amount of fat deposited in the abdominal cavity, and the amount of fat deposited around the middle of the body and the build up of plaque in blood vessels.
During the study, researchers fed 41 female monkeys a Western-style diet containing fat and cholesterol for 32 months. The researchers monitored the monkey’s social behavior and ovarian function, along with other biological variables, including BMI, stress biomarkers, and the amount of fat in the abdomen and elsewhere in the body.
The researchers found that monkeys whose abdominal fat to subcutaneous fat was high were also the subordinate, highly stressed monkeys. These monkeys were socially isolated, targets of aggression, received less grooming, had impaired ovarian function and had additional biomarkers of stress. The researchers also found these subjects to have higher heart rates late in the day and more plaque in their blood vessels.
The impaired ovarian function in female monkeys is a significant finding because few protective hormones were being produced. Researchers believe this discovery should prompt new studies into fat distribution and ovarian function in women.
Shively speculates that stress and buildup of visceral fat may be eroding the natural protection from the ovaries. She stated, “Suppressed ovarian function is a very serious condition in a woman. Women who are hormone-deficient will develop more atherosclerosis and be at greater risk of developing coronary heart disease and other diseases such as osteoporosis and cognitive impairment.”