High amounts of fat in food, such as ice cream, not only affect a person’s stomach but also their brain. Some of the fat travels to the brain, which then causes the brain to send out signals to all of the cells in the body. These signals “tell” the cells to disregard the hormones leptin and insulin, which tell the body to “stop” eating to regulate body weight. When a human eats, these hormones send signals to the body to stop eating once the body is full, but these hormones do not always work when a human eats something enjoyable like “junk” food. Leptin is released to stop the feeling of hunger by fat tissue in the body and insulin slows the desire for food by increasing in the pancreas after detection of blood sugar from a meal.
In a study done at the University of Texas Southwestern Medical Center at Dallas, Dr. Deborah Clegg analyzed what kinds of fats affected the brain in this way. Dr. Clegg believes that the fat actually changed the chemical composition of the brain because the fat is incorporated into the brain. Dr. Clegg performed this study by looking at effects of different fats on the brain of animals after exposure by three different methods: injection directly into the brain, feeding the animal through a stomach tube, and infusion into the carotid artery a few times a day. Palmitic acid and oleic acid were the specific fats used. Palmitic acid is a saturated fatty acid and is found in foods such as butter and beef while oleic acid is an unsaturated fatty acid found in food such as olive oil. The results showed that palmitic acid affected the signaling pathways of the leptin and insulin over about three days while the oleic acid did not affect the hormones. These studies were done on animals but Dr. Clegg believes that the saturated fatty acids will affect a human’s brain in a similar way. In another study with rats, the saturated fats, especially palmitic acid, caused the insulin modulator to localize to the cell membranes in the hypothalamus, which slowed the insulin signaling in the brain. Dr. Clegg hopes to soon determine a way to reverse the effects of the palmitic acid on the brain signaling.