It is common knowledge that what you eat can affect how you feel and, conversely, that how you feel can affect what you eat. Many people feel depressed, agitated, and tense before eating carbohydrate-rich foods, but happy and relaxed afterwards. High protein, low carbohydrate diets are sometimes associated with feelings of depression and an intense craving for foods such as chocolate.
Until about 30 years ago, most nutritional scientists denied that mood can be affected by diet. They believed that the membrane separating the blood from the brain (the blood-brain barrier) effectively kept dietary chemicals out of the brain. More recent research has forced many of these scientists to change their mind. It has been demonstrated that certain chemicals, such as the amino acid tryptophan, can penetrate the blood-brain barrier and affect behaviour. Mood appears to be affected by a complex interaction between diet and other factors, including sex, hormone levels, time of day, and even time of month. After eating carbohydrates, men tend to become calmer and women sleepier. A high carbohydrate meal eaten for breakfast usually has less effect than the same meal taken at lunch. Women tend to have a keener desire for carbohydrates for the 10 days before menstruation than during the 10 days after.
Although most scientists now agree that diet can cause mood swings, they are still unsure about the precise mechanisms involved. As yet, they are unable to predict with certainty the effects of specific types of food on the mood of a particular individual. See also serotonin.
Subjects: Medicine and Health.