C ARBOHYDRATES AND M AJOR D EPRESSION

13.3.5 C ARBOHYDRATES AND M AJOR D EPRESSION

Depression is a serious mental disorder affecting about 1 in every 20 individuals at some time in their life. 112 To be diagnosed with major depression, a person must have a depressed mood or loss of interest or pleasure in nearly all activities as well as a number of other symptoms, such as a change in appetite or weight, sleep, and psychomotor activity; feeling fatigued, worthless, or guilty; having difficulty con- centrating, thinking, or making decisions; or having suicidal thoughts, plans, or

suicide attempts. 95 While these are the typical and diagnostic features of major depression, it has also been documented that about 25% of individuals with major depression experience carbohydrate cravings. 48,69,113 Depressed individuals also report that their preference for sweet carbohydrate- and fat-rich foods increases as

they become depressed, 48 and they also consume more carbohydrates, particularly from sugars, 47 as revealed in Table 13.1. This should not be surprising, as it has been demonstrated that food cravings tend to lead to consumption of the craved food. 103

TABLE 13.1 Mean Daily Carbohydrate Intake in Depressed and Nondepressed

Individuals (Mean ± Standard Deviation)

SD t-ratio

Carbohydrate (g) 330

118 2.86 a Sugars (g)

89 63 2.43 a Sucrose (g)

29 25 2.19 a a p < 0.05.

Adapted from data taken from Christensen, L. and Somers, S., Int. J. Eating Disord., 20, 105, 1996.

Dietary Carbohydrates as Mood and Performance Modulators

Why would the depressed individuals report a change in preference for sweet carbohydrate-rich foods as they became depressed and then proceed to consume such foods? These individuals report consuming such foods to combat their depres-

sive symptoms, 78 which essentially means that they are engaging in a form of self- medication. The interesting component is that they report using caffeine in the same manner, so both caffeine and sweet carbohydrate-rich foods seem to be used for the ameliorative effect that they have on depressive symptoms.

While the self-medication hypothesis has not been investigated in individuals with major depression, several studies have focused on the effects of carbohydrates on depressive symptoms. Moorhouse et al. 114 investigated the effect of administering

a carbohydrate-rich and protein-poor, or a protein-rich and carbohydrate-poor break- fast, mid-morning, mid-afternoon, and evening snack to alcohol-dependent individ- uals and controls for two consecutive days. These investigators found that the alcohol-dependent individuals with carbohydrate cravings demonstrated an increase in depression after consumption of the carbohydrate-rich breakfast and snacks, whereas the protein-rich breakfast and snacks had no deleterious effect. These investigators hypothesized that “clinical populations who crave sugar are paradox- ically sensitive to its adverse effect on mood” (Moorhouse et al., 114 p. 641).

This hypothesis is supported by a number of studies 115–117 that my students and I have conducted. In the first series of studies, 115,117 we found that eliminating added

sucrose and caffeine from the diet of selected emotionally distressed individuals ame- liorated their distress. The constant theme running through these studies was that the individuals who benefit from eliminating added sucrose and caffeine were depressed. Therefore, we conducted a study 116 investigating the effect of eliminating added sucrose and caffeine from the diet of individuals experiencing a current episode of major depression. Table 13.2 reveals that the experimental group who eliminated added sucrose and caffeine not only experienced a significant amelioration in their depression, but this decline in depression was also apparent at the 3-month follow-up.

TABLE 13.2 Mean Depression Scores after 3-Week Dietary Elimination of Added Sucrose and Caffeine (Experimental) or Red Meat and Artificial Sweeteners (Control) and 3-Month Follow-Up of Individuals Who Demonstrated a Significant Amelioration in Depression in the Experimental Group (Mean ± Standard Deviation)

3-Week Dietary Intervention

3-Month Follow-Up

Experimental

Control

Depression Measure

M SD MMPI-D

9.50 8.29 23.10 9.12 5.43 6.27 SCL-90 Depression Scale

Note : MMPI-D = MMPI Depression Scale; BDI = Beck Depression Inventory; SCL-90 = Symptom

Checklist-90. Higher scores indicate increased severity of depression. Adapted from data from Christensen, L. and Burrows, R., Behav. Ther., 21, 183, 1990.

Functional Food Carbohydrates

Although these studies have revealed that some individuals experiencing a cur- rent episode of major depression can benefit from eliminating added sucrose and

caffeine from their diet, it is important to emphasize that this ameliorative effect does not exist with all depressed individuals. In most of our studies, 115,117 we have identified the sensitive individuals using a single-case design followed by double- blind challenges, which is very time-consuming. However, given that Moorhouse et al. 114 revealed that only carbohydrate-craving alcohol-dependent men experienced an increase in depression following the high-carbohydrate breakfasts and snack foods, it is possible that individuals with major depression and reporting carbohy- drate cravings would represent the sensitive population. It is also possible that these individuals represent atypical depressed individuals, as some of the features of these

individuals are increased appetite, hypersomnia, and leaden paralysis. 95 These are also characteristic symptoms of individuals who profit from eliminating caffeine and

added sucrose from their diet.