*3.6. Fats*

Compared with other categories of nutrients, a large number of animal studies have investigated the effects of increased intake of fat on rodent models of anxiety (Figure 9). Many animal studies (*n* = 39) have reported an anxiogenic effect of a high fat diet. A smaller number have reported a similar effect from diets high in cholesterol (*n* = 5) and trans fats (*n* = 6). A large number of animal studies have reported anxiolytic effects of omega-3 fatty acids (*n* = 35), Docosahexaenoic acid (*n* = 9), Eicosapentaenoic acid (*n* = 3), and alpha-linolenic acid (*n* = 4). Human observational studies reported an association between higher intake of omega-3 fatty acids and lower levels of anxiety.


**Figure 9.** Studies assessing dietary fats and anxiety. ■ Higher intake or levels associated with decreased anxiety. ■ No association between intake or levels and anxiety. ■ Higher intake or levels associated with increased anxiety.

> Twenty-two human experimental studies have measured changes in anxiety symptoms following supplementation with omega-3 fatty acids. Eleven studies reported an improvement in anxiety symptoms, the remaining studies were equivocal. Two of three meta-analyses of trials delivering omega-3 fatty acid supplements reported benefit to anxiety symptoms [37–39]. While nine of the experimental studies included participants with psychiatric disorders such as eating disorders, substance use disorders and ADHD, only one trial involved participants with anxiety disorders [40]. In this trial, researchers provided polyunsaturated fatty acids (omega-3 and omega-6) to 126 sufferers of test anxiety and reported an improvement in symptom severity after three weeks.
