Anxiety disorders, depressive disorders, and other mental illnesses are often seen strictly as brain disorders. Considering the fact that people are rather quick to recommend better nutrition as a means of managing all kinds of physical illnesses — just think: how many times have people recommended chicken soup or freshly squeezed orange juice when you've had a common cold? — this is a curious phenomenon.
Research shows that young people who begin eating more fruit see significant improvements in both physical and mental wellbeing after only two weeks . This alone indicates that mental health is closely linked to nutrition.
Can Nutritional Deficiencies Be A Root Cause Of Anxiety Disorders?
At the most basic level, we know that food-insecure parents are more likely to suffer from major depression and generalized anxiety disorder than those who have plenty of food, and that children growing up in food-insecure homes have higher rates of behavioral problems . Not having enough food typically means that the food that someone does consume is of poor nutritional quality, and in addition, and poverty itself is detrimental to mental health.
Do vitamin and mineral deficiencies actually cause anxiety, though?
Good quality nutrition was not, however, found to be a predictor of positive mental health outcomes. This means it is not yet clear whether children with anxiety disorders and depression turn to poor quality foods because of their mental illnesses, or whether a poor diet actively leads to anxiety and depression. 
Because we do know that there is a link between nutrition and mental health outcomes, as well as that mood disorders and anxiety disorders tend to make their appearance between the ages of six and 13 , it only makes sense for any parent to take this information into account, and to investigate nutrition as a means of improving the symptoms of childhood anxiety disorders.
Nutritional Supplements That May Help Ease Anxiety
Carbohydrate consumption leads to the release of insulin in the body, which in turn leads triggers the release of tryptophan, which influences neurotransmitters in the brain. Here, it is important to note that while everybody requires carbs, not all carbs are equal. High glycemic index foods may offer a fast temporary improvement in mood — which is why people suffering from depression and anxiety disorders may crave them — but it is low glycemic index foods like whole grains that result in a more moderate but also more long-term mood improvement. 
Children suffering from depression and anxiety disorders also benefit from Omega-3 fatty acids [6, 7], which can be obtained from dietary sources such as fatty fish and chia seeds as well as through dietary supplements.
While there is some evidence that B vitamins, including folate and vitamin B12, play a role in causing and exacerbating the symptoms of depression, no such specific link has been found between B vitamins and anxiety disorders. As depression and anxiety frequently co-exist, however, parents should certainly ensure that their child gets enough B vitamins.  Adequate zinc and magnesium intake also has a positive impact on mood. 
Selenium is one nutrient that has specifically been linked to decreased anxiety [5, 9, 10 ]. As such, parents of children suffering from separation anxiety disorder, social anxiety disorder, generalized anxiety disorder, obsessive compulsive disorder or specific phobias will want to discuss supplementation with their children's healthcare providers.
One further thing to consider is that people who are taking SSRI antidepressants for anxiety have been found to absorb calcium less well . Parents of children and adolescents who are taking SSRIs such as Prozac will want to ask their child's physician whether their child needs to take a calcium supplement.
The link between anxiety, nutrition in general, and nutritional deficiencies in particular, requires further study. Meanwhile, it is clear that the quality of nutrition does have some impact on mental wellbeing, and that particular nutrients have the potential to decrease the symptoms of anxiety disorders as well as depression, which frequently co-exists with anxiety.
Parents of children who were diagnosed with anxiety disorders should not expect symptoms to subside as the result of improved nutrition alone — cognitive behavioral therapy and antidepressant medications represent the most effective forms of anxiety management in children. [12, 13] In addition, you may want to try out natural and herbal remedies for anxiety in children.