Tryptophan deficiency can cause symptoms such as insomnia, low levels of serotonin, depression, anxiety, impulsiveness, irritability, inability to concentrate, weight loss and poor growth in children, according to the World's Healthiest Foods. When tryptophan deficiency is accompanied by a vitamin B-3 deficiency, symptoms can include dementia.
According to the World's Healthiest Foods, natural food sources of L-tryptophan include bananas, nuts, soybeans, red meat, seeds, dairy products, shellfish, tuna and turkey. Tryptophan is compromised in the cooking process so I would suggest you receive it through the consumption of raw food sources listed above. This way you will know that you are receiving the nutrient as nature attended!