The foods listed below are known to trigger inflammatory responses and lower serotonin, causing BDNF to decrease as well. A reduction in serotonin and BDNF leads to depressive feelings. Furthermore, low BDNF can hinder the repair of nerve and brain cells, which can thereby cause even more depression.
Sugar: Consuming sugar, and particularly fructose, directly inhibits the production of BDNF and causes cognitive decline. Fructose combined with glucose in a molecule is what we call table sugar. Avoid added sugar as much as possible. Furthermore, sugar triggers inflammatory responses in the body, resulting in reduced serotonin release.
Bad fats: Bad fats cause inflammatory responses in the body, and this leads to a reduction in serotonin release via inflammatory factors. The bad fats are typically plant-based omega-6 fats used for frying, such as sunflower, soy, and peanut oil. Hydrogenated (vegetable) fats are also bad fats.
Dairy: Dairy can also promote inflammation at high intakes. It is best not to consume sweetened or unleavened dairy products. So unsweetened kefir or yoghurt can be eaten in moderation.
Gluten: Eat as few grain-based products as possible. Gluten can also cause inflammation, especially in allergic reactions. Oats, and therefore oatmeal, can be eaten though.
Alcohol: Alcohol is fermented sugar and is best avoided altogether. If alcohol is drunk anyway, half to a whole glass of wine a day can be consumed without too much harm. Above that, alcohol already becomes an inflammation promoter.
Meat: Game, grass-fed meat and wild fish are no problem provided red meat is eaten in a limited way (advice is max 2 times a week). Any fish that has not been wild-caught or fed other than natural is best not eaten. Grain- and corn-fed animal products are also not recommended.