The modern diet can cause serious damage to the brains of fetuses
In the human brain there are millions-millions (trillions) of nerve cells with long extensions called axons and dendrites, as well as ten times as many glial cells. Since every cell is surrounded by a fatty cell membrane, the surface area of these cells is huge and therefore the brain needs a large amount of fatty acids to build the cell membranes. Mammals, including humans, are not able to produce all the fatty acids and we must get them from food. Two important examples are the unsaturated fatty acids omega-3 and omega-6.
The common diet in the western world, and especially the food sold in fast food chains, is rich in calories and carbohydrates. It is rich in omega-6 unsaturated fatty acids and low in omega-3. Before the industrial revolution, the amount of omega-6 in food was equal to the amount of omega-3, while today there are 15 times more omega-6 than omega-3. Moreover, in the US, about 30% of pregnant women are In morbid obesity, due to the consumption of food high in calories but low in nutritional value. However, both during the period of fetal development and after birth, it is important that the newborn receive from the mother, through the placenta and then during the breastfeeding process, an omega-3 acid that is so essential for the development of the brain and its activity.
The relative absence of omega-3 in the modern diet in general and the western diet in particular has been linked to a variety of human ailments, such as inflammatory diseases, cardiovascular problems, immune system function, bone health and even depression and various mental illnesses. In fact, it has been accepted for some time that there is a connection between the low levels of omega-3 in our diet and depression, but the evidence supporting this assumption is far from solid, and above all, the mechanism of action of omega-3 in the context of neuropsychiatric problems remains unknown.
However, in March 2011, an article was published in the journal Nature Neuroscience discussing the effect of the ratio between omega-6 and omega-3 in the diet on neural activity in the brain of mice, and in particular on the activity of the system known as the endocannabinoid system. The nerve cells have receptors for various neurotransmitters, including type 1 endocannabinoid receptors (CBR1). The endocannabinoids that activate the receptors are substances created in the body and are similar to the active substances of the cannabis plant (hashish) and hence their name. CBR1 receptors are involved in various cognitive processes and determining moods, and their underactivity can lead to depression. [See "Who's Afraid of Hashish", Scientific American Israel, August 2011.]
And back to the research: the researchers tested in mice the effect of a diet low in omega-3 already in the stages of embryonic development. One group of mice received food rich in omega 6 without omega 3 during pregnancy and another group received food rich in omega 3. After birth, the offspring from each group received the same diet as the mothers throughout their lives. The research was very comprehensive and it examined the effects of nutrition on the neural activity of the offspring, especially of the endocannabinoid system and also included behavioral experiments.
The results are instructive. In mice whose diet was low in omega-3, the endocannabinoid system did not function and CBR1-controlled neural phenomena simply did not occur. The damage was caused only in the CBR1 system and not in other receptor systems in the brain, and was manifested mainly in two areas of the brain that are important for mental balance: the prefrontal cortex and another area known as the nucleus accumbens. These changes were not found in the control group that received omega-3. In behavioral experiments, the mice raised without omega-3 showed signs of depression, while the mice in the group that received omega-3 behaved normally.
Foods rich in omega 3 include North Sea fish, such as tuna, salmon or cod, as well as flax seeds, walnuts and green vegetables. The effect of the composition of food on the development of our body and especially on the development of the brain, on our mood and on our behavior always arouses interest. Here is a direct example of how the composition of the food affects these factors.
And more on the subject
Nutritional omega-3 deficiency abolishes endocannabinoid-mediated neuronal functions. M. Lafourcade et al, In Nature Neuroscience, vol. 14, no. 3 pages 345-352, July 10, 2011