Offspring of rats with insufficient omega-3 fatty acid in their diets tend to have increased anxiety
A study on rats found that when mothers lacked sufficient amounts of omega-3 polyunsaturated fatty acids in their diets during pregnancy and weaning, their offspring exhibited increased innate anxiety. Female offspring, in particular, showed heightened learned anxiety. Omega-3 supplementation after weaning did not reduce innate anxiety but did ameliorate learned anxiety in female rats. The paper was published in Behavioral Neuroscience.
In humans, adolescence and early adulthood are vulnerable periods for the development of psychiatric disorders. Nearly 75% of lifetime cases of anxiety and depression begin during this stage of life. Although research has identified many factors that can reduce or increase the risk of such developments, one factor that has not been sufficiently studied is maternal diet and individual dietary intake.
Studies have particularly linked deficiencies in omega-3 polyunsaturated fatty acids with an increased risk of several psychiatric disorders, including mood and anxiety disorders, schizophrenia, attention-deficit/hyperactivity disorder, and autism. Anxiety is a common symptom across these disorders, and research has suggested that omega-3 polyunsaturated fatty acid supplements can be effective in treating anxiety in young people.
Omega-3 polyunsaturated fatty acids are essential fats found in foods like fish, flaxseeds, and walnuts. They are known for their role in supporting heart health, reducing inflammation, and contributing to brain function. However, not enough is known about the effects that deficiencies in these fats during pregnancy and breastfeeding could have on offspring.
Study author Alina P. Bogachuk and her colleagues conducted research on rats to explore how omega-3 fatty acid deficiency in mothers would affect their offspring’s anxiety. They also investigated whether supplementing the offspring’s diet with omega-3 fatty acids post-weaning (after they stop breastfeeding and start eating regular food) could mitigate or eliminate these adverse effects.
The study was conducted on a group of Long Evans rats, a strain characterized by their distinctive black and white fur, commonly used in research due to their docile nature.
Rats were divided into three groups: offspring of mothers deficient in omega-3 polyunsaturated fatty acids who continued on the deficient diet after weaning (19 rats), offspring of mothers deficient in omega-3 polyunsaturated fatty acids who were shifted to an adequate diet (with sufficient omega-3 fatty acids) after weaning (25 rats), and offspring of mothers with adequate omega-3 intake who also remained on an adequate diet after weaning (21 rats).
The rats were housed in pairs, with an approximately equal number of males and females in each group. Researchers fed them a diet containing 60% carbohydrates, 20% protein, 10% fat, 5% fiber, and small amounts of salts, vitamins, and tert-butylhydroquinone (a preservative used to extend the shelf life of food). This was the diet for omega-3-deficient rats. For the adequate diet (no omega-3 deficiency), the researchers added flaxseed oil, which contained about 4% omega-3 fatty acids. It is important to note that the base diet also contained some omega-3 polyunsaturated fatty acids, but in lower quantities.
The researchers performed two types of behavioral experiments to assess innate anxiety (using the Elevated Plus Maze) and learned anxiety (using the Probabilistic Punishment Task). Both types of experiments were conducted at night, when rats are naturally active. Learned anxiety in rats is a conditioned response where the animals develop anxiety-like behaviors after being exposed to stressful or aversive conditions. The researchers also conducted a number of biochemical analyses of the rats’ tissues.
Results showed that both male and female adolescent rats from mothers fed a diet deficient in omega-3 fatty acids had higher innate anxiety compared to rats from mothers on adequate diets. Female rats from these deficient mothers also had increased learned anxiety. While switching to an adequate diet (supplemented with flaxseed oil to provide more omega-3 fatty acids) did not reduce innate anxiety, it did ameliorate learned anxiety in females.
“Thus, the beneficial effects of supplementation on adolescent anxiety may be sex-specific and depend on the type of anxiety. We also found that n-3 PUFA [omega-3 polyunsaturated fatty acid] deficiency influences microglia [a type of immune cells in the brain] function in adolescents in the amygdala and nigrostriatal, but not mesolimbic, brain regions. Collectively, these data suggest that while n-3 PUFA dietary supplementation may be effective in reducing adolescent anxiety, this effect is context-, sex-, and brain network-specific,” the study authors concluded.
The study highlights the importance of omega-3 fatty acids for psychological development and their potential protective role in mental health. However, it should be emphasized that this study was conducted on rats, not humans. While humans and rats share many physiological similarities, they are still very different species, and the effects on humans might not be identical.
The paper, “Impact of Supplementation With Omega-3 Fatty Acids After Maternal Dietary Deficiency on Adolescent Anxiety and Microglial Morphology,” was authored by Alina P. Bogachuk, David S. Jacobs, and Bita Moghaddam.
