Depression and anxiety are mediated by rumination and worry. They are perseverative and negative towards oneself, and demand attention. Rumination is past-oriented, repetitive thoughts concerning themes of loss and perceived mistakes; in contrast, worry is future-oriented, negative thinking.
The genetic risk of rumination and worry were recently identified and discovered to have an association with genes for folate metabolism. Low blood folate levels are associated with severe depression and a poorer response to antidepressant drug therapy. Some, but not all, studies have reported that folate supplementation in the diet is an effective and safe add-on to standard antidepressant treatments.
A recent very large study investigated genes linked to rumination and worry within groups of individuals (18 to 69 years old) with suboptimal (10,638 subjects) versus optimal (61,983 subjects) dietary folate intake. Folate intake was estimated by monitoring food and beverage consumption, excluding any supplements. The cut-off point of a healthy level of folate intake was set to 200 µg per day.
Rumination was assessed using a standard 10-item Ruminative Response Scale. Five of these items belong to the brooding subscale, representing a “moody pondering” and passive comparison of the subject’s current situation with unachieved high standards set by others.
Numerous studies have shown that perseverative negative thinking can lead to many physical and mental disorders. The current study reported that genes that are highly associated with rumination, at least in the suboptimal folate intake subjects, are also involved in brain development and adult cognitive function. How does this explain the features of rumination? Rumination may be associated with specific deficits of memory such that people have difficulty discarding negative memories that are no longer relevant. Essentially, we may ruminate partially because we fail to forget an unfortunate event.
The results revealed some additional interesting relationships. For example, individuals with symptoms of worry, who also had optimal folate intake, had significantly more genes that are related to cancer diseases. That’s probably not good to know if you tend to worry. However, if you are someone who worries a lot, the study offers this advice, eat more folate-containing foods, such as legumes, asparagus, eggs, and leafy greens. The study discovered that folate intake was inversely associated with worrying. Interestingly, the study found no association between folate intake and rumination.
In summary, worry, which is a future-oriented type of negative thinking, is sensitive to dietary folate intake, while rumination, which is past-oriented, is not altered by dietary folate intake.