Unbalanced eating habits, a cause of depression

The Yomiuri Shimbun Hirofumi Imaizumi uses food models to teach patients about ideal meals at the National Center of Neurology and Psychiatry in Kodaira, Tokyo.

Many people with depression are, in fact, suffering from metabolic syndrome.

Recent studies have shown that psychological conditions such as depression are sometimes caused by unbalanced eating habits that lead to obesity or lack of nutrition. To combat this, hospitals have been increasing efforts to educate patients on food and nutrition.

I visited the National Center of Neurology and Psychiatry in Kodaira, Tokyo, to find out more about the wide range of their projects, from research into the basics of nutrition to nutrition education for outpatients (see below).

The centre has a nutritional management office, which has seen an increase in the number of patients seeking nutrition education classes on scheduled psychiatric outpatient clinic days. Recently, many patients are seen showing photos saved on their smartphones of all the meals they had prior to the visit to the office's manager, Hirofumi Imaizumi, or other nutritionists.

"What do you think? I tried really hard," said one patient, to which a nutritionist responded: "Looks great. You had plenty of vegetables."

When patients have had three proper meals a day, with relatively small portions of rice and plenty of fruit and vegetables, Imaizumi praises them. Patients are not asked to count calories because the task is deemed onerous.

"Even when you have a bento from a convenient store, you can easily add a side dish of vegetables, or have some vegetable juice without added sugar, to improve the nutritional balance of your meal," Imaizumi said. "Many of our patients live alone so it is important for them to be able to work on their diet continually and with ease."

People who suffer from depression typically have an unstable lifestyle, especially when it concerns meals.

In one case, an overweight man suffering from depression who habitually had extra meals late at night had difficulty getting up in the morning. Imaizumi instructed him to have early evening meals and also to go to sleep earlier. This change gradually helped the man lose weight, become more active, and recover from depression.

People tend to have the impression that patients suffering from depression cannot eat well and lose weight because of that. Actually, many patients tend to be overweight with high neutral fat and blood sugar levels, according to research done by the centre's Mental Disorder Research Department Director Hiroshi Kunugi and others.

A part of the brain that regulates our desire for food and drink also controls our stress levels. This explains why patients could be overweight due to stress.

It has also been pointed out that metabolic disorders, such as diabetes, can cause a minor but chronic inflammation of tissue, thereby increasing the risk of developing depression or lowering the function of insulin, which is known to reduce blood sugar levels. The latter can have a detrimental effect on brain function.

Nutrition deficiency can have other psychological effects. For example, it has been learned that iron deficiency can cause a variety of symptoms including poor concentration, fatigue and irritation. Postnatal depression, which can be experienced after giving birth and losing a large amount of blood, has been correlated to iron deficiency.

"Although it is not always effective for everyone suffering from postnatal depression, many people do recover after taking iron supplements," Kunugi said.

There are many nutrients that are related to psychological conditions. For instance, a deficiency in folic acid, which is found in great quantities in green and yellow vegetables and influences the function of neurotransmitters, can lead to loss of motivation.

But it is necessary to be aware that there are also some nutrients that can cause harm to the body when taken in excess through supplements.

Medical treatment for depression has typically comprised two aspects: drug therapy and counseling. But Kunugi said, "Like lifestyle-related diseases, it's also important that we carefully provide instruction on food, nutrition, and exercise [for patients with depression]."