Tomatoes Lower Depressive Symptoms

27 Dec

A team of Chinese and Japanese scientists has discovered that people eating tomatoes regularly are less likely to suffer from depression than those who eat tomatoes less than once a week.

Tomatoes Lower Depressive Symptoms

However you decide to eat tomatoes, they will help keep the blues away. Photo:

The research team led by Kaijun Niu from Tianjin Medical University in China published its findings in the Journal of Affective Disorders recently.

They noted that while there have been a number of past studies that have compared the effects of “dietary antioxidant nutrients” (including folic acid and Vitamin E) on depressive symptoms, very little research has been done on the relationship between tomatoes and depressive symptoms.

Background of the Tomato Research

Scientists know that a lack of anti-oxidants can lead to symptoms of depression. They also know that lycopene – the red-coloured “carotenoid” found predominantly in tomatoes, and also in a few other red fruits and vegetables – is one of the most power antioxidants there is.

So they decided to investigate the relationship between various vegetables (including tomatoes) and typical “depressive symptoms” in elderly people living in the community.

A total of 986 people, aged at least 70 years, took part in the research study which analysed what they ate and what depressive symptoms they exhibited during this time. The researchers made no attempt to diagnose the symptoms of depression shown, and the exact concentration of lycopene in the tomatoes consumed was not calculated.

Motivation for Research

It is a well-known fact that stress-related diseases and disorders have increased rapidly over the past 20 to 30 years, and that depression has become a public health problem worldwide. Further, depressive symptoms can increase the risk of coronary disease and worsen medical “disorders”, even promote disabilities.

According to the research report, “Oxidative stress may accelerate aging and increase the risk of chronic diseases, such as coronary heart disease, cancer, and rheumatoid arthritis; dietary intake of tomatoes/tomato products containing lycopene have been shown to be related to decreased risk of these chronic medical illnesses.”

The Research Study and Food

Researchers compiled a questionnaire that included 75 different items of food (categorized into four groups) and specific serving sizes. The four categories were:

  • Green leafy vegetables,
  • Chinese cabbage and cabbage,
  • Burdock, carrot, lotus root, onions and pumpkin,
  • Tomatoes – including ketchup, and tomato that had been stewed or used in a stew.

Participants were required to show how often they had eaten the different types of food during a one-year period.

Other Variables

There are always additional variables when it comes to research, and those taken into account included:

  • the height and weight of those participating in the study,
  • blood pressure and hypertension,
  • blood samples used to measure blood glucose and any indication of diabetes,
  • socio-demographics – including age, sex and education,
  • level of care and support available,
  • health issues including physical illness, pain and medication,
  • smoking and drinking,
  • exercise.

The dependent variable used was depressive symptoms, while the independent variable was tomatoes and tomato products and other vegetables consumed.

Results of the Study

A total of 34.9% of participants were classified as having mild depressive symptoms, and 20.2% with severe symptoms.

Males, smokers, people with a lower educational level, and those who were either widowed or divorced ate fewer tomatoes; and those who were married ate significantly more tomatoes!

Furthermore, those people who consumed tomatoes regularly had significantly lower depressive symptoms. The regular consumption of other vegetables made no difference at all.

Overall, state the researchers, “These results suggest that a tomato-rich diet may have beneficial effect on the prevention of depressive symptoms.”

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