Could green leafy vegetables reduce the risk of type 2 diabetes?

The prevalence of type 2 diabetes is increasing across the world.  Fruit and vegetable consumption has already been linked to prevention of heart disease and cancer and now a new study has found that increasing green leafy vegetables is significantly associated with a reduced incidence of type 2 diabetes (1).  The authors of the review study wanted to look at the evidence for fruit and vegetable intakes and the prevention of type 2 diabetes.  They found that summary estimates from studies showed that a greater intake of green leafy vegetables was associated with around a 14% reduction in the risk of type 2 diabetes and they conclude that “Increasing daily intake of green leafy vegetables could significantly reduce the risk of type 2 diabetes and should be investigated further”.

The study was published in the British Journal of Medicine.  Green leafy vegetables include, for example, spinach, cabbage, lettuce, herbs such as parsley and broccoli.  Eating just over one extra serving a day was associated with the 14% reduced risk of getting type two diabetes.  The findings do not prove that green leafy vegetables prevent diabetes but the research does point to the importance of a healthy diet and lifestyle in disease prevention.  The research may indicate that people who eat more green leafy vegetables may also eat an overall healthier diet and may exercise more – factors that could affect the likelihood of getting diabetes.  Further investigation is certainly warranted.

The authors conclude that “Results from our meta-analysis support recommendations to promote the consumption of green leafy vegetables in the diet for reducing the risk of type 2 diabetes. The results support the growing body of evidence that lifestyle modification is an important factor in the prevention of type 2 diabetes.  The potential for tailored advice on increasing intake of green leafy vegetables to reduce the risk of type 2 diabetes should be investigated further”.

Green leafy vegetables are high in antioxidants, minerals such as magnesium and short chain (alpha linolenic acid) omega 3 fatty acids as well as polyphenols (bioactive plant chemicals that act as antioxidants in the body).  This could account for their possible diabetes preventative effects. 

According to the authors of the study (1) low consumption of fruit and vegetables is common throughout the world. They cite a 2005 study published by the World Health Organization estimating that inadequate consumption of fruit and vegetables could have accounted for 2.6 million deaths worldwide in the year 2000.  Separate research found that in 2002, 86% of adults in Britain ate fewer than the recommended five portions of fruit and vegetables a day, with 62% consuming fewer than three portions (2)

The study is important because dietary factors represent potentially modifiable risk factors for many diseases.  Encouraging individuals to eat healthily, especially including a variety of vegetables and fruits in their diet, and to exercise regularly is a good way of improving health parameters.  Individuals need not be discouraged or overwhelmed by attempting to dramatically change their lifestyles overnight.  Small steps toward healthier living need to be viewed as important and worthwhile since they all count and add up over time. 

(1) Carter P et al.  2010.  Fruit and vegetable intake and incidence of type 2 diabetes mellitus: systematic review and meta-analysis.  BMJ.  341:c4229, doi:10.1136/bmj.c4229

(2)BMJ-British Medical Journal (2010, August 19). Green leafy vegetables reduce diabetes risk, study finds. ScienceDaily. Retrieved August 20, 2010, from­ /releases/2010/08/100819214607.htm


Written by Ani Kowal