Eating more fruit and vegetables helps to lower blood pressure. New research may help to reveal why.

Researchers have discovered that people who eat more vegetable protein have a lower blood pressure. In particular, one component of vegetable protein, glutamic acid, appears to have a direct relation to blood pressure: the more glutamic acid you eat, the lower your blood pressure will be.

Vegetables that are high in glutamic acid include

• broccoli
• cabbage
• soy (used to make tofu)
• durum wheat (used to make pasta)
• rice
• grains (used to make bread).

The results come from the INTERMAP study (the International Study of Macro/Micronutrients and Blood Pressure), which looked at the blood pressures and eating habits of 4,680 people from the UK, US, China and Japan. It found that people who ate nearly 5% more glutamic acid than other people had a lower average systolic blood pressure (top number) of 1.5-3.0mmHg and a lower average diastolic blood pressure (bottom number) of 1.0-1.6mmHg.

At the moment, there are no studies into the safety of eating large doses of glutamic acid, so it is recommended that you do not take glutamic acid supplements, but instead eat at least five portions of fruit and vegetables a day. The additional benefit of this approach is that you will also be lowering your saturated fat intake and taking in many other helpful antioxidants and vitamins at the same time.