Component of vegetable protein may reduce blood pressure

grains and pulsesResearchers examined dietary amino acids, the building blocks of protein, and their effect on blood pressure.

Glutamic acid is the most common amino acid and accounts for almost a quarter (23 percent) of the protein in vegetable protein and almost one fifth (18 percent) of animal protein.

They found that a 4.72 percent higher dietary intake of the amino acid glutamic acid as a percent of total dietary protein correlated with lower group average systolic blood pressure, lower by 1.5 to 3.0 millimeters of mercury (mm Hg). Group average diastolic blood pressure was lower by 1.0 to 1.6 mm Hg. 

Systolic blood pressure is the force when the heart beats; diastolic pressure is the pressure when the heart rests between beats. 

This average lower blood pressure seems small from an individual perspective. But, on a population scale, it represents a potentially important reduction, said Jeremiah Stamler, M.D., lead author of the study. 

“It is estimated that reducing a population’s average systolic blood pressure by 2 mm Hg could cut stroke death rates by 6 percent and reduce mortality from coronary heart disease by 4 percent,”

said Stamler, Professor Emeritus of the Department of Preventive Medicine in the Feinberg School of Medicine at Northwestern University in Chicago, Ill. 

Based on American Heart Association 2009 statistics, 6 percent of stroke deaths would be more than 8,600 people and four percent of coronary heart deaths represents about 17,800 lives saved per year. 

“High blood pressure is a major cardiovascular disease risk factor, and blood pressure tends to rise with age starting early in life so that the majority of the U.S. population age 35 and older is affected by pre-hypertension or hypertension,” he said. “We have a massive public health problem, and trying to address it by the strategy that has prevailed for years — diagnosis and drug treatment — is inadequate. While clinically useful, it fails as a long-term approach for ending this massive problem.” 

The only long-term approach is to prevent pre-hypertension and hypertension by improved lifestyle behaviours, Stamler said. This includes maintaining a healthy body weight, having a fruit and vegetable-rich eating pattern and participating in regular physical activity.  

Researchers analyzed data from the International Study on Macro/Micronutrients and Blood Pressure (INTERMAP), on 4,680 people ages 40-59 in 17 rural and urban populations in China, Japan, the United Kingdom and the United States. INTERMAP is a basic population study aiming to clarify the role of multiple nutrients in the etiology of unfavourable blood pressure patterns prevailing for most middle-aged and older individuals. Stamler and colleagues analyzed data from eight blood pressure tests, four diet recall surveys and two 24-hour urine collections for each participant.

“Although our research group and others earlier reported an association between higher consumption of vegetable protein and lower blood pressure, as far as we know this is the first paper on the relation of glutamic acid intake to blood pressure,”

said Ian J. Brown, Ph.D., co-author of the study and a research associate in the Department of Epidemiology and Public Health at Imperial College London.

Common sources of vegetable protein include beans, whole grains — including whole grain rice, pasta, breads and cereals — and soy products such as tofu. Durum wheat, which is used to make pasta, is also a good source of vegetable protein.

Stamler noted that there are no data on the possible effects of glutamic acid supplements and emphasized the importance of “improved habitual food intake for the prevention and control of hypertension, not popping pills.”

To learn how to cook with vegetable proteins and other whole foods, why not come along to a Cooking for Health course, held throughout the year in Somerset, UK.

How to make seitan

SEITAN is the protein extracted from wheat or spelt and is sometimes called “wheat meat”.  In the Far East, seitan has been used as a source of vegetarian protein for centuries.  It is rich, nourishing and creates strength and vitality.  Seitan may be used instead of meat in a wide range of dishes, for example, spaghetti Bolognese, lasagne, cottage pie, stir-fries, spring rolls and casseroles.  It is not recommended for those who are gluten intolerant or who suffer from coeliac disease.

Broccoli with vegan seitan as a meat substitute

Broccoli and seitan stir fry

Seitan can be bought ready-made in jars from health food stores but it is very easy to make at home.

yakso seitan

Here are the instructions for making your own seitan:

1.  Choosing the flour

It is only possible to make seitan from strong wheat or spelt flour typically used to make bread.  Other flours do not have sufficient quantities of protein of the right structure to stay bound together.  Wheat flour makes a harder, more firm seitan than spelt flour.

2.  Ingredients

  • 6 cups whole wheat or spelt bread flour or high-gluten unbleached white flour
  • 3 cups water
  • 1/2 cup tamari or soy sauce
  • 12 slices fresh ginger, each 1/8 inch thick,
  • 1 piece of kombu, about 3 inches long.

3.  Method

Mix the flour and slowly add the water to make a medium-stiff but not sticky dough.

Knead the dough by hand on a breadboard or tabletop, until it feels a bit like an earlobe, for about 10-15 minutes.   Add a little more water if needed to get the right consistency.

Allow the dough to rest in a bowl of cold water for about 30 minutes.

While the dough is resting, prepare the stock.

In a large pot, bring to boil 2.5 litres of water.  Add the tamari or soy, ginger, and kombu, and simmer for 15 minutes. Remove from heat and allow to cool.  This stock must be cold before it is used.  The cool liquid causes the gluten to contract and prevents the seitan from acquiring a bread-like texture.  The stock will be used to cook the seitan later.

Meanwhile, it is time to start washing the dough; use warm water to start with. Warm water loosens the dough and makes the task easier. Some people knead the dough while it is immersed in water in a bowl.  Alternatively, it can be rinsed under running water, with the flow stream about as thick as a pencil. The dough can be held in/over a colander to catch any pieces of dough that fall off.

The water will look very milky at first and then gradually becomes more ‘transparent’.  In the final rinses, use cold water to tighten the gluten.  After about 10 to 15 minutes, you will begin to feel the dough become firmer and more elastic.  The water will no longer become cloudy as you knead it.  To make sure you have kneaded and rinsed it enough, lift the dough out of the water and squeeze it.  The liquid oozing out should be clear, not milky.  The size of the ball will be considerably smaller than when you began.

Place the rinsed seitan in an empty bowl and let it rest for 15 minutes until the dough relaxes. After the dough has been rinsed for the last time in cold water, the gluten will have tightened and the dough will be tense, tough, and resistant to taking on any other shape.

Put the seitan in the cold tamari stock.  Bring the stock to a boil, lower the temperature, and simmer in the stock for 1 1/2 to 2 hours (45 minutes if the seitan is cut into small pieces).  This second step may also be done in a pressure cooker, in which case it would take between 30-45 minutes.

To store seitan, keep it refrigerated, immersed in the stock.  Use it within 1 week of preparation.

seitan-sweet-and-sour

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