Nutritional Pearls: Could The Mediterranean Diet Affect Blood Pressure?
During a routine exam, Mary, a 27-year-old woman, expresses concern over her family history of high blood pressure. She shows you print outs of several articles from the internet exploring the possible heart-health benefits of the Mediterranean diet, and asks if you think switching to the diet will lower her risk.
How do you advise your patient?
What is the correct answer?
(Answer and discussion on next page)
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Answer: The Mediterranean Diet has been shown to decrease augmented blood pressure levels.
That study was a pilot of just 25 women between the ages of 19 and 30 who followed a Mediterranean-style diet for 10 days and their usual diet for 10 days. Before and after each 10-day period they responded to a battery of tests measuring such aspects of mood as depression, anxiety, and vigor, as well as cognitive tests that measured executive function and aspects of memory.
Today's article, from the same university and including one researcher from the earlier study, builds on that earlier research.2 Once again, 24 women between the ages of 20 and 38 were randomly assigned to either follow a Mediterranean-style diet for 10 days, then their usual diet for 10 days, or the reverse: first their usual diet, then a Mediterranean-style diet.
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As with the earlier research, their moods were tested before and after each 10-day dietary period, but this time the researchers also tested heart function in various ways, including both central blood pressure (in the aorta) and brachial (the arm) pressures, blood flow velocity (the speed at which the blood flows), and augmentation pressure (how much the systolic pressure in the aorta is increased by the stiffness of the walls of the aorta).
Once again those following a Mediterranean-style diet tested higher in scales of contentment and alertness as well as lower in confusion. In terms of cognition, they tested higher in secondary memory, but lower in working memory. Finally, augmentation pressure was reduced in those following a Mediterranean-style diet (this is a good result).
One thing that struck me about both studies is that the Mediterranean-style diet the researchers prescribe to their participants is rather restrictive. The women were instructed to increase their "consumption of fruits, vegetables, oily fish, low-fat dairy, and nuts" while avoiding "all pre-prepared, packaged, and processed foods." They were also told "to abstain from consuming [red] meat, butter and margarine, caffeinated/energy drinks, added sugars and salts," and alcohol. Alert readers will note that moderate intake of red meat, butter, and alcohol is in fact part of a Mediterranean Diet.
Further, coffee and tea are known to be good for you, and if these women were habitual caffeinated coffee (or other beverage) drinkers, why ask them to give up all caffeine for ten days when they are likely to experience caffeine withdrawal? Both studies are certainly interesting, but I feel the results are weakened by the methods.
2. Lee J, Pase M, Pipingas A, Raubenheimer J, et al. Nutrition 2015;31(5):647-652.