Olive oil and high blood pressure

Written by Keith vonB

High blood pressure is also known clinically as Hypertension.

High blood pressure is responsible for about half of heart disease and two thirds of strokes, according to the World Health Organization. Approximately 7.1 million deaths a year are estimated to be caused by high blood pressure.

EPIC study

This study is about: olive oil and mediterranean diet

European Prospective Investigation into Cancer and Nutrition (EPIC) study

This study confirmed that the Mediterranean diet, olive oil, vegetables and fruit were all responsible for the good blood pressure in this population (20,343 people had never been diagnoised with high blood pressure). They were able to isolate each one of the above foods (including olive oil) and determine that individually they were responsible for lowering the systolic and diastolic blood pressure.

Mutual adjustment between olive oil and vegetables, which are frequently consumed together, indicated that olive oil has the dominant beneficial effect on arterial blood pressure in this population, concluded the authors.

References

Overview of the study

American Journal of Clinical Nutrition (vol 80, no 4, 1012-1018)

Second University of Naples study

This study is about: mediterranean diet

This study involved 180 patients, 99 men and 81 women over 2 years who had metabolic syndrome. The American Heart Association has more information on their website about metabolic syndrome. Essentially metabolic syndrome is a group of factors that are grouped into one diagnosis. Some of these factors are high blood pressure, low HDL ("good") choleserol, insulin resistance, and excessive fat tissue in and around the abdomen.

This study deals with the metabolic syndrome as a whole, not isolating high blood pressure. During the 2 year study period, 1/2 of the patients followed the Mediterranean diet, and the other 1/2 followed what they called a "prudent diet" consisting of 50-60% carbohydrates, 15-20% proteins and less than 30% fat.

The researchers found that after two years, patients in the Mediterranean diet group had significant decreases in body weight, blood pressure, levels of glucose, insulin, total cholesterol, and triglycerides and a significant increase in levels of high-density lipoprotein cholesterol. Moreover, only forty patients consuming the Mediterranean regime still had features of the metabolic syndrome, compared with 78 patients following the control diet, and the prevelance of the metabolic syndrome was almost halved in the Mediterranean group.

References

JAMA (Journal of American Medical Association) Vol. 292 No. 12, September 22/29, 2004 abstract

Overview of the study - look 1/2 way down under "Metabolic syndrome"

Effects of dietary fat on healthy men.

This study is about: olive oil

This study examined food records from American men, all 30-55 years old with resting blood pressures below 160/100 mm Hg. The systolic and diastolic blood pressures "correlated significantly and inversely with monounsaturated fat consumption". In other words they found a significant link between a lower blood pressure and a higher intake of monounsaturated fat.

Out of all oils, olive oil has one of the highest percentages of monounsaturated fat. Even more importantly, in this study the detailed analysis of the fats found that the decrease in blood pressure was specific to oleic acid, the main component of olive oil.

References

Associations of dietary fat, regional adiposity, and blood pressure in men

JAMA Vol. 257 No. 23, June 19, 1987 abstract

The reduced need for blood pressure medications

This study is about: Olive Oil

I think this quote says it all:

"The most important finding in this study is that the daily use of olive oil, about 40 grams per day, markedly reduces the dosage of [blood pressure medication] by about 50% in hypertensive patients on a previously stable drug dosage," says L. Aldo Ferrara, MD, associate professor of internal medicine at the Frederico II University of Naples in Naples, Italy, and the study's lead author.

All of the people in the study had high blood pressure and were on medication to control it. For six months one half of the members of the study went on a diet that had olive oil in it and one half were on a diet that had sunflower oil in it. Then, after six months, they switched. Olive oil primarily a monounsaturated fat and sunflower oil is mostly polyunsaturated fat.

The men consumed about 40 grams (4 tablespoons) of extra-virgin olive oil a day and the women consumed about 3 tablespoons a day.

As the blood pressure of the people in the study dropped, they would reduce their blood pressure medicine. Daily drug dosage was reduced 48% while on the extra-virgin olive oil diet, as compared to 4% on the sunflower oil diet. Every patient who was on the sunflower oil diet required high blood pressure medicine, while 8 of the people on the extra-virgin olive oil diet needed no drug therapy at all.

They noted in the study that they think that the drop in blood pressure was due to the polyphenols that are in the extra-virgin olive oil.