With the holiday season, there has been a break in our weekly articles on lifestyle diseases and in particular high blood pressure control using lifestyle interventions.  Please note that we whole-heartedly support pharmaceutical intervention in management of hypertension, but also recognise that many medicines have significant unpleasant side effects, (no less on your monthly budget), and don’t get to the cause of hypertension in the first place.

ALSO READ : Turning the Tide – Dealing with the scourge of hypertension (Part 5)

This is most often caused by harmful lifestyle choices.  If we can target these lifestyle choices, we not only improve our blood pressure fairly dramatically, but we also decrease the risks associated with wrong habits – such as diabetes, obesity, heart disease, auto-immune diseases and cancer.  No one lives forever, but the quality as well as quantity of our lives can be significantly increased.  You may feel that the restrictions associated with lifestyle interventions are not worth the few extra years, but wait until you start having symptoms like angina, breathlessness, aching arthritic joints, diabetic ulcers, lethargy and constant fatigue resulting from obesity – by then it is more difficult to return to a healthy life.  Much better to choose now at the beginning of a new year to adopt at least some of the healthy interventions that can improve the quality of your health.

One of the big controversies in the dietary world these days – in fact over the last 40 years: Robert Atkins popularised the low carb (carbohydrate), high fat/protein diet, also called a ketogenic diet.

Although he is no longer alive, he has many proponents who support his theories, like our famous Prof Tim Noakes who has given unequivocal support, and has written much popular literature on the subject of a ketogenic diet (called the Banting diet in South Africa).  In fact many doctors and even some dieticians have climbed on the band wagon.

However over the years, as more long term research has been done, the risks associated with the ketogenic diet are beginning to manifest.  We will not address that controversy in detail in this blog, as we are specifically talking about high blood pressure, and in particular about the role of fats in the diet in influencing vascular resistance.  But mention of the Banting diet is relevant because it emphasises a high fat intake, and a low carb (carbohydrate) intake.

Just a brief lesson about the pathophysiology of cardiovascular health (atherosclerosis in particular).  The blood vessels throughout our bodies are lined by amazingly slippery, but also very highly functional endothelial cells. 

Part of their function is to keep blood in the right place, prevent blood clots when they are not supposed to, and to encourage blood clots, when there is damage to the endothelium resulting in bleeding.  The endothelium is also involved in the formation of new blood vessels, and recruitment of immune defence cells.  As mentioned in part 5 of this series, endothelial cells also produce nitric oxide, which causes blood vessels to dilate and increase blood flow and prevent platelets from sticking to the vessel walls.

Impaired endothelial function is a common denominator in vascular disease, and is one of the early events in the development of atherosclerosis.  It is often seen in patients affected by high blood pressure, high cholesterol, coronary artery disease and type 2 diabetes.

One of the non-invasive tests of assessing endothelial function is called Flow Mediated Dilatation (FMD) which uses ultrasound to measure changes in the diameter of the brachial artery down the front of the arm.  “Healthy endothelial cells will respond to a stimulus by releasing nitric oxide and causing the brachial artery to dilate, while unhealthy cells will not.”  Stimuli can be things like exercise and healthy foods.  Factors which diminish the body’s response to these stimuli include dietary intake of sugar, salt, but also tobacco, stress, etc.

It is well known that a fatty meal, particularly of saturated fats,  can diminish the production of nitric oxide by endothelial cells. “All oils, both animal and plant derived, tend to worsen endothelial function.  Within hours of ingesting fat, arteries stiffen and the ability to dilate is impaired.”  This can last up to 3 hours.  Surprisingly, olive oil was found to have the same impairment to endothelial function as the rest of these high-fat meals.  A study done in 2007 “showed a similar detrimental effect on endothelial function after the intake of olive, soybean and palm oils.”

Even extra virgin olive oil fairs no better than any other plant oil on its effect on endothelial function.  Various studies quoted in the following reference have shown that it was not the olive oil in the Mediterranean diet that was responsible for lower heart disease in the long term, but in fact was the high intake of fruits and vegetables typical of the Mediterranean diet that was the main protective factor.  As the authors say, the protective effect was not because of the olive oil, but in spite of the olive oil.  “Researchers concluded that the Mediterranean diet’s heavy ‘inclusion of antioxidant-rich fruits, vegetables and their products, apparently provide some protection against the direct impairment in endothelial function produced by high-fat foods, including olive oil.’”

Other information shows that olive oil, like other oils, can actually contribute to atherosclerosis.  This begins with the deposition of waxy plaques – clumps of fat and debris – on the surface of the vessel wall. 

This fat then becomes oxidised, releasing dangerous free radicals that further damage blood vessels.  Patients with narrowing of blood vessels from atherosclerosis who were studied for a year with follow-up angiograms were shown to have significant increase in new atherosclerotic lesions whether they used saturated animal fat, mono-unsaturated fats (like olive oil) or polyunsaturated fats.  The only way the lesions stopped growing was by decreasing all added fat intake.

“The scientific evidence clearly shows that olive oil plays a role both in damaging blood vessels as well as forming atherosclerotic plaques.  ‘Causing less damage’ is a far cry from ‘promoting heart health’ as so many people believe is the case with olive oil.”  It must also be remembered that between 14-17% of olive oil is saturated, artery-clogging fat, no less saturated than the saturated fat of roast beef, which we know is associated with atherosclerosis and heart disease.

Here is a fairly comprehensive but very readable article on the use of olive oil and its harmful effects on the body from which much of the above information is drawn. You will find the references to the research quoted, in this article.

Here is a video that explains the role of olive oil in health/disease.

So does this mean you should avoid all plant oils including olive oil?  Well if you are just starting on the journey of healthful living, you might find it a bit difficulty to switch completely to a low oil diet.  Of course, taking the olive oil in the unrefined form, as in olives is much healthier, in that the olives have a multitude of other substances which modifies the negative effects – such as fibre, plant sterols, and minerals.  Remember oil is one of the most refined substances on earth, and even olive oil has minimal nutrients besides just fat, and perhaps a few oil-based vitamins.  The starting point might be to cut back on fried foods, and oily salad dressings.  There are many recipes available on various sites that are low in oil.

Remember the harmful effects of even olive oil can be countered by taking in large portions of fruits and vegetables in their natural state, together with legumes and whole grains.

ALSO READ : Turning the Tide – Dealing with the scourge of hypertension (Part 4)

To my knowledge there are only two scientists and their teams who have proved that it is possible to reverse atherosclerosis and drop the risk of heart attacks through diet and lifestyle interventions – Drs Dean Ornish from San Francisco, and Cr Caldwell Esselstyn from the Cleveland Clinic.  Both of these researchers used a low-fat, whole food plant-based diet.  Although both these doctors were addressing atherosclerosis, particularly as it relates to coronary arteries, a common side benefit was in the reduction of blood pressure. Other benefits were reduction of intermittent claudication related to peripheral vascular disease; reversal of male impotence, and even improved sexual function in women; reduction in arthritis pain; weight loss and reversal of obesity; reversal of diabetes; general improvement of well-being and mental function.  Other researchers have also confirmed reduced risk of cancer and even reversal of early cancer with a whole-food, plant-based diet.

I have never come across any studies that have shown reversal of atherosclerotic plaques in people partaking a ketogenic diet, or even a Mediterranean diet, for that matter. And yet the Mediterranean diet is haled as being the heart-healthiest diet around.

What about the claim by many clinicians of the importance of essential fatty acids in brain health, and their insistence on eating fatty fish, or some animal products to provide these essential fatty acids.  And it is true that there are some people who find it difficult to obtain all the essential fatty acids from a pure plant-based diet, because of a lack of natural enzymes.  The main plant-based omega-3 fatty acid is ALA (alpha-linoleic acid).  The other two, DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) are found mostly in animal products.

An article from the Physician’s Committee for Responsible Medicine states:  “While most plants are low in fat, the fats they do contain are in the perfect amounts to allow ALA to convert to EPA and DHA.  More fats in the diet make this conversion difficult.  The key is to consume an overall low-fat, plant-based diet.  No supplements required.  In fact researchers followed 4000 patients over a five-year periods, and showed that supplements don’t slow cognitive decline.  Nor do these supplements improve heart health.  Instead, omega-3 supplements may increase men’s risk of developing prostate cancer.”  See the article for references.

Dr Esselstyn quips, on the claims that the brain will not develop properly if you don’t take enough animal-based essential fatty acids: “the animal with the largest brain in the world is an elephant, and elephants are vegetarians”.  Just because a diet is plant-based doesn’t guarantee that it is healthy.  There is so much junk food that is vegetarian.  The healthiest diet is one based upon whole foods – unrefined foods that still contain a full complement of the whole range of nutrients as designed by the Creator – fibre, phytochemicals, minerals, carbohydrates, fats, proteins, vitamins, etc.  The key is variety in the diet.  Whole-food, plant-based eaters also consume large volumes of food because the foods are naturally low in kilojoules.

This in turn provides more nutrients.  Some people insist on a predominantly raw diet, but many nutrients are more available through cooking – just don’t cook them to “death”!

In summary, a diet rich in plants and low in refined foods, of which oil is the most refined, is the healthiest diet to promote vascular health, and help to reduce not only blood pressure, but also so many other lifestyle-related illnesses.

If you would like information about recipes and practical implementation of this information please contact me through my receptionist at 039 6821414 or leave a comment on this blog.

Trusting that one of your resolutions for the new year includes adopting a healthy lifestyle.

Dave Glass

Dr David Glass graduated from UCT in 1975. He spent the next 12 years working at a mission hospital in Lesotho, where much of his work involved health education and interventions to improve health, aside from the normal busy clinical work of an under-resourced mission hospital.

He returned to UCT in 1990 to specialise in obstetrics/gynaecology and then moved to the South Coast where he had the privilege of, amongst other things, ushering 7000 babies into the world. He no longer delivers babies but is still very clinically active in gynaecology.

An old passion, preventive health care, has now replaced the obstetrics side of his work. He is eager to share insights he has gathered over the years on how to prevent and reverse so many of the modern scourges of lifestyle – obesity, diabetes, ischaemic heart disease, high blood pressure, arthritis, common cancers, etc.

He is a family man, with a supportive wife, and two grown children, and four beautiful grandchildren. His hobbies include walking, cycling, vegetable gardening, bird-watching, travelling and writing. He is active in community health outreach and deeply involved in church activities. He enjoys teaching and sharing information.

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