Do Omega-3s Lower Blood Pressure in Young, Healthy Adults?

Written by Dr. Steve Chaney on . Posted in Omega-3s and Blood Pressure, omega-3s in young adults

What Is The Omega-3 Index And Why Is It Important?

Author: Dr. Stephen Chaney

 

Do omega-3s lower blood pressure in healthy adults?

omega-3s lower blood pressure young adultsThe literature on the potential health benefits of omega-3s is very confusing. That’s because a lot of bad studies have been published. Many of them never determined the omega-3 status of their subjects prior to omega-3 supplementation. Others relied on dietary recalls of fish consumption, which can be inaccurate.

Fortunately, a much more accurate measure of omega-3 status has been developed and validated in recent years. It’s called the Omega-3 Index. Simply put, the Omega-3 Index is the percentage of EPA and DHA compared to 26 other fatty acids found in cellular membranes. Using modern technology, it can be determined from a single finger prick blood sample. It is a very accurate reflection of omega-3 intake relative to other fats in the diet over the past few months. More importantly, it is a measure of the omega-3 content of your cell membranes, which is a direct measure of your omega-3 nutritional status.

A recent extension of the Framingham Heart Study reported that participants with an Omega-3 Index >6.8% had a 39% lower risk of cardiovascular disease than those with an Omega-3 Index <4.2% (WS Harris et al, Journal of Clinical Lipidology, 12: 718-724, 2018 ). Although more work needs to be done, an Omega-3 Index of 4% or less is generally considered indicative of high cardiovascular risk, while 8% or better is considered indicative of low cardiovascular risk. For reference, the average American has an Omega-3 Index in the 4-5% range. In Japan, where fish consumption is much higher and cardiovascular risk much lower, the Omega-3 Index is in the 9-11% range.

Previous studies have suggested that omega-3 fatty acids lower blood pressure to a modest extent. Thus, it is not surprising that more recent studies have shown an inverse correlation between Omega-3 Index and blood pressure. However, those studies have been done with older populations, many of whom had already developed high blood pressure.

From a public health point of view, it is much more interesting to investigate whether it might be possible to prevent high blood pressure in older adults by optimizing omega-3 intake in a young, healthy population, most of whom had not yet developed high blood pressure. Unfortunately, there were no studies looking at that population. The current study was designed to fill that gap.

 

How Was The Study Done?

omega-3s lower blood pressure young healthy adultsThe current study (M.G. Filipovic et al, Journal of Hypertension, 36: 1548-1554, 2018 ) was based on data collected from 2036 healthy adults, aged 25-41, from Liechtenstein. They were participants in the GAPP (Genetic and Phenotypic Determinants of Blood Pressure) study. Participants were excluded from the study if they had been diagnosed with high blood pressure and were taking medication to lower their blood pressure. They were also excluded if they had heart disease, chronic kidney disease, other severe illnesses, obesity, sleep apnea, or daily use of non-steroidal anti-inflammatory medications.

Blood samples were collected at the time of their enrollment in the study and frozen for subsequent determination of Omega-3 Index. Blood pressure was also measured at their time of enrollment in two different ways. The first was a standard blood pressure measurement in a doctor’s office.

For the second measurement they were given a wearable blood pressure monitor that recorded their blood pressure over 24 hours every 15 minutes during the day and every 30 minutes while they were sleeping. This is considered more accurate than a resting blood pressure measurement in a doctor’s office because it records the variation in blood pressure, while you are sleeping, while you are exercising, and while you go about your everyday activities.

 

Do Omega-3s Lower Blood Pressure In Young, Healthy Adults?

omega-3s lower blood pressure young adults equipmentNone of the participants in the study had significantly elevated blood pressure. The mean systolic and diastolic office blood pressures were 120±13 and 78±9 respectively. The average Omega-3 Index in this population was 4.6%, which is similar to the average Omega-3 Index in the United States.

When they compared the group with the highest Omega-3 Index (average = 5.8%) with the group with the lowest Omega-3 Index (average = 4.6%):

  • The office measurement of systolic and diastolic blood pressure was decreased by 3.3% and 2.6% respectively
  • While those numbers appear small, the differences were highly significant.
  • The 24-hour blood pressure measurements showed a similar decrease.
  • Blood pressure measurements decreased linearly with increasing Omega-3 Index. [In studies of this kind, a linear dose-response is considered an internal validation of the differences observed between the group with the highest Omega-3 Index and the group with the lowest Omega-3 Index.]

The authors concluded: “A higher Omega-3 Index is associated with statistically significant, clinically relevant, lower systolic and diastolic blood pressure in normotensive, young and healthy individuals. Diets rich omega-3 fatty acids may be a strategy for primary prevention of hypertension.”

 

What Does This Mean For You?

omega-3s lower blood pressure young adults questionPerhaps I should first comment on the significance of the relatively small decrease in blood pressure observed in this study.

  • These were young adults, all of whom had normal or near normal blood pressure.
  • The difference in Omega-3 Index was rather small (5.8% to 4.6%). None of the participants in the study were at the 8% or above that is considered optimal.
  • Liechtenstein is a small country located between Switzerland and Spain. Fish consumption is low and omega-3 supplement consumption is rare.

Under these conditions, even a small, but statistically significant, decrease in blood pressure is remarkable.

We should think of this study as the start of the investigation of the relationship between omega-3 status and blood pressure. Its weakness is that it only shows an association between high Omega-3 Index and low blood pressure. It does not prove cause and effect.

Its strength is that it is consistent with many other studies showing omega-3 fatty acids lower blood pressure. Furthermore, it suggests that the effect of omega-3s on blood pressure may also be seen in young, healthy adults who have not yet developed high blood pressure.

Finally, the authors suggested that a diet rich in omega-3s might reduce the incidence of high blood pressure by slowing the age-related increase in blood pressure that most Americans experience. This idea is logical, but speculative at present.

However, the GAPP study is designed to provide the answer to that question. It is a long-term study with follow-up examinations scheduled every 3-5 years. It will be interesting to see whether the author’s prediction holds true, and a higher Omega-3 Index is associated with a slower increase in blood pressure as the participants age.

 

Why Is The Omega-3 Index Important?

 

The authors of this study said: “The Omega-3 Index is very robust to short-term intake of omega-3 fatty acids and reliably reflects an individual’s long-term omega-3 status and tissue omega-3 content. Therefore, the Omega-3 Index has the potential to become a cardiovascular risk factor as much as the HbA1c is for people with diabetes…” That is a bit of an overstatement. HbA1c is a measure of disease progression for diabetes because it is a direct measure of blood sugar control.

In contrast, Omega-3 Index is merely a risk factor for cardiovascular disease. However, if it is further validated by future studies, it is likely to be as important for predicting cardiovascular risk as are cholesterol levels and markers of inflammation.

However, to me the most important role of Omega-3 Index is in the design of future clinical studies. If anyone really wants to determine whether omega-3 supplementation reduces cardiovascular risk, high blood pressure, diabetes or any other health outcome they should:

  • Start with a population group with an Omega-3 Index in the deficient (4-5%) range.
  • Supplement with omega-3 fatty acids in a double blind, placebo-controlled manner.
  • Show that supplementation brought participants up to an optimal Omega-3 Index of 8% or greater.
  • Look at health outcomes such as heart attacks, cardiovascular deaths, hypertension, stroke, or depression.
  • Continue the study long enough for the beneficial effects of omega-3 supplementation to be measurable. For cardiovascular outcomes the American Heart Association has stated that at least two years are required to obtain meaningful results.

These are the kind of experiments that will be required to give definitive, reproducible results and resolve the confusion about the health effects of omega-3 fatty acids.

 

The Bottom Line

 

An accurate measure of omega-3 status has been developed and validated in recent years. It’s called the Omega-3 Index. Simply put, the Omega-3 Index is the percentage of EPA and DHA compared to 26 other fatty acids found in cellular membranes.

Although more work needs to be done, an Omega-3 Index of 4% or less is generally considered indicative of high cardiovascular risk while 8% or better is considered indicative of low cardiovascular risk.

Previous studies have shown an inverse correlation between Omega-3 Index and blood pressure. However, these studies have been done with older populations, many of whom had already developed high blood pressure.

From a public health point of view, it is much more interesting to investigate whether it might be possible to prevent high blood pressure in older adults by optimizing omega-3 intake in a young, healthy population, most of whom had not yet developed high blood pressure. Until now, there have been no studies looking at that population.

The study described in this article was designed to fill that gap. The participants in this study were ages 25-41, were healthy, and none of them had elevated blood pressure.

When the group with the highest Omega-3 Index (average = 5.8%) was compared with the group with the lowest Omega-3 Index (average = 4.6%):

  • Both systolic and diastolic blood pressure were decreased
  • Blood pressure measurements decreased linearly with increasing Omega-3 Index.

The authors concluded: “A higher Omega-3 Index is associated with statistically significant, clinically relevant, lower systolic and diastolic blood pressure in normotensive, young and healthy individuals. Diets rich omega-3 fatty acids may be a strategy for primary prevention of hypertension.”

Let me translate that last sentence into plain English for you. The authors were saying that optimizing omega-3 intake in young adults may slow the age-related increase in blood pressure and reduce the risk of them developing high blood pressure as they age. This may begin to answer the question “Do omega-3s lower blood pressure in young, healthy adults?”

Or even more simply put: Aging is inevitable. Becoming unhealthy is not.

For more details, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Latest Article

Can Plant-based Diets Be Unhealthy?

Posted September 10, 2019 by Dr. Steve Chaney

Do Plant-Based Diets Reduce Heart Disease Deaths?

Author: Dr. Stephen Chaney

 

plant-based diets vegetablesPlant-based diets have become the “Golden Boys” of the diet world. They are the diets most often recommended by knowledgeable health and nutrition professionals. I’m not talking about all the “Dr. Strangeloves” who pitch weird diets in books and the internet. I am talking legitimate experts who have spent their life studying the impact of nutrition on our health.

Certainly, there is an overwhelming body of evidence supporting the claim that plant-based diets are healthy. Going on a plant-based diet can help you lower blood pressure, inflammation, cholesterol and triglycerides. People who consume a plant-based diet for a lifetime weigh less and have decreased risk of heart disease, diabetes, and cancer.

But, can a plant-based diet be unhealthy? Some people consider a plant-based diet to simply be the absence of meat and other animal foods. Is just replacing animal foods with plant-based foods enough to make a diet healthy?

Maybe not. After all, sugar and white flour are plant-based food ingredients. Fake meats of all kinds abound in our grocery stores. Some are very wholesome, but others are little more than vegetarian junk food. If you replace animal foods with plant-based sweets, desserts, and junk food, is your diet really healthier?

While the answer to that question seems obvious, very few studies have asked that question. Most studies on the benefits of plant-based diets have compared population groups that eat a strictly plant-based diet (Seventh-Day Adventists, vegans, or vegetarians) with the general public. They have not looked at variations in plant food consumption within the general public. Nor have they compared people who consume healthy and unhealthy plant foods.

This study (H Kim et al, Journal of the American Heart Association, 8:e012865, 2019) was designed to fill that void.

 

How Was The Study Done?

plant-based diets studyThis study used data collected from 12,168 middle aged adults in the ARIC (Atherosclerosis Risk in Communities) study between 1987 and 2016.

The participant’s usual intake of foods and beverages was assessed by trained interviewers using a food frequency questionnaire at the time of entry into the study and again 6 years later.

Participants were asked to indicate the frequency with which they consumed 66 foods and beverages of a defined serving size in the previous year. Visual guides were provided to help participants estimate portion sizes.

The participant’s adherence to a plant-based diet was assessed using four different well-established plant-based diet scores. For the sake of simplicity, I will include 3 of them in this review.

  • The PDI (Plant-Based Diet Index) categorizes foods as either plant foods or animal foods. A high PDI score means that the participant’s diet contains more plant foods than animal foods. A low PDI score means the participant’s diet contains more animal foods than plant foods.
  • The hPDI (healthy plant-based diet index) is based on the PDI but emphasizes “healthy” plant foods. A high hPDI score means that the participant’s diet is high in healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) and low in animal foods.
  • The uPDI (unhealthy plant-based diet index) is based on the PDI but emphasizes “unhealthy” plant foods. A high uPDI score means that the participant’s diet is high in unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) and low in animal foods.

For statistical analysis the scores from the various plant-based diet indices were divided into 5 equal groups. In each case, the group with the highest score consumed the most plant foods and least animal foods. The group with the lowest score consumed the least plant foods and the most animal foods.

The health outcomes measured in this study were heart disease events, heart disease deaths, and all-cause deaths. Again, for the sake of simplicity, I will only include 2 of these outcomes (heart disease deaths and all-cause deaths) in this review. The data on deaths were obtained from state death records and the National Death Index. (Yes, your personal information is available on the web even after you die.)

 

Do Plant-Based Diets Reduce Heart Disease Deaths?

plant-based diets reduce heart deathsThe participants in this study were followed for an average of 25 years.

The investigators looked at heart disease deaths over the 25 years and compared people with the highest intake of plant foods to people with the highest intake of red meat and other animal foods. The results were:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

What Else Did The Study Show?

The investigators made a couple of other interesting observations:

  • The association of the overall diet with heart disease and all-cause deaths was stronger than the association of individual food components. This underscores the importance of looking at the effect of the whole diet on health outcomes rather than the “magic” foods you hear about on Dr. Strangelove’s Health Blog.
  • Diets with the highest amount of healthy plant foods were associated with higher intake of carbohydrates, plant protein, fiber, and micronutrients, including potassium, magnesium, iron, vitamin A, vitamin C, folate, and lower intake of saturated fat and cholesterol.
  • Diets with the highest amount of unhealthy plant foods were associated with higher intake of calories and carbohydrates and lower intake of fiber and micronutrients.

The last two observations may help explain some of the health benefits of plant-based diets.

 

Can Plant-Based Diets Be Unhealthy?

plant-based diets unhealthy cookiesNow, let’s return to the question I asked at the beginning of this article: “Can plant-based diets be unhealthy?” Although some previous studies have suggested that unhealthy plant-based diets might increase the risk of heart disease, this study did not show that.

What this study did show was that an unhealthy plant-based diet was no better for you than a diet containing lots of red meat and other animal foods.

If this were the only conclusion from this study, it might be considered a neutral result. However, this result clearly contrasts with the data from this study and many others showing that both plant-based diets in general and healthy plant-based diets reduce the risk of heart disease deaths and all-cause deaths compared to animal-based diets.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

There is one other subtle message from this study. This study did not compare vegans with the general public. Everyone in the study was the general public. Nobody in the study was consuming a 100% plant-based diet.

For example:

  • The group with the highest intake of plant foods consumed 9 servings per day of plant foods and 3.6 servings per day of animal foods.
  • The group with the lowest intake of plant foods consumed 5.4 servings per day of plant foods and 5.6 servings per day of animal foods.

In other words, you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet.

 

The Bottom Line

A recent study analyzed the effect of consuming plant foods on heart disease deaths and all-cause deaths over a 25-year period.

When the investigators looked at heart disease deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

A more subtle message from the study is that you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet. The people in this study were not following some special diet. The only difference was that some of the people in this study ate more plant foods and others more animal foods.

For more details on the study, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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