VTE

Written by Dr. Steve Chaney on . Posted in Food and Health, Health Current Events, Supplements and Health

Benefits of Omega-3

Author: Dr. Stephen Chaney

venous-thomboembolism

 When a blood clot ends up in your lungs, it can be deadly. But that blood clot didn’t start out in your lungs. It initially formed in your veins where it is referred to as a thrombus. Then it broke off and migrated to your lungs – a process called venous thromboembolism or VTE. Venous thromboembolism is the third most common form of cardiovascular disease, killing around 100,000 Americans each year.

What if something as simple as adding more omega-3 fatty acids to your diet could dramatically decrease your risk of VTE? That’s exactly what a recent study (Hansen-Krone et al, J. Nutr., 144: 861-867, 2014) has suggested. It claims that one of the benefits of omega-3 in your diet may be to help prevent venous thromboembolism.

What Is Venous Thromboembolism or VTE?

As described above, venous thromboembolism starts when a blood clot (also called a thrombis) forms in a vein. About 2/3 of the time, the blood clot forms in the deep veins in the leg (called deep vein thrombosis or DVT) and stays there before eventually dissolving. The symptoms of deep vein thrombosis or DVT are generally leg pain and swelling.

About 1/3 of the time, the clot breaks loose and travels to the lung where it blocks blood flow to a portion of the lung (a process called pulmonary embolism). The symptoms of pulmonary embolism are severe shortness of breath, chest pain when breathing or coughing, and death! While the first two symptoms are pretty frightening, it’s the last symptom (death) that we’d really like to avoid.

Why Might Omega-3s Prevent Venous Thromboembolism or VTE?

One of the benefits of Omega-3s is they have been shown to reduce inflammation and platelet aggregation, two of the most important risk factors for venous thromboembolism. So it is logical to think that omega-3s might help reduce the risk. However, good scientists don’t rely on logic alone. They test their hypotheses by doing clinical studies.

Unfortunately, the results of previous clinical studies have been mixed. One study showed a protective effect of omega-3s, but two other studies found no correlation between omega-3 fatty acid intake and VTE. However, these studies had some significant limitations:

benefits-of-fish-oil-pills

  • They were all performed with populations in the United States where fish consumption is relatively low and many of the fish have low omega-3 content. As a consequence omega-3 fatty acid intake was low and there wasn’t much of a range in intake.
  • Some of the studies did not ask about the use of omega-3 supplements. In a country where 37% of the population takes fish oil supplements, that is a huge omission.
  • They did not measure omega-3 fatty acid levels in the blood to verify that their dietary surveys were accurate.

 

Do Omega-3s Prevent Venous Blood Clots or DVT?

pulmonary-embolism

The current study (Hansen-Krone et al, J. Nutr., 144: 861-867, 2014) followed 23,631 people aged 25-97 from Tromso, Norway for 16 years.

  • The participants filled out a comprehensive dietary survey at the time of enrollment where they indicated the number of times per week they ate fish and how often they used fish oil supplements.
  • The scientists in charge of the study verified the estimated omega-3 intake from the dietary analysis in a subgroup of the population by measuring omega-3 fatty acid levels in their blood.
  • Finally, they utilized Norway’s excellent health records to determine how many of the people in their trial experienced a venous thromboembolism – either fatal or non-fatal.

The results were pretty impressive:

  • Blood level measurements of omega-3 fatty acids verified the omega-3 intake estimates from the dietary survey. There was a direct correlation between estimated intake and blood levels of the omega-3 fatty acids.
  • Those participants who ate fish most often (≥3 times/week) were 22% less likely to experience a VTE than those who ate fish least often (1-2 times/week). That difference was borderline significant.
  • Those participants who ate fish most often and took fish oil supplements were 48% less likely to experience a venous thromboembolism than those who ate fish least often and took no fish oil supplements. That difference was highly significant.

 

Strengths & Weaknesses of the Study

Since not all of the previous clinical studies have reached the same conclusion, it is important to look at the strengths and weaknesses of the study compared to the previous studies.

Strengths of the Study:

  • Tromso is located on the northeast coast of Norway, so fish consumption is high and most of the local fish are excellent sources of omega-3 fatty acids. Consequently, omega-3 intake was relatively high, which significantly increases the chance of seeing an effect if one exists. Fish consumption in the US is generally lower and not all of the fish consumed are good sources of omega-3s.
  • The study also took into account the use of omega-3 supplements. Some of the US studies did not.
  • The estimates of omega-3 intake from the dietary survey were verified by blood analysis of omega-3 fatty acids.

Weaknesses of the Study:

  • The amount of omega-3 fatty acids in the supplements was not recorded, so it is unclear what level of omega-3 fatty acid intake was required to see a significant decrease in VTE risk. This will make it difficult for future investigators to repeat the study.
  • They did not measure other nutrients that might affect the venous thromboembolism risk.

 

The Bottom Line

1)     VTE is a serious condition with a high rate of mortality.

2)     A recent study suggests that a combination of high fish consumption and fish oil supplement use may significantly decrease the risk of venous thromboembolism.

3)     It is interesting to note that even three servings/week of omega-3 rich fish was not enough to cause a significant decrease in venous thromboembolism risk. It required additional omega-3s from fish oil supplements before the decreased risk was significant.

4)     Not all previous studies have come to the same conclusion. So while the most recent study had several improvements in design compared to previous studies, the case can’t be considered closed. More studies are clearly needed.

5)     This study suggests that omega-3 fatty acids may help prevent VTE from occurring. You should not consider them to be a treatment for the condition. If you are experiencing symptoms of venous thromboembolism (leg pain and swelling for deep vein thrombosis (DVT) or shortness of breath and pain when breathing for pulmonary embolism), don’t reach for your fish oil capsules. Call your doctor right away.

 

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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Comments (2)

  • Joanne M. Cottrell

    |

    I enjoy reading Dr Cheney’s newsletters and appreciate his reference to the particular studies. There is just so much hype out there and the information that is being presented to the masses has no scientific basis. I like fish, however I don’t consume it three times a week. Walleye, whitefish, Cod, and many of the types that are mild in taste do not contain the Ogema 3’s. This article is making me realize that I do need to be consistent in finding and taking a high quality Omega 3 supplement. Thank You Dr. Chaney!

    Reply

  • Muriel Donaldson

    |

    Very interesting. Looking forward to your newsletters.
    Muriel

    Reply

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Latest Article

Best Diet For Heart Disease Prevention

Posted July 9, 2019 by Dr. Steve Chaney

Are The American Heart Association’s Recommendations Correct?

Author: Dr. Stephen Chaney

 

What is the best diet for heart disease prevention? 

diet for heart disease preventionHeart disease is a killer. It continues to be the leading cause of death – both worldwide and in industrialized countries like the United States and the European Union. When we look at heart disease trends, it is a good news – bad news situation.

  • The good news is that heart disease deaths are continuing to decline in adults over 70.
  • The decline among senior citizens is attributed to improved treatment of heart disease and more seniors following heart-healthy diets.
  • The bad news is that heart disease deaths are starting to increase in younger adults, something I reported in an earlier issue, Heart Attacks Increasing in Young Women of “Health Tips From the Professor.”
  • The reason for the rise in heart disease deaths in young people is less clear. However, the obesity epidemic, junk and convenience foods, and the popularity of fad diets all likely play a role.

Everyone has a magic diet for reducing heart disease risk. The American Heart Association tells us to avoid fats, especially saturated fats. Vegans tell us to avoid animal protein. Paleo and keto enthusiasts tell us carbs are the problem. Who is correct?

Of course, we don’t eat fats, carbohydrates, or proteins. We eat foods. That is why a recent study (T Meier et al, European Journal of Epidemiology, 34: 37-45, 2019) is so important. It reported which foods increase and which decrease the risk of premature heart disease deaths.

How Was The Study Done?

diet for heart disease prevention studyThe authors of the current study analyzed data from the “Global Burden of Diseases (GBD) Study”, a major world-wide effort designed to estimate the portions of deaths caused by various risk factors.

The current study focused on the impact of 12 dietary risk factors on heart disease deaths between 1990 and 2016 for 51 countries in four regions (Western Europe, Central Europe, Eastern Europe, and Central Asia).

The dietary risk factors were:

  • Diets low in fiber, fruits, vegetables, legumes, nuts and seeds, polyunsaturated fatty acids, omega-3 fatty acids, and whole grains.
  • Diets high in sodium, processed meats, sugar-sweetened beverages, and trans fatty acids.

Saturated fat and meat were not explicitly included in the GBS Study data. However, diets low in polyunsaturated fats and omega-3 fats are likely high in saturated fats. Similarly, diets low in fruits, vegetables, whole grains, and legumes are likely higher in meats. The study also did not include dairy, and some recent studies suggest that some dairy foods may decrease heart disease risk.

For simplicity I will only consider the findings from Western Europe because their diet and heart disease death trends are similar to those in the United States.

 

Best Diet for Heart Disease Prevention?

plant-based diet bestThe study found that in 2016 (the last year for which data were available):

  • Dietary risk factors were responsible for 49.2% of heart disease deaths.
  • 6% of all diet-related heart disease deaths occurred in adults younger than 70, and that percentage has been increasing in recent years.

When they looked at the contribution of individual foods to diet related heart disease deaths, the percentages were:

  • Diets low in whole grains = 20.4%
  • Diets low in nuts and seeds = 16.2%
  • Diets low in fruits = 12.5%
  • Diets high in sodium = 12.0%
  • Diets low in omega-3s = 10.8%
  • strong heartDiets low in vegetables = 9.0%
  • Diets low in legumes = 7.0%
  • Diets low in fiber = 5.7%
  • Diets low in polyunsaturated fats = 3.7%
  • Diets high in processed meats = 1.6%
  • Diets high in trans fatty acids = 0.8%
  • Diets high in sugar-sweetened beverages = 0.1%

So, what is the best diet for heart disease prevention?

In short, this study concluded:

  • A primarily plant-based diet is the best protection against premature death due to heart disease.
  • All plant-based food groups (whole grains, nuts and seeds, fruits, vegetables, and legumes) play an important role in reducing heart disease deaths.
  • Meat was not included in the analysis, but it is likely that most people’s diets in this region of the world contained some meat. The most likely take-away is that meat does not affect heart disease risk in the context of a primarily plant-based diet.
  • Dairy was not included in the analysis either, but some studies suggest dairy, particularly fermented dairy foods, reduce heart disease risk.
  • Finally, the study concluded: “Compared to other…modifiable risk factors (physical inactivity, drug and alcohol abuse, tobacco smoking, obesity, etc.), an altered diet is the most effective means of preventing premature deaths from cardiovascular disease in Western Europe.”

While every study has its weaknesses, this study is consistent with multiple previous studies showing that primarily plant-based diets are best for reducing heart disease risk. You will find a more complete discussion of these studies in my book “Slaying The Food Myths.”

 

Are the American Heart Association’s Recommendations Correct?

With this study’s results in mind we can now ask whether the recommendations of the American Heart Association and other popular diets are correct. Are they likely to reduce heart disease deaths?

  • The American Heart Association Recommends a dietary pattern that emphasizes a variety of fruits and vegetables, whole grains, nuts and legumes, skinless poultry and fish, and low-fat dairy products. This study supports those recommendations.
  • This study also supports the heart-health benefits of the Mediterranean and DASH diets.
  • Meat and dairy were not explicitly considered in this study. Thus, the results of this study are also consistent with vegan and semi-vegetarian diets.
  • However, low carb diets like Paleo and keto eliminate some of the key food groups (whole grains, fruits, and legumes) that appear to be essential for reducing heart disease risk. 40% of the heart-health benefits in this study came from those 3 food groups. Thus, this study does not support claims that those two diets are heart-healthy long term.

 

The Bottom Line

 

Everyone has a magic diet for reducing heart disease risk. The American Heart Association tells us to avoid fats, especially saturated fats. Vegans tell us to avoid animal protein. Paleo and keto enthusiasts tell us carbs are the problem. Who is correct?

A recent study provides some important clues. It looked at dietary patterns associated with reduced risk of premature death from heart disease in Western Europe. The study concluded:

  • A primarily plant-based diet is the best protection against premature death due to heart disease.
  • All plant-based food groups (whole grains, nuts and seeds, fruits, vegetables, and legumes) play an important role in reducing heart disease deaths.
  • Meat did not appear to affect heart disease risk in the context of a primarily plant-based diet.
  • Dairy was not included in the analysis, but some studies suggest dairy, particularly fermented dairy foods, reduce heart disease risk.
  • Finally, the study concluded: “Compared to other…modifiable risk factors (physical inactivity, drug and alcohol abuse, tobacco smoking, obesity, etc.), an altered diet is the most effective means of preventing premature deaths from cardiovascular disease.”

While every study has its weaknesses, this study is consistent with multiple previous studies showing that primarily plant-based diets are best for reducing heart disease risk. You will find a more complete discussion of these studies in my book “Slaying The Food Myths.”

With this study’s results in mind we can now ask whether the recommendations of the American Heart Association and other popular diets are correct. Are they likely to reduce heart disease deaths?

  • The American Heart Association Recommends a dietary pattern that emphasizes a variety of fruits and vegetables, whole grains, nuts and legumes, skinless poultry and fish, and low-fat dairy products. This study supports those recommendations.
  • This study also supports the heart-health benefits of the Mediterranean and DASH diets.
  • Meat and dairy were not explicitly considered in this study. Thus, the results of this study are also consistent with vegan and semi-vegetarian diets.
  • However, low carb diets like Paleo and keto eliminate some of the key food groups (whole grains, fruits, and legumes) that appear to be essential for reducing heart disease risk. 40% of the heart-health benefits in this study came from those 3 food groups. Thus, this study does not support claims that those two diets are heart-healthy long term.

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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