You may have heard that fish oil is great for lowering blood pressure. It’s true. Both human and animal studies show fish oil lowers blood pressure. But that’s not all. Fish oil also affects platelets and blood vessels in a way that protects against stroke. And stroke is the number-one risk with high blood pressure.
However, not all fish oils will have these affects. A study recently appeared in the journal Hypertension that clearly shows that not all fish oils are equally effective at lowering blood pressure.
When researchers have studied the medical use of fish oils, the two components that stand out are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are the major factors in fish oil. Almost all fish oil capsules on the market these days have a ratio of 0.66 DHA to EPA. But is this the best ratio for lowering blood pressure? That’s what the authors of this study set out to learn.
The study was a double-blind, placebo-controlled trial, which is one of the best types of studies. The researchers enrolled 56 overweight men with moderately elevated blood lipids (cholesterol and triglycerides) for the study. They gave one-third of the men 4 grams per day of purified EPA, DHA, or olive oil. They used the olive oil as the placebo. The men continued in their same diets, and the researchers monitored their blood pressure for six weeks.
I’ve told you in the past that checking blood pressure can be a fairly chancy thing. Blood pressures vary from minute to minute. They also vary considerably depending on certain circumstances, including stress, sleep, coffee intake, and exercise. So the researchers in this case used a special blood pressure monitoring device that was able to check blood pressures every 15 minutes, both day and night. They were then able to analyze averages, and thus get a much more accurate idea of what effect these supplements had on blood pressure. Here’s what they found.
The DHA supplements worked. They were able to increase the DHA blood levels by a factor of four. And only DHA was able to reduce the average 24-hour and daytime blood pressure. The DHA treated group had an average fall in systolic blood pressure (the higher number) of 5.8, and an average fall in diastolic blood pressure (the lower number) of 3.3. Then an unexpected result occurred.
DHA also reduced average heart rates by almost four beats per minute. How is that possible? There’s really only one explanation for this very significant lowering of the heart rate: The DHA supplements had to improve overall heart function independent of lowering the blood pressure. Seems like an ideal supplement to me – one that lowers blood pressure and at the same time improves heart function. Now compare this to what the EPA did.
EPA had no significant effect on either blood pressure or heart rate despite the fact that the EPA supplements increased the blood EPA levels nine times. According to the authors, “The results of this study suggest that DHA is the principal omega-3 fatty acid in fish and fish oils that is responsible for their blood pressure and heart rate lowering effects in humans.”
I showed you in the past how DHA is great for protecting your brain from dementia and other brain problems. To me, it seems like a miracle nutrient.
So Are You Taking the Right Kind of Fish Oil?
The more I read about the powers of DHA, the more convinced I am that it is the right fish oil to take daily. There’s nothing wrong with EPA. But taking a supplement with a ratio of 0.66 DHA to EPA will only give you a small amount of DHA. There are several manufacturers that make fish oil capsules that have a higher ratio of DHA.
The one I use is from Source Naturals. They make a fish oil called “Arctic Pure DHA” that has a DHA/EPA ratio of 6.8, almost 10 times better for lowering blood pressure than the more typical capsules. Nutricology’s (www.nutricology.com) DHA Fish Oil Concentrate is an excellent product too. It has a ratio of 10.8.
Then there’s the issue of dose. In order to get the same amount of DHA used in this study, you will need to take seven of the Source Naturals or Nutricology capsules twice a day. That’s what I would recommend you do for the first six weeks. After that, your body’s cells will be saturated in DHA. Most people will find that taking only two to three capsules twice a day will maintain these results.
Why High Doses Are Vital
You do need to make sure you get your levels up high enough initially. In fact, the New York Times published a surprising statement by Dr. Robert Clarke, a professor of epidemiology at the University of Oxford. He said, "Carefully done trials provide no support for the hypothesis that fish oil supplements help." What prompted him to make such a shocking claim?
His statement came as a result of a meta-study published in the Journal of the American Heart Association. The study looked at 10 large trials totaling 77,917 subjects and concluded that there's no scientific support that taking fish oil supplements is going to prevent heart attacks.
In that article, the researchers concluded, "This meta-analysis demonstrated that omega-3 fatty acids [fish oils] had no significant association with fatal or nonfatal coronary heart disease or any major vascular events. It provides no support for current recommendations for the use of such supplements in people with a history of coronary heart disease." But here's why this conclusion is problematic.
Another meta-study, published only three months before, reached an entirely different conclusion. In that study, the researchers found 14 randomized controlled trials involving 71,899 men and women. What they found was a statistically significant 1.6% less chance of dying from a heart attack in the people who took fish oil supplements than in those who did not.
Admittedly, 1.6% is not much of an improvement. But, according to the authors, since there are no side effects from fish oil supplements as compared to medications, "even a modest benefit is meaningful."
But why is it that the studies don't show a better risk reduction with fish oils? After all, we’ve seen that the right fish oil can lower blood pressure. And that should decrease heart attack risk. So what’s the disconnect?
It might be that the doses were too small.
According to the authors of the second study, “A possible explanation for the mixed results in randomized controlled trials regarding both fatal and non-fatal coronary heart disease events relates to dosage.”
They went on to explain that when a combined dosage of EPA and DHA was greater than 1 gram per day, the decrease in risk went up to 8%. And in another trial using 1.8 grams per day there was a statistically significant 19% risk reduction.
Other Benefits of Using the Right Fish Oil
In any event, no matter how much fish oil supplements decrease heart disease risk, research has confirmed the health benefits of fish oil supplements in so many areas that they are arguably one of the most important supplements that we can take.
Other benefits include reduced risk of heart arrhythmias, better diabetes management, decreased blood fats, improved cognitive function, improved mood disorders, higher IQs in children, blood clot prevention, better weight control, improved eye health, and lower levels of inflammation.
I stand by my recommendation that you make sure most of that “combined dosage” comes from DHA. If you have a fish oil brand that you like, you might need to increase your dosage to ensure you get enough DHA.
And if you’re choosing a different brand than the ones I’ve recommended, you need to make sure it’s as pure as possible. In fact, a study came out a few years ago that revealed that many brands of fish oil contain measurable amounts of PCBs. The state of California recognizes these contaminates as carcinogens.
Also, as I have reported in the past, poorly manufactured fish oils can contain both rancid fats and mercury. Fish oil is extremely vulnerable to heat and oxygen. So, when you buy a fish oil supplement, don’t go cheap. Spend a little more and get a high-quality product.
The list of all the health enhancing and preventive benefits of fish oil supplements goes on and on and only gets longer every year. That is why I take two fish oil capsules every day of my life – even though I have no medical condition and feel great. So don't wait until the doc tells you that you need to be on a blood pressure medication for the rest of your life. My best advice is to get proactive now while your blood pressure is perfectly fine.