Many people don't realize that Omega-3s affect your heart health—and if you eat a plant-based diet, new research shows it's likely you're not getting enough of them.
One of the best things we can do to prevent or reverse heart disease is to eat a whole-foods, plant-based diet. But is there more we can do?
How Omega-3s Impact Your Heart Rate
The latest research on omega-3s focuses on heart rate variability (HRV) as a gauge of overall cardiovascular health.
HRV is the change in the time interval between heartbeats. If the time between your heartbeats changes very little, you would have a lower HRV; whereas, if the time between beats varies considerably—say, in response to changing levels of stress—you would have a higher HRV.
In general, it’s a good thing to have higher variability, because it indicates a greater ability to respond to stress. In other words, your heart is able to react to a new circumstance—exercise, rest, stress, etc.—and continue to function properly. On the other hand, people with low HRV are more likely to experience sudden, unexpected cardiac death.
How does all this relate to omega-3s? Unfortunately, people with low omega-3 levels are more likely to have low HRV.
Why Many Vegans Don’t Get Enough Omega-3s
There are three notable types of omega-3s: ALA, EPA, and DHA. And if you eat a 100% plant-based diet, it’s likely you’re missing out on two of them.
ALA is abundantly available in many plant foods like flax and chia seeds, walnuts, tofu, greens, and squash. But finding food sources of EPA and DHA is a little more complicated.
Since EPA and DHA are mainly found in microalgae and other seaweeds, humans do not typically consume these important fatty acids directly; rather they are usually ingested as part of seafood. Thus, most vegetarians and vegans are not obtaining these omega-3s in their diet, unless they consume very large amounts of seaweed.
Both DHA and EPA can technically be converted from ALA, but the conversion rates from ALA to DHA or EPA are extremely low, ranging from undetectable to around 10%.
Non-fish eaters may have an increased conversion efficiency, however, so it is possible that vegetarians and vegans may convert more EPA and DHA from ALA than the rest of the population. Still, what small amount of science exists on the subject is relatively young, so if you eat a plant-based diet, you should pay extra consideration to your omega-3 intake.
Study: Vegans Have Lower Levels of Omega-3s (and Lower Heart Rate Variability) than Omnivores
In fact, there is evidence that vegans may have lower levels of circulating omega-3s than other segments of the population.
In the recent study on HRV, when 23 vegans were compared to 24 omnivores (all volunteers), the vegan cohort did have significantly lower levels of EPA and DHA than omnivores.
The omega-3 index is a measure of the concentration of EPA and DHA in the blood. Greater than 8% has been identified as optimal for cardiac protection. In this study, the vegans had a mean omega-3 index of 2.7% compared with 5.4% in omnivores.
Although both groups were below optimal, the vegans had significantly lower levels of omega-3s.
That is a concern, and not just because of HRV. Omega-3s have a role in reducing inflammation and decreasing our risk of heart disease, cancer, arthritis and cognitive decline. And these lower levels of omega-3s did in fact correlate with lower HRV: the vegans studied had lower HRV during the waking hours, compared with omnivores, although no difference during sleep.
Admittedly, this was a small study. And the impact of low levels of omega-3s, and reduced HRV, on cardiovascular risk is complex and requires further research. It does, however, point to a possible mechanism by which those following a vegan diet can further reduce inflammation and cardiovascular risk.
How to Protect Your Heart and Healthspan
We’ve seen that Omega 3’s have a large impact on heart health… so what can do to protect yourself and make sure you’re getting enough?
One whole-foods approach to improving your heart rate variability is to “go nuts”! A study published by the Journal of the American Heart Association found that increased consumption of pistachio nuts resulted in increased HRV. While eating more nuts won’t likely correct low omega-3 levels, evidence suggests it might be good for your heart in other ways.
If you’re looking for a direct way of increase your circulating levels of omega-3s, consider fortified foods, increasing your consumption of seaweed, or supplementing, with a vegan source of EPA and DHA.
Whatever you do, don’t ignore omega-3s! They’re critical to maintaining a strong cardiovascular system and for many other aspects of your health. Yet, as we can see in this study, many of us are not getting enough of them.
Written by Dr. Pamela Fergusson, RD, PhD.