Friday Favorites: Benefits of Flaxseeds for Inflammation

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Previously, I’ve explored the potent antihypertensive effect of dietary flaxseed in hypertensive patients. This was a double-blind, randomized, placebo-controlled trial where they disguised ground flaxseed in baked goods, versus like flax-free placebo muffins, and got an extraordinary drop in high blood pressures. As you can imagine, the flaxseed industry was overjoyed, praising the impressive findings, as was I. After all, high blood pressure is the single largest risk factor for death on the planet earth. Yes, we give people medications—lots and lots of medications, but most people don’t take them, as in 9 out of 10 people take less than 80 percent of their prescribed blood pressure pills. Just 8 percent.

It’s not difficult to understand why. “Patients are asked to follow an inconvenient and potentially costly regimen, which will likely have a detrimental effect on [their] health-related quality of life to treat a mostly asymptomatic condition.” So, they may feel worse instead of better, due to the side effects. The answer, then, is to give them more drugs to counteract the effects of the first drugs— like giving men Viagra to counteract the erectile dysfunction caused by their blood pressure pills.

How about using a dietary strategy instead, especially if it can be just as effective? And indeed, the drop in blood pressures they got in the flaxseed study “was greater than the average decrease observed with the standard dose of anti-hypertensive [drugs].” And, flaxseeds are cheaper too, compared to even single medications, and most patients are on multiple drugs. And it has good side effects beyond their anti-hypertensive actions—but not all good. Taking tablespoons of flaxseed a day is a lot of fiber for people who have been living off of cheeseburgers and milkshakes their whole lives, and it can take a little while for your gut bacteria to adjust to the new bounty. So, people who start out with low-fiber diets may want to take it slow at first.

Not all studies have shown significant blood pressure-lowering effects. There have been over a dozen trials by now, involving more than a thousand subjects. And yes, put them all together, and overall, there were significant reductions in both systolic and diastolic blood pressures—the upper and lower numbers—following supplementation with various flax seed products. None were as dramatic as that six-month trial. The longer trials tended to show better results, and some of the trials just used flaxseed oil or some kind of flaxseed extract. The thought is that the whole is greater than the sum of its parts. “Each of the components of interest within flaxseed, [the omega-3’s, the cancer-fighting lignans, all the soluble fiber and plant proteins,] all contribute towards [the] blood pressure reduction.” Okay, but how? Why? What’s the mechanism?

Some common blood-pressure medications, like Norvasc or Procardia, work by reducing the ability of the heart to contract, or slowing the heart down. And so, it’s possible that’s how flaxseed works too. But no. “Dietary flaxseed reduces…blood pressure without cardiac involvement but [rather,] through changes in plasma oxylipins.” What are oxylipins?

“Oxylipins are a group of fatty acid metabolites” involved in inflammation, and as a result, have been implicated in many pro-inflammatory conditions including cardiovascular disease and aging. “The best characterized oxylipins in relation to cardiovascular disease are derived from the long chain omega-6 fatty acid [known as] arachidonic acid, found preformed in animal products, particularly chicken and eggs,” and can be made inside the body from junky omega-6 rich oils, such as cottonseed oil. But, elevated levels of pro-inflammatory oxylipins in older subjects are normalized by flaxseed consumption.

That’s how we think flaxseed consumption reduces blood pressure in patients with hypertension: by inhibiting the enzyme that makes these pro-inflammatory oxylipins. I’ll spare you from the acronym overload, but basically, eating flaxseeds inhibits the activity of the enzyme that makes these pro-inflammatory oxylipins, called leukotoxin diols, which in turn may lower blood pressure. “Identifying the biological mechanism adds confidence to the antihypertensive actions of dietary flaxseed.”

But that’s not all oxylipins do. Oxylipins may play a role in the aging process. But we may be able to beneficially disrupt these biological changes associated with inflammation and aging with a nutritional intervention like flax seed. Older adults (around age 50) have higher levels of this arachidonic acid-derived oxylipin, compared to younger adults (around age 20). “These elevated concentrations of pro-inflammatory oxylipins in the older age group…may [help] explain the higher levels of inflammation in older versus younger individuals.” As we get older, we’re more likely to be stricken with inflammatory conditions like arthritis; and so, this elevation of pro-inflammatory oxylipins may predispose individuals to chronic disease conditions. But what if you took those older adults and gave them muffins—ground flax seed-containing muffins?

Four weeks later, their levels dropped to here, down to like 20-year-old levels, demonstrating “that a potential therapeutic strategy to correct the deleterious pro-inflammatory oxylipin profile is via a dietary supplementation with [flax].”

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• Rodriguez-Leyva D, Weighell W, Edel AL, et al. Potent antihypertensive action of dietary flaxseed in hypertensive patients. Hypertension. 2013;62(6):1081-9.
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• Caligiuri SP, Rodriguez-Leyva D, Aukema HM, et al. Dietary Flaxseed Reduces Central Aortic Blood Pressure Without Cardiac Involvement but Through Changes in Plasma Oxylipins. Hypertension. 2016;68(4):1031-8.
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• Caligiuri SP, Aukema HM, Ravandi A, Guzman R, Dibrov E, Pierce GN. Flaxseed consumption reduces blood pressure in patients with hypertension by altering circulating oxylipins via an α-linolenic acid-induced inhibition of soluble epoxide hydrolase. Hypertension. 2014;64(1):53-9.
• Mazzaglia G, Ambrosioni E, Alacqua M, et al. Adherence to antihypertensive medications and cardiovascular morbidity among newly diagnosed hypertensive patients. Circulation. 2009;120(16):1598-605.
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• Borzecki AM, Oliveria SA, Berlowitz DR. Barriers to hypertension control. Am Heart J. 2005;149(5):785-94.
• Caligiuri SPB, Parikh M, Stamenkovic A, Pierce GN, Aukema HM. Dietary modulation of oxylipins in cardiovascular disease and aging. Am J Physiol Heart Circ Physiol. 2017;313(5):H903-H918.
• Food sources of arachidonic acid (PFA 20:4), listed in descending order by percentages of their contribution to intake, based on data from the National Health and Nutrition Examination Survey 2005-2006. National Institutes of Health.

Image credit: Petra via pixabay. Image has been modified.

Motion graphics by Avocado Video