Flaxseed Lowers Blood Pressure

A new study found that ground flaxseed powerfully lowers blood pressure:

A patient population with peripheral artery disease (PAD) was selected as ideal to benefit from dietary flaxseed. . . . Patients received 30g of milled flaxseed (or placebo) each day over 6 months. [I eat  50 g/day — Seth] . . . No significant adverse events were associated with flaxseed ingestion. . . . SBP in the placebo group increased by ~3 mmHg and DBP remained the same over the experimental period. However, SBP levels were ~10 mmHg lower (P<0.04) and DBP was ~8 mmHg lower (P<0.004) in the flax group compared to placebo. In the flaxseed group, patients with a SBP <140 mmHg at baseline did not receive an anti-hypertensive effect but patients who entered the trial with a SBP > 140 mmHg at baseline obtained a sustained and significant 15 and 7 mmHg reduction in SBP and DBP, respectively, during the six months. . . . one of the most potent anti-hypertensive effects ever observed by a dietary intervention.

This supports my belief that we can improve our overall health by trying to improve our brains (which are more sensitive than the rest of the body). I have blogged about flaxseed oil many times. I became interested in it when I noticed it improved my balance. Balance measurements showed that the optimal dose  (2-4 T/day) was higher than flaxseed oil manufacturers suggested.  Then I and others noticed that taking this amount of flaxseed oil produced big improvements in gum health. Tyler Cowen, for example, no longer needed gum surgery. Go home, said the surgeon.

Thanks to Grace Liu.

11 Replies to “Flaxseed Lowers Blood Pressure”

  1. it says milled flaxseed, not flaxseed oi. Could lignans or other constituents of the milled seed contribute to the effect, or is it the oil? The excerpt doesn’t say what underlies the mechanism for BP modulation.

    Seth: That’s a good point. You’re right, it could easily be the lignans not the oil that produces the BP improvement.

  2. An interesting review article from 2004 investigated numerous cardiovascular benefits of flaxseed, flax meals (no oil) and flax oil (no lignans).

    The results?

    “Flaxseed contains 35% of its mass as oil, of which 55% is alpha-linolenic acid (ALA). Flax meal, which is devoid of oil, contains the lignan secoisolariciresinol diglucoside (SDG). Flaxseed, flaxseed with very low ALA, flaxseed oil, flax lignan complex (FLC), and SDG reduce the development of hypercholesterolemic atherosclerosis by 46%, 69%, 0%, 73%, and 34%, respectively, in the rabbit model. FLC and SDG slow the progression of atherosclerosis but have no effect in regression of atherosclerosis. Suppression of atherosclerosis by flaxseed is the result of its lignan content and not the result of ALA content.”

    The study goes on to say;
    “Flaxseed and flaxseed oil do not have antioxidant activity except they suppress oxygen radical production by white blood cells. Flaxseed oil/ALA has variable effects on inflammatory mediators/markers (interleukin [IL]-1beta, IL-2, IL-4, IL-6, IL-10, tumor necrosis factor-alpha, interferon-gamma, C-reactive protein, and serum amyloid A). Doses of ALA less than 14 g/d do not affect inflammatory mediators/markers, but 14 g/d or greater reduce inflammatory mediators/markers.”

    if flaxseed oil is 55%ALA, and you need a minimum 14g of ALA, then you need 25g of flaxseed oil, which is about 30mL.
    Seth’s dose for noticeable reduction in inflammation of 2tbsp is 40 mL, so in great agreement with this study!

    So flax oil is anti-inflammatory, and flax meal is anti-atherosclerotic, sounds like ground flaxseed, rather than just oil, is the way to go.

    Flax does have a bunch of phytoestrogens, and their effects -good or bad- are not all known, but one well known effect is to induce premature birth in pregnant women.

    Finally, there are some toxins in flaxseed (not oil) -cyanogenic glycosides – which can be reduced by fermentation

    And, our old friends, lactobacillus, can do this

    This might explain why my flax sourdough (made with kefir whey) bubbles/expands much more than my buckwheat sourdough – getting rid of all that cyanide!

  3. Seth said:
    “This supports my belief that we can improve our overall health by trying to improve our brains”

    Wouldn’t protecting the blood-brain-barrier be a good first step to improve our brains, by keeping out disruptive chemicals and pathogens?

    If so, should we avoid man-made chemicals that cross the blood-brain-barrier — things like sugar alcohols, antihistamines, and ace inhibitors?

    Better yet, let’s avoid all unnecessary drugs and the doctors that prescribe them.

  4. I take flaxseed oil regularly but have noticed no improvement in bp or gum health as a result.

    I made pizza last night with flaxseed and almond crust and was surprised to see my blood pressure was much lower than it had been for weeks.

  5. @ Alex,

    The procedure is, really, quite simple.

    Get some Kefir – store bought or (much better, and surprisingly simple) make your own. I use kefir instead of yoghurt as kefir has yeasts in it.

    Get some flour – I make flax “flour” by putting flax seeds in a coffee grinder. I then mix this 50/50 with buckwheat flour, though I have also done it with rice, quinoa, amaranth and sorghum flours (I used to use wheat and rye in my pre-paleo days)

    In a quart size canning jar (or other non-metallic container) mix 1 part kefir to 2parts (by volume) flour, and then add enough water to make a soft paste (not a thick dough). Jar should be no more than half full.

    Leave it on the countertop overnight and then put it in the fridge, and leave for another day, or two.

    It is then ready to use. To keep a continuous culture, which I do, you simply add enough flour (and water) to at least double the volume, and put 1/3 to 1/2 of that back into the container – and use the rest for whatever it is your are making. The culture gets better with each “generation”

    When I am making a batch of something, I make up the mix from the sourdough starter and leave it out overnight – it will double in volume. if making something like pancakes, involving eggs, only add these right before you cook. I also mix in a saturated fat, like butter or coconut oil – the saturated fats help protect the omega3s against oxidation.

    Rye traditionally makes the best (most active) sourdoughs, but I have found my 50% flax to be even more active. Using 100% flax doesn’t give very good texture.

    Do not use high heat when cooking with flax…

    Warning – making sourdough (and kefir) is addictive!

    All you could ever want to know (and then some) about kefir, and where I got the sourdough concept from, is at Dom’s Kefir Site

  6. Paul, OK, thanks. You’re not concerned with the micro-organisms breaking-down the omega-3 fatty acids in the flax? Also, do you use the culture as simply a starter when making something else (like sourdough bread), or is the culture ever the main ingredient in the dish? Are there recipes? Thanks again.

  7. Seth,

    Do you take both flaxseed oil and flaxseed meal?


    Seth: Yes. flaxseed oil in Berkeley, ground flaxseed in Beijing.

  8. Hi Alex,

    I really have no idea what the microbes do or don;t do to the ALA in flax, that’s an interesting topic to research!
    I do know that kefir grains work best i whole milk, they do some kind of digestion on the butterfat, though I don;t know what, specifically.

    As to the culture, I keep the quart jar about 3/4 full. I sometimes take some out and just mix some eggs and cook directly as pancakes or dumplings.
    i don;t make bread anymore but if i was then I would use half the jar to start the bread mix (and let it sourdough for a day or two) and then top up the jar with fresh flour and water (and a pinch of salt). Be aware that sourdoughing whole grain flour (even buckwheat) can make for really *sour* dough.

    As for recipes, well,the theme of Seth’s site is self-experimentation, and that’s how I approach cooking in general!

  9. Seth, how big of an issue is rancidity / freshness in regard to flaxseed or flax oil? Some sources seem to say I’ll be in danger if I don’t buy the oil or flaxseed every few days, freeze it, only grind it the day I’m consuming it.

    What do you think is a sensible regimen regarding avoiding rancid flax?

    Seth: I discovered it was a big issue. At one point I got flaxseed oil in China. I later discovered it was inactive. Presumably due to too much time at room temperature. Now I used freshly ground flaxseed. Haven’t had trouble with inactivity. I freeze the flaxseeds when they arrive (at my apartment) but they are not frozen before that (e.g., for months after being harvested). And they sit at room temperature in my apartment for a week or so.

  10. I appreciate the help. May I ask how you know whether the flax has become inactive? Is there a physical effect that fails to occur in that case? Thanks again.

    Seth: I was measuring how fast I can do arithmetic. When I switched from the Chinese flaxseed oil to the American flaxseed oil (better refrigerated) I suddenly got faster. I had previously found, using American flaxseed oil, that flaxseed oil produces this effect (faster arithmetic). That’s how I learned that the Chinese flaxseed oil was inactive — or less active.

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