I spend the majority of my blogging efforts helping you avoid spinning your wheels seeking worthless diagnostic testing and useless Alternative Medicine therapies. Instead, I focus on evidence-based Endocrinology and counsel you to address the other boring, unsexy stuff: diet, exercise, sleep, and stress management. Therefore, when I discover an opportunity to write about something you’re probably not doing for your health that is easy to implement and has a huge ROI (return on investment), I get excited.
First, let’s cover my critical disclosures. I must confess that the title of this post is shameless click-bait and intentionally sensationalistic/misleading. I have not discovered a “cure” for hypertension, nor can I claim that my intervention will do for you what it has done for me. While there are data suggesting that the strategy I have implemented in my own life is a wise idea, consider this post anecdotal evidence. In addition, there are certain groups of people who absolutely should not attempt to do what I describe (e.g. advanced kidney disease), so consult your health care provider before making any changes. As always, my Disclaimer applies to everything you see or hear on this blog.
I Have Hypertension
I am lean and decently muscular (but I’m no Dr. Naiman), I eat a fairly healthy diet, and I love exercise – but my BP (blood pressure) returns to the 150s/90s whenever I try to stop my medication. I am aware of a few things that may negatively impact my BP. My sleep quality is often not as great as I’d like, I’m not stingy with the salt in my cooking, and my stress management is a lifelong work-in-progress. Plus, I have a strong family history of hypertension (without obesity).
After trying a few different regimens of medication, I eventually discovered that a miniscule dose of chlorthalidone kept me < 120/80. That near-homeopathic dose worked great for years, until sometime in the last 6-12 months, when my pressure started creeping up into the 130-140s/80-90s. As I highly value well-seasoned food and didn’t have another obvious lever to pull, I increased the dose of my medication from near-homeopathic to low. My BP then returned closer to normal.
I wasn’t totally satisfied with that, however, as I had a nagging sensation there was something I could do better (besides the obvious/smart move to lower dietary salt) to improve my blood pressure and lower my cardiovascular risk. From somewhere deep in the memory banks, I recalled that potassium (K) intake correlates with blood pressure; embarrassingly, I didn’t remember much more than that – and I certainly couldn’t list the top five K-rich foods. So I decided to look into the issue further.
Potassium-Rich Foods are Good for You – Who Knew?
It turns out there are copious data showing that diets higher in potassium correlate with lower blood pressure. It just so happens that most high-potassium foods are fruits and vegetables – long-promoted as critical components of a healthy diet, but chronically under-consumed in the standard Western diet.
What I find most interesting is that the BP-lowering effect of potassium is seen even at higher levels of sodium intake. This is good news for salt-lovers like me. Nonetheless, lowering sodium (Na) intake where possible (like decreasing canned and boxed foods) remains a worthy endeavor; some studies show that the ratio of Na:K is a stronger predictor of cardiovascular disease and mortality than sodium or potassium intake alone.
Why Not Take Potassium Pills?
Ah, that question must have come from one of my fellow Americans – we are all about the easy fix in this country, am I right? As I see it, there are a couple of things one should consider before implementing this strategy.
First, it is not entirely clear how much of the BP-lowering benefit is from potassium itself in K-rich foods. K may also be a marker for other beneficial components of diets rich in fruits, vegetables, nuts, and dairy products. For example, the flavonoids and polyphenols in certain citrus fruits have been found to have anti-hypertensive effects. Ditto for the magnesium and lactotripeptides in dairy products, and the omega-3 fatty acids in fish (EPA/DHA) and nuts (ALA).
Second – and I will get into more personal detail about this shortly – increasing your dietary K almost guarantees you will be eating a healthier diet than however you eat now. More fruits, vegetables, nuts, salmon, eggs, and yogurt? Yes, please! Notice what isn’t on the menu: bread, pasta, cereal, rice, tortillas…you get the idea.
But, if you’re still enamored of the easy fix, there have been several meta-analyses showing that potassium supplements do, indeed, have a meaningful BP-lowering effect (one meta-analysis failed to show an effect, though only 6 trials were included). The most recent meta-analysis I could find showed benefit but had some limitations. Although the authors included 23 trials, they could only perform their most meaningful statistical analysis (change score analysis) on 8 of those trials. Also, the results cannot be extrapolated to normotensive people (for prevention purposes), since the trials were of hypertensive subjects.
One middle-ground strategy you may wish to consider (if you can embrace the taste) is replacing your cooking salt with a higher-K salt substitute. This 2014 study of 282 Tibetans was patient-blinded, randomized and controlled. The subjects using a salt substitute of 65% NaCl/25% KCl/10% MgSO4 showed fairly impressive reductions in BP compared to the control subjects.
Regardless of what you do to increase your K intake, remember that the Na:K ratio is still important. If you’re scarfing down canned soups and frozen dinners, you’re probably not going to completely negate the downstream consequences of that by consuming 2-3 extra grams of K per day.
How Does Potassium Lower Blood Pressure and Why is This Not Discussed?
Physiology geeks and conspiracy theorists may be interested in how potassium lowers BP and why this isn’t a more popular topic in the doctor’s office, respectively. Dietary K intake appears to cause loss of sodium in the urine, leading to less retention of sodium and therefore lower BP (less retained Na means less water will migrate to follow it, which means there is less volume in the vessels, which means lower pressure). Other purported mechanisms include inhibition of proliferation of smooth vascular muscle cells and reducing vascular resistance.
What is really fascinating is that dietary potassium seems to have the same effect on the kidney as a thiazide diuretic, with respect to driving more Na excretion. For those who are exquisitely sensitive to thiazide-type diuretics (like me), it then makes sense that ramping up dietary K would decrease BP in a significant fashion.
So why aren’t doctors shouting this from the rooftops? It seems like a no-brainer intervention, doesn’t it? If you’re a conspiracy theorist (I am not, but some of my commenters clearly are), there is no money in dietary K or K pills. Since doctors only know what Big Pharma shoves down our throats at conferences they sponsor, of course we’re ignorant of this strategy.
While I do think that K would get more air time if it could be packaged into a pricey pill, I think the conspiracy angle is too simplistic and overly cynical (and I’m a cynic!). The DASH (Dietary Approaches to Stop Hypertension) diet – which is high in potassium – has been recommended by major medical societies and physicians for years, but patient adherence has been dismal. Not that I’m blaming patients entirely…physicians tend to do a relatively poor job of counseling patients about diet, for lots of reasons. It’s time-consuming. We didn’t learn enough about nutrition in medical school and have to learn it on our own later. After seeing our patients continue to eat the same crappy diets – despite our best efforts at counseling – we become fatalistic about the inevitability of this outcome.
What I have learned over the past six months – and would like to share with you – is that simply focusing on increasing K-rich foods is: not hard; leads naturally to decreased consumption of less-healthy foods; and seems to meaningfully lower BP.
What Does a Potassium-Rich Diet Look Like?
The United States government recommends 4700mg of dietary K daily. Using that as my goal intake, I googled “high potassium foods.” From there, I culled that extensive list down to the highest K foods that I either already eat regularly or wouldn’t mind eating more regularly. For me, that list looks like this:
- avocado 900mg
- egg 125mg
- tomato 450mg per med tomato
- mushrooms 400mg per 10 small
- coffee 115mg per 8 oz
- salmon 600mg per 6 oz
- white beans 1200mg per cup
- black beans 740mg per cup
- plain NF yogurt 580mg per cup
- spinach 840mg per cooked cup
- edamame 680mg per cup
- beets 520mg per cup
- broccoli 450mg per cup
- lentils 370mg per 1/2 cup
- pistachios 300mg per oz (49 nuts)
- cantaloupe 340mg per 1/4 melon
- tiny orange 200mg
- sweet potato 700mg
With that list of K-superfoods, I was confident I’d be able to hit 4700mg most days. It turned out that my confidence was misplaced, as the best I did while actively logging was 4350mg. My typical intake was more like 2200-3600mg – better than my old diet, but falling far short of the brass ring. Fortunately, in America, if we fall short of our goals, we move the goal posts closer.
I did a bit more digging, and the World Health Organization recommends K intake of 3500-4700mg, suggesting that there is BP-benefit to be seen at the lower end of the range. Further, there are more data suggesting that even just pushing K intake to the high 2000’s can cause a reduction in blood pressure. That was great news for my goal-setting.
Changing My Diet
In order to have a prayer of meeting my target, I had to abandon my experiment with Time Restricted Feeding. I just couldn’t eat enough potassium while skipping breakfast. Do I miss TRF? Not really. I’ve always enjoyed eating breakfast, so now I’ve returned to enjoying that.
But breakfast is different for me now. To cram in the K, I have to focus on what gives me the most bang for my buck. One of my current go-to breakfasts is black coffee, 1/2 avocado, sliced tomato, 1 egg, 1/2 cup non-fat Greek yogurt, and a high-K fruit in the yogurt. Breads are gone – they don’t get me any closer to target, and I’m stuffed by the time I finish all that other food. You hear that, Low Carb Cardiologist? I’m eating less bread!
For lunch, I started out by making some epically large spinach salads with beans, pistachios, beets, other high-K vegetables, and goat cheese. They tasted awesome and left me satiated, with the added bonus of no post-lunch afternoon slump. Unfortunately, after a month of eating copious amounts of (often) raw vegetables, I had to accept the fact that my (ahem) persistent and significant GI distress necessitated some cookery of the plant matter. Now, if I’m eating spinach and beans for lunch, I’ve sauteed them in olive oil and garlic the night before. Problem solved – suffice it to say that cooked vegetables may be gentler on the gut for some people.
Dinners are too variable for me to make sweeping generalizations; let’s just say I do my best.
Now 6 months into this dietary adjustment, I am back to taking my baseline, near-homeopathic dose of chlorthalidone. As long as I really focus on packing in the K, my BP tends to run around 120/80. When I am less diligent (which happens), it starts climbing closer to 130/mid-80s. I do struggle with losing my appetite for some of my go-to high-K meals – sometimes I just need to recharge the taste buds with something completely different. Usually, that something does not directly advance me toward my goal. On the other hand, it typically provides enough respite to allow me to resume my higher-K eating at the next meal. Let’s call that a win.
I suspect if I could cut Na further and increase K a little more – thereby decreasing the Na:K ratio – I’d be off medication entirely (since K acts like a thiazide-type diuretic). But realistically, I don’t see a more intensive diet than what I’m doing as sustainable for me. Given that I spend a fair amount of time counseling my patients to only employ dietary strategies that feel sustainable, I’ve decided to stick with my moderately successful plan. Perfect is the enemy of good enough, and all that.
As with any other attempt to become healthier, there is no “finish line.” This requires constant, daily attention to every meal. Sure, it gets easier with time, as choices become more ingrained/automatic. But the content of some meals are not in my control, so I need to make up for it the next time I eat. This is sometimes easier said than done but is worth the effort.
Have any of you made a concerted effort to increase the potassium in your diet? What have you noticed, if anything? Are there any doctors reading who counsel their patients to increase dietary potassium? Do any of you prescribe potassium pills with the intention to lower blood pressure? Comment below!
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