How to Prevent High Blood Pressure

Welp, I am officially done with my food service rotation... only one 2-week rotation left, with Miss Ana Zeller of Practical Nutrition, and I have a feeling this one will be the best of them all! Then, I'll be able to sit for the Registered Dietitian exam! That's right, Burn's gonna have credentials. Can't wait!

Okay, less about me, more about hypertension, aka high blood pressure (BP). As much as I have no interest in school food service, I have to admit my food service rotation gave me an immense amount of time each day to read research articles and learn shit. Over this past week, I've been absolved in hypertension... time to share.

First, some background info about hypertension... it's a pretty serious problem. Hypertension is the leading cause of cardiovascular disease (forget cholesterol), affecting approximately 1 billion individuals worldwide. More than 72 million Americans, or nearly 1 in 3 adults, are estimated to have hypertension but only 34% are able to return to a healthy blood pressure, via either drugs or lifestyle change. In 2008, 54,707 Americans died from hypertension, and another 300,000 died from related conditions. According to projections, over 90% of adults in the United States will develop hypertension by age 65. That is absurdly high. Right now, hypertension remains the most common reason for patients to visit the physician’s office (1).

I think it's safe to say that if you want to live a long, healthy life, this is something you need to avoid, no? Just say no to hypertension. Here's how.


1. Sodium and Potassium
I couldn't help but group these two together, as they're inextricably linked. We often tend to focus on sodium more than anything else when it comes to blood pressure, relegating potassium to last-kid-picked-in-gym-class status. But that would be a mistake, for potassium is a superior team player... dare I say it is the Tim Tebow of electrolytes?

Bad jokes aside, if you've read my article on the dangers of sodium restriction, then you know that reducing salt in the diet isn't always a good idea. Salt is needed for life, it's a NUTRIENT. When we don't get enough of it, sometimes bad things happen.

Which brings me to my next point: We don't get nearly enough potassium. In pre-agricultural times, our ancestors consumed at least 6000 mg/day, but today we only get around 2000ish (2). That's a generous estimate; many of us are much worse. The RDA for potassium is 4700 mg/day, I would say that's a good number to shoot for.

Getting more potassium eliminates the need to restrict your sodium.
Sodium and potassium are like teammates. Turns out, potassium is more effective at lowering your blood pressure when sodium intake is high... er, not even "high" necessarily, just as long as it's not super low. And sodium restriction will lower your blood pressure more effectively when potassium intake is low (1, 3). You may have to think about that one for a minute.

Even more enlightening, it looks like increasing your potassium intake completely eliminates the phenomenon of "salt-sensitivity". I talked about this in the salt post, linked previously... 30-50% of us are supposedly salt-sensitive, meaning more sodium increases our blood pressure. But there's good evidence showing A) that those who are more salt-sensitive (blacks and the elderly) are more likely to be potassium deficient, and B) that feeding these people the RDA's worth of potassium eliminates said salt-sensitivity (4). Straight from the paper, "Salt sensitivity occurs when dietary potassium is even marginally deficient but is dose-dependently suppressed when dietary potassium is increased within its normal range." Interesting eh?? (For those of you who know your shit, yes genetic differences in renin levels likely play a role in this too, but I think potassium status is more important.)

So, it comes down to this... if you're an average American getting about 3700 mg sodium and 2000 mg potassium every day, you have 3 choices. A) Reduce sodium. B) Increase potassium. or C) Do both.

My recommendation? Go with B. Remember, these are nutrients; I'd rather get more of them than restrict them. The best potassium sources are white potatoes, leafy greens, dairy products, avocados, and bananas... basically any fresh, whole food is a good source of potassium. Incidentally, incorporating more of these foods will cut your sodium intake in the process. Double whammy. You could also take a potassium supplement if that's more your speed; that is how they do it in most studies after all. But you'd be taking a lot of pills since the dosage is capped at 99 mg potassium per pill. And you'd be missing out on all the other good stuff you get from fresh food. Up to you.

How creationists think we got potassium. (har har har)

2. Overeating and Obesity
I've listed it 2nd, but weight loss/gain is arguably the most important determinant of your blood pressure. The research is remarkably clear and consistent on this: Overeat and gain weight and your blood pressure will rise. Lose the weight again, and your blood pressure will return to normal.

In a study of college students, those who gained more than 5% of their bodyweight in a year showed concurrent increases in blood pressure. This increase in blood pressure was reversed when the weight was lost (5).

In a prospective study of healthy adults, overconsumption of calories produced an increase in blood pressure in just 8 weeks, and this was accompanied by the worsening of many other markers for cardiovascular health (6).

It's even true in children... a 2-year study of 5-19 year old kids showed that those who gained the most weight experienced a 4.5-fold greater increase in systolic blood pressure than those who gained the least weight (7).

No doubt about it folks... body fat and blood pressure go hand in hand. Luckily, losing weight is the #1 most effective way to bring your blood pressure back down to earth (8). And another point...it turns out that sodium intake and calorie intake are often tied together; those with higher sodium intakes tend to eat more calories overall (9). I wonder if this is a confounder in the sodium/blood pressure relationship hmmmm...

3. Other Factors
Okay so when it comes to blood pressure, as far as I'm concerned, it starts and ends with sodium, potassium, and weight control. But there are a few other things that may help as well.

Protein has been shown to be of some assistance in controlling blood pressure. A meta-analysis of randomized controlled trials shows a slight reduction in BP when carbohydrates are replaced with protein (10). But the effect is small. I'm not convinced it's the protein though... those who eat more protein tend to eat fewer calories overall, since protein is the most satiating macronutrient per calorie (11).

Exercise may help as well. According to the American College of Sports Medicine, those with hypertension can expect a reduction of 5-10 points off their systolic and diastolic BP numbers following several months of consistent exercise (12). That's quite a hefty reduction. Only about 2/3 of the population will see this reduction, however... the rest of us are non-responders. Still, worth a try if you're up for it.

So that's it. Let me break it down for those of you who are too lazy to read all those words. There are five steps...

1. Get more potassium. Potatoes, leafy greens, dairy, avocados, etc. 
2. Lose any excess, unwanted body weight.
3. Eat protein and move your body.
4. Enjoy a healthy blood pressure.
5. Celebrate with hookers and cocaine.

Only half kidding about the last part. When it comes down to it, it's the same old advice: Eat real food... fruits, veggies, meat, starchy tubers, nuts, seeds, and dairy. Then move your body. 

At the very least, I hope these last couple of posts have quenched your desire to eliminate all of the sodium in your life.  Spend more time with your good old friend potassium. He's been neglected over all these years... give him a chance.