Since being diagnosed with heart disease, how I view my research has taken on a new meaning. While before I would go about it thinking my work is for those patients I see in the hospital, now I wonder how it can also help me. How can I delay or prevent the progression of atherosclerosis in my heart to prevent having a heart attack?
Since I’m active, eat healthy (or at least I think so), don’t smoke and my cholesterol and blood sugar are okay, that leaves blood pressure as one of the key risk factors I may need to address. Managing blood pressure is important because high blood pressure (hypertension) is a key risk factor for heart disease.
My blood pressure has usually been on the high-normal side, but back in 1996, it was up around 160/96. This is super-high! Ideal blood pressure is <120/80 and hypertension is ≥140/90. I went on to have a 24-hour blood pressure monitor. Basically it’s a cuff you wear all day and night that pumps up every hour or so. Not so good for a romantic night! This test confirmed the high blood pressure.
I was in the middle of exams for my grad courses so I thought the stress could have caused it. After a few weeks (and when exams were over) it went down to the high 130s over mid-80s. On the high-ideal side, but the doctor was okay with it. It’s remained at that value since.
When we think of managing blood pressure, the first thing most of us think of is sodium. We need to get our sodium down. We can’t eat this, or should avoid that because it’s high in sodium. A lot has been written about salt (or more precisely sodium) and there is some controversy regarding how effective current guidelines are, so I’ll leave that to another day. What I’m interested in is potassium. This is something we need more of. I like that idea because when it comes to diet, there is too much of don’t eat that or eat less of that talk. With potassium, we need to eat more.
Potassium (atomic number 19 and symbolized by K) is an overlooked nutrient, but it’s extremely important and many of us don’t get the necessary amount. Our bodies use potassium for a number of things like muscle contraction and creating nerve impulses. When it comes to blood pressure, potassium helps to regulate sodium levels, along with relaxing the arteries more, which together can lower blood pressure. High intakes of potassium are associated with more sodium being excreted through urine (natriuresis), which is a good thing.
Dietary studies of increasing potassium intake have reported substantial reductions in blood pressure. The most popular is the DASH (Dietary Approaches to Stop Hypertension) diet of increased fruits and vegetables, along with lean meats, fish and whole grains. After 30 days, the DASH diet resulted in lower blood pressure (equivalent to one antihypertensive medication) with the greatest effects on those people with the highest sodium dietary intake. As you might guess, even though the DASH diet increases potassium intake, it is much more than that, it is an overall healthy nutrition regimen, so one can’t say the blood pressure lowering is due just to higher potassium.
While getting your nutrition from whole foods is the best way, it makes it difficult to determine what is the effect of individual nutrients. In this case, the study of supplements is helpful. A review of randomized controlled studies found that potassium supplementation can result in an average reduction in blood pressure of 4.3/2.5. A modest reduction but relevant nonetheless.
Now reducing blood pressure is all well and good, but do we really care about that? I don’t. I care whether I’ll have a heart attack or stroke, or that my kidneys continue to function. Having good blood pressure is a means to an end. Work from our PURE study in over 100 000 people found that higher potassium was associated with less heart disease and premature death. The limitation of the PURE study is that it is observational and can’t indicate that high or low potassium prevents or causes premature death, however, it is consistent with other observational studies. Supporting these findings is an earlier, small randomized trial that found less heart disease using potassium enriched salt compared to regular salt.
Guidelines from the Institute of Medicine recommend a daily intake of 4700 mg/day for adult men and women. The problem, is that the average intake is less than half that in the US. This is likely due to a Western-type diet which is low in fruits and vegetables.
While we often think of bananas as a food high in potassium, there are many other foods that are high in potassium. Red kidney beans are packed with potassium (plus they are a good source of protein and fibre). One cup gives you nearly 2600 mg of potassium. That’s more than half your daily intake. Green leafy vegetables, nuts, squash, tomatoes and avocados are also great sources (for a full list see here).
So what am I doing to increase my potassium levels? Each day I usually have a banana, quarter cup of almonds and a tomato as high sources of potassium, however, that won’t get me to my daily target, so I’ve started adding spinach into my sandwiches and eating an orange a day.
One recipe that I’ve come up with is what I call the Pantry Salad. I call it that because I grab a bunch of foods that we usually have in our pantry and mix it together. For this version here, it contains spinach (1 cup), almonds (1/4 cup), canned mandarin oranges (1/2 can), red kidney beans (1/6 cup), tomato, pumpkin seeds (1/4 cup) and half an avocado. I wouldn’t say that this is enough as a meal by itself, but it does contain 1700 mg of potassium, which is over a third of the recommended daily intake.
The one situation where people may need to be cautious about too much potassium in their diet is if they have problems with their kidneys. These people should seek advice from a physician or clinical dietitian before increasing potassium. For the overwhelming majority of us (including me), we can definitely benefit from getting more potassium. In doing so, we’ll also improve our overall diet as foods high in potassium are full of other important nutrients as well.