HEALTH NEWS

Want to Lower Your Risk of Heart Disease? Eat More Bananas

Written by Jim Pietrangelo on October 19, 2017

New research indicates that food rich in potassium can reduce the chances of vascular calcification and aortic stiffness.

heart disease and banana

Banana lovers… rejoice.

That also goes for lovers of avocado, cantaloupe, pumpkin, lentil, and other potassium-rich foods.

New research is raising the possibility that doctors may one day be able to help patients avoid some heart disease by analyzing their potassium levels.

Researchers at the University of Alabama at Birmingham (UAB) recently concluded a study involving mice that draws a correlation between reduced dietary potassium and the formation of vascular calcification and aortic stiffness.

Aortic stiffness, commonly known as “hardening of the arteries,” is predictive of heart disease in humans.

In their study, researchers found increased levels of aortic stiffness in mice fed a reduced-potassium diet compared to mice fed normal amounts of potassium.

Further experimentation found that reduced potassium appears to encourage the expression of certain gene markers.

These, in turn, promote calcification of vascular smooth muscle cells by transforming them into bone-like cells.

The researchers concluded that, at least in the mouse model, reduced dietary potassium actually promotes elevated aortic stiffness.

Conversely, a potassium-rich diet seems to lessen vascular calcification and aortic stiffness.

“The findings have important translational potential since they demonstrate the benefit of adequate potassium supplementation on prevention of vascular calcification in atherosclerosis-prone mice, and the adverse effect of low potassium intake,” Dr. Paul Sanders, professor of nephrology in the UAB Department of Medicine and a study co-author, said in a press statement.

Why we need potassium

Dr. Morton Tavel, clinical professor emeritus of medicine (cardiology) at the Indiana University School of Medicine, writes:

“Potassium is a dietary mineral necessary for many bodily functions. It plays an important role in holding blood pressure down, working in opposition to sodium.”

“Potassium is also needed for normal muscle growth,” Tavel adds, “and for nervous system and brain function. In addition to reducing blood pressure, potassium seems to work by protecting blood vessels from damage and excessive thickening.”

Healthline spoke about the UAB study, and about potassium’s effects on the heart in general, with Dr. Sean P. Heffron, cardiologist and instructor of medicine at NYU Langone Health in New York.

“Certainly, anything that is a new mechanism that potentially has a role in atherosclerosis in humans is very interesting to me, both as a clinician and a researcher,” Heffron said.

“[This study] is a testament to one of the components of a vegetable-intense, healthy-oil diet like the Mediterranean diet,” he added. “It shows one aspect of why that is repeatedly shown to have cardiovascular benefit. And we need to get people to adhere more to diets like that; to eat more fruits and vegetables.”

No “magic bullets”

Some physicians do worry, however, about those who subscribe to the “magic bullet” theory.

Dr. Robert S. Greenfield, medical director of non-invasive cardiology and cardiac rehabilitation at MemorialCare Heart & Vascular Institute at Orange Coast Memorial Medical Center in California, commented on this very issue.

“There’s really no one magic bullet,” Greenfield told Healthline. “You know, vascular and heart problems, it’s more complicated than that. There are a whole variety of things that contribute to either health or disease, and taking one particular component out is not going to change the course of disease.”

“When it comes to potassium, I kind of worry a little bit about people trying to take too much,” said Greenfield. “You know, there are a lot of people walking around, especially middle-age people, that may have minor kidney problems that don’t even register on a lab test, and they may not handle potassium sufficiently, and you certainly don’t want to take too much.”

Heffron picked up on this point.

“In the absence of kidney disease, most people are able to handle pretty hefty doses of potassium via the urinary system and excrete it to a very good degree,” he said.

But, Heffron warned, “Anything can be taken to the extreme, and we see that on occasion.”

Like Greenfield, Heffron cautions, “The real concern is individuals with kidney disease, in which case high levels of blood potassium are far more common.”

“And high levels of blood potassium, which are generally asymptomatic, can be actually very dangerous from a heart standpoint,” added Heffron. “Not so much from a vascular disease standpoint, but from an arrhythmia standpoint in provoking very dangerous and potentially deadly arrhythmias.”

How much is too much?

Tavel writes, “Although there is some debate regarding the optimal amount of dietary potassium, most authorities recommend a daily intake of at least 4,700 milligrams.”

“Most Americans consume only half that amount per day,” continues Tavel, “which would make them deficient as regards this particular recommendation.”

All of the physicians that Healthline spoke with suggest that if you eat a healthy diet, one rich in fruits, vegetables, grains, and monounsaturated fats, you should get all the potassium you normally need.

But they also counsel against too little or too much potassium.

Greenfield said, “Nowadays we actually worry if the potassium [level] goes too high because all of the medicines that are commonly used have a tendency to raise potassium.”

“So I get concerned,” said Greenfield, “that if someone doesn’t know that, and they read this article and feel they’re going to go to the vitamin shop, that they’ll pick up some potassium tablets and start popping them all the time. Because it could be dangerous.”

Supplements vs. healthy foods

There is little debate about the role of supplements versus eating healthy foods as a way to fulfill your daily potassium requirements.

Greenfield said, “It seems that the minerals, vitamins, and nutrients inside pills and supplements don’t seem to be as valuable as when they’re in the natural state.”

Heffron agrees that it certainly is possible that you can get all the potassium you need from eating healthy.

“If you eat a great diet, you don’t need supplements,” he said.

However, as a caveat, he noted, “Unfortunately, it’s a minority of the people that do eat an adequate diet.”

Barring a healthy diet, supplements may serve as a reasonable alternate source of potassium.

Some potassium rich foods

Tavel supplied Healthline with a list of some foods that he writes, “can satisfy your needs as well as your eating pleasure.”

Some of those, along with their potassium content, are as follows:

  • sweet potatoes: 694 milligrams (mg) each
  • fresh tomatoes: 664 mg per 1/4 cup
  • fresh beets: 644 mg per 1/2 cup
  • white beans: 600 mg per 1/2 cup

Also high on the list of potassium-rich foods are:

  • yogurt
  • most beans
  • clams (canned or fresh)
  • prunes
  • carrots
  • meaty fish
  • molasses
  • soy
  • squash
  • bananas
  • milk
  • orange juice

For reference, the National Kidney Foundation provides a comprehensive list of potassium-rich foods.

Rainbows and the bottom line

With regard to the UAB study, Heffron said, “I wouldn’t categorize it a ‘breakthrough.’ It has a lot of interesting associations in a novel mechanism that they’ve demonstrated. That being said, it is limited to mice and to petri dishes, and whether that translates into humans is a huge leap, for sure.”

Greenfield emphasizes the importance of a healthy lifestyle with regard to vascular health. That includes eating a heart-healthy diet and getting regular exercise.

“Tell me about your blood pressure,” Greenfield said. “Tell me about your cholesterol level. I mean, if you want to talk about arterial stiffness, having a nice low cholesterol level and a normal blood pressure are probably two very important things to do to keep your arteries compliant and healthy and prevent them from getting a stiffness.”

As for your diet, “If you go by the adage, you know, your diet should be the colors of a rainbow where you have all sorts of fruits and vegetables, you’re pretty much going to have all the nutrients you need if you follow those healthy guidelines,” said Greenfield.

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