Debunking the common belief that blood pressure rises naturally with age
BY DR. MICHAEL GREGER, M.D.
Hammer Performance Tip: High blood pressure is associated with a multitude of serious health problems including heart attack, stroke, kidney damage, vision loss, memory loss, and fluid in the lungs. The American Heart Association and Hammer Nutrition recommend that athletes consume no more than 2,300 mg of sodium (or 1 teaspoon of salt) per day. The most effective way to reduce sodium intake is to replace processed and packaged foods with a plant-based, whole foods diet. Skip the salt at the dinner table. And when replenishing electrolytes, choose Endurolytes, which contain a full spectrum of minerals, not just salt. The moderate sodium levels in Endurolytes will not overwhelm your body's natural ability to regulate this mineral. Read why rising blood pressure is not a standard part of aging...
For the first 90% of our evolution, humans ate diets containing less than a quarter teaspoon of salt a day, because, for the first 90% of our evolution, we ate mostly plants. We went millions of years without saltshakers, so our bodies evolved into salt-conserving machines. This served us well until we discovered that salt could be used to preserve foods. Without refrigeration, this was a big boon to human civilization. But where does that leave us now, when we no longer have to live off of pickles and jerky?
We are genetically programmed to eat 10 times less salt than we do now. Even many "low-salt" diets can be considered high-salt diets. That's why it's critical to understand what the concept of "normal" is when it comes to salt.
Having a "normal" salt intake can lead to a "normal" blood pressure, which can help us to die from "normal" causes, like heart attacks and strokes.
Doctors used to be taught that a normal systolic blood pressure (the top number) is approximately 100 plus age, and indeed, 100 is about what we're born with. Babies have a blood pressure of about 95 over 60. That 95 can go to 120 in our 20s and 140 in our 40s (the official cut-off for high blood pressure), and keep climbing as we age. The rise of blood pressure with age once was considered normal; and if that's normal, then heart attacks and strokes must be "normal" too, since risk starts rising when blood pressure starts rising above 100.
But if blood pressures above 100 are associated with disease, then maybe they should be considered abnormal, perhaps caused by our abnormally high salt intake - 10 times more than what our bodies were designed to handle. Maybe, if we just ate a natural amount of salt, our blood pressures naturally would not go up with age, and we'd be protected.
Of course, to test that theory you'd have to find a population in modern times that doesn't use salt, or eat processed food, or go out to eat. For that, you'd have to go deep into the Amazon rainforest.
Testing the no-salt "normal" theory
Meet the Yanomamo people, a no-salt culture. And so, what happens to their blood pressure? They start out with a blood pressure of about 100 over 60 and end up with a blood pressure of about 100 over 60. Though theirs is described as a salt deficient diet, that's like saying they have a diet deficient in Twinkies. They're the ones, it seems, who have normal salt intakes, which apparently leads to having truly normal blood pressures. When in their 50s, they have the blood pressure of a 20 year old. What percentage of the population tested had high blood pressure? Zero, whereas elsewhere in Brazil, up to 38% of the population might have high blood pressure.
But look, some would argue, it could have been other factors: The Yanomamos didn't drink alcohol; they ate a high-fiber, plant-based diet; they got lots of exercise; and they had no obesity. There are other plant-based populations who eat little salt and experience no rise of blood pressure with age, but how do we know that the unchanged blood pressure is due to the lack of salt? Ideally, we'd conduct an interventional trial. Imagine if we took people literally dying from out-of-control high blood pressure, so called malignant hypertension - where you go blind from bleeding into your eyes, your kidneys shut down, and your heart fails - and we withheld from these patients blood pressure medications, so that their fate is certain death, and then put them on a Yanomamo level of salt intake (a normal-for-the-human-species salt intake). If instead of dying, they walked away cured of their hypertension, then that would pretty much seal the deal.
Enter Dr. Walter Kempner and his rice and fruit diet. Patients came in with blood pressures ranging from 210/140 down to 80/60. How was Dr. Kempner able to ethically withhold all modern blood pressure medications and treat with diet alone? The drugs hadn't been invented yet. This was back in the 1940s. Now the diet wasn't just extremely low salt, but it was strictly plant-based and also extremely low in fat, protein, and calories. Yet there is no doubt that Kempner's rice diet achieved remarkable results, and Kempner is now remembered as the person who demonstrated, beyond any shadow of doubt, that high blood pressure can often be lowered by a low enough salt diet.
Forty years ago, it was acknowledged that the evidence is very good, if not conclusive, that a low enough reduction of salt in the diet would result in the prevention of essential hypertension - that rising of blood pressure as we age - and its disappearance as a major public health problem. It looks like we knew how to stop this four decades ago. In that time, how many people have died? Today, high blood pressure may wipe out 400,000 Americans every year; that's more than 1,000 unnecessary deaths a day.
This article was reprinted with permission from the author.
Reference: Dr. Michael Greger
[bio] Michael Greger, M.D., is a physician, author, and internationally recognized speaker on public health issues. All proceeds from his speaking engagements and the sale of his books and DVDs are donated to his nonprofit NutritionFacts.org, a science-based, non-commercial website.