Diet and blood pressure are intimately linked. One of the chief culprits is sodium, a major component of salt. In this post, we’ll discuss some of the details surrounding the relationship between salt and blood pressure.
The 2019 Global Burden of Disease Report update published in Lancet has reported that suboptimal diet is responsible for 1 out of every 5 deaths, globally.
One out of every five…
It’s hard to emphasize how big of a deal that is. Even if it happens to be an overshot by some amount, it’s safe to say that poor diets are an area where health systems should increase their focus.
But “suboptimal diet” can mean a lot of different things. For example, some people are undernourished, failing to consume recommended levels of essential micronutrients like iodine or macronutrients like protein.
Others are overnourished, consuming too many calories.
Others still consume adequate calories but are imbalanced in their diets, consuming too few healthy foods and too many unhealthy foods.
So what’s one of the major problems? Unsurprisingly (if you’re reading this post) has to do with salt and blood pressure.
The report noted that high sodium diets are one of the most significant contributors to suboptimal intake, echoing an earlier Burden of Disease report published by the American Medical Association. This report highlighted that high blood pressure is America’s 3rd leading disease risk factor alone, attributing high sodium diets as a major reason.
Hypertension, also referred to as high blood pressure, is a major risk factor for several chronic diseases, including cardiovascular disease, the greatest killer worldwide. About one-half of individuals with stroke and ischemic heart disease can be attributed to the effects of hypertension.
Unfortunately, most Americans are not meeting these recommendations.
The chart below plots data from the NHANES surveys of American diets. The orange lines at the top corresponds to the percentage of Americans who eat more sodium than the recommended average daily (orange y-axis on the right) at any given particular age (x-axis on bottom). For example, over spike of over 80% of US adults aged 32 consume more sodium than the recommended amount, every day. The blue bars represent how many excess mg of sodium we are eating each day, above and beyond the recommended levels. For example, 46-year-olds are consuming nearly 1800 mg more sodium than they should every day.
But it’s not just the US that overconsumes sodium.
The public health link between salt and blood pressure is a global concern. As the world has increasingly adopted Western dietary practices and processed foods have become more ubiquitous, high-sodium diets are now pervasive. And along with these high sodium diets, high blood pressure has been rising globally, too. On average, the globe overconsumes sodium by 86%. As you can see in the chart below, the greenish region running vertically between 1 and 3 grams per day represents the recommended amount of dietary sodium. But the dotted line shows the global average at around 5.5 grams per day.
Each horizontal bar, color-coded for each region of the world, extends outward towards its regional average of sodium consumption. For example, East Asians consume the most sodium, on average, at nearly 8 grams per day.
With the exception of most African regions and the Caribbean, every other region on Earth is consuming too much sodium.
Are we all just turning the salt shaker upside down and going crazy?
While it’s best not to go overboard, in truth, the salt you add to your cooked meals is not the source of our overconsumption. Americans, on average, consume approximately 71% of their daily sodium from restaurants and processed foods.
Salt is a good preservative, which is why many processed, packaged foods are high in sodium. It would be wise to check the nutrition label for foods purchased from a store, and try to forgo restaurant outings for more cooked meals more often.
When it comes to blood pressure, sodium gets all of the attention. But it’s important to think about your potassium intake, too.
Sodium is hypertensive. Excessive sodium can lead to higher blood pressure. Potassium is hypotensive. Potassium tends to lower blood pressure.
A healthy balance between sodium and potassium intake can go a long way towards maintaining a healthy blood pressure. Unfortunately, our diets are a bit out of sorts when it comes to this balance.
We already saw the chart previously showing that, on average, the US and the world consumes far too much sodium every day. But what about potassium?
From the same NHANES, the chart below shows the average daily consumption of potassium compared against recommended levels. As you can see, we are now failing in the opposite direction.
At any given age, the line shows the percentage of people who meet the recommended daily levels of potassium (y-axis on the left). Typically, fewer than 10% of the population consumes the recommended amount of potassium on a daily basis.
It starts to become clear why high blood pressure is such a pervasive problem. More salt raises blood pressure, while more potassium lowers blood pressure. But we are eating more salt than recommended levels, and less potassium than recommended levels.
The DASH diet (dietary approaches to stop hypertension) is recommended by many leading health organizations as a healthy diet to help combat high blood pressure. The Mediterranean Diet is also highly recommended.
In general, these diets naturally lead to less sodium consumption and more potassium consumption. By encouraging the consumption of more home-cooked, whole-foods based meals with plenty of fruits, vegetables, legumes, and whole grains, your mineral intake will become much better aligned with the recommended levels. And with less salt, your blood pressure will likely drop, too.
One final note on some salt and blood pressure controversy. Some will argue that salt (sodium) does not raise everyone’s blood pressure. And that’s true!
Some individuals are less sensitive to the physiological connection between salt and blood pressure. Some people are just born with good genes, right?
Well, not so fast. This doesn’t mean they’re off the hook, completely.
Excessive sodium intake, as discussed in this recent review, is still correlated to several health risks unrelated to blood pressure.
High salt intake is associated with arterial stiffness and cardiac hypertrophy in healthy, normotensive patients. That means, in patients without high blood pressure, high salt intake still may lead to cardiovascular health risks. And another example relates to the relationship between high sodium intake and target organ damage.
Furthermore, many individuals do see direct correlations between high sodium diets and blood pressure. High sodium diets are directly linked to roughly 3 millions deaths every year. So even in the absence of these other links to health risks, it is dangerous for public health to eschew the merits of consuming salt in a balanced way.
Most of the world could stand to eat less salt. But high blood pressure is more than just your diet. As a final parting note, here is a list of lifestyle modifications to consider.