The Surprising Link Between Sugar and Hypertension

From a dietary standpoint, highly processed foods, such as prepared meals, chips, and breads, are the perfect storm of unhealthy eating, with those foods containing greater amounts of salt, fat, and sugar than their nonprocessed counterparts, such as fresh produce and whole grains.

The sodium content in processed foods has been of particular concern, given the prevalence of these foods in the American diet and implicated by many experts as a major catalyst for hypertension.

But new research has found that we may have been putting all of the blame on the wrong ingredient. In a review article published online in 2015 in the journal Open Heart, researchers culled interventional and epidemiological studies and came up with an eye-opening conclusion: Excessive amounts of sugar, not salt, may be more strongly and directly linked to hypertension and the risk of developing cardiovascular problems.

Examining the data

According to one meta-analysis cited in the review, higher sugar intake significantly increased systolic blood pressure (6.9 mm Hg, or 7.6 mm Hg when industry-financed studies were excluded) and diastolic blood pressure (5.6 mm Hg, or 6.1 mm Hg when industry studies weren’t considered) when compared to diets with lower sugar consumption. The review article also notes that for some individuals, a high-sugar diet caused rises in blood pressure after just a few weeks.

But here is perhaps the most sobering statistic of all: Individuals who consumed between 10 percent and 24.9 percent of their calories from added sugars had a 30 percent increased risk of mortality from cardiovascular disease; those who consumed 25 percent or more of their calories from added sugars faced an almost threefold risk.

Table sugar—also called sucrose—is made up of two monosaccharides: glucose and fructose. Excessive amounts of the latter seem to have the most detrimental effects on the cardiovascular system, including increased blood pressure and blood pressure variability (which increases the risk of stroke), along with increased heart rate and demand for oxygen by the heart. It may also contribute to inflammation, insulin resistance, and other metabolic problems.

Beverages sweetened with high-fructose corn syrup, which contains more fructose than glucose, have been shown in some research to produce higher blood pressure readings in healthy people than those sweetened with sucrose, while both drinks similarly increased heart rates.

In terms of sugar’s effects on blood fats and cholesterol, increased intake may indepen- dently increase triglyceride, total cholesterol, and “bad” LDL cholesterol levels. It may also reduce levels of “good” HDL cholesterol.

What about salt?

Salt, which is mostly made up of the element sodium, isn’t completely off the hook, although research is conflicting.

A study published in March 2015 in the Journal of the American College of Cardiology cites clinical data showing that even in the absence of an actual increase in blood pressure, excess sodium in the diet could harm the body, including blood vessels (for example, increased arterial stiffness), the heart (enlarged heart muscle), the kidneys (reduced renal function), and the brain (adverse sympathetic nervous system reactions).

Eating too much salt can cause your body to hold onto any extra water, increasing the volume of blood in the arteries. Sodium can also cause small arteries to constrict, producing greater resistance to blood flow. The end result: a rise in blood pressure.

However, the authors of the review in Open Heart point out that in some instances, reducing sodium can actually have harmful effects. They cite a cascade of unintended health consequences related to sodium-reducing efforts—namely an increased intake of products containing less sodium but more sugar, which, in turn, may have triggered increases in blood pressure, obesity, diabetes, elevated cholesterol, and overall heart risk.

Citing data gathered from more than 100,000 patients, the authors say the ideal sodium intake lies somewhere between 3 grams (3,000 milligrams) and 6 grams (6,000 milligrams) a day for lower risks of death and heart events. Levels above and below this may have unintended health consequences, such as increased cardiovascular and all- cause mortality in patients with diabetes, and increased hospitalizations and mortality in patients with congestive heart failure, according to the researchers. This range runs contrary to many hypertension guidelines, which call for consuming less than 2.3 grams (2,300 milligrams) of sodium a day.

Our advice

According to the analysis authors, to make a dent in hypertension rates and other cardiovascular problems, focus these days should shift away from salt and be put on sugar intake, with the caveat that it’s added sugars—not those occurring naturally in fruit or other whole foods—that are likely harmful. Indeed, increasing intake of whole fruits in the diet may actually help lower blood pressure.

While researchers continue to investigate the degree to which salt or sugar is to blame, the overall message remains the same: Eat fewer processed foods, for the sake of your heart.