A study from the Netherlands, published in European Heart Journal, has found that women may be able to combat the effects of sodium by eating a potassium-rich diet, potentially decreasing their risk of CVD.
According to the World Health Organization (WHO), cardiovascular diseases (CVD) are the leading cause of death worldwide, ending some 17.9 million lives each year.
In the United States, CVD causes 1 in 4 deaths in men, and 1 in 5 deaths in the entire population. A quarter of all deaths in the United Kingdom are due to CVD. Key risk factors are high blood pressure, high cholesterol, and smoking, but diet is also a contributing factor.
A diet high in sodium is widely believed to increase the risk of high blood pressure. Processed foods, particularly ultra-processed foods, often contain high levels of salt, so many people find it hard to control their sodium intake.
Prof. Tim Spector, co-founder of ZOE, told Medical News Today:
“Well-conducted and large cohort — [the study was started] in the 90s which is actually quite a long time ago now: Our food environment and sources of sodium in the diet have changed quite a lot since then. The authors also recognize that drawing a clinically impactful conclusion from one 24-hour urine sample is a serious limitation.”
The large-scale study took almost 25,000 participants from the EPIC-Norfolk study in the U.K. Participants ranged in age from 40 to 79, with mean ages of 59 for men and 58 for women. At the start of the study, all participants filled out a lifestyle questionnaire. Researchers then measured their blood pressure and collected a urine sample. The estimated dietary intake of sodium and potassium levels by measuring urinary levels of these two minerals.
Researchers analyzed the effect of potassium intake on blood pressure, after adjusting for age, sex, and sodium intake.
In women, they found a negative correlation between potassium intake and systolic blood pressure (SBP) — as intake increased, SBP decreased. The effect was greatest in those women who had the highest sodium intake. In women with a high sodium intake, every 1 gram increase in daily potassium was associated with 2.4 millimeters of mercury (mm/Hg) lower SBP.
“Lowering the SBP by just over 1 mm/Hg is not clinically significant in practice. What it does indicate is that sodium intake alone is not the only factor we should be concentrating on when preventing CVD, and personalized nutrition approaches are key in achieving optimal health outcomes,” noted Prof. Spector.
The researchers found no association between potassium intake and blood pressure in men. The WHO recommends that adults should consume 3,510 milligrams (mg) of potassium and no more than 2,000 mg of sodium per day. Most adults currently have too much sodium and too little potassium in their diet.
To increase potassium intake, a person should include foods that are high in potassium in their diet.
Prof. Spector offered similar advice, saying: “I think the advice we should be giving is to increase whole plant foods, naturally high in potassium, such as avocados, legumes, artichokes, beets, and apricots, and minimize ultra-processed foods which are often very high in sodium.”
The researchers followed up with participants after a median of 19.5 years, with the last recordings in March 2016. During this time, 55% were hospitalized or died due to CVD. The researchers looked for any association between dietary potassium and cardiovascular events, having controlled for age, sex, body mass index, sodium intake, use of lipid-lowering drugs, smoking, alcohol intake, diabetes and prior heart attack or stroke.
They found that, overall, those with the highest potassium intake had a 13% lower risk of cardiovascular events than those with the lowest. When analyzed separately, high potassium intake reduced the men’s risk by 7%, and the women’s by 11%. Dietary sodium did not influence the relationship between potassium and CVD.
“The results suggest that potassium helps preserve heart health, but that women benefit more than men. The relationship between potassium and cardiovascular events was the same regardless of salt intake, suggesting that potassium has other ways of protecting the heart on top of increasing sodium excretion,” explains study author Prof. Liffert Vogt, from Amsterdam University Medical Centers in the Netherlands.
Although higher potassium intake had the greatest effect in those women with a high-sodium diet, current advice is to limit sodium intake.
“Reducing sodium intake alone does not allow for a diet which improves health, it simply tries to reduce risk by removing a single component of food, which is too reductionist,” said Prof. Spector. “The salt reduction program in the U.K. launched nearly 20 years ago has helped decrease salt content in processed foods but CVD prevalence has shown little evidence of change — reducing sodium intake is not the magic bullet in the fight against CVD,” he pointed out.
So, perhaps particularly for women increasing the intake of potassium-rich foods could be an effective way to try and protect cardiovascular health.