Dietary cholesterol linked to increased systolic blood pressure
MedWire News: Japanese researchers suggest that reducing the intake of dietary cholesterol could improve adverse blood pressure levels in the general population.
This is based on the finding that, in men and women from four different countries, dietary cholesterol intake is positively associated with systolic blood pressure.
Writing in the Journal of Hypertension, the team adds that this association occurs without cross-country heterogeneity and is significantly stronger for women than for men.
Masaru Sakurai (Kanazawa Medical University, Ishikawa, Japan) and colleagues used data from the International Study of Macro/Micro-nutrients and Blood Pressure (INTERMAP) to assess the relationship between dietary cholesterol intake and blood pressure in 4680 participants (aged 40-59 years) from 17 population samples in Japan, People's Republic of China, the UK, and the USA.
Data for the participants was collected from four 24-hour dietary recalls, two 24-hour urine collections, eight blood pressure readings, and questionnaires on demographics and other possible confounders.
After controlling for multiple variables including age, gender, and other dietary variables, Sakurai's team showed that dietary cholesterol was directly related to systolic blood pressure in all participants.
A 2-standard deviation increase in dietary cholesterol (131.0mg/1000kcal) resulted in an estimated 0.9-mmHg increase in systolic blood pressure for all participants, and a 1.1-mmHg increase for nonhypertensive patients.
The team says: "Possible mechanisms to account for a relationship between dietary cholesterol and blood pressure are dietary cholesterol-related endothelial dysfunction and arterial stiffness.
"Serum cholesterol is strongly associated with endothelial dysfunction and reduced nitric oxide bioavailability, which may lead to functional arterial stiffening."
Interestingly, the researchers noticed that associations between blood pressure and dietary cholesterol were slightly stronger in a subcohort of nonhypertensive patients (n=3671).
They say that individuals diagnosed with adverse cardiovascular risk factors, such as high blood pressure, tend to decrease dietary cholesterol intake to reduce serum cholesterol levels and to prevent atherosclerosis, and this may cause an underestimation of relationships between blood pressure and dietary cholesterol.
The researchers conclude that a population-wide reduction of dietary cholesterol intake may contribute, along with many other improvements in nutrition, to prevention and control of adverse blood pressure levels across the general population.
However, they add that it is not possible to elucidate the independent effect of reduced dietary cholesterol on blood pressure from their trials, due to multifactorial dietary modifications.
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By Nikki Withers