Low levels of linoleic acid and α-linolenic acid and high levels of arachidonic acid in plasma phospholipids are associated with hypertension.

Key Points

In this study, to obtain a dietary recommendation for preventing hypertension, the association between plasma fatty acids (FA) composition and estimated desaturase (the key enzyme involved in conversion of linoleic acid, LA and alpha-linolenic acid, ALA to long chain essential FA) activity, and hypertension was investigated in Japanese men. The study population comprised of 315 Japanese men (52.2±7.3 years old) who participated in a health examination conducted in 2007, 2008, 2009, 2011 and 2013.  The results showed that the plasma level of LA in the subjects with hypertension was significantly lower than that in those without hypertension. Logistic regression analysis demonstrated that higher quartiles of LA were associated with a lower prevalence of hypertension. The 1.4 fold increase in the mean levels of LA decreased the prevalence of hypertension to 0.39 and 0.17 fold. Animal studies indicate that LA may reduce the BP by serving as a substrate for vasoactive prostaglandins and promote the relaxation of vascular smooth muscle cells.  After adjusting for the confounding factors, logistic analysis indicated that higher quartiles of ALA were associated with a lower prevalence of hypertension. It has been reported that ALA affects the structure of the cell membrane and regulates cell function. The effects of ALA on the cell membrane, at least partially, may explain its association with BP. In conclusion, LA and ALA, and AA were associated with hypertension. Higher plasma levels of LA and ALA, and lower levels of AA were associated with the reduced prevalence of hypertension. The plasma levels of these FAs reflect the dietary intakes indicating that higher intakes of LA and ALA, and lower intakes of AA, prevent an increase in BP. Thus, dietary intake of FAs may be an important determinant in the prevention of hypertension.

ABSTRACT

Dietary fat is an important determinant in the development and progression of high blood pressure (BP), a major risk factor for cardiovascular diseases and mortality. The aim of the present study was to determine the association between plasma phospholipid fatty acids and hypertension in Japanese men. The plasma level of linoleic acid (LA) in the subjects with hypertension (systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg) was identified to be significantly higher than that in the healthy controls. Following adjustment for age, body mass index, physical activity, smoking status, alcohol consumption, salt intake, and serum levels of glucose and hemoglobin A1c, higher plasma levels of LA and α-linolenic acid (ALA), and lower levels of arachidonic acid (AA) were significantly associated with a lower prevalence of hypertension. The odds ratio (OR) for the highest quartile (Q4) versus the lowest quartile (Q1) of LA was 0.17 (P=0.003), the OR for Q4 versus Q1 of ALA was 0.26 (P=0.042) and the OR for Q4 versus Q1 of AA was 2.04 (P=0.047). These results indicate that elevated levels of LA and ALA, and reduced levels of AA in the plasma prevent hypertension.