The relationship between fatty acids and cardiovascular diseases (CVD) has attracted widespread concern for decades. Apart from the past diet-heart hypothesis showing that dietary fatty acids prevent CVD by regulating blood lipids, recently the American Heart Association has recommended the replacement of dietary saturated fats with dietary unsaturated fats.1

Saturated fatty acids (SFAs) have no double bond between the individual carbon atoms in their backbone. Humans obtain SFAs mainly from foods containing animal fats and certain vegetable products. Most contemporary dietary guidelines suggest a restriction of saturated fat intake because of its significant association with CVD risk. According to the Dietary Guidelines for Americans, saturated fat intake should be limited to < 10% of total calories per day.2 However, a large cohort study has revealed that higher dietary SFA intake was associated with lower stroke risk.3 The effect of SFAs on CVD and stroke is still controversial. Consumption of unsaturated fatty acids (USFAs), which contain at least one double bond in their backbone, has been popular in many countries for their protective effect on regulating blood lipids. Previous studies reported that a higher intake of USFAs may protect against stroke and was independently associated with a lower risk of stroke and cardiovascular diseases.4,5 However, inconsistent findings have been reported by a Cochrane review of randomized controlled trials, indicating that higher intake of polyunsaturated fatty acids may slightly reduce stroke risk.6

Circulating fatty acids could accurately reflect blood concentration. Stroke is prevalent in hypertensive population. In order to elucidate the relationship between circulating fatty acids and stroke, we studied the relationship between circulating levels of fatty acids and acute ischemic stroke (AIS) including both SFAs and USFAs in hypertensive patients.