ADELAIDE, AUSTRALIA. Salt (sodium) restriction can help lower blood pressure in people with hypertension, but is less effective in people with normal pressure. Blood pressure tends to rise with age and there is some evidence that sodium restriction may help reduce this age-related increase. Taking fish oil supplements is also effective in lowering blood pressure in hypertensive individuals, but its effect on people with normal pressure is unclear.
Australian researchers report that a combination of taking fish oil supplements and salt restriction is highly effective in lowering both systolic and diastolic blood pressure in elderly people with normal pressures. Their study involved 50 healthy volunteers aged 60 to 80 years whose mean initial systolic and diastolic blood pressures were 133 and 77 mm Hg respectively. The participants were randomly assigned to one of four groups. Group 1 supplemented with 8 fish oil capsules per day (providing 4.2 g of omega-3 fatty acids) while maintaining a normal sodium intake. Group 2 supplemented with fish oil while consuming a low-sodium diet. Group 3 supplemented with sunflower oil combined with normal sodium intake while group 4 took sunflower oil while consuming a low-sodium diet. After 4 weeks the mean systolic blood pressure in group 1 had decreased by 8.9 mm Hg and the diastolic pressure by 6.0 mm Hg. There were no significant changes in blood pressure in the group supplementing with fish oil while maintaining a normal sodium intake. The researchers conclude that sodium restriction combined with taking fish oil supplements effectively lowers blood pressure. They suggest that this finding may be of particular relevance in the treatment of hypertension in the elderly.
Cobiac, Lynne, et al. Effects of dietary sodium restriction and fish oil supplements on blood pressure in the elderly. Clinical and Experimental Pharmacology and Physiology, Vol. 18, 1991, pp. 265-68