Dr. Greger posted a video a few weeks ago: How To Prevent High Blood Pressure With Diet:
He cited this old study which showed, not only did African natives enjoy low blood pressure throughout their lifetimes, their pressures declined as they got older, the opposite of what happens to 21st Century Americans:
Blood Pressure In The African Native, The Lancet, January 1929
“We’ve known for nearly a century that high blood pressure need never occur. Researchers measured the blood pressure of a thousand people in rural Kenya who ate a diet centered around whole plant foods. Whole grains, beans, vegetables, fruit, and dark green leafies. Up until age 40, the blood pressures of rural Africans were about the same as Europeans and Americans, down around 120s over 80s, but as Westerners age, their pressures creep up such that by age 60 the average person is hypertensive, exceeding 140 over 90. But what about those not following the Western diet? Their pressures improved with age, not only did they not develop hypertension, their blood pressures actually got better.”
He says their diet of whole plant foods was behind that. Do you think? Plant foods supply a lot of potassium, and that can mitigate the effects of high sodium. But I think Africans’ low sodium diets also played a part. Here’s a recent study:
Effect Of Sodium Restriction On Blood Pressure Of Unstable Or Uncontrolled Hypertensive Patients In Primary Care, Nutrition Research and Practice, April 2015
Sodium intake decreased from 161 mmol/24 h (9.3 g of salt) to 108 mmol/24 h (6.2 g of salt) and from a 146 mmol/24 h baseline mean sodium excretion, net decrease was 28 mmol/24 h after intervention. Corresponding net decreases in SBP/DBP were 15.2/1.9 mmHg (P < 0.001).
CONCLUSION: The results of the present study indicate that reduced sodium intake can lower blood pressure (BP) after 4 weeks in unstable or uncontrolled hypertensive patients.
They cut their salt intake by 50% which caused their systolic blood pressure (the top number) to drop 15 points! And they were still eating over 6 grams of salt (~2300 mg of sodium) a day.