Professor Aung Than Ba Tu
The Impact of “The Salt Wars” on the Treatment and Control of Hypertension in Myanmar
The “Salt-Blood Pressure Hypothesis” states that an increase in the intake of salt leads to an increase in blood pressure and subsequently increases the risk of cardio-vascular events – a point of contention for decades, says this Review. It further claims that the overall benefit of salt restriction on those with hypertension during “The Salt Wars” of the first half of 1900’s, both in Europe and the USA, were based on uncon- trolled case-reports, that well-designed controlled studies indicate that the results of low salt diet were effective in only approximately 25 % of in- dividuals with hypertension and that a low salt diet was not a reasonable strategy for treating hypertension.
What was and what is the impact of “The Salt Wars” on the treatment and control of hypertension in Myanmar?
Almost all our clinical knowledge and practice was derived from our colonial masters – the British. At the time when they departed Myanmar when it gained Independence, the low- salt Kempner rice-diet published in 1944 was much in vogue and the British doctors here in Myanmar as well as in the UK must have taken up this method of treating hypertension and its associated ideas on pathogenesis even though based on uncontrolled trials, and trans- mitted their beliefs and clinical practice to the Myanmar doctors whom they trained here and in the UK and who later became the future teachers in the medical school and the leaders of the medical profession in Myanmar. The low- salt Kempner rice diet was adopted in Myanmar.
As a medical student and a young doc- tor in the 1950’s, I remember having been taught about the Kempner rice-diet and it was espe- cially appealing because it was based on rice which is our staple food.
Belief in the effectiveness of the low-salt, low protein Kempner rice-die for treatment of hypertension was translated by many into the idea that low salt also worked for treating hypertension. In the Textbook of Internal Medicine (2nd edition 1986) published by the Myanmar Medical association, the chapter on Hypertensive Cardiovascular Disease accepted the renin-angiotensin- aldosterone system as the underlying pathoge- netic mechanism for hypertension and diuretics as a first step for patients in the basic therapeu- tic regime of hypertension treatment, although it does mention that prolonged use of diuretics in the elderly may induce treatment failure.
Later, as stated in the review, others showed a lack of significant effect on blood pres- sure with sodium restriction and adverse effects such as reduced glomerular filtration rate and risk of renal ischaemia.
Further on, with a better pre-treatment controlled period it was demonstrated that only 41% responded with significant lowering of blood pressure to a low salt diet as against 64% claimed by Kempner. Other well-controlled trials showed only 29 %, 19% or no response to the Kempner rice-diet. The review says that from 1904 to 1949, studies of low-salt diet as a treatment for hyper- tension were favorable in twenty-one and unfavorable in seven. Many times salt restriction caused serious consequences.
History of Dietary Salt
For millions of years, primitive man ate a vegetarian diet and did not consume much salt apart from small amounts naturally found in fruits, berries and roots. With the development of civilization when our ancestors started eat- ing animal foods, they began to need more salt and as herdsmen, they had looked for salt from various sources such as brine and rock salt deposits. Salt became a precious commodity and was carried and traded across continents in cara- vans and ships across the oceans and seas; thus, creating the salt route. Salt was given as wages.(Latin argentum = salary). Idioms such as “ worth its salt” was used to express that some- one or something deserves respect and has value. Salt was offered to gods and the holiness con- cept of salt changed to superstition as in this say- ing : “if salt is spilled, you had to throw it over your left shoulder”.
Is Salt a culprit or an Innocent By-stander in Hypertension ?
A Review in the American Journal of Medicine
(Dinicolantonia, J.J. & O’Keefe, J.H.)
(2017,130.893-899)
Abstract : For decades, the notion that an excessive con- sumption of salt (NaCl) leads to hypertension has persisted. However, the idea is based on opinion, not scientific proof. Despite this, every health organization, agency, and clinician around the world have been advising salt restriction, espe- cially to hypertensive patients. The present review article suggests that the consumption of a high salt diet is not the cause of hypertension and that there are other factors, such as added sugars which is causative for inducing hyperten- sion and cardiovascular disease.
However, this review states that according to WHO estimates in 2008, the prevalence rate of hypertension in the Indian population was 32.5% and a serious public health threat to the health care system and cardiovascular health status in India.
Recent studies in India show that the prevalence of hypertension is approximately 25% in urban areas and 10% in rural areas. Indians consume about 11 g of salt per day (Na- 4400 mg/d) as against WHO recommendation of <2000 mg sodium/day. In Myanmar, according to recent available information, the average salt intake in Yangon is 9.3g per person per day (Sodium 3000 mg/d) and the recommended daily dietary salt intake for Myanmar is <6 g/d while the WHO recommends <5 g/d. According to WHO and FAO recommendations for India and elsewhere, our aim should be to reduce our salt intake per person per day.
The Communicable Diseases program admits that hypertension is particularly prevalent and has been largely neglected so far and will now be dealt with under the Cardiovascular Diseases project. The Package of Essential NCDs (PEN) includes control of hypertension. So, a decision will have to be made by those concerned as to the amount of salt intake that should be aimed at and recommended.
In view of the “The Salt Wars” and controversy as revealed in these two Reviews and the questionable role of sodium and salt in the causation and control of hypertension, there will of course be much discussion and may be some more studies needed for such a large and long-term program.
REFERENCES
1. James. J, Jams H.O. History of the salt wars. American Journal of Medicine 2017, 130, 1011-1014.
Author Information
Emeritus Medical Researcher
Director-General, Dept. of Medical Research, Myanmar.
Director (Research and Human Resources)
World Health Organization, S.E.A Region.
Professor of Medicine, Institute of Medicine 2, Yangon
