It's funny, I had the intention some days ago to post about this article and another one also published in Scientific American in 2011 but with a different purpose, to show how journalists can mislead incautious readers by misrepresenting data and hiding ("ignoring"?) information. Gary Taubes is fighting his personal crusade against processed food and high carb diets,
e.g., read his book "Good Calories, Bad Calories" (among others), or just have a look at the following article:
nytimes.com - What if It's All Been a Big Fat Lie? (The New York Times)
By Gary Taubes. July 7, 2002
nytimes.com/2002/07/07/magazine/what-if-it-s-all-been-a-big-fat-lie.html?pagewanted=all&src=pm
Since there's also some statistical correlation between obesity and higher blood pressure, and he believes that the high carb diet is responsible of the present obesity epidemics, he has decided to exonerate high sodium diets to exclusively blame high carb and processed foods for the high rates of hypertension. For instance, take this paragraph:
"In 1972, when the National Institutes of Health introduced the National High Blood Pressure Education Program to help prevent hypertension, no meaningful experiments had yet been done. The best evidence on the connection between salt and hypertension came from two pieces of research. One was the observation that populations that ate little salt had virtually no hypertension. But those populations didn’t eat a lot of things — sugar, for instance — and any one of those could have been the causal factor."
— Gary Taubes.
nytimes.com - Salt, We Misjudged You (The New York Times)
By Gary Taubes. June 2, 2012 Oakland, Calif.
nytimes.com/2012/06/03/opinion/sunday/we-only-think-we-know-the-truth-about-salt.html
But what about the the following? Why Gary Taubes has decided not to mention these studies? The first of them was published in... 1974. He must have heard about them, they are often cited in papers on the subject:
Although several factors may contribute to the lower BP, numerous studies have demonstrated the profound importance of salt intake. For instance, a study in the Pacific Islands where one undeveloped community used seawater in their foods and the other did not, showed that the community using seawater had higher BP [21]. Another study of 2 rural communities in Nigeria, one of which had access to salt from a salt lake and the other did not, showed differences in salt intake and differences in BP, and yet in all other aspects of lifestyle and diet, the 2 communities were similar [22].The Qash'qai, an undeveloped tribe living in Iran who had access to salt deposits on the ground, developed high BP and a rise in BP with age similar to that which occurred in developed communities, but in all aspects,they lived a lifestyle similar to undeveloped communities who did not have access to salt [23].
...
21. Page LB, Damon A, Moellering Jr RC: Antecedents of cardiovascular
disease in six Solomon Islands societies. Circulation 1974;49:1132-1146.
22. Uzodike VO: Epidemiological studies of arterial blood pressure and hypertension in relation to electrolyte excretion in three Igbo communities in Nigeria. Thesis (MD), University of London, 1993.
23. Page LB, Vandevert DE, Nader K, et al: Blood pressure of Qash'qai pastoral nomads in Iran in relation to culture, diet, and body form. Am J Clin Nutr 1981;34:527-538.
Reference:
- He FJ and MacGregor GA. Reducing population salt intake worldwide: from evidence to implementation. Prog Cardiovasc Dis (2010) vol. 52 (5) pp. 363-82
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More detailed information about those same studies and an additional one from a book published in 1998:
Solomon islanders
The effect of salt intake on the blood pressure of the Solomon islanders, some of whom, unlike the Yanomamos, had had some modest contact with western civilisation was studied by Lot Page in six of the islands. The physical fitness of all the participants was excellent, in keeping with other studies in a primitive society which indicates that the low blood pressure is not due to ill health as has sometimes been proposed. All six tribes were Melanesians living in villages in rural areas with no electricity or other western conveniences. Their habitats varied, three were in the mountains and three on or near the coast. Their main staple diet was potato and vegetables. Those on the coast also ate a great deal of fish and were able to purchase tinned meat, fish, rice and bread. Those who lived in the mountains ate less than 2 g of salt per day, while two of the three tribes who lived near the coast ate 3 to 8 g of salt per day, and the other cooked in copious amounts of sea water and had a salt intake of 9 to 15 g of salt per day. The potassium intake, which was not given, must have been substantial. An increase in blood pressure with age occurred in the women of the three tribes with the highest salt intake, but there was no such change in the men. In the three tribes with the lowest salt intake only 1% had high blood pressure, in the two tribes with a moderate intake of salt 3% had high blood pressure, and in the tribe which cooked in sea water which had the highest salt intake 8% had high blood pressure. It is probable that the relatively moderate effect of salt on blood pressure and lack of rise of blood pressure with age in men was related to a high potassium intake. Usually when individuals from primitive communities on a low-salt high potassium diet move to a western way of life the resultant increase in salt intake is associated with a considerable reduction in potassium, which accentuates the rise in arterial pressure caused by raised salt intake. *There was no evidence that contact with western influences including increased access to fats had had any consistent effect on weight, which suggests that the change in the diet which caused the hypertension was the raised salt intake.*
The Mundurucu and the Caraja in Brazil
A further example, from Brazil, of the effect on blood pressure of increasing the salt intake of a primitive tribe with minimal accompanying contact with western civilisation, while another adjoining tribe remained primitive. Forty-five years prior to the study the Mundurucu had moved from a savana-like forest to be near to a Franciscan mission on the Cururu river where they had come under the influence of the Catholic church and thereby access to salt. Otherwise, there was no substantial change in their diet. The Caraja lived on a nearby river and continued to eat their traditional low-salt diet. There was a rise in blood pressure with age in the men of the Mundurucu and a similar but not significant trend in the women. The blood pressure of the Caraja did not rise with age. The Mundurucu's contact with western ways consisted mainly of accepting some of the culture of Catholic Brazil. There was no change in climate or their surroundings. They were certainly not exposed to the stress of western urban life and diet. Unless it is suggested that religious conversion induced a deeply disturbing harmful effect rather than a joyful uplift, it is probable that the rise in arterial pressure was due to increased salt intake. Glieberman is more cautious,
Although the salt could be the major factor, the relinquishing of traditional religious beliefs for the levels of Catholicism may be causing an unconscious stress which would be difficult to evaluate.
The Qash 'qai in Iran
There is one striking study which demonstrates that, whatever subsidiary factors may be suggested other than the dietary intake of salt, to account for the relatively low blood pressure of primitive communities, they were not sufficient to prevent the blood pressure rising in one primitive population that habitually consumed a high-salt diet and lived in relative isolation from western culture. The study, also by Lot Page, is in a population of traditional nomadic herdsmen of the Qtsh'qai tribe of Turkish origin in southern Iran who have been in this area for approximately 400 years. The total population was estimated to be about 400,000, a large proportion of whom continued to practice pastoral nomadism, herding goats and sheep. In response to the needs of the animals for pasture and water, the Qash'qai migrated summer and winter over distances varying from 50 to 600 km. The study took place at six sites that covered an area which contained many natural surface deposits of salt which the tribe used liberally. These salt deposits are presumably on the surface of the numerous salt domes associated with the vast accumulation of oil in the Persian Gulf. The most important dietary staple was the very thin flat bread, baked daily, consumed at every meal. It contained an average of 2% salt by weight. Salt was also added in plentiful amounts when cooking meats and in the preparation of cheese and milk, and it was also added at the table, even to the bread. Drinking water was usually low in salt but sometimes natural salt water sources were used for drinking during periods of travel. Two water samples contained 3 and 7 g of salt per litre. The mean urinary salt excretion in the men was 11 g per day and in the women 9 g per day, the 24-hour potassium excretion around 2 g per day in each. This high-salt/low-potassium intake is typical of the diet in western culture and contrasts with the low-salt/high-potassium intakes of primitive societies who mainly eat fruit and vegetables. The men weighed 59 kg and the women 49 kg. The blood pressure in this nomadic primitive society consuming a diet with the same level of salt intake as that of economically developed societies, increased with age in both the men and the women, as in developed societies, but in contrast to them there was no tendency for an increase in body weight.
Nigeria
A recent study of two related rural tribes in Nigeria, one of whom had access to a salt lake and used salt in its cooking, whereas the other had no access to salt, showed that urinary salt excretion was increased in those who added salt to their food compared to those who did not, and that there was a highly significant difference in blood pressure between the two tribes who were identical in all other characteristics that were studied.
- MacGregor G.A. and Wardener H.E. Salt Diet and Health. (Chapter: Populations, salt and blood pressure). Cambridge University Press. Aug 11, 1998. ISBN: 0521583527
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That said, Gary Taubes is not the only journalist in Scientific American embarked in cleaning the bad reputation that high salt diets have garnered in the last 4 decades. Melinda Wenner Moyer is working in the same campaign to debunk any realtion between salt and hypertension. Unfortunately also using questionable tactics:
scientificamerican.com - It's Time to End the War on Salt
By Melinda Wenner Moyer. July 8, 2011
scientificamerican.com/article.cfm?id=its-time-to-end-the-war-on-salt
The way the information is presented in this article i clearly biased. For instance, there's no mention to any of the studies that found a clear direct correlation between salt intake and blood pressure (I gave the references of some of them below in the appendix). Besides she tergiverses the information taken from some of the references that she gives to push forward her particular agenda. Here you are a clear example:
"Intersalt, a large study published in 1988, compared sodium intake with blood pressure in subjects from 52 international research centers and found no relationship between sodium intake and the prevalence of hypertension. In fact, the population that ate the most salt, about 14 grams a day, had a lower median blood pressure than the population that ate the least, about 7.2 grams a day. In 2004..."
— Melinda Wenner Moyer.
Anyone who only read this comment about the study could conclude erroneously that those populations that in the study were taking less salt in their diet had the highest blood pressure whereas in the 4 centers in which sodium intake was lowest, the mean blood pressure was by far the lowest of all 52, and the only centers in which there was no increase in blood pressure with age were among those 4 populations. If there isn't positive correlation in the other 48 centers is probably due to the fact that in all of them the amounts of salt are beyond the upper limit in which a significant fraction of the population is capable to tolerate in the long-term without causing a progressive increase in blood pressure. It would be like comparing the effects caused by tobacco in different populations in which individuals smoke an average of 30 or 40 cigarettes a day. It's likely that the effects aren't linear since there's a different individual susceptibility to the active ingredients and other agents present in the tobacco smoke.
If you read the conclusions of the actual INTERSALT study, you will probably perceive a quite different picture:
(1) Within centres sodium excretion was significantly related to blood pressure in individual subjects, and at least in part this relation was independent of body mass index and alcohol intake. Sodium excretion was also significantly related across centres to the slope on of blood pressure with age. Thus lower average sodium and hence on cardiovascular mortality.
(2) The four Intersalt populations with low sodium excretion had low median blood pressures, low prevalence of hypertension, and either a decrease or only a small increase of blood pressure with age.
(3) Cross centre analyses of sodium excretion and median blood pressure and of sodium excretion and the prevalence of hypertension showed a positive association when all 52 centres were included but not when the four populations with low sodium values were excluded. The inconsistency with the findings inindi- vidual subjects might reflect the role of confounding variables that differed widely across centres but less so within centres.
(4) Potassium excretion was negatively and independently associated with blood pressure of individual subjects within centres after adjustment for sodium excretion, body mass index, and alcohol intake.
(5) The relation of the urinary sodium to potassium ratio to blood pressure in individual subjects followed a pattern similar to that for sodium but more strongly and consistently.
(6) Body mass index and high alcohol intake were strongly, positively, and independently associated with blood pressure in individual subjects.
- Intersalt Cooperative Research Group. Intersalt: an international study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion. BMJ (1988) vol. 297 (6644) pp. 319-28
ncbi.nlm.nih.gov/pubmed/3416162
PDF: cbi.nlm.nih.gov/pmc/articles/PMC1834069/pdf/bmj00297-0019.pdf
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Besides, the validity of some of the conclusions that she cites to support her view are more than questionable. Particularly the following one:
"A 2003 Cochrane review of 57 shorter-term trials similarly concluded that "there is little evidence for long-term benefit from reducing salt intake."
— Melinda Wenner Moyer.
The search for evidence for long-term benefit from reducing salt intake out of shorter-term trials is probably as well grounded as the search for benefit in endurance exercise by studying the effects of 100 m sprints.
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APPENDIX
Excerpts from articles with references of studies supporting the direct relation between sodium intake, blood pressure, arterial hypertension and rate of related diseases such as stroke and cardiovascular disease:
Introduction
For several million years the ancestors of humans ate a diet that contained less than 0.25 g of salt per day. Humans are therefore genetically programmed to this amount of salt. The recent change, in evolutionary terms, to the high salt intake of 10–12 g/day [1,2] presents a major challenge to the physiological systems to excrete these large amounts of salt through the kidney. There has been little time for physiological systems to adapt. The consequence is that the high salt causes a rise in blood pressure (BP) [1,3], increases the risk of cardiovascular disease (CVD) [4], renal disease [5–7], bone demineralization [8] and stomach cancer [9]. In this article, we will review the evidence that relates salt intake to raised BP and CVD.
- He FJ and MacGregor. Salt, blood pressure and cardiovascular disease. Curr Opin Cardiol (2007) vol. 22 (4) pp. 298-305
ncbi.nlm.nih.gov/pubmed/17556881
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Results of the Dietary Approaches to Stop Hypertension (DASH)-Sodium trial provide further evidence of inhomogeneity of salt sensitivity in the population [15–18]. When dietary sodium intake was lowered by ~100 mmol/d (from high to low salt intake) in persons consuming the control diet, systolic blood pressure was reduced by a mean of 6.7 mm Hg overall; by 8.3 mm Hg in hypertensives vs. 5.6 mm Hg in normotensives (p < 0.05); by 7.5 mm Hg in participants over age 45 vs. 5.3 mm Hg in younger persons (p < 0.05); and by 8.0 mm Hg in African Americans vs. 5.1 mm Hg in other racial/ethnic groups (p < 0.01) [16].
- Franco and Oparil. Salt sensitivity, a determinant of blood pressure, cardiovascular disease and survival. Journal of the American College of Nutrition (2006) vol. 25 (3 Suppl) pp. 247S-255S
ncbi.nlm.nih.gov/pubmed/16772636
Paper: jacn.org/content/25/suppl_3/247S.long
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Prospective cohort studies have shown that salt intake was related to CVD. A recent meta-analysis of 13 cohort studies with 177,025 participants for a follow-up period between 3.5 and 19 years showed that an increase of 5 g/day in salt intake was associated with a 23% increase in the risk of stroke and a 14% increase in total CVD [19]. After excluding one study which had serious methodological problems,20 the pooled analysis showed that a 5g/day increase in salt intake was associated with a 17% increase in CVD risk (Figure 1) [19].
- He FJ et al. WASH-world action on salt and health. Kidney International (2010) vol. 78 (8) pp. 745-53
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DISCUSSION
In this long term follow-up of two completed lifestyle intervention trials, people with prehypertension assigned to a sodium reduction intervention experienced a 25-30% lower risk of cardiovascular outcomes in the 10 to 15 years after the trial. This magnitude of risk reduction was evident in each trial, in most sub- group analyses, and in various sensitivity analyses,...
In conclusion, sodium reduction, previously shown to lower blood pressure and prevent hypertension, also seems to prevent cardiovascular disease. The TOHP interventions reduced sodium intake by about 25% to 35%, approaching current recommendations for a 50% decrease in the amount of sodium in food in the United States [46]. The observed reduction in cardiovascular risk associated with this sodium decrease was substantial and provides strong support for population-wide reduction in dietary sodium intake to prevent cardiovascular disease.
- Cook NR et al. Long term effects of dietary sodium reduction on cardiovascular disease outcomes: observational follow-up of the trials of hypertension prevention (TOHP). BMJ (2007) vol. 334 (7599) pp. 885-8
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Salt and CVD
A reduction in salt intake lowers BP, and as raised BP throughout its range is a major risk factor for CVD, this would be predicted to reduce CVD. Based on the falls in BP from a meta-analysis of randomized salt reduction trials [43], it was estimated that a reduction of 6 g/d in salt intake would reduce stroke by 24% and coronary heart disease (CHD) by 18%. This would prevent approximately 35,000 stroke and CHD deaths a year in the United Kingdom[84]
and approximately 2.5 million deaths worldwide.
...
Another prospective cohort study [5] that measured 24-hour urinary sodium on usual salt intake in a random sample of 2436 Finnish men and women aged 25 to 64 years showed that an increase of 6 g/d in salt intake was related to an increase of 56% in CHD deaths, 36% in CVD deaths, and 22% in all deaths (Fig 8) [5].
...
Another outcome trial of more than 2.5 years in elderly Taiwanese veterans (n = 1981) showed that switching from the usual salt to potassium-enriched salt (49% sodium chloride, 49% potassium chloride, 2% other additives) with a subsequent reduction of 17% in salt intake and an increase of 76% in potassium intake as measured by urinary sodium/creatinine ratio and potassium/creatinine ratio, resulted in a 40% decrease in CVD mortality [102].
- He FJ and MacGregor GA. Reducing population salt intake worldwide: from evidence to implementation. Prog Cardiovasc Dis (2010) vol. 52 (5) pp. 363-82
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Dietary salt intake, cardiovascular risk, and incidence of hypertension The publications cited by us reported and discussed mostly only the adjusted relative risks. We calculated changes in absolute risks from the raw data provided in some studies. An increase in the intake of dietary salt of 100 mmol (approximately 5.8 g NaCl) is associated with an increase in cardiovascular events of 51% and in overall mortality of 26%, as was shown by a 7 year prospective study from Finland, which included 1173 men and 1263 women whose salt intake was deter- mined by measuring their renal excretion of sodium (e5).
In a recently published meta-analysis of 13 studies with 177 025 participants and study periods ranging from 5 to 19 years, an increase in the intake of dietary salt of 5 g/day was associated with an increase in the rate of strokes of 23% and of cardiovascular morbid- ities of 17% (6). A high intake of salt leads to greater mortality due to stroke independently of a rise of blood pressure (e6, e7).
...
A reduced dietary intake of salt is accompanied by a lowering of blood pressure in the population. Restricting the daily salt intake by 0.9 g, which was monitored by measuring sodium excretion, and increasing the amount of fruit and vegetables in people’s diets in a Japanese village of 550 inhabitants was associated with a fall in average systolic blood pressure of 2.7 mm Hg within a year, compared with a control village where the dietary salt intake increased by 0.7 g/d during the same time period. The diastolic blood pressure remained the same (13).
...
Expected successes
The extent of salt reduction and targeted fall in blood pressure determine the success of restricting the salt intake in the general population. If the dietary salt intake is moderately reduced by 3 g/d, the systolic blood pressure reduction in normotensive individuals is expected to be 1.8 to 3.5 mm Hg (24, e28). Lowering systolic pressure is associated with a relative risk reduction for ischemic heart disease and cardiovascular mortality of 4% to 5% and a fall in overall mortality of 3% (25). In the US, a reduction of salt intake to an average of 5.8 g/d is expected to result in an annual reduction of hypertension cases by 11 million and annual cost savings of 18 billion dollars in the healthcare system (e29). A decreased incidence of hypertension as a result of salt restriction would thus counteract the increased rates in overweight, diabetes, and terminal renal failure that have been seen in the US and Europe in recent years (e30).
- Klaus D et al. Salt restriction for the prevention of cardiovascular disease. Dtsch Arztebl Int (2010) vol. 107 (26) pp. 457-62
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The meta-analysis [6] revealed that the effect of restricting salt in free-living normotensive subjects (people who had been counselled about salt intake but who were not enrolled in tightly controlled trials) was not statistically significant. After adjustment for error in the measurement of urinary excretion of sodium, the decrease in blood pressure for normotensive subjects after a reduction in sodium intake of 100 mmol/day was 1.0 mm Hg for systolic blood pressure and 0.1 mm Hg for diastolic blood pressure [6].
Although these results suggest that salt restriction yields only modest effects in terms of reducing blood pressure, this panel recognizes that excessive intake of salt in the North American diet should be avoided. A downward shift in the entire distribution of systolic blood pressure by 1 mm Hg is likely to reduce the annual mortality rate from stroke by 3%, the mortality rate from coronary artery disease by 2% and the annual all-cause mortality rate by 1.5% [70].
- Fodor JG et al. Lifestyle modifications to prevent and control hypertension. 5. Recommendations on dietary salt. Canadian Hypertension Society, Canadian Coalition for High Blood Pressure Prevention and Control, Laboratory Centre for Disease Control at Health Canada, Heart and Stroke Foundation of Canada. CMAJ (1999) vol. 160 (9 Suppl) pp. S29-34
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Among Western European countries, Portugal has one of the highest mortality rates for stroke (twice that of coronary disease) and of incidence of gastric cancer [2]. The first population study devoted to evaluate salt consumption in Portugal was recently undertaken and published.3 In that study [3] (426 persons aged 22–72 years), the mean daily salt consumption measuring 24 h urinary sodium (validated by creatinuria) was found to be 11.9±4.2 g day-1 (median 1⁄4 11.4 g salt day-1), which correlated with casual blood pressure and aortic stiffness. If we introduce such new data of Portu- guese salt consumption in the regression line plotting death from stroke and urinary sodium excretion, as shown in figure 8 of the article by He and MacGregor,[1] the position of Portugal will drop exactly within the regression line and not much above that line as it appears in figure 8. It also agrees more closely to the line plotting sodium excretion and death from stomach cancer as shown in figure 10 [1]. All these data reinforce the message stressed by He and MacGregor1 and suggest that such a high salt consumption might contribute both to the abnor- mally high mortality by stroke and gastric cancer in Portugal.
- Polonia J and Martins L. A comprehensive review on salt and health and current experience of worldwide salt reduction programmes. Journal of Human Hypertension (2009) vol. 23 (11) pp. 771-2
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Some successful population intervention studies Population decreases in BP, even if modest, could yield substantial reductions in cardiovascular disease morbidity and mortality. A population-wide 2 mmHg decrease in DBP is estimated to reduce hypertension prevalence by 17 %, and the risk of CHD (coronary heart disease) and stroke by 6 and 15 % respectively [53]. Another estimate indicated that a 5 mmHg population-wide reduction in SBP would decrease CHD and stroke mortality by 9 and 14% respectively (Figure 4). Many population-based intervention studies have been carried out. Some did not achieve a reduction in salt intake and, consequently, there was no difference in BP [54,55]; however, studies in which salt intake was successfully decreased show a reduction in population BP. In Japan, a national campaign reduced salt intake between 1.5–4g/day, resulting in a population BP reduction and an 80% reduction in stroke mortality notwithstanding an increase in other cardiovascular risk factors [56].
Finland provides one of the best examples of a popu- lation-based salt reduction. From the 1970s, it had a population salt-reduction policy based on regulation and education [57]. By 2002, salt intake had decreased by 40 % (Figure 5). Notably, there were remarkable decreases in population BP (>10 mmHg), and stroke and CHD mortality (>70 %). The reduction in salt intake was estimated to be a major contributory factor[57].
- Mohan S and Campbell NRC. Salt and high blood pressure. Clin Sci (2009) vol. 117 (1) pp. 1-11
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Based on the effects of high salt intake on blood pressure and on the prominent role of high blood pressure in promoting cardiovascular diseases, it has been suggested that a population-wide reduction in salt intake could substantially reduce the incidence of cardiovascular disease [2]. On the basis of the results of a meta-analysis of randomised controlled trials of salt reduction [3], it was estimated that a reduction in habitual dietary salt intake of 6 g a day would be associated with reductions in systolic/diastolic blood pressure of 7/4 mm Hg in people with hypertension and 4/2 mm Hg in those without hypertension. At the population level these reductions in blood pressure could predict an average lower rate of 24% for stroke and 18% for coronary heart disease [4].
- Strazzullo P et al. Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies. BMJ (2009) vol. 339 pp. b4567
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Finally, an insightful introduction on the topic:
Humans, like all other mammals, consumed less than 0.25 g of salt per day during several million years of evolution. About 5000 years ago, the Chinese discovered that salt could be used to preserve foods. Salt then became of great economic importance as it was possible to preserve foods during the winter and allowed the development of settled communities. Salt was the most taxed and traded commodity in the world, with intake reaching a peak around the 1870s. However, with the invention of the deep freezer and the refrigerator, salt was no longer required as a preservative. Salt intake had been declining, but with the recent large increase in the consumption of highly salted processed foods, salt intake is now increasing again. The average salt intake in most countries around the world is approximately 9 to 12 g/d, with many Asian countries having mean intakes more than 12 g/d [1]. Salt intake is commonly more than 6 g/d in children older than 5 years and increases with age [1].
Humans are genetically programmed to a salt intake of less than 0.25 g/d. The recent changes (in evolutionary terms) to a high salt intake present a major challenge to the physiologic systems to excrete these large amounts of salt through the kidneys. The consequence is that the high salt intake causes a rise in blood pressure (BP) [2,3], thereby, increasing the risk of cardiovascular disease (CVD) [4,5], and renal disease [6-8].
- He FJ and MacGregor GA. Reducing population salt intake worldwide: from evidence to implementation. Prog Cardiovasc Dis (2010) vol. 52 (5) pp. 363-82
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