I enjoy the DK and need to comment on a posting about a sodium study (pasted from the DK News Feed below the fold).
I believe that the press release about theTufts study was very one-sided in that it only looked at cardiovascular deaths, but leaves out important recent information about all cause mortality.
There has been mounting evidence for over a decade that very low sodium intake might independently cause harm due to possible increased levels of plasma renin, aldosterone, noradrenaline, total cholesterol, LDL cholesterol, and insulin resistance. Meanwhile, a 2014 Meta-Analysis published in the Journal of HTN, which looked at all cause mortality, supports a recommended sodium intake of 2645-4945 mg. This will take a while to filter down but I am confident that in 5-10 years the AHA and FDA will change their recommendations to something closer to 3000-4000 mg of sodium.
None of our current nutrition advice will need to change except that it is fine to use a salt shaker with small to medium sized holes and enjoy a moderate amount of salt to taste. This will not be an excuse to eat fast food or other highly processed foods! A typical chain restaurant might use 2000-3000 mg of sodium in one meal, and one huge meal at a chain restaurant is noted to contain almost 5000 mg of sodium in one meal! In addition to using huge amounts of salt (because it is a preservative), processed foods also use other questionable additives and processing methods described by Michael Pollen in his many famous books such as The Omnivore’s Dilemma.
I will paste the research information with references under the block quote below the fold. I have a Masters Degree in Nutrition Science and am a Registered Dietitian. This is my first diary so please go easy on me!
I became interested in sodium research years ago. As a dietitian I tried to follow all of the standard USDA approved nutrition messages that I was teaching, including low fat and low sodium. Avoiding sodium caused me to feel weak and actually pass out twice. I assumed that I must have an unusual condition, and felt much better after I allowed myself to use salt to taste again. Eating very low fat (this was in the 1990's) caused me to eat more total carbohydrate than before and pushed me into a pre-diabetic state. I still have pre-diabetes but I would probably have full-blown diabetes if I had not gone back to using olive oil and eating avocados and nuts again, as evidenced by the fact that every time I ate a normal rice bowl containing 2 cups of rice with stir fried chicken and vegetables, my blood sugar went over 200. Now I use quinoa instead of rice, and only one cup at a time, but that is another story.
I work with pregnant hispanic women, many of whom love to eat fresh fruits or vegetables sprinked with lime and salt. When I encourage them to eat more fresh fruits and vegetables they often tell me that they can't, because then they will have use salt. I show them a 1/8 teaspoon, which only contains 300 mg of sodium, and ask if they would use more than that. They always say "No, of course not!" So they are avoiding healthy fruits and vegetables due to fear of using a little bit of salt.
Pregnant women often are light headed from low blood pressure, but they do not like to hear me recommending that they add a small amount of salt to their foods to taste, because they are so used to the typical message about the evils of salt.
I am pasting the following from tonight's DK Overnight News Digest. I disagree with its conclusions, because the study only looked at cardio-vascular deaths and did not look at all cause mortality:
THU AUG 14, 2014 AT 09:00 PM PDT
Overnight News Digest -- "Post a Paper, Go to Jail" Edition
Medical News
Estimated 1.65 million global cardiovascular deaths each year linked to high sodium consumption
Tufts University
Researchers found the average level of global sodium consumption in 2010 to be 3.95g per day, nearly double the 2.0g recommended by the World Health Organization. All regions of the world were above recommended levels, with regional averages ranging from 2.18g per day in sub-Saharan Africa to 5.51g per day in Central Asia.Tufts University
More than 1.6 million cardiovascular-related deaths per year can be attributed to sodium consumption above the World Health Organization's recommendation of 2.0g (2,000mg) per day, researchers have found in a new analysis evaluating populations across 187 countries. The findings were published in the August 14 issue of The New England Journal of Medicine.
"High sodium intake is known to increase blood pressure, a major risk factor for cardiovascular diseases including heart disease and stroke," said first and corresponding author Dariush Mozaffarian, M.D., Dr.P.H., dean of the Friedman School of Nutrition Science and Policy at Tufts University, who led the research while at the Harvard School of Public Health. "However, the effects of excess sodium intake on cardiovascular diseases globally by age, sex, and nation had not been well established."
The researchers collected and analyzed existing data from 205 surveys of sodium intake in countries representing nearly three-quarters of the world's adult population, in combination with other global nutrition data, to calculate sodium intakes worldwide by country, age, and sex. Effects of sodium on blood pressure and of blood pressure on cardiovascular diseases were determined separately in new pooled meta-analyses, including differences by age and race. These findings were combined with current rates of cardiovascular diseases around the world to estimate the numbers of cardiovascular deaths attributable to sodium consumption above 2.0g per day.
My position is explained below, in information from a powerpoint presentation that I gave to the doctors at my workplace last month. They loved it and have adopted its message for our group of clinics:
Paradigm Shift on Sodium Recommendations
There has been mounting evidence for over a decade that very low sodium intake might independently cause harm due to possible increased levels of plasma renin, aldosterone, noradrenaline, total cholesterol, LDL cholesterol, and insulin resistance.(1,2)
A major report by the IOM in 2013 concluded that current recommendations for 1500-2300 mg sodium intake are unfounded.
IOM 2013 Report Findings Summary:
1. Excessive sodium intake is harmful--but “excessive” amount was not defined. Studies defined “excessive sodium” differently: from more than 2700 mg to more than 10,000 mg. (3)
2. Evidence does not support the use of 2300 mg as an Upper Limit (UL). (3)
3. Research does not support a specific limit of 1500 mg to any population subgroups (3)
4. Further studies are needed to define Adequate Intake (AI) and Upper Limit (UL). (3)
What is the safest sodium intake?
A 2014 Meta-Analysis published in the Journal of Hypertension
supports a recommended sodium intake of 2645-4945 mg.
BACKGROUND: The effect of sodium intake on population health remains
controversial. The objective was to investigate the incidence of all-cause
mortality (ACM) and cardiovascular disease events (CVDEs) in populations
exposed to dietary intakes of :
Low sodium:<115 mmol = Less than 2645 mg.
Low usual sodium: 115-165 mmol = 2645-3795 mg.
High usual sodium: 166-215 mmol = 3795-4945 mg.
High sodium: >215 mmol = More than 4945 mg.
“Strengths of this analysis were the power of a substantial number of participants
(n = 274,683) and the fact that most of the included studies adjusted the
outcome for multiple assumed confounders .
Their conclusions showed that the population usual sodium intakes of
2645-4945 mg resulted in statistically significant improved outcomes:
9% lower relative risk of all cause mortality than LOW sodium <2645, and
16% lower relative risk of all cause mortality than HIGH sodium >4945.
(5)
Summary: the Sodium J Curve
1. Sodium recommendations should be changed to approximately 2745 and 4945 mg respectively unless there is a specific medical need for sodium restriction.
We should be able to safely recommend 3000-4000 mg total daily sodium.
2. Even in the case of someone who has demonstrated sodium sensitive hypertension, the 2014 study questions the usefulness of slightly lower blood pressure when compared with the possible risks of increased mortality from sodium restriction.
3. The often cited 2012 AHA Manhattan Study on sodium and stroke risk actually supports the J Curve hypothesis if you ignore their extrapolation and look at the data closely. I encourage you to do this and would love to discuss it. (4)
4. None of our current nutrition advice needs to change except that it is fine to
use a salt shaker with small to medium sized holes and enjoy a moderate amount of salt to taste! :-)
5. This is not an excuse to eat fast food or other highly processed foods! A typical chain restaurant might use 2000-3000 mg of sodium in one meal, (as well as other questionable additives and processing methods described by Michael Pollen in his many famous books such as The Omnivore’s Dilemma.)
(1,2,5)
How was it so easy to convince ourselves that everyone should limit sodium so strictly?
There is plenty of anecdotal evidence against high sodium, because, in a sodium sensitive individual with high blood pressure, a very high sodium intake in one day could trigger a cardiac event. In the 1990's we believed that 25% of humans were probably sodium sensitive. Therefore a public health message for everyone to restrict sodium would theoretically protect millions of people from cardiac events.
The DASH studies are cited as the best evidence of the efficacy of low sodium diets, but
they should not, because:
---The DASH diet also includes high levels of magnesium and potassium from 8-
11 servings of fruits and vegetables and nuts, seeds or legumes at least 4-5
times each week.
---The DASH diet limits added sugar to 15g or less each day. Recent studies
show strong correlation between added sugars and CVD.
Early sodium studies had many confounding factors, because the higher sodium populations were usually eating fast foods and processed foods that were also rich in trans fats and added sugars, which we now know are strong contributors to CVD. These factors were ignored when those studies were conducted, so it was easy to mistake the moderately high sodium as the culprit. (On the other hand, very low sodium kills you slowly and with subtlety.)
Again, the research confirmed that very high sodium is worse than very low sodium, but we should define high sodium as more than 4900 mg. I am confident that the current sodium recommendations are too low.
I am very interested in feedback and hope that this information will be shared.
Works Cited
1. Effects of sodium restriction on blood pressure, renin, aldosterone, catecholamines, cholesterols. JAMA 1998; 279:1383–1391.
2. Dietary sodium restriction impairs insulin sensitivity in noninsulin- dependent diabetes mellitus. J Clin Endocrino Metab 1998; 83:1552-1557.
3. Institute of Medicine. Sodium Intake in Populations: Assessment of Evidence. Washington, DC: The National Academies Press, 2013.
4. Dietary sodium and risk of stroke in the Northern Manhattan study. Stroke 2012; 43: 1200-1205
5. Compared With Usual Sodium Intake, Low- and Excessive-Sodium Diets Are Associated With Increased Mortality: A Meta-Analysis. Am J Hypertens pub online March 20, 2014.doi:10.1093/ajh/hpu028
11:23 AM PT: I removed some inflammatory language that was in the original diary. I appreciate all of the excellent feedback!