Doctor's Note

Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. Be sure to check out Dietary guidelines: corporate guidance and all the videos on dietary guidelines. And don't forget, there are 1,449 subjects covered in my other videos–please feel free to explore them!

For some context, please check out my associated blog posts: Wisconsin Milk Marketing Board accused of making illegally deceptive claims and Uric Acid From Meat and Sugar

  • Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. Be sure to check out Dietary guidelines: corporate guidance and all the videos on dietary guidelines. And don’t forget, there are 1,449 subjects covered in my other videos–please feel free to explore them!

    • HemoDynamic, M.D.

      Dr G.,
      You may have already seen this study that was published last month on Salt intake by Alderman and Cohen:

      Salt appears  to have a “J-shaped” relation to cardiovascular outcomes. Sodium intakes above and below the range of 2.5 to 6.0 grams/day are associated with increased cardiovascular risk.

      Interesting stuff: http://www.ncbi.nlm.nih.gov/pubmed

      • http://nutrientuniverse.blogspot.co.uk/ JAMESKB

         Yeah I don’t know, but salt seems okay to me, when combined with a healthy diet. By cutting meat and junk food you’re already drastically cutting your sodium intake.

  • msatin

    Hi Mike,

    A few things. Can you furnish your readers with any reference to the actual clinical evidence used to substantiate the recommendation of 1,500 mg sodium per day? Even one will do.

    You mention that 92,000 lives a year would be saved if we consumed sodium at the Dietary Guidelines recommended levels – is that from clinical evidence or from a speculative model based on debatable assumptions such as the defunct Rose population strategy?

    You sound like you have had considerable hands-on experience in the food industry – did you?

    Speaking about transfats, New York instituted an absolute ban on transfats in December 2006. Can you tell me with your untrammeled view of nutrition what has been the positive health outcomes for new Yorkers – better cholesterol profiles, reduced cardiovascular disease, reduced mortality – what? (And please, don’t get into “it’s multifactorial, so we can’t really tell” argument.) For years the NYC Health Dept promised to run the numbers since the ban – but five years on and I’ve heard nothing other than myth-informers continuing to make assumptions without data. Have you seen any results?

    And finally, since I am with the Salt Institute, you and your followers may believe that you have dedicated your career and accomplished more for consumers than I have – you know, highly nutritious food products, publications on nutrition, food safety and food poisoning, etc., etc. Would you be willing to make a public comparison of such accomplishment? I feel obliged to do this because you give the impression that our motives are driven uniquely by the wish to sell more salt. I would like to convey the dedication we have to informing the consumers of all the credible peer-reviewed science cautioning against the current salt recommendations. And don’t use the names of our great institutions as a substitute for actual evidence. It’s easy to go along with the establishment – but unchallenged recommendations such as those for hormone replacement therapy are the sort of disaster that can happen. People can eat as much or as little salt as they want, but they should do so from a point of fact and knowledge, not of myth and ignorance.

    Morton Satin
    Salt Institute

  • http://www.facebook.com/reid.albecker Reid Albecker

    John McDougall seems to not have a problem with salt, per se:
    http://www.youtube.com/watch?v=aVtOzOROUqE

    I would be curious if you allow that he may be correct.

    • Toxins

      Reid, please check out this video by Dr. Greger that brings up some points Dr. McDougall may not be currently aware of.

      http://nutritionfacts.org/videos/salt-ok-if-blood-pressure-is-ok/

    • BarbaraH

      Dr. McDougall recommends a low-salt diet. All he’s saying in this video is, don’t pin all the blame on salt. You can sprinkle a little on your food, as long as your food starts out whole food plant based – which translates to a low salt diet.

      For further clarification, see this newsletter:

      http://www.drmcdougall.com/misc/2008nl/aug/salt.htm

      Here are two passages from it:

      Eating salt is not wrong when it is added in small amounts to otherwise healthy ingredients, like starches and vegetables. The basic ingredients of McDougall meals are very low sodium; you then add salt to taste.

      A basic diet of starches, vegetables, and fruits (the McDougall Diet) with no added sodium provides less than 500 mg of sodium daily. Adding a half-teaspoon of salt to the surface of your McDougall dishes daily adds about 1100 mg of sodium—making the total daily intake 1600 mg. The “low-sodium diet” fed to a hospitalized patient, following a massive heart attack, under the expert guidance of doctors and dietitians, contains 2000 mg of sodium. Now you understand why I am comfortable putting the saltshaker on the dining tables at our programs.

  • maybush1

    Hello Dr. Greger, I was curious about your take on a new report of a recent study (http://www.msnbc.msn.com/id/45224421/ns/health-heart_health/#.TrrabPSImU8) that appears to demonstrate possible heart health issues with a low-salt diet (increases cholesterol, increases fat, increases hormone levels). It also appears to be adding to previous studies showing similar results. Thanks for any information you can provide.

    • Michael Greger M.D.

      None of the studies over 4 weeks in length noted in the review cited by MSNBC showed any negative effects on cholesterol and in fact the American Heart Association (AHA) has just gone further and recommended that everyone shoot for 1500 mg a day (not just those at high risk). According to the AHA, cutting American sodium intake 1,200 mg per day could lead to as many as 66,000 fewer strokes, almost 100,000 fewer heart attacks, and up to 92,000 fewer deaths. It’s hard to get down to the recommended 1,500mg a day unless one sticks to an unprocessed plant-based diet.

      • sel

        Mr.Greger, I was thinking…if you look at the Gerson therapy (where patients are not allowed salt at all), in the first weeks the body starts to remove salt from tissues bringing it into the bloodstream. As I remember, there were reported even cases of salt surges in blood stream after several weeks, given this continuos strict saltless diet. Therefore, one can’t really emit theorems upon the “bad” long term/general effects of reducing salt intake, as the msnbc study did. Is it? :)

  • wickedchicken

    So much conflicting info….. confusing.

    • DrDons

      The data is not conflicting in good studies. Different interpretations can be confusing especially from individuals who don’t keep up with the studies or just “parrot” recommendations that are put out by special interest groups. There is some disagreement on the absolute levels of salt but they are on the low end of about 1500 mg/day. However our consumption of salt in today’s world generally occurs in processed foods. In addition to Dr. Greger’s excellent points and his other video’s on salt and sodium see.. http://nutritionfacts.org/topics/sodium/ I would recommend Dr. McDougall’s August 2008 newsletter article on Salt(see his website, go to “Hot Topics read more, click on Hypertension to see the article). There are minor disagreements between the experts but as one expert,Jeff Novick RD, has said “there is agreement on 95% so don’t get lost in the 5%”. I would follow a whole foods plant based diet and if you add salt only do so in small amounts at the table.

      • HemoDynamic, M.D.

        That is a great quote by Jeff!

  • msatin

    The Intersalt study demonstrated that average sodium (not salt, DrDons) consumption around the world ranges from 120 – 210 mmols or 2,760 – 4,830 mg per day. This is nowhere near the recommended 1,500 mg Na/day. In fact, when life expectancy is charted against sodium consumption around the world, it is clear that the more salt consumed, the longer the life expectancy. While no cause and effect relationship between sodium intake and lifespan is implied, the data does demonstrate the compatibility between life expectancy and the associated high levels of sodium intake. On the other hand, the four low-salt outliers in the Intersalt study (who consumed 500- 1,400 mg Na/day) all have life expectancies of less than 50 years.

    With reference to special interests, we cannot ignore two very important conflicts of interest – intellectual passion and institutional arrogance. I am certain that there are many individuals in this debate that believe that their ‘mission’ is so altruistic and important that minor exaggerations or omissions are allowable – the ends justify the means. Sorry, that is just not on – opinions don’t count, only evidence will do and when it is not available, then we are obliged to everything to get it.

    Some well known institutions and agencies believe that their word cannot be challenged – well, even the might and reputation of the Holy Roman Empire was unable to make the sun revolve around the earth for Gallileo. And so it will be for the IOM and the FDA. It is evidence, not institutional fiat that will describe the effect of salt on heath.

    Get over blood pressure and start considering total health outcomes – if not, we risk repeating the tragedy of the establishment recommendations for hormone replacement therapy.

    • Toxins

      msatin,

      vegans are at risk when consuming too much sodium due to high blood pressure. The reasoning is is that when a vegan has high blood pressure, since there is no plaque in the arteries to furnish the higher pressures, strokes are more common due to ruptures of the arteries. This is seen happening in Japan due to high sodium from (i assume) soy sauce. I am not sure if Dr. Greger has released the video yet discussing this but if he hasn’t done so, it will be released in the coming weeks.

      • Real World Vegan

        elevated blood pressure is only an issue when constant and chronic and is the state we call hypertension. it generally comes paired with hardened arteries because the lack of flexibility in the arterial walls means the blood us under more pressure. the transient blood pressure that can be caused by consuming salt with a meal [because salt causes us to hold water and temporarily increases volume] is not the same and does not cause or indicate disease. drinking a lot of water can have a similar transient effect on blood volume but we dont get warnings to keep water intake low.

        the only real exception is for people unlucky enuf to be both sodium sensitive and hypertensive. right now that number is around 10% of grown-ups. most people already know if theyre sodium sensitive because they get the bloat shortly after they eat something salty. but its easy to scope out yourself by drinking a glass of salty water and watching the results. if your fingers look like sausages and your rings get tight and hour or so after, chances are youre sensitive. there is no risk in doing this test yourself, and extra sodium is easy to flush out with a couple of extra glasses of fresh water.

        and lets face it, a lot of vegan food really can use a pinch of salt. its easier to eat well when your food actually tastes good.

        • Toxins

          An old post and without evidence on my part I must say, I have learned a lot in 2 years of studying. Regardless of the topic at hand, I find food to be quite enjoyable without added sodium. Your tongue can adapt, and Dr. Greger even has a video coming out showing just this.

  • msatin

    Toxins,

    I find your comment on vegans rather interesting and somewhat contradictory. Under normal circumstances, because of the nature of their diet, vegans should consume high levels of potassium. That alone should have a very strong influence on blood pressure regardless of salt consumption. Could you list the publication that you refer to?
    Thanks

    • Toxins

      I am having difficulty locating it because I don’t remember where I saw it. When i stumble upon it again ill share it here.

      • BarbaraH

        Toxins, was this it? http://www.diseaseproof.com/archives/hurtful-food-salt-potentially-more-dangerous-for-vegans-and-vegetarians.html

        First paragraph:

        Adapted from Dr. Fuhrman’s book Disease Proof Your Child:
        Although a low-saturated-fat vegan diet may markedly reduce risk for coronary heart disease, diabetes, and many common cancers, the real Achilles’ heel of the low-fat vegan diet is the increased risk of hemorrhagic (vessel rupture leading to bleeding) stroke at a late age.

        • Toxins

          Thank you Barbara! That was it I believe! all your posts here are very informative, good job!

  • BarbaraH

    I had never heard of the “intersalt” study, so I looked it up on Wikipedia. (Yay! It’s back.)

    Surprise surprise:

    The Intersalt study was an observational study that showed an association between dietary salt, measured by urinary excretion, and blood pressure.[1] The study was based on a sample of 10 079 men and women age 20-59 sampled from 52 populations spread across the world.
    The results were disputed by the Salt Institute (the salt producers’ trade organisation), who demanded that the results be handed over for re-analysis.[2] A re-analysis was published in 1996 and the results were the same.[3] The results have since been confirmed by the TOHP I and TOHP II studies.[4]

  • msatin

    The interpretation of the Intersalt study is still in full dispute. As it turned out, the per capita consumption of sodium in the majority of countries ranged between 130 – 210 mmol or 3 – 5 g per day the equivalent of 7.8 – 13 g salt per day. The results indicated that there was not a clear pattern between the level of salt intake and blood pressure and if anyone takes the trouble to look at the data this is plainly obvious. However, there were 4 populations (all primitive, rural) among the 52 groups that showed very low salt intakes and far lower than average blood pressures. The lowest consumption population in this group was the primitive Yanomami Indians, who live in the Brazilian rain forest. Normally, data points that are way out from the rest of the pattern are considered outliers and are omitted from the analysis. In this case, the outliers were included and a line drawn from their tight grouping all the way over to the tight grouping of the rest of the population in order to show that a pattern relating salt consumption to blood pressure did indeed exist (which was the objective of the Intersalt study in the first place). This manipulation has been considered illegitimate in the literature by most statisticians (see Petitti et al). As many papers have since stated it does not prove a link between salt and BP as say it dies. In other words it remains a polemic and is not considered solid science.

    While the advisability of making comparisons between modern Western societies and those that have vastly different lifestyles, levels of physical activity, caloric intakes and environmental stresses is legitimately open to question, the issue of life-long low BP among the Yanomami was repeatedly used as a justification. The Yanomami are described in the ethnographic literature as an aggressive and violence-prone people. The stress associated with this character along with the continual exposure to environmental stresses, does not appear to influence the BP of the Yanomami as they would other people. While their abnormal BP profile has been attributed to reduced salt consumption, a far more likely reason appears to be the almost complete absence of a D/D genotype – a genetic trait shared with other Amerindians such as the Xingu Indians of the Amazonian rainforest, one of the other four outlier points and the New Guinea Papuans – another of the Intersalt outliers. Notwithstanding their lack of an age-related rise in blood pressure, these populations are all characterized as small stature, high mortality and high fertility populations with a low life expectancy. Another interesting circumstance is that, despite their long history of evolution in a salt-limited rainforest environment, they have never acclimatized to low sodium intake and have chronically high levels of plasma renin. Nevertheless, the inclusion of the outlier data in the formal Intersalt analysis, however misguided, continues to be used to show the ‘relationship’ between salt intake and blood pressure, as it was in Wikipedia.

  • BPCveg

    Dear Morton Satin (Mr. Vice President of Science and Research at the Salt Institute),

    On behalf of followers of nutritionfacts.org, I assure you that we are taking your point of view with a grain of salt.

  • Michael Greger M.D.

    For some context, please check out my associated blog post Wisconsin Milk Marketing Board Accused of Making Illegally Deceptive Claims!

  • http://nutrientuniverse.blogspot.co.uk/ JamesKB

    What’s your recommendation for sodium intake? The RDA is 1,500. To get that from whole food sources:

    Kale 4000g
    Broccoli 4000g
    Spinach 2000g
    Celery 2000g
    Carrots 2300g

    Obviously you can split it between them but you would still be eating a lot of each.

    I calculated an average healthy day of eating to give you about 350mg. Is that enough?

    • http://nutritionfacts.org/ Michael Greger M.D.

       No, that’s the upper limit (for high risk groups). You only need about 500mg

      • http://nutrientuniverse.blogspot.co.uk/ JamesKB

        Well that’s a relief :). It is classified as the RDA though. RDI is about 2, 500. It’s funny that were sometimes to take RDAs as requirements then other times as limits it seems.

    • Toxins

      Current recommendations are actually set at 2500 per day but this is more of an extreme upper limit then a recommendation. Safe levels are seen 1200-1500 or less. The estimated minimum required amount to maintain good health is said to
      be about 115 mgs per day by the National Academy of Science.

  • http://www.facebook.com/eogrey Eric O’Grey

    If a regular person only needs about 500 mg salt intake per day, what should be my intake if I run 60 miles per week? I find that I get bad leg cramps, very dehydrated, and have symptoms of electrolyte deficiency if I don’t consume a lot of salt, and take salt tabs during a marathon. I use Himalayan sea salt if it makes a difference.

    • Toxins

      In the words of Jeff Novick (a well known plant based dietician) :

      “Endurance athletes who work out in high temperatures who are adapted to a high sodium diet can lose sodium though their sweat.

      However,
      when one adapts to a low sodium diet, which can take about a week or
      so, they will lose much less sodium through their sweat and this will
      not be an issue.”

      Our sodium needs are set at a bare minimum of 113 mg per day

    • veggiedude

      When I used to work out a lot, to avoid cramps I would take a couple Glucose tablets before bed. It seemed to work for me.

    • Андрей Ханевский

      100 miles per week on a regular basis not eating salt and am NOT having any problems above described!

  • Dave Macias

    At work the office is torn between two side of the a salt issue, there are a numberof people that prefer their coffee to be brewed by adding salt. This group says that the salt will help take the bitterness out of the coffee, not to mention the faact that they also add flavored creamers and suagr after being brewed and prior to tasting. They also say that by using Sea Salt it is better for them healthwise, pure. Then there are the others that do not want to add salt and want to drink the old fashion way, just Black Coffee. For those in the office that would like to reduce their personal sodium level, does this amount of additional salt matter?

  • Chelsea

    I am horribly confused over salt. I have been vegan for 8 months so I’m assuming that in eliminating all forms of animal products (except for when I make a mistake!) from my diet means that my sodium levels have gone down significantly. I’ve also read some of Dr Joel Fuhrman’s opinions on salt and that less is better for your health. But I’ve also noticed that a lot of raw vegans still use salt in the recipes they post all over the internet – does this mean it’s still okay for me to salt my food? What’s the difference between the different types of salt (table salt, sea salt, maldon salt… I even saw “LO-SALT” at the supermarket recently… sodium-reduced salt!)? Should I avoid salting my food at all? Or, if I eat a whole-foods diet (nothing processed) and make all my own food, is it okay for me to put salt in it?
    I’ve also had a friend tell me she became salt *deficient* when she and her husband decided to do the low-salt diet thing years ago. As a result she now has to take a couple of granules of sea salt every morning otherwise she has problems with dehydration (something to do with salt helping cells retain water). I’m obviously not an expert so any clarification on this issue would be huuugely appreciated :) Thanks so much.

  • DBussone

    I am in a culinary program which advocates the use of a lot of sea salt and justifies it from a culinary perspective. You tell us that from a health perspective that salt is harmful and that it does a lot of damage to our arteries. Exactly what kind of damage does too much salt do?

  • Joel Adams

    Hello! I have a quick two-part question about salt. First is, if I eat a large salad but the only way I can enjoy it (and therefore will eat it) is by adding salty things like pickles and banana peppers, is it better to eat it with a lot of salt than not at all? Second part is if I a exercising a lot do I need to worry so much about it? I do resistance training three times a week, play squash and/or tennis twice a week and touch football once a week. P.S. I am vegan and make about 90% of my food myself so I’m not getting processed meat or anything in my diet.

  • Alan

    Hello Michael
    Thank you for your efforts with this website.

    Re. Salt
    I understand that North America is a particularly cold environment [1/3 of the USA is ice with other large areas frequently experiencing ice], and that North Americans are notorious for a lack of exercise.
    What I don’t know is the dietary composition of your food, I suspect that North Americans (incl./n.incl. Canadians) regularly have a high salt component to their foods.
    As such a reaction of stating in guidelines a particularly low salt intake may encourage members of the public to approach half way toward the very low recommendations – this makes logical managerial sense.

    Consider more “normal” warmer countries such as are experienced in much of the rest of the world (I do recognise that California is the US state with the greatest population and that experiences a more “normal” temperature).
    For better or for worse the USA has led the Westernised nations for the past 60 odd years, including in health guidelines.
    As such we have ridiculous guidelines telling us that we should be consuming less salt in environments that never reach freezing point – and as a result many people suffer and end up with medical conditions or even in hospital from a lack of salt.

    PLEASE
    Stop advising that salt is universally bad, salt is essential for retaining water in the body, yet is lost readily through (primarily) sweat and urine.

    An excess of salt disproportionate to your daily needs (perspiration and fluid intake) may prove unhealthy across an aggregate time frame, however there is no innate problem with the consumption of salt – and no universal limit, it is an essential nutrient (albeit a mineral) to our health and well-being.

    One of the more difficult OH&S considerations to manage is the intake of fluid in warmer environments (i.e. the management is responsible for ensuring the workers adequate intake of fluid). Without suitable and adequate salt intake the workers will not realise that they are suffering heat stress, or at risk of or already suffering heat stroke because the body realises thirst not from a lack of water but from a imbalance of ions in proportion to it’s internal fluids.

    This discussion could go on for a very long time and cover many important points, however I hope that you have got the idea by now.

    I don’t object to your stating a recommended salt intake level of 1500mg/day – I just want you to consider this from a more broad context (and I know that you have a technical background and so this should not be foreign to you) to specify that this recommendation is based upon assumptions and to try to make clear what those assumptions are before simply stating that “this is good” and “that is bad”.

    I’ll stop here before this becomes a novel.

    Thank you again for your efforts with this website.

    Regards

    • Tommasina

      Alan, what an interesting perspective! From my experiences traveling in hot humid countries, I can say that my consumption of salt (and potassium via potatoes and bananas) went up dramatically so I could retain water and avoid dehydration. Thanks for sharing!