Who was it that made salt the scapegoat in the worlds rush to explain the cause of high blood-pressure? Sure scientists have proven that cholesterol is bad, but where is the definitive research proving that salt is the culprit? The reality is that we, as a species, have increased the incidence of a plethora of other health worries after we starting playing games with the mineral balance in our salt intake. We – especially those of us on a Japanese diet – should be going out of our way to take more salt and definitely should ignore the MLHW’s advice to keep our salt intake below 9g/day.
Think that sounds a little controversial? Not according to Yoshiaki Murakami (村上譲顕) who has spent his entire adult life researching the health benefits of salt and swears by everything from salt toothpaste and shampoo to a movement to bring back the traditional art of natural sea salt making in Japan. I’ve got at admit that I was skeptical too but a flip through his latest book while I was visiting the Salt and Tobacco Museum in Shibuya (たばこと塩の博物館) the other day was enough to convince me to buy a copy and come to my own conclusion.
Murakami’s book is called Nihonjin niha shioga tarinai! (日本人には塩が足りない！ “The Japanese don’t get enough salt!”) () He tells the story of how as a child he was always tired, lethargic, cold, atopic and prone to sickness. Until of course he woke up to the therapeutic value of salt at the age of 19 and he hasn’t looked back since. While I am no scientist, I feel that he (quite surprisingly) does a decent job of providing scientific rationale to his argument.
The crux of his argument is as follows: Too much of a anything is not good for you. Any food source has its highest nutritional value for us in its natural form and so less processing is better. The ‘salt’ that we unknowingly buy in the supermarket (here is where it gets interesting) isn’t really salt. It is an artificially processed supplement containing 99% sodium chloride (NaCl). “Natural sea salt” as it always has been for the past few mileniums is only 90~95% NaCl and the remaining 5~10% is made up of vital nutrients that are essential to our bodies functioning healthily. Whereas your body will always naturally dispose of any excess “natural sea salt” it can’t deal well with the manufactured NaCl that we fill our food with these days. Who knows, maybe he is right?
So what other minerals are contained in “natural sea salt”?
- Magnesium chloride (often known in Japanese as nigari にがり)
- Magnesium sulphate
- Potassium chloride
- Potassium sulphate
Ever since Japan introduced the Ion-exchange Membrane Electro-dialysis Method (イオン交換膜方法) of salt production in 1971 the vast majority of these minerals have been removed from table salt. Almost all of the salt that you will find on supermarket shelves is 99%+ NaCl. The body is constantly working to balance it’s amount of sodium vs potassium and calcium vs magnesium. If this becomes unbalanced then your body starts playing funny tricks on you. Sometimes that can mean sucking out the stores of calcium or sodium from your bones.
If you are as cynical as I am then you are probably already wondering why on earth we all have taken for granted the fact that more salt leads to higher blood pressure. According to Murakami (and I’d love to hear some rebuttal from any scientists out there in the comments section below), the primary piece of research that pointed the finger at salt as being the cause of high blood pressure (hypertension) was a 1953 paper by George Meneely, an American academic who experimented by feeding 10 rats the human equivalent of 200g of salt a day for the human equivalent of 40 years and also only let them drink salt water (1%) instead of normal water. Of those 10 rats, 4 of them developed high blood pressure. You can come to your own conclusions but if this is true then it sounds like a pretty unrealistic and inconclusive study if you ask me. Unfortunately the closest thing that I could find to the paper on the internet was this one which sounds like a different study to me. Surely if this man was responsible for our modern medical assumption that salt = high blood pressure then a little more would come out of a google search?
To his credit, Murakami then goes on to quote numerous academics whose unsung research actually points out the fact that there is no obvious correlation between salt intake and high bloodpressure. For the sake of brevity you can follow the following links yourself for examples:
- Rene Quinton (A 19th century French physiologist) “L’Eau de mer, milieu organique”
- Kyuzo Aoki (青木久三) Professor of Nagoya City University 「逆転の健康読本」
- Yumi Ishihara (石原結實) 「『塩』をしっかり摂れば、病気は治る」
- Professor Emeritus Akikazu Takada (高田明和) of Hamamatsu Medical University 「健康神話にだまされるな」
- Professor Toru Abo (阿保徹) of Niigata University 「老けない人の免疫力」
- Ryoichi Obitsu (帯津良一), director of the Obitsu Sankei Hospital 「達者でポックリ」
- Professor Emeritus Akio Shimada (島田彰夫) of Miyazaki University 「伝統食の復権」
- Sadamu Ichikura (一倉定) 「食事を変えなければ大和民族は衰亡する」
- Former Professor Shiro Kawashima (川島四郎) of Ohbirin University 「まちがい栄養学」
- Dr. Hideki Mukai (向井秀樹) of the Ohashi Hospital, Toho University 「アトピーの「かゆみ」をとる塩療法」
- Hideo Makuuchi (幕内秀夫)「粗食のすすめ」(while this isn’t a research paper it is a best seller that the author recommends on macrobiotics)
While there probably isn’t a lot of research supporting it, he does point out a few reasons why the logic might apply more to Japanese than people living in other countries. Climate: The high humidity in Japan means that people in Japan will naturally cleanse their bodies by sweating out a lot more of any unnecessary salt than people living in drier climates. Diet: there is a lot more sodium found in meat and so a Western diet provides more sodium without taking salt separately compared to a traditional Japanese diet. The Japanese even go out of their way to put nigari (bittern) into their Tofu! Water: As water naturally has more minerals in it in Europe than elsewhere, Europeans are less in need of the minerals that Japanese can obtain from natural sea salt. (and in fact European natural rock salt (岩塩, gan’en) does have less minerals than Japanese natural sea salt so there is nothing to worry about!)
Think about it. Why is that people in “the west” are constantly saying that Japanese food is healthy but for some reason the Japanese themselves are complaining that it is high in salt and not healthy despite having an extremely long life-expectancy. We’d love to hear any good reasons why not to believe it! Please comment below! If you are even slightly intrigued I do recommend reading his book as it is pretty light reading yet quite well written.