Were they wrong about Salt?

There is one key thing about nutrition that modern Western Medicine gets wrong over and over and over. 
I call it the "all or nothing" approach to nutrition. Basically, every food group, ingredient, or nutrient is either good for you (eat it all the time!) or bad for you (never, ever, ever eat that!). When the medical research seems to indicate a connection between a particular food item and a health condition, the response is to reduce the intake of that food down to as close to zero as possible. There have been many vilified foods: saturated fat in the recent past, carbohydrates currently, and for many people, ever since a high blood pressure reading at the doctor's office, salt. For a long time the recommendation has been to reduce intake of sodium as low as possible, with a maximum of 1,500mg/day for those with hypertension or cardiovascular disease. The problem is that nutrients don't work like that. Nutrients work in a  way that has been described by many as "The Goldilock's Principle".


In 2013 the National Academies of Science's Institute of Medicine undertook a massive evaluation of all the available evidence. They combed through hundreds of studies on the relationship between sodium intake and cardiovascular disease, kidney health, blood pressure and blood lipid levels. What they found should change how we think about salt intake. (here's a link to the study)

Just right...What they found is that reducing your sodium intake down to 1,500mg/day doesn't provide additional benefits to blood pressure. It also increases the risk of adverse effects. It leads to an increase in triglyceride levels, negatively impacts insulin levels, and increases the risk of chronic heart disease when compared to those consuming a more moderate level of sodium. Reducing sodium intake IS an appropriate intervention only IF your sodium intake is extremely high, (say 5,000mg/day or more) but if you are getting the typical amount for an American (2,900-4,200mg/day) you are unlikely to gain additional benefits by further reducing your sodium intake. That's because optimal sodium intake, like most nutrients, is defined by "the Goldilock's principle" (you thought I'd never come back and explain that, didn't you?) Basically, you could draw the optimal intake for sodium as a bell curve with an optimal range somewhere in the middle. Get a lot more, or a lot less than that optimal range and symptoms start to pop up. You want it to be "just right.". (there are a few genetic variants for which sodium restriction will have a more pronounced effect, the bell curve moves to the left for people with these genetic variants. These "salt-sensitive" people are identified by our genetic consultations.) When you do consume salt, it's a good idea to move around the world (Himalayan sea salt this month, Mediterranean sea salt next month) as each region will produce salt with slightly different trace mineral content; mixing it up will optimize your intake of these trace minerals.

*A Little Aside: To Iodize or not to iodize? 
The presence of iodine in the absence of sufficient selenium (rampant in America) can trigger autoimmune thyroid disease. Iodization of our salt coincided with a 4 fold increase in auto-immune thyroid disease. However, Americans are often also iodine deficient. What to do? My recommendation to my patients is to get your iodine by regularly consuming seafood and seaweed (sources that contain both iodine and selenium), and to avoid iodized salt. 

So, what is the optimal Nutritional Approach to High Blood Pressure
There is, however, a large body of evidence supporting increasing potassium intake to improve blood pressure. (Here's a massive meta-analysis) This isn't surprising as sodium and potassium work in a push-pull relationship, controlling cell membrane gradients, and influencing kidney excretion of one another. Adequate intake for potassium is 4,700mg/day for adults. In addressing high blood pressure in patients, I've often had them track their daily potassium intake. The majority of my patients found they were consuming in the neighborhood of 2,000mg/day, or less than half of the recommended daily intake. Once they bring their potassium intake up, blood pressure drops. It is a great intervention because it is rapid, reliable, and simple to implement. Track your potassium intake for 1 week and maintain at least 4,700mg/day. By the end of the week you can expect your blood pressure to be down by around 15 points (seriously).

Two other important nutrients for blood pressure control are magnesium, and soluble fiber. You can get potassium, magnesium, and soluble fiber in plentiful amounts with a single intervention: eat more fruits and veggies. Aim for at least 6 servings per day. It's easy: reach for a fruit or veggie instead of potato chips or a granola bar when you want a snack. Have a fruit or veggie with each meal. ​