Research by Miriam LeMaistre
We all remember the war on fat in the 1990s. Low-fat cookies were all the rage, and butter substitutes lined our pantry shelves. Of course, this was swinging the health pendulum too far, and we now know that certain fats are good for your health. And now we find ourselves in a similar predicament, but this time on salt…
The effect of salt on health (especially heart health) is confusing. For every study that suggests salt is unhealthy, another one does not. The bottom line is that research has not found a strong connection between a reduced-sodium, lower blood pressure, and better health. Of course, too much sodium in your diet can have adverse effects. Also, many high sodium foods are highly processed which we can all agree are terrible for our health but may falsely implicate salt as a primary culprit. Eliminating too much salt from our diet may also prove problematic.
How Does Sodium Impact Health?
Sodium is essential for our bodies to function. Low-sodium diets are associated with higher triglycerides, cholesterol, and even higher blood pressure. When salt intake is cut, the body responds by releasing an enzyme and a hormone, renin, and aldosterone, that increase blood pressure. Similarly, cutting salt to low levels triggers a release of adrenaline and noradrenaline, contributing to a 2.5% increase in cholesterol and a 7% increase in triglycerides. Those correlations may be surprising to many, but we are used to discussing salt related to heart health — and salt impacts way more than that.
Experts advocating (for healthy levels) of salt intake have been more vocal about how salt benefits our health more broadly, and the conversation around salt is starting to gain attention. If we deprive ourselves of salt, the effects can include digestion issues, headaches, muscle cramps, and brain fog. Sodium is connected to mental functions like memory and executive functioning, which covers tasks such as planning, goal execution, and impulse control.
When it comes to cognitive and athletic performance, Louisa Nicola, a neuroscientist and neurophysiologist, helped clarify this connection:
“When it comes to electrolytes, sodium seems to be the most important for brain health. Even mild decreases in sodium levels can cause cognitive complaints, and when we look at elite athletes, we see the average athlete loses 1 to 3 liters of sweat per hour. Sodium and chloride (salt), magnesium, potassium, and calcium primarily make up sweat. The average loss of sodium per liter of sweat is about 200mg. A hydration protocol consisting of sodium and other forms of electrolytes during a game can increase the efficiency of their brain so the athlete can perform better.”
Because sodium is such an important factor in our hydration and has an independent effect on how well we think and plan, it's crucial to monitor our sodium before, during, and after we are active.
Whether we are athletes or not, salt serves essential purposes for everyone in regulating our insulin, transporting neurotransmitters, promoting blood flow, and helping balance other minerals that help our bodies function, such as magnesium and calcium. We need to keep healthy and adequate levels of salt intake to support multiple systems.
Sleep and Salt - Is There a Connection?
We know sleep is a vital part of our health, and if salt helps our health, it stands to good reason that there may be a connection between salt and sleep, too, right?
Evidence of this connection is starting to emerge. As we noted above, research has shown a relationship between low sodium diets and increased adrenaline production. The adrenaline activates our stress response (a.k.a. fight or flight response/sympathetic nervous system) and is associated with fatigue and lower sleep quality.
Another study found that people with insomnia had lower sodium levels in their bloodstream, and this same group of patients had poorer health outcomes. Also, one interesting study found restricted salt intake accelerated the process of decreased body temperature and lowered the metabolic rate of brown fat that can occur as we age. Lower metabolic rates of brown fat are a pathway to more inflammation and chronic pain, which can negatively impact sleep. When brown fat tissue metabolism is reversed or increased in rats, they have more slow wave sleep (SWS).
Although this link between sodium intake and sleep is less clear, these studies support that having adequate sodium levels in our bodies helps promote sleep quality indirectly by supporting our stress response system, body temperature, and fat metabolism.
How Much Salt Do We Need?
Although there is some debate on this topic, the American Heart Association recommends 2,300mg of sodium intake per day or about one teaspoon. The average American consumes 3,400mg.
We can hit that sweet spot in our salt intake by considering the sodium from our diets, factoring in our activity levels and ensuring we get enough salt through options ranging from salt tablets to sprinkling sea salt on our veggies. We do not want to get sodium through foods such as canned soups and processed or cured meats.
It's clear that too little or too much salt can negatively impact our overall health and sleep. Our bodies love moderation, balance, and consistency in our salt intake and sleep (and everything really)!