Influencers are claiming that most of us should be taking in a lot more salt than is recommended. Are they right?
Influencers are claiming that most of us should be taking in a lot more salt than is recommended. Are they right?
Related listening:
Are we eating too much protein (or not enough)? (Nutrition Diva #699)
What is water weight? (Nutrition Diva #468)
Mentioned in this episode:
Potassium content of common foods (Nutrition Over Easy Blog)
Sodium: Dietary Reference Intakes for Adequacy (NIH)
Sodium: Dietary Reference Intakes for Toxicity (NIH)
Urinary Sodium and Potassium Excretion and Risk of Cardiovascular Events | Acute Coronary Syndromes (JAMA)
Effects of subacute dietary salt intake and acute volume expansion on diastolic function in young normotensive individuals (European Heart Journal)
Welcome to the Nutrition Diva podcast, a show where we take a closer look at the latest nutrition trends and headlines, so that you can make more informed decisions about what you eat. I’m your host Monica Reinagel and I have been getting lots of questions lately about salt.
Victoria, who is a registered dietitian, recently wrote about what she sees as an unsafe trend.
“I keep seeing social media influencers raving about a new product called LMNT, which contains 1000 mg of sodium per packet. The creators claim that consuming 4-6,000 milligrams of sodium per day is beneficial for health. And a lot of these influencers say they are drinking multiple packets per day.”
Meanwhile, the most recent Dietary Guidelines for Americans continues to stress the need for Americans to reduce the amount of sodium they are taking in. And in order to help people reach these targets, the FDA is pressuring food manufacturers to reduce the amount of sodium in their foods.
So which is it? Are we taking in too much sodium or too little?
Although you’d never guess it from all the hand-wringing about reducing sodium, sodium is an essential nutrient. Without it, we would die.
Most essential nutrients have a Daily Recommended Intake–the amount needed to prevent deficiency. And with many nutrients (protein comes to mind), there is a difference between the minimum amount necessary to prevent diseases of deficiency and the amount that promotes optimal health. The DRI are only concerned with the former.
For more on efforts to increase the recommended intake of protein for certain populations, see my episode #699 on whether protein recommendations are too high or too low.
Some nutrients don’t have a DRI because researchers don’t feel they have enough data to establish what amounts are necessary. Instead, these nutrients get an AI (Adequate Intake), which is the amount typically consumed by apparently healthy people.
Some nutrients also have a “tolerable upper limit” assigned to them, which is defined as “the highest average daily intake level of a nutrient, which if consumed on a habitual basis, is likely to pose no risk of adverse health effects for nearly all apparently healthy individuals.” Translation: intakes beyond that upper limit are potentially problematic.
There is no DRI for sodium, because extremely low sodium diets are so rare and so hard to achieve that there’s just not enough data to say how low is too low. (However, I have seen researchers guestimate that the lower threshold might be close to 500 mg a day for adults.) The thing is that sodium is widely enough distributed through the food supply that, under normal circumstances, if you’re consuming enough calories to sustain life, you’re consuming enough sodium to sustain life.
(Abnormal circumstances might include extreme heat, exertion, or other situations that would cause excessive perspiration, or extended and severe vomiting or diarrhea, which can deplete the body’s electrolytes. In these situations, the sodium would normally get from diet might not be enough.)
In any case, instead of a DRI for sodium, we have an AI of 1500 mg per day for adults–reflecting the amount that is typically consumed by healthy individuals. We also have an TUL of 2,300 mg per day for adults. This is the amount beyond which there is a concern for adverse effects. And the adverse event that nutrition scientists are worried about for intakes above 2,300 mg per day is high blood pressure.
However, not everyone has high blood pressure. And higher sodium diets do not cause high blood pressure in everyone. When you look at the entire population–and not just those with or at higher risk of hypertension, it appears that the people at lowest risk of cardiovascular disease and deaths from all causes are taking in a lot more than 2,300 mg per day.
Now, this is all correlational data, so we can’t say with any certainty that higher sodium intakes are making these people healthier. But the relationship is a classic J-shaped curve. People with very low and very high sodium intakes have higher rates of cardiovascular disease and higher mortality rates. The sweet-spot….the lowest point on that J-shaped curve…is between 3,000 and 6,000 mg per day.
That means that the 2,300 mg recommended by the Dietary Guidelines and the 1500 mg recommended by the American Heart Association are both in a higher-risk category.
Average daily intake for American adults, much to the dismay of public health officials, is around 3,500 mg per day–right in the sweet spot. What’s more, a meta-analysis found that “Cutting down on the amount of salt has no clear benefits in terms of likelihood of dying or experiencing cardiovascular disease.”
I know. It’s shocking. And this is what’s driving all the buzz around influencers drinking (and selling) salt water.
The guy behind LMNT–the product that my listener, Victoria, asked about–is Robb Wolf. He’s a research biochemist turned author and influencer, chiefly known as a proponent of the “Paleo” diet. The Paleo diet, of course, aims to mimic the dietary patterns of our prehistoric ancestors–based on the idea that these are foods humans are evolutionarily adapted to eating. It focuses on eating mostly whole, unprocessed foods such as meat, fish, eggs, vegetables, fruits, nuts, and seeds and avoids processed foods, added sugars, alcohol, as well as most dairy products, legumes, and grains.
When followed closely, a Paleo diet is likely to be a very low sodium diet. Wolf also is an avid exerciser, which, as I mentioned earlier, can increase sodium requirements. And apparently, Wolf discovered that he felt a lot better when he increased his salt intake. Now he sells packets containing ½ teaspoon of salt for about $1.50 a piece. (And, believe it or not, people buy them.)
But I think we’re looking at this question through too narrow a lens. Sodium does not work in a vacuum but in concert with other electrolytes. And CDC data suggest that a high potassium intake largely offsets the negative effects of a high sodium intake. Where do we get potassium? Fruits, Vegetables, Beans and legumes, Nuts and seeds, dairy, meat, and fish.
Most (70-80%) of the sodium in the modern American diet, on the other hand, comes from processed and prepared foods…including lots of salty snacks, fast food, and other restaurant meals. In other words, a high sodium intake may simply be a proxy for poor diet. In terms of reducing health risks, getting people to increase their intake of fresh foods (and potassium) might be a whole lot more effective than nagging them to reduce their sodium.
So, Job One would be to make sure you’re including plenty of fresh foods in your diet to ensure adequate potassium intake. In the show notes, I’ve included a link to a cheat sheet with some good dietary sources of potassium.
And then, if you don’t have high blood pressure and you’re just curious to see whether you’d feel better with a bit more salt than you currently consume, you could certainly test that hypothesis.
If you have any health conditions, are taking medications, or have a family history of hypertension, I’d strongly suggest checking in with your doctor before going rogue on sodium. But, the research that I’ve shared here would suggest that–in the context of a healthy diet containing plenty of potassium-rich foods–you could increase your total sodium intake from all sources (not just supplements) to 4,000 mg (about 2 teaspoons of table salt) a day without putting yourself in a higher risk category. If you are exercising very aggressively and perspiring a lot, you might be able to tolerate even more. But again, the overall quality of your diet is key, not just the sodium level.
And risk categories are statistics, not guarantees. Your mileage (and results) may vary.
Be aware, as well, that increasing your sodium intake can lead to a transient increase in your blood pressure.. This effect is more pronounced if you’re over 55. And, again, you need to talk with your doctor about whether this is acceptable and appropriate in your situation.
Taking in more salt can also lead to water retention, which can make rings and waistbands feel tight. Although it may seem counter-intuitive, increasing your fluid intake can help. See also my episode on water weight.
I know this episode is a little on the long side but I also want to quickly address a claim that some of these influencers are making, namely, that adding salt to water makes it more hydrating.
Sodium (and chloride) are both involved in fluid uptake and transport in the body. If your sodium levels are very low (say, you just ran a marathon in very hot weather), adding some salt to water could help your body rehydrate more efficiently. However, under normal circumstances, you get more than enough sodium from food to get the job done. Drinking a glass of salt water when you wake up in the morning, for example, will not hydrate you any better than drinking a glass of plain water–because you will likely have gotten more than enough sodium from last night’s dinner to assure efficient hydration.
Thanks to Victoria and all the others who wrote to ask about this. If you have a question you'd like me to answer, you can email me at nutrition@quickanddirtytips.com. You can also leave me a message at 443-961-6206
I’d also like to invite you to check out my other podcast. It’s called the Change Academy, where we explore the art and science of creating positive behavior change, both in our own lives, and in our workplaces and communities. You can find it on all the major podcast platforms. Just search for Change Academy.
Nutrition Diva is a Quick and Dirty Tips podcast and is supported by a fantastic team, which includes Brannan Goetschius, Nathan Semes, Davina Tomlin, Holly Hutchings, Morgan Christianson, and Kamryn Lacy.
That's all for this episode. Thanks for listening! I'll see you next week.