Are you eating enough salt?

The following is an edited transcription based on the above video to provide additional context and support. 

One of the more interesting things about insulin resistance and metabolic function in the body is the relationship that salt can play. We’ve been told for decades that we need to eat less salt due to the possibility of salt causing high blood pressure, which in turn would increase the risk of heart disease.

A problem with this view is that one of the greatest predictors of heart disease is insulin resistance[1]. When we view salt restriction through the lens of what it does to insulin resistance, the story gets a little complicated. There are abundant clinical studies to show that when we cut salt too much, it actually increases insulin, and when insulin goes up, so does insulin resistance. That’s right–deliberate salt restriction can increase insulin resistance in humans[2]. Ironically, low-salt diets also increase LDL cholesterol[3], which is the most beloved (if misplaced)[4] marker of heart disease.

The effect on insulin is due to how the body handles water–insulin has a water-retaining effect. Salt (and its parts sodium and chloride) is a molecule of life–it is so essential that when dietary salt is reduced, the body seeks to retain whatever it already has. Thus, by cutting salt in the diet, we activate insulin and other processes to try and hold on to whatever salt we have left. And as salt restriction continues, the insulin remains elevated, which begins to promote a degree of insulin resistance.

But the connection between insulin and salt retention is moderated by another hormone–aldosterone. It’s aldosterone, which insulin activates, that actually tells the kidneys to reduce the amount of salt that is being lost in the urine by pulling it back into the blood. And where salt goes, water follows. In other words, as the body is holding onto salt, it’s also holding onto more water. As water retention increases, it increases the volume of the blood, which in turn increases blood pressure.

Ultimately, these physiological findings hint at a value in scrutinizing insulin rather than salt when it comes to controlling blood pressure. So rather than worrying about how much salt is on your foods, perhaps there’s a value in worrying how the foods will impact your insulin levels. Furthermore, if you are struggling with insulin resistance and high blood pressure, this sounds a little paradoxical, but perhaps there is some reason to be sure you’re eating enough salt. It’s certainly worth controlling dietary carbohydrates to help control insulin and let the dietary salt work itself out.[5]

References

1. https://cardiab.biomedcentral.com/articles/10.1186/s12933-018-0762-4
2. https://www.sciencedirect.com/science/article/pii/S002604951000329X?casa_token=ySizbaKHfu8AAAAA:gL7jY4oZ5RIQxeHk5m-buBpTQY8qRw72hQkjwqcioc3lr6IGYbl0zhXVSM9eafMPBvlpezUg67E
3. https://www.sciencedirect.com/science/article/pii/S0021915008000063?casa_token=i_2_FDRpGwQAAAAA:ldSFrDLqYu_aCMWAO8iBvqTBCw-OLdcoHB-WAn0y9SZIrgIVqi3L2HuQzuvL7DdlKuZdX6MhFAU
4. https://agsjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1532-5415.2004.52455.x?casa_token=DNQ1Bbwd2vkAAAAA%3AawIo1ATArSPmRjlvMoTUUN_ktspD00CckdY2k-tLqKQdvIXSHz3hb35fvPCI_H3Mq5muDQbHjnnfYaBN
5. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-789X.2012.01021.x?casa_token=8-wMfcu4tw8AAAAA%3AckSDcPzuYArM3K5KEUJisEu7-zHhys8tJAW4VUoBpe1dlmGdaFEaEGIpF_W6bfkJ3_g0ZQL1Z27YA-5t