Let me start by saying I’m a salt-o’holic. Since I was 5 years old and watched my father salting his salad (I thought hey, salad doesn’t taste good, if he salts it maybe that helps. It did!) I’ve been hooked. I have hypertension and know it’s bad for me to consume this much. So now comes the ‘I recommend you do as they say, not as I do’ advice. Actually I have cut way back on salt lately, but it isn’t the first time, it often doesn’t last very long.
We need salt, it is a requirement for life, but we really don’t need much more than what is contained in the natural food we eat. Our gut (and microbiome) can probably handle a little more, but we shouldn’t indulge in much more than that on a daily basis. I’ve seen several websites and Facebook pages suggesting that people should consume large amounts of salt, actually drink glasses of salt water several times per day! This is suppose to fix some condition or another according to the authors. What do all of these sites have in common? Very little, or usually, no, scientific research to back up their claims.
People using huge amounts of salt to treat various conditions are basically covering up their symptoms. Taking heroin daily to cover up aches and pains isn’t a good idea either. Salt is not an internal medicine unless you are deficient (and very few people are). It puts a huge load on the kidneys and every cell in the body.
“A Western lifestyle with high salt consumption can lead to hypertension and cardiovascular disease. High salt may additionally drive autoimmunity by inducing T helper 17 (TH17) cells, which can also contribute to hypertension. Induction of TH17 cells depends on gut microbiota… Here we show that high salt intake affects the gut microbiome in mice…In line with these findings, a moderate high-salt challenge in a pilot study in humans reduced intestinal survival of Lactobacillus spp., increased TH17 cells and increased blood pressure. Our results connect high salt intake to the gut–immune axis and highlight the gut microbiome as a potential therapeutic target to counteract salt-sensitive conditions.”
Autoimmune encephalitis causes subacute deficits of memory and cognition.
“a HSD boosts TH17 generation and exacerbates actively induced experimental autoimmune encephalomyelitis” — Nature Published 30 November 2017
If we don’t have a strong microbiome, or we have poor microbiota diversity, it can effect our ability to produce hormones.
“a moderate high-salt challenge in a pilot study in humans reduced intestinal survival of Lactobacillus spp., increased TH17 cells and increased blood pressure. Our results connect high salt intake to the gut–immune axis and highlight the gut microbiome as a potential therapeutic target to counteract salt-sensitive conditions…
There are monoamine-containing enterochromaffin cells in the mucosa and submucosa of different portions of the stomach and small intestines. The gut microbiota can influence the ability of enterochromaffin cells to produce serotonin, dopamine, and norepinephrine that can influence the behavior of the host, termed brain gut microbiome axis and renal function, termed gastrorenal reflex. The absence of gut microbiota has been reported to increase anxiety-like behavior and decreased dopamine turnover in the frontal cortex, hippocampus, and striatum in response to acute stress in rats… Gut microbiota can influence the production of monoamines by enterochromaffin cells. The gut production of serotonin, dopamine, and norepinephrine can affect not only the behavior of the host (brain-gut axis) but also the ability of the kidney to excrete a sodium load (gastro-renal axis).” — PubMed ID#PMC4578629
“In the third study, a group led by Dr. David Hafler discovered that increased salt concentrations boosted the development of both mouse and human naive T cells into Th17 cells. This led them to explore the molecular pathways involved in Th17 cell development. They also found that mice fed a high-salt diet developed a more severe form of EAE (autoimmune encephalomyelitis)… The incidence of certain autoimmune diseases in our society, including multiple sclerosis and type 1 diabetes, has been rising over recent decades. This research suggests that one factor may be that we now eat more processed foods with high levels of salt.” — NIH.GOV
If you are familiar with the fermentation of foods it should be easy to see how consuming large amounts of salt can drastically change the microbiome. Salt is used in fermentation to limit what bacteria will grow to a very narrow spectrum of bacterial species. Our gut does the same same thing by maintaining a low (acidic) pH. High amounts of salt lowers the pH, but it also harms many strains of bacteria that should be living in our gut.
Needless to say this dramatic shift in the microbiome is not healthy in other regards as well. Too much salt will certainly hold down diversity, and diversity is known to be a strong marker for good gut health and a lower risk for IBS/IBD. The strains that are held back by this high salt intake are not yet well documented, but some could be very important for good health. For instance, the studies showed that the low diversity caused by high salt intake led to anxiety symptoms in the mice being studied.
In conclusion, too much salt in the diet can throw off the microbiome. One of the many affects of this is increased blood pressure. This action is separate from the well known ability of excess salt to cause water retention. This can also change our epigenetics and cause us to become salt-sensitive, and perhaps lead to autoimmune conditions. Does this mean we should quit eating salt? No, but it might not be a good idea to supplement it (like several unscientific protocols suggest people should be doing), consume less processed foods (and there are many reasons to do to that), and perhaps put the salt shaker away and use herbs and spices instead.