Too much of this ingredient leads to autoimmune diseases, new research shows. Here's how to cut back.
Scientists are looking at how salt affects our cells, and they're finding more reasons to avoid htoo much of it.
For more than a century, doctors have warned that too much salt in your diet can lead to high blood pressure, heart disease and stroke - and many of the reasons for these effects are well known. But recently scientists have been looking deeper, into the cellular level, and they are finding additional reasons to minimize sodium intake; it is bad for immune cells, creating patterns of gene expression and activity seen in a variety of autoimmune diseases such as multiple sclerosis, lupus, rheumatoid arthritis, and type-1 diabetes.
Salt is a major part of the ocean from which life evolved on this planet. We carry that legacy in our blood, which tastes salty. It is an important element for conducting electrical signals along nerves and balancing water and metabolites transported throughout our bodies. We need to consume about 500 milligrams of salt each day to maintain these functions, more with exercise and heavy sweating as that is a major way the body loses salt. The problem is that most Americans eating a modern western diet consume about 3400 milligrams, 1.5 teaspoons per day.
Evidence has been accumulating over the last few years that elevated levels of sodium can be harmful to at least some types of immune cells. The first signal came in monocytes, which are immune cells that travel to various tissues in the body, where some of them turn into macrophages, a subset of white blood cells that can directly kill microorganisms and make chemical signals that bring other types of immune cells into play.
Two years ago, Dominik N. Müller from the Max-Delbrueck-Center in Berlin, Germany and Markus Kleinewietfeld, an immunologist at Hasselt University in Belgium, ran a study where they fed people pizza and then measured their immune cell function. “We saw that in any monocytes, metabolic function was down, even after a single salty meal,” Kleinewietfeld says. It seemed to be the cellular equivalent of the sluggish feeling we get after eating too much. The cells were able to recover but more research is needed to answer questions about what dose of sodium causes impairment, how long the damage lasts, and whether there is a cumulative effect of salt toxicity.
Kleinewietfeld and his colleagues have hypothesized that too much salt could be a significant factor in the increased number of autoimmune diseases and allergies over the last few generations.
The latest series of experiments focused on a type of T cell called T regulatory cells, or Tregs. Most T cells release inflammatory mediators to fight pathogens and, once that job is done, Tregs come along to calm down their hyperactive brethren. Failure to do so can result in continued inflammation and possibly autoimmune diseases.
In the lab, Kleinewietfeld and his large team of international collaborators saw that high levels of sodium had a huge effect on Tregs, upregulating 1250 genes and downregulating an additional 1380 genes so that they looked similar to patterns of gene expression seen in autoimmune diseases.
Digging deeper, they found that sodium affected mitochondria, the tiny organelles inside of cells that produce much of its energy. The sodium was interfering with how the mitochondria use oxygen, which resulted in increased levels of an unstable form of oxygen that can damage cell function. The researchers injected those damaged Tregs into mice and found that they impaired the animals' immune function, allowing the inflammation to continue rather than shutting it down.
That finding dovetailed nicely with a 2019 paper in Nature from Navdeep Chandel's lab at Northwestern University, which showed in mice that inhibiting the mitochondrial use of oxygen reduced the ability of Tregs to regulate other T cells. “Mitochondria were controlling directly the immunosuppressive program, they were this master regulator tuning the right amount of genes to give you proper immunosuppression,” Chandel said. “And if you lose that function, then you get autoimmunity.”
Kleinewietfeld's team studied the Treg cells of humans and found that sodium can similarly decrease mitochondrial use of oxygen and immunosuppressive activity. “I would have never predicted that myself,” Chandel says, but now researchers can look at the mitochondria of patients with autoimmune disease and see if their gene expression also changes under high salt conditions. He sees the link between the patterns of gene expression in Tregs generated by high salt exposure and those patterns seen in autoimmune diseases, but he is cautious about claiming a causal effect.
Kleinewietfeld and his colleagues have hypothesized that too much salt could be a significant factor in the increased number of autoimmune diseases and allergies over the last few generations. He says a high salt diet could also have an indirect effect on immune function through the way it affects the gut microbiome and the molecules made by microbes when they break down food. But the research results are too preliminary to say that for sure, much less parse out the role of salt compared with other possible factors. “It is still an exciting journey to try to understand this field,” he says.
Additionally, it is difficult to say precisely how this research in animals and human cell cultures will translate into a whole human body. Individual differences in genetics can affect how the body absorbs, transports, and gets rid of sodium, such that some people are more sensitive to salt than are others.
So how should people apply these research findings to daily life?
Salt is obvious when we sprinkle it on at the table or eat tasty things like potato chips, but we may be unaware of sodium hidden in packaged foods. That's because salt is an easy and cheap way to boost the flavor of foods. And if we do read the labeled salt content on a package, we focus on the number for a single serving, but then eat more than that.
Last September, the U.S. Food and Drug Administration (FDA) began a process to update labels on the content of food, including what is meant by the word “healthy” and how food manufacturers can use the term. Many in the food industry are resisting those proposed changes.
Chandel cautions against trying to counter the effects of salt by reaching for foods or supplements full of antioxidants, which, in theory, could reduce the harmful effects on mitochondria caused by a heavy hand with the salt shaker.
Until labels are updated, it would be prudent to try to reduce sodium intake by cutting down on packaged foods while making your own food at home, where you know just how much salt has been added. The Mayo Clinic offers guidance on how to become more aware of the sodium in your diet and eat less of it.
Chandel thinks many people will struggle with minimizing salt in their diets. It’s similar to the challenge of eating less sugar, in that the body craves both, and it is difficult to fight that. He cautions against trying to counter the effects of salt by reaching for foods or supplements full of antioxidants, which, in theory, could reduce the harmful effects on mitochondria caused by a heavy hand with the salt shaker. “Dietary antioxidants have failed in just about every clinical trial, yet the public continues to take them,” Chandel says. But he is optimistic that research will lead us to a better understanding of how Tregs function, and uncover new targets for treating autoimmune diseases.
Podcast: The future of brain health with Percy Griffin
Percy Griffin, director of scientific engagement for the Alzheimer’s Association, joins Leaps.org to discuss the present and future of the fight against dementia.
Today's guest is Percy Griffin, director of scientific engagement for the Alzheimer’s Association, a nonprofit that’s focused on speeding up research, finding better ways to detect Alzheimer’s earlier and other approaches for reducing risk. Percy has a doctorate in molecular cell biology from Washington University, he’s led important research on Alzheimer’s, and you can find the link to his full bio in the show notes, below.
Our topic for this conversation is the present and future of the fight against dementia. Billions of dollars have been spent by the National Institutes of Health and biotechs to research new treatments for Alzheimer's and other forms of dementia, but so far there's been little to show for it. Last year, Aduhelm became the first drug to be approved by the FDA for Alzheimer’s in 20 years, but it's received a raft of bad publicity, with red flags about its effectiveness, side effects and cost.
Meanwhile, 6.5 million Americans have Alzheimer's, and this number could increase to 13 million in 2050. Listen to this conversation if you’re concerned about your own brain health, that of family members getting older, or if you’re just concerned about the future of this country with experts predicting the number people over 65 will increase dramatically in the very near future.
Listen to the Episode
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4:40 - We talk about the parts of Percy’s life that led to him to concentrate on working in this important area.
6:20 - He defines Alzheimer's and dementia, and discusses the key elements of communicating science.
10:20 - Percy explains why the Alzheimer’s Association has been supportive of Aduhelm, even as others have been critical.
17:58 - We talk about therapeutics under development, which ones to be excited about, and how they could be tailored to a person's own biology.
24:25 - Percy discusses funding and tradeoffs between investing more money into Alzheimer’s research compared to other intractable diseases like cancer, and new opportunities to accelerate progress, such as ARPA-H, President Biden’s proposed agency to speed up health breakthroughs.
27:24 - We talk about the social determinants of brain health. What are the pros/cons of continuing to spend massive sums of money to develop new drugs like Aduhelm versus refocusing on expanding policies to address social determinants - like better education, nutritious food and safe drinking water - that have enabled some groups more than others to enjoy improved cognition late in life.
34:18 - Percy describes his top lifestyle recommendations for protecting your mind.
37:33 - Is napping bad for the brain?
39:39 - Circadian rhythm and Alzheimer's.
42:34 - What tests can people take to check their brain health today, and which biomarkers are we making progress on?
47:25 - Percy highlights important programs run by the Alzheimer’s Association to support advances.
Show links:
** After this episode was recorded, the Centers for Medicare and Medicaid Services affirmed its decision from last June to limit coverage of Aduhelm. More here.
- Percy Griffin's bio: https://www.alz.org/manh/events/alztalks/upcoming-...
- The Alzheimer's Association's Part the Cloud program: https://alz.org/partthecloud/about-us.asp
- The paradox of dementia rates decreasing: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7455342/
- The argument for focusing more resources on improving institutions and social processes for brain health: https://www.statnews.com/2021/09/23/the-brain-heal...
- Recent research on napping: https://www.ocregister.com/2022/03/25/alzheimers-s...
- The Alzheimer's Association helpline: https://www.alz.org/help-support/resources/helpline
- ALZConnected, a free online community for people affected by dementia https://www.alzconnected.org/
- TrialMatch for people with dementia and healthy volunteers to find clinical trials for Alzheimer's and other dementia: https://www.alz.org/alzheimers-dementia/research_p...
Employers can create a culture of “Excellence From Anywhere” to reduce the risk of inequality among office-centric, hybrid, and fully remote employees.
COVID-19 prompted numerous companies to reconsider their approach to the future of work. Many leaders felt reluctant about maintaining hybrid and remote work options after vaccines became widely available. Yet the emergence of dangerous COVID variants such as Omicron has shown the folly of this mindset.
To mitigate the risks of new variants and other public health threats, as well as to satisfy the desires of a large majority of employees who express a strong desire in multiple surveys for a flexible hybrid or fully remote schedule, leaders are increasingly accepting that hybrid and remote options represent the future of work. No wonder that a February 2022 survey by the Federal Reserve Bank of Richmond showed that more and more firms are offering hybrid and fully-remote work options. The firms expect to have more remote workers next year and more geographically-distributed workers.
Although hybrid and remote work mitigates public health risks, it poses another set of health concerns relevant to employee wellbeing, due to the threat of proximity bias. This term refers to the negative impact on work culture from the prospect of inequality among office-centric, hybrid, and fully remote employees.
The difference in time spent in the office leads to concerns ranging from decreased career mobility for those who spend less facetime with their supervisor to resentment building up against the staff who have the most flexibility in where to work. In fact, a January 2022 survey by the company Slack of over 10,000 knowledge workers and their leaders shows that proximity bias is the top concern – expressed by 41% of executives - about hybrid and remote work.
To address this problem requires using best practices based on cognitive science for creating a culture of “Excellence From Anywhere.” This solution is based on guidance that I developed for leaders at 17 pioneering organizations for a company culture fit for the future of work.
Protect from proximity bias via the "Excellence From Anywhere" strategy
So why haven’t firms addressed the obvious problem of proximity bias? Any reasonable external observer could predict the issues arising from differences of time spent in the office.
Unfortunately, leaders often fail to see the clear threat in front of their nose. You might have heard of black swans: low-probability, high-impact threats. Well, the opposite kind of threats are called gray rhinos: obvious dangers that we fail to see because of our mental blindspots. The scientific name for these blindspots is cognitive biases, which cause leaders to resist best practices in transitioning to a hybrid-first model.
The core idea is to get all of your workforce to pull together to achieve business outcomes: the location doesn’t matter.
Leaders can address this by focusing on a shared culture of “Excellence From Anywhere.” This term refers to a flexible organizational culture that takes into account the nature of an employee's work and promotes evaluating employees based on task completion, allowing remote work whenever possible.
Addressing Resentments Due to Proximity Bias
The “Excellence From Anywhere” strategy addresses concerns about treatment of remote workers by focusing on deliverables, regardless of where you work. Doing so also involves adopting best practices for hybrid and remote collaboration and innovation.
By valuing deliverables, collaboration, and innovation through a focus on a shared work culture of “Excellence From Anywhere,” you can instill in your employees a focus on deliverables. The core idea is to get all of your workforce to pull together to achieve business outcomes: the location doesn’t matter.
This work culture addresses concerns about fairness by reframing the conversation to focus on accomplishing shared goals, rather than the method of doing so. After all, no one wants their colleagues to have to commute out of spite.
This technique appeals to the tribal aspect of our brains. We are evolutionarily adapted to living in small tribal groups of 50-150 people. Spending different amounts of time in the office splits apart the work tribe into different tribes. However, cultivating a shared focus on business outcomes helps mitigate such divisions and create a greater sense of unity, alleviating frustrations and resentments. Doing so helps improve employee emotional wellbeing and facilitates good collaboration.
Solving the facetime concerns of proximity bias
But what about facetime with the boss? To address this problem necessitates shifting from the traditional, high-stakes, large-scale quarterly or even annual performance evaluations to much more frequent weekly or biweekly, low-stakes, brief performance evaluation through one-on-one in-person or videoconference check-ins.
Supervisees agree with their supervisor on three to five weekly or biweekly performance goals. Then, 72 hours before their check-in meeting, they send a brief report, under a page, to their boss of how they did on these goals, what challenges they faced and how they overcame them, a quantitative self-evaluation, and proposed goals for next week. Twenty-four hours before the meeting, the supervisor responds in a paragraph-long response with their initial impressions of the report.
It’s hard to tell how much any employee should worry about not being able to chat by the watercooler with their boss: knowing exactly where they stand is the key concern for employees, and they can take proactive action if they see their standing suffer.
At the one-on-one, the supervisor reinforces positive aspects of performance and coaches the supervisee on how to solve challenges better, agrees or revises the goals for next time, and affirms or revises the performance evaluation. That performance evaluation gets fed into a constant performance and promotion review system, which can replace or complement a more thorough annual evaluation.
This type of brief and frequent performance evaluation meeting ensures that the employee’s work is integrated with efforts by the supervisor’s other employees, thereby ensuring more unity in achieving business outcomes. It also mitigates concerns about facetime, since all get at least some personalized attention from their team leader. But more importantly, it addresses the underlying concerns about career mobility by giving all staff a clear indication of where they stand at all times. After all, it’s hard to tell how much any employee should worry about not being able to chat by the watercooler with their boss: knowing exactly where they stand is the key concern for employees, and they can take proactive action if they see their standing suffer.
Such best practices help integrate employees into a work culture fit for the future of work while fostering good relationships with managers. Research shows supervisor-supervisee relationships are the most critical ones for employee wellbeing, engagement, and retention.
Conclusion
You don’t have to be the CEO to implement these techniques. Lower-level leaders of small rank-and-file teams can implement these shifts within their own teams, adapting their culture and performance evaluations. And if you are a staff member rather than a leader, send this article to your supervisor and other employees at your company: start a conversation about the benefits of addressing proximity bias using such research-based best practices.