Personalized nutrition apps could provide valuable data to people trying to eat healthier, though more research must be done to show effectiveness.
As a type 2 diabetic, Michael Snyder has long been interested in how blood sugar levels vary from one person to another in response to the same food, and whether a more personalized approach to nutrition could help tackle the rapidly cascading levels of diabetes and obesity in much of the western world.
Eight years ago, Snyder, who directs the Center for Genomics and Personalized Medicine at Stanford University, decided to put his theories to the test. In the 2000s continuous glucose monitoring, or CGM, had begun to revolutionize the lives of diabetics, both type 1 and type 2. Using spherical sensors which sit on the upper arm or abdomen – with tiny wires that pierce the skin – the technology allowed patients to gain real-time updates on their blood sugar levels, transmitted directly to their phone.
It gave Snyder an idea for his research at Stanford. Applying the same technology to a group of apparently healthy people, and looking for ‘spikes’ or sudden surges in blood sugar known as hyperglycemia, could provide a means of observing how their bodies reacted to an array of foods.
“We discovered that different foods spike people differently,” he says. “Some people spike to pasta, others to bread, others to bananas, and so on. It’s very personalized and our feeling was that building programs around these devices could be extremely powerful for better managing people’s glucose.”
Unbeknown to Snyder at the time, thousands of miles away, a group of Israeli scientists at the Weizmann Institute of Science were doing exactly the same experiments. In 2015, they published a landmark paper which used CGM to track the blood sugar levels of 800 people over several days, showing that the biological response to identical foods can vary wildly. Like Snyder, they theorized that giving people a greater understanding of their own glucose responses, so they spend more time in the normal range, may reduce the prevalence of type 2 diabetes.
The commercial potential of such apps is clear, but the underlying science continues to generate intriguing findings.
“At the moment 33 percent of the U.S. population is pre-diabetic, and 70 percent of those pre-diabetics will become diabetic,” says Snyder. “Those numbers are going up, so it’s pretty clear we need to do something about it.”
Fast forward to 2022,and both teams have converted their ideas into subscription-based dietary apps which use artificial intelligence to offer data-informed nutritional and lifestyle recommendations. Snyder’s spinoff, January AI, combines CGM information with heart rate, sleep, and activity data to advise on foods to avoid and the best times to exercise. DayTwo–a start-up which utilizes the findings of Weizmann Institute of Science–obtains microbiome information by sequencing stool samples, and combines this with blood glucose data to rate ‘good’ and ‘bad’ foods for a particular person.
“CGMs can be used to devise personalized diets,” says Eran Elinav, an immunology professor and microbiota researcher at the Weizmann Institute of Science in addition to serving as a scientific consultant for DayTwo. “However, this process can be cumbersome. Therefore, in our lab we created an algorithm, based on data acquired from a big cohort of people, which can accurately predict post-meal glucose responses on a personal basis.”
The commercial potential of such apps is clear. DayTwo, who market their product to corporate employers and health insurers rather than individual consumers, recently raised $37 million in funding. But the underlying science continues to generate intriguing findings.
Last year, Elinav and colleagues published a study on 225 individuals with pre-diabetes which found that they achieved better blood sugar control when they followed a personalized diet based on DayTwo’s recommendations, compared to a Mediterranean diet. The journal Cell just released a new paper from Snyder’s group which shows that different types of fibre benefit people in different ways.
“The idea is you hear different fibres are good for you,” says Snyder. “But if you look at fibres they’re all over the map—it’s like saying all animals are the same. The responses are very individual. For a lot of people [a type of fibre called] arabinoxylan clearly reduced cholesterol while the fibre inulin had no effect. But in some people, it was the complete opposite.”
Eight years ago, Stanford's Michael Snyder began studying how continuous glucose monitors could be used by patients to gain real-time updates on their blood sugar levels, transmitted directly to their phone.
The Snyder Lab, Stanford Medicine
Because of studies like these, interest in precision nutrition approaches has exploded in recent years. In January, the National Institutes of Health announced that they are spending $170 million on a five year, multi-center initiative which aims to develop algorithms based on a whole range of data sources from blood sugar to sleep, exercise, stress, microbiome and even genomic information which can help predict which diets are most suitable for a particular individual.
“There's so many different factors which influence what you put into your mouth but also what happens to different types of nutrients and how that ultimately affects your health, which means you can’t have a one-size-fits-all set of nutritional guidelines for everyone,” says Bruce Y. Lee, professor of health policy and management at the City University of New York Graduate School of Public Health.
With the falling costs of genomic sequencing, other precision nutrition clinical trials are choosing to look at whether our genomes alone can yield key information about what our diets should look like, an emerging field of research known as nutrigenomics.
The ASPIRE-DNA clinical trial at Imperial College London is aiming to see whether particular genetic variants can be used to classify individuals into two groups, those who are more glucose sensitive to fat and those who are more sensitive to carbohydrates. By following a tailored diet based on these sensitivities, the trial aims to see whether it can prevent people with pre-diabetes from developing the disease.
But while much hope is riding on these trials, even precision nutrition advocates caution that the field remains in the very earliest of stages. Lars-Oliver Klotz, professor of nutrigenomics at Friedrich-Schiller-University in Jena, Germany, says that while the overall goal is to identify means of avoiding nutrition-related diseases, genomic data alone is unlikely to be sufficient to prevent obesity and type 2 diabetes.
“Genome data is rather simple to acquire these days as sequencing techniques have dramatically advanced in recent years,” he says. “However, the predictive value of just genome sequencing is too low in the case of obesity and prediabetes.”
Others say that while genomic data can yield useful information in terms of how different people metabolize different types of fat and specific nutrients such as B vitamins, there is a need for more research before it can be utilized in an algorithm for making dietary recommendations.
“I think it’s a little early,” says Eileen Gibney, a professor at University College Dublin. “We’ve identified a limited number of gene-nutrient interactions so far, but we need more randomized control trials of people with different genetic profiles on the same diet, to see whether they respond differently, and if that can be explained by their genetic differences.”
Some start-ups have already come unstuck for promising too much, or pushing recommendations which are not based on scientifically rigorous trials. The world of precision nutrition apps was dubbed a ‘Wild West’ by some commentators after the founders of uBiome – a start-up which offered nutritional recommendations based on information obtained from sequencing stool samples –were charged with fraud last year. The weight-loss app Noom, which was valued at $3.7 billion in May 2021, has been criticized on Twitter by a number of users who claimed that its recommendations have led to them developed eating disorders.
With precision nutrition apps marketing their technology at healthy individuals, question marks have also been raised about the value which can be gained through non-diabetics monitoring their blood sugar through CGM. While some small studies have found that wearing a CGM can make overweight or obese individuals more motivated to exercise, there is still a lack of conclusive evidence showing that this translates to improved health.
However, independent researchers remain intrigued by the technology, and say that the wealth of data generated through such apps could be used to help further stratify the different types of people who become at risk of developing type 2 diabetes.
“CGM not only enables a longer sampling time for capturing glucose levels, but will also capture lifestyle factors,” says Robert Wagner, a diabetes researcher at University Hospital Düsseldorf. “It is probable that it can be used to identify many clusters of prediabetic metabolism and predict the risk of diabetes and its complications, but maybe also specific cardiometabolic risk constellations. However, we still don’t know which forms of diabetes can be prevented by such approaches and how feasible and long-lasting such self-feedback dietary modifications are.”
Snyder himself has now been wearing a CGM for eight years, and he credits the insights it provides with helping him to manage his own diabetes. “My CGM still gives me novel insights into what foods and behaviors affect my glucose levels,” he says.
He is now looking to run clinical trials with his group at Stanford to see whether following a precision nutrition approach based on CGM and microbiome data, combined with other health information, can be used to reverse signs of pre-diabetes. If it proves successful, January AI may look to incorporate microbiome data in future.
“Ultimately, what I want to do is be able take people’s poop samples, maybe a blood draw, and say, ‘Alright, based on these parameters, this is what I think is going to spike you,’ and then have a CGM to test that out,” he says. “Getting very predictive about this, so right from the get go, you can have people better manage their health and then use the glucose monitor to help follow that.”
Anita Freeman, left, hugs her sister Elizabeth Martin at a bakery in Huntington Beach, California, in 2009 — a year before Elizabeth's cancer diagnosis. (Courtesy Anita Freeman)
For five weeks, Anita Freeman watched her sister writhe in pain. The colon cancer diagnosed four years earlier became metastatic.
"I still wouldn't wish that ending on my worst enemy."
At this tormenting juncture, her 66-year-old sister, Elizabeth Martin, wanted to die comfortably in her sleep. But doctors wouldn't help fulfill that final wish.
"It haunts me," Freeman, 74, who lives in Long Beach, California, says in recalling the prolonged agony. Her sister "was breaking out of the house and running in her pajamas down the sidewalk, screaming, 'Help me. Help me.' She just went into a total panic."
Finally, a post-acute care center offered pentobarbital, a sedative that induced a state of unconsciousness, but only after an empathetic palliative care doctor called and insisted on ending the inhumane suffering. "We even had to fight the owners of the facility to get them to agree to the recommendations," Freeman says, describing it as "the only option we had at that time; I still wouldn't wish that ending on my worst enemy."
Her sister died a week later, in 2014. That was two years before California's medical aid-in-dying law took effect, making doctors less reliant on palliative sedation to peacefully end unbearable suffering for terminally ill patients. Now, Freeman volunteers for Compassion & Choices, a national grassroots organization based in Portland, Oregon, that advocates for expanding end-of-life options.
Palliative sedation involves medicating a terminally ill patient into lowered awareness or unconsciousness in order to relieve otherwise intractable suffering at the end of life. It is not intended to cause death, which occurs due to the patient's underlying disease.
In contrast, euthanasia involves directly and deliberately ending a patient's life. Euthanasia is legal only in Canada and some European countries and requires a health care professional to administer the medication. In the United States, laws in seven states and Washington, D.C. give terminally ill patients the option to obtain prescription medication they can take to die peacefully in their sleep, but they must be able to self-adminster it.
Recently, palliative sedation has been gaining more acceptance among medical professionals as an occasional means to relieve suffering, even if it may advance the time of death, as some clinicians believe. However, studies have found no evidence of this claim. Many doctors and bioethicists emphasize that intent is what distinguishes palliative sedation from euthanasia. Others disagree. It's common for controversy to swirl around when and how to apply this practice.
Elizabeth Martin with her sister Anita Freeman in happier times, before metastatic cancer caused her tremendous suffering at the end of her life.
(Courtesy Anita Freeman)
"Intent is everything in ethics. The rigor and protocols we have around palliative sedation therapy also speaks to it being an intervention directed to ease refractory distress," says Martha Twaddle, medical director of palliative medicine and supportive care at Northwestern University's Lake Forest Hospital in Lake Forest, Illinois.
Palliative sedation should be considered only when pain, shortness of breath, and other unbearable symptoms don't respond to conventional treatments. Left to his or her own devices, a patient in this predicament could become restless, Twaddle says, noting that "agitated delirium is a horrible symptom for a family to witness."
At other times, "we don't want to be too quick to sedate," particularly in cases of purely "existential distress"—when a patient experiences anticipatory grief around "saying goodbye" to loved ones, she explains. "We want to be sure we're applying the right therapy for the problem."
Encouraging patients to reconcile with their kin may help them find inner peace. Nonmedical interventions worth exploring include quieting the environment and adjusting lighting to simulate day and night, Twaddle says.
Music-thanatology also can have a calming effect. It is live, prescriptive music, mainly employing the harp or voice, tailored to the patient's physiological needs by tuning into vital signs such as heart rate, respiration, and temperature, according to the Music-Thanatology Association International.
"When we integrated this therapeutic modality in 2003, our need for using palliative sedation therapy dropped 75 percent and has remained low ever since," Twaddle observes. "We have this as part of our care for treating refractory symptoms."
"If palliative sedation is being employed properly with the right patient, it should not hasten death."
Ethical concerns surrounding euthanasia often revolve around the term "terminal sedation," which "can entail a physician deciding that the patient is a lost cause—incurable medically and in substantial pain that cannot adequately be relieved," says John Kilner, professor and director of the bioethics programs at Trinity International University in Deerfield, Illinois.
By halting sedation at reasonable intervals, the care team can determine whether significant untreatable pain persists. Periodic discontinuation serves as "evidence that the physician is still working to restore the patient rather than merely to usher the patient painlessly into death," Kilner explains. "Indeed, sometimes after a period of unconsciousness, with the body relieved of unceasing pain, the body can recover enough to make the pain treatable."
The medications for palliative sedation "are tried and true sedatives that we've had for a long time, for many years, so they're predictable," says Joe Rotella, chief medical officer at the American Academy of Hospice and Palliative Medicine.
Some patients prefer to keep their eyes open and remain conscious to answer by name, while others tell their doctors in advance that they want to be more heavily sedated while receiving medications to manage pain and other symptoms. "We adjust the dosage until the patient is sleeping at a desired level of sedation," Rotella says.
Sedation is an intrinsic side effect of most medications prescribed to control severe symptoms in terminally ill patients. In general, most people die in a sleepy state, except for instances of sudden, dramatic death resulting from a major heart attack or stroke, says Ryan R. Nash, a palliative medicine physician and director of The Ohio State University Center for Bioethics in Columbus.
"Using those medications to treat pain or shortness of breath is not palliative sedation," Nash says. In addition, providing supplemental nutrition and hydration in situations where death is imminent—with a prognosis limited to hours or days—generally doesn't help prolong life. "If palliative sedation is being employed properly with the right patient," he adds, "it should not hasten death."
Nonetheless, hospice nurses sometimes feel morally distressed over carrying out palliative sedation. Implementing protocols at health systems would help guide them and alleviate some of their concerns, says Gregg VandeKieft, medical director for palliative care at Providence St. Joseph Health's Southwest Washington Region in Olympia, Washington. "It creates guardrails by sort of standardizing and normalizing things," he says.
"Our goal is to restore our patient. It's never to take their life."
The concept of proportionality weighs heavily in the process of palliative sedation. But sometimes substantial doses are necessary. For instance, an opioid-tolerant patient recently needed an unusually large amount of medication to control symptoms. She was in a state of illness-induced confusion and pain, says David E. Smith, a palliative medicine physician at Baptist Health Supportive Care in Little Rock, Arkansas.
Still, "we are parsimonious in what we do. We only use as much therapeutic force as necessary to achieve our goals," Smith says. "Our goal is to restore our patient. It's never to take their life."
Steven Pinker, a cognitive psychologist at Harvard, argues that the ideals of the Enlightenment deserve a vigorous moral defense.
The government shutdown. A volatile stock market. Climate change.
It's so easy to get discouraged by the latest headlines, argues Steven Pinker, that we lose sight of the bigger picture: life today is actually improving.
"To appreciate the world, we've got to look at numbers and trends."
Pinker, a cognitive psychologist from Harvard, says in his book "Enlightenment Now" that we're living at the greatest moment of progress in history, thanks to reason, science, and humanism. But today, he says, these ideals are under-appreciated, and we ignore them at our peril.
So he set out to provide a vigorous moral defense of the values of the Enlightenment by examining the evidence for their effectiveness. Across a range of categories from happiness and health to peace and safety, Pinker examines the data and reassures readers that this is a pretty great time to be alive. As we kick off the new year, he's hopeful that our embrace of science and reason will lead to an even more prosperous future. But political and cultural hurdles must still be overcome before the heroic story of human progress can continue to unfold.
Pinker spoke with our Editor-in-Chief Kira Peikoff in advance of the book's paperback release, which hits stores next Tuesday. This interview has been edited and condensed for clarity.
One anecdote you describe in the book was particularly striking: how the public reacted when the polio vaccine was announced. People took the day off work to celebrate, they smiled at each other in the streets, they offered to throw parades. Today, it's hard to imagine such prevalent enthusiasm for a new advance. How can we bring back a culture of respect and gratitude for science?
That's such a good question. And I wish I knew the answer. My contribution is just to remind people of how much progress we've made. It's easy to ignore if your view of the world comes from headlines, but there are some built-in biases in journalism that we have to counteract. Most things that happen all of a sudden are bad things: wars break out, terrorists attack, rampage shootings occur, whereas a lot of the things that make us better off creep up by stealth. But we have to become better aware of them.
It's unlikely that we're going to have replications of the great Salk event, which happened on a particular day, but I think we have to take lessons from cognitive science, from the work of people like Daniel Kahneman and Amos Tversky, showing how misled we can be by images and narratives and that to appreciate the world, we've got to look at numbers and trends.
The cover of "Enlightenment Now," which comes out in paperback next week.
You mention that the President's Bioethics Council under Bush was appointed to deal with "the looming threat of biomedical advances." Do you think that professional bioethicists are more of a hindrance than a help when it comes to creating truly enlightened science policy?
I do. I think that there are some problems in the culture of bioethics. And of course, I would not argue against that the concept of bioethics. Obviously, we have to do biomedical research and applications conscientiously and ethically. But the field called Bioethics tends to specialize in exotic thought experiments that tend to imagine the worst possible things that can happen, and often mire research in red tape that results in a net decrease in human welfare, whereas the goal of bioethics should be to enhance human welfare.
In an op-ed that I published in the Boston Globe a few years ago, I said, deliberately provocatively, that the main moral imperative of bioethics is to get out of the way since there's so much suffering that humans endure from degenerative diseases, from cancer, from heart disease and stroke. The potential for increasing happiness and well-being from biomedical research is just stupendous. So before we start to drag out Brave New World for the umpteenth time, or compare every advance in genetics to the Nazis, we should remember the costs of people dying prematurely from postponing advances in biomedical research.
Later in the book, you mention how much more efficient the production of food has become due to high-tech agriculture. But so many people today are leery of advances in the food industry, like GMOs. And we will have to feed 10 billion people in 2050. Are you concerned about how we will meet that challenge?
Yes, I think anyone has to be, and all the more reason we should be clear about what is simultaneously best for humans and for the planet, which is to grow as much food on this planet as possible. That ideal of density -- the less farmland the better -- runs up against the ideal of the organic farming and natural farming, which use lots of land. So genetically modified organisms and precision agriculture of the kind that is sometimes associated with Israel -- putting every last drop of water to use, delivering it when it's needed, using the minimum amount of fertilizer -- all of these technologically driven developments are going to be necessary to meet that need.
"The potential for increasing happiness and well-being from biomedical research is just stupendous."
You also mention "sustainability" as this big buzz word that you say is based on a flawed assumption that we will run out of resources rather than pivot to ingenious alternatives. What's the most important thing we can do as a culture to encourage innovation?
It has to be an ideal. We have restore it as what we need to encourage, to glorify in order to meet the needs of humanity. Governments have to play a role because lots of innovation is just too risky with benefits that are too widely diffuse for private companies and individuals to pursue. International cooperation has to play a role. And also, we need to change our environmental philosophy from a reflexive rejection of technology to an acknowledgement that it will be technology that is our best hope for staving off environmental problems.
And yet innovation and technology today are so often viewed fearfully by the public -- just look at AI and gene editing. If we need science and technology to solve our biggest challenges, how do we overcome this disconnect?
Part of it is simply making the argument that is challenging the ideology and untested assumptions behind traditional Greenism. Also, on the part of the promoters of technology themselves, it's crucial to make it not just clear, but to make it a reality that technology is going to be deployed to enhance human welfare.
That of course means an acknowledgement of the possible harms and limitations of technology. The fact that the first widely used genetically modified crop was soybeans that were resistant to herbicides, to Roundup -- that was at the very least a public relations disaster for genetically modified organisms. As opposed to say, highlighting crops that require less insecticide, less chemical fertilizers, less water level. The poster children for technology should really be cases that quite obviously benefit humanity.
"One of the surprises from 'Enlightenment Now' was how much moral progress depends on economic progress."
Finally, what is one emerging innovation that you're excited about for 2019?
I would say 4th generation nuclear power. Small modular reactors. Because everything depends on energy. For poor countries to get rich, they are going to have to consume far more energy than they do now and if they do it via fossil fuels, especially coal, that could spell disaster. Zero-carbon energy will allow poor countries to get richer -- and rich countries to stay rich without catastrophic environmental damage.
One of the surprises from "Enlightenment Now" was how much moral progress depends on economic progress. Rich countries not only allow the citizens to have cool gadgets, but all kinds of good things happen when a country gets rich, like Norway, Netherlands, Switzerland. Countries that are richer on average are more democratic, are less likely that to fight wars, are more feminist, are more environmentally conscientious, are smarter -- that is, they have a greater increase in IQ. So anything that makes a country get richer, and that's going to include a bunch of energy, is going to make humanity better off.