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.”
Overabundance of dissolved carbon dioxide poses a threat to marine life. A new system detects elevated levels of the greenhouse gases and mitigates them on the spot.
To date, though, methods for measuring CO2 in water at scale have been either intensely expensive, requiring fancy sensors that pump CO2 through membranes; or prohibitively complicated, involving a series of lab-based analyses. And that’s led to a bottleneck in efforts to remove carbon as well.
But recently, Boudinot cracked part of the code for measurement and mitigation, at least on a small scale. While the rest of the industry sorts out larger intricacies like getting ocean carbon markets up and running and driving carbon removal at billion-ton scale in centralized infrastructure, his decentralized method could have important, more immediate implications.
Specifically, for shellfish hatcheries, which grow seafood for human consumption and for coastal restoration projects. Some of these incubators for oysters and clams and scallops are already feeling the negative effects of excess carbon in water, and Vycarb’s tech could improve outcomes for the larval- and juvenile-stage mollusks they’re raising. “We’re learning from these folks about what their needs are, so that we’re developing our system as a solution that’s relevant,” Boudinot says.
Ocean acidification can wreak havoc on developing shellfish, inhibiting their shells from growing and leading to mass die-offs.
Ocean waters naturally absorb CO2 gas from the atmosphere. When CO2 accumulates faster than nature can dissipate it, it reacts with H2O molecules, forming carbonic acid, H2CO3, which makes the water column more acidic. On the West Coast, acidification occurs when deep, carbon dioxide-rich waters upwell onto the coast. This can wreak havoc on developing shellfish, inhibiting their shells from growing and leading to mass die-offs; this happened, disastrously, at Pacific Northwest oyster hatcheries in 2007.
This type of acidification will eventually come for the East Coast, too, says Ryan Wallace, assistant professor and graduate director of environmental studies and sciences at Long Island’s Adelphi University, who studies acidification. But at the moment, East Coast acidification has other sources: agricultural runoff, usually in the form of nitrogen, and human and animal waste entering coastal areas. These excess nutrient loads cause algae to grow, which isn’t a problem in and of itself, Wallace says; but when algae die, they’re consumed by bacteria, whose respiration in turn bumps up CO2 levels in water.
“Unfortunately, this is occurring at the bottom [of the water column], where shellfish organisms live and grow,” Wallace says. Acidification on the East Coast is minutely localized, occurring closest to where nutrients are being released, as well as seasonally; at least one local shellfish farm, on Fishers Island in the Long Island Sound, has contended with its effects.
The second Vycarb pilot, ready to be installed at the East Hampton shellfish hatchery.
Courtesy of Vycarb
Besides CO2, ocean water contains two other forms of dissolved carbon — carbonate (CO3-) and bicarbonate (HCO3) — at all times, at differing levels. At low pH (acidic), CO2 prevails; at medium pH, HCO3 is the dominant form; at higher pH, CO3 dominates. Boudinot’s invention is the first real-time measurement for all three, he says. From the dock at the Navy Yard, his pilot system uses carefully calibrated but low-cost sensors to gauge the water’s pH and its corresponding levels of CO2. When it detects elevated levels of the greenhouse gas, the system mitigates it on the spot. It does this by adding a bicarbonate powder that’s a byproduct of agricultural limestone mining in nearby Pennsylvania. Because the bicarbonate powder is alkaline, it increases the water pH and reduces the acidity. “We drive a chemical reaction to increase the pH to convert greenhouse gas- and acid-causing CO2 into bicarbonate, which is HCO3,” Boudinot says. “And HCO3 is what shellfish and fish and lots of marine life prefers over CO2.”
This de-acidifying “buffering” is something shellfish operations already do to water, usually by adding soda ash (NaHCO3), which is also alkaline. Some hatcheries add soda ash constantly, just in case; some wait till acidification causes significant problems. Generally, for an overly busy shellfish farmer to detect acidification takes time and effort. “We’re out there daily, taking a look at the pH and figuring out how much we need to dose it,” explains John “Barley” Dunne, director of the East Hampton Shellfish Hatchery on Long Island. “If this is an automatic system…that would be much less labor intensive — one less thing to monitor when we have so many other things we need to monitor.”
Across the Sound at the hatchery he runs, Dunne annually produces 30 million hard clams, 6 million oysters, and “if we’re lucky, some years we get a million bay scallops,” he says. These mollusks are destined for restoration projects around the town of East Hampton, where they’ll create habitat, filter water, and protect the coastline from sea level rise and storm surge. So far, Dunne’s hatchery has largely escaped the ill effects of acidification, although his bay scallops are having a finicky year and he’s checking to see if acidification might be part of the problem. But “I think it's important to have these solutions ready-at-hand for when the time comes,” he says. That’s why he’s hosting a second, 70-liter Vycarb pilot starting this summer on a dock adjacent to his East Hampton operation; it will amp up to a 50,000 liter-system in a few months.
If it can buffer water over a large area, absolutely this will benefit natural spawns. -- John “Barley” Dunne.
Boudinot hopes this new pilot will act as a proof of concept for hatcheries up and down the East Coast. The area from Maine to Nova Scotia is experiencing the worst of Atlantic acidification, due in part to increased Arctic meltwater combining with Gulf of St. Lawrence freshwater; that decreases saturation of calcium carbonate, making the water more acidic. Boudinot says his system should work to adjust low pH regardless of the cause or locale. The East Hampton system will eventually test and buffer-as-necessary the water that Dunne pumps from the Sound into 100-gallon land-based tanks where larvae grow for two weeks before being transferred to an in-Sound nursery to plump up.
Dunne says this could have positive effects — not only on his hatchery but on wild shellfish populations, too, reducing at least one stressor their larvae experience (others include increasing water temperatures and decreased oxygen levels). “If it can buffer water over a large area, absolutely this will [benefit] natural spawns,” he says.
No one believes the Vycarb model — even if it proves capable of functioning at much greater scale — is the sole solution to acidification in the ocean. Wallace says new water treatment plants in New York City, which reduce nitrogen released into coastal waters, are an important part of the equation. And “certainly, some green infrastructure would help,” says Boudinot, like restoring coastal and tidal wetlands to help filter nutrient runoff.
In the meantime, Boudinot continues to collect data in advance of amping up his own operations. Still unknown is the effect of releasing huge amounts of alkalinity into the ocean. Boudinot says a pH of 9 or higher can be too harsh for marine life, plus it can also trigger a release of CO2 from the water back into the atmosphere. For a third pilot, on Governor’s Island in New York Harbor, Vycarb will install yet another system from which Boudinot’s team will frequently sample to analyze some of those and other impacts. “Let's really make sure that we know what the results are,” he says. “Let's have data to show, because in this carbon world, things behave very differently out in the real world versus on paper.”
Many children use makeup and body products such as glitter, face paint and lip gloss. Scientists are pointing to the harmful chemicals in some of these products, and advocates are looking to outlaw them.
In 2013, Toxic-Free Future launched Mind the Store to challenge the nation’s largest retailers in adopting comprehensive policies that eliminate toxic chemicals in their personal care products and packaging, and develop safer alternatives.
Now, more efforts are underway to expose and mitigate the harm in cosmetics, hair care and other products that children apply on their faces, heads, nails and other body parts. Advocates hope to raise awareness among parents while prompting manufacturers and salon professionals to adopt safer alternatives.
A recent study by researchers at Columbia University Mailman School of Public Health and Earthjustice, a San Francisco-based nonprofit public interest environmental law organization, revealed that most children in the United States use makeup and body products that may contain carcinogens and other toxic chemicals. In January, the results were published in the International Journal of Environmental Research and Public Health. Based on more than 200 surveys, 70 percent of parents in the study reported that their children 12 or younger have used makeup and body products marketed to youth — for instance, glitter, face paint and lip gloss.
Childhood exposure to harmful makeup and body product ingredients can also be considered an environmental justice issue, as communities of color may be more likely to use these products.
“We are concerned about exposure to chemicals that may be found in cosmetics and body products, including those that are marketed toward children,” said the study’s senior author, Julie Herbstman, a professor and director of the Columbia Center for Children's Environmental Health. The goal of the survey was to try to understand how much kids are using cosmetic and body products and when, how and why they are using them.
“There is widespread use of children’s cosmetic and body products, and kids are using them principally to play,” Herbstman said. “That’s really quite different than how adults use cosmetic and body products.” Even with products that are specifically designed for children, “there’s no regulation that ensures that these products are safe for kids.” Also, she said, some children are using adult products — and they may do so in inadvisable ways, such as ingesting lipstick or applying it to other areas of the face.
Earlier research demonstrated that beauty and personal care products manufactured for children and adults frequently contain toxic chemicals, such as lead, asbestos, PFAS, phthalates and formaldehyde. Heavy metals and other toxic chemicals in children’s makeup and body products are particularly harmful to infants and youth, who are growing rapidly and whose bodies are less efficient at metabolizing these chemicals. Whether these chemicals are added intentionally or are present as contaminants, they have been associated with cancer, neurodevelopmental harm, and other serious and irreversible health effects, the Columbia University and Earthjustice researchers noted.
“Even when concentrations of individual chemicals are low in products, the potential for interactive effects from multiple toxicants is important to take into consideration,” the authors wrote in the journal article. “Allergic reactions, such as contact dermatitis, are some of the most frequently cited negative health outcomes associated with the use of cosmetics.”
Children’s small body side, rapid growth rate and immature immune systems are biologically more prone to the effects of toxicants than adults.
Adobe Stock
In addition to children’s rapid growth rate, the study also reported that their small body size, developing tissues and organs, and immature immune systems are biologically more prone to the effects of toxicants than adults. Meanwhile, the study noted, “childhood exposure to harmful makeup and body product ingredients can also be considered an environmental justice issue, as communities of color may be more likely to use these products.”
Although adults are the typical users of cosmetics, similar items are heavily marketed to youth with attention-grabbing features such as bright colors, animals and cartoon characters, according to the study. Beyond conventional makeup such as eyeshadow and lipstick, children may apply face paint, body glitter, nail polish, hair gel and fragrances. They also may frequent social media platforms on which these products are increasingly being promoted.
Products for both children and adults are currently regulated by the U.S. Food and Drug Administration under the Federal Food, Drug, and Cosmetic Act of 1938. Also, the Fair Packaging and Labeling Act of 1967 directs the Federal Trade Commission and the FDA “to issue regulations requiring that all ‘consumer commodities’ be labeled to disclose net contents, identity of commodity, and name and place of business of the product's manufacturer, packer, or distributor.” As the Columbia University and Earthjustice authors pointed out, though, “current safety regulations have been widely criticized as inadequate.”
The Personal Care Products Council in Washington, D.C., “fundamentally disagrees with the premise that companies put toxic chemicals in products produced for children,” industry spokeswoman Lisa Powers said in an email. Founded in 1894, the national trade association represents 600 member companies that manufacture, distribute and supply most personal care products marketed in the United States.
No category of consumer products is subject to less government oversight than cosmetics and other personal care products. -- Environmental Working Group.
“Science and safety are the cornerstones of our industry,” Powers stated. For more than a decade, she wrote, “the [Council] and our member companies worked diligently with a bipartisan group of congressional leaders and a diverse group of stakeholders to enhance the effectiveness of the FDA regulatory authority and to provide the safety reassurances that consumers expect and deserve.”
Powers added that the “industry employs and consults thousands of scientific and medical experts” who study the impacts of cosmetics and personal care products and the ingredients used in them. The Council also maintains a comprehensive database where consumers can look up science and safety information on the thousands of ingredients in sunscreens, toothpaste, shampoo, moisturizer, makeup, fragrances and other products.
However, the Environmental Working Group, which empowers consumers with breakthrough research to make informed choices about healthy living, believes the regulations are still not robust enough. “No category of consumer products is subject to less government oversight than cosmetics and other personal care products,” states the organization’s website. “Although many of the chemicals and contaminants in cosmetics and personal care products likely pose little risk, exposure to some has been linked to serious health problems, including cancer.”
The group, which operates the Skin Deep Database noted that “since 2009, 595 cosmetics manufacturers have reported using 88 chemicals, in more than 73,000 products, that have been linked to cancer, birth defects or reproductive harm.”
But change, for both adults and kids, is on the horizon. The Modernization of Cosmetics Regulation Act of 2022 significantly expanded the FDA’s authority to regulate cosmetics. In May 2023, Washington state adopted a law regulating cosmetics and personal care products. The Toxic-Free Cosmetics Act (HB 1047) bans chemicals in beauty and personal care products, such as PFAS, lead, mercury, phthalates and formaldehyde-releasing agents. These bans take effect in 2025, except for formaldehyde releasers, which have a phased-in approach starting in 2026.
Industry and advocates view this as a positive development. Powers, the spokesperson, praised “the long-awaited” Modernization Cosmetics Regulation Act of 2022, which she said, “advances product safety and innovation.” Jen Lee, chief impact officer at Beautycoutner, a company that sells personal care products, also welcomes the change. “We were proud to support the Washington Toxic-Free Cosmetics Act (HB 1047) by mobilizing our community of Brand Advocates who reside in Washington State,” Lee said. “Together, they made their voices heard by sending over 1,000 emails to their state legislators urging them to support and pass the bill.”
Laurie Valeriano, executive director of Toxic-Free Future, praised the upcoming Washington state law as “a huge win for public health and the environment that will have impacts that ripple across the nation.” She added that “companies won’t make special products for Washington state.” Instead, “they will reformulate and make products safer for everyone” — adults and children.
You shouldn’t have to be a toxicologist to shop for shampoo. -- Washington State Rep. Sharlett Mena
The new legislation will require Washington state agencies to assess the hazards of chemicals used in products that can impact vulnerable populations, while providing support for small businesses and independent cosmetologists to transition to safer products.
The Toxic-Free Future team lauds the Cosmetics Act, signed in May 2023.
Courtesy Toxic-Free Future
“When we go to a store, we assume the products on the shelf are safe, but this isn’t always true,” said Washington State Rep. Sharlett Mena, a Democrat serving in the 29th Legislative District (Tacoma), who sponsored the law. “I introduced this bill (HB 1047) because currently, the burden is on the consumer to navigate labels and find safe alternatives. You shouldn’t have to be a toxicologist to shop for shampoo.”
The new law aims to protect people of all ages, but especially youth. “Children are more susceptible to the impacts of toxic chemicals because their bodies are still developing,” Mena said. “Lead, for example, is significantly more hazardous to children than adults. Also, since children, unlike adults, tend to put things in their mouths all the time, they are more exposed to harmful chemicals in personal care and other products.”
Cosmetologists and hair professionals are taking notice. “Safety should be the practitioner’s number one concern” in using products on small children, said Anwar Saleem, a hair stylist, instructor and former salon owner in Washington, D.C., who is chairman of the D.C. Board of Barbering and Cosmetology and president of the National Interstate Council of State Boards of Cosmetology. “There are so many products on the market that it can be confusing.”
Hair products designed and labeled for children's use often have milder formulations, but “every child is unique, and what works for one may not work for another,” Saleem said. He recommends doing a patch test, in which the stylist or cosmetologist dabs the product on a small, inconspicuous area of the scalp or skin and waits anywhere from an hour to a day to check for irritation before continuing to serve the client. “Performing a patch test, observing children's reactions to a product and adequately adjusting are essential.”
Saleem seeks products that are free from harsh chemicals such as sulfates, phthalates and parabens, noting that these ingredients can be irritating and drying to the hair and scalp. If a child has sensitive skin or allergies, Saleem opts for hypoallergenic products.
We also need to ensure that less toxic alternatives are available and accessible to all consumers. It’s often under-resourced, low-income populations who suffer the burden of environmental exposures and do not have access or cannot afford these safer alternatives. -- Lesliam Quirós-Alcalá.
Lesliam Quirós-Alcalá, an assistant professor in the department of environmental health and engineering at the Johns Hopkins Bloomberg School of Public Health, said current regulatory loopholes on product labeling still allow manufacturers to advertise their cosmetics and personal care products as “gentle” and “natural.” However, she said, those terms may be misleading as they don’t necessarily mean the contents are less toxic or harmful to consumers.
“We also need to ensure that less toxic alternatives are available and accessible to all consumers,” Quirós-Alcalá said, “as often alternatives considered to be less toxic come with a hefty price tag.” As a result, “it’s often under-resourced, low-income populations who suffer the burden of environmental exposures and do not have access or cannot afford these safer alternatives.”
To advocate for safer alternatives, Quirós-Alcalá suggests that parents turn to consumer groups involved in publicizing the harms of personal care products. The Campaign for Safe Cosmetics is a program of Breast Cancer Prevention Partners, a national science-based advocacy organization aiming to prevent the disease by eliminating related environmental exposures. Other resources that inform users about unsafe ingredients include the mobile apps Clearya and Think Dirty.
“Children are not little adults, so it’s important to increase parent and consumer awareness to minimize their exposures to toxic chemicals in everyday products,” Quirós-Alcalá said. “Becoming smarter, more knowledgeable consumers is the first step to protecting your family from potentially harmful and toxic ingredients in consumer products.”