Paying a monthly fee to get personalized advice on what foods to eat and dietary supplements to take for optimal health is a growing trend among those who can afford it. Such recommendations are no longer based solely on an individual’s genetics. Companies now offer advice based on the gut microbiome, nutritional biomarkers in blood, food preferences, and lifestyle and health information from digital devices such as smart watches, fitness trackers, and continuous glucose monitors.
Products range from simple surveys and diet trackers to more complex at-home kits for collecting stool or blood samples. Consumers mail their specimens to a laboratory and a few weeks later get a list of foods to eat more of and foods to avoid. In some cases, they are also advised to take certain supplements, which are often sold by the same company that provides the advice. Some companies also offer coaching services by a dietitian to help consumers change eating behaviors.
“They all have their own models,” says Peter Lurie, president of the Center for Science in the Public Interest (CSPI), a consumer advocacy group focused on healthy eating. “It’s fascinating and frightening all at the same time,” he says, referring to the explosion of personalized nutrition products.
Lurie is excited about the science at the core of personalized nutrition. But he is concerned that claims about the products are ahead of the science. “More is being promised than can actually be delivered,” he says.
The personalized nutrition industry is growing rapidly and changing by the week, says Mariëtte Abrahams, CEO and founder of consulting firm Qina, which developed a database of who does what in the personalized nutrition industry. Companies use the platform to connect with one another. What started as about 16 companies focused on nutritional genetics a decade ago is now a highly fragmented industry with more than 425 companies offering some sort of personalized nutrition product or service, according to Abrahams.
Most personalized nutrition companies do not base their recommendations on science, Abrahams says. The largest segment of the industry, and the fastest growing, relies on consumer preferences, such as plant-based, gluten-free, or keto diets, combined with health goals, such as losing weight, boosting energy or mental alertness, or improving sleep, she says. But the science of personalized nutrition is progressing substantially. Scientists are starting to publish their findings in top-tier journals, and companies are turning those findings into subscription services that predict a person’s ideal diet.
With the most basic services, consumers typically complete a survey with their food preferences and goals, as well as gender, age, and body mass index. Some companies recommend ingredients like cinnamon, chamomile, or vitamin C solely on the basis of answers provided in the survey, Abrahams says. Others use survey answers, diet tracking, and blood tests of nutritional biomarkers such as vitamin D, calcium, or magnesium to make recommendations, she adds.
Several companies began offering nutritional advice based on an individual’s microbiome composition about 5 years ago. Today there are more than 30 personalized nutrition firms focused on the microbiome, according to Abrahams.
One of those companies, DayTwo, offers a personalized nutrition approach for controlling blood glucose levels. The approach is based on work led by researchers at the Weizmann Institute of Science (Cell 2015, DOI: 10.1016/j.cell.2015.11.001). The work integrates data from the gut microbiome with blood measurements, dietary habits, physical activity levels, and physical measurements such as body mass index to predict a person’s blood sugar levels after meals.
The company claims on its website that its model “more accurately predicts glycemic response for foods and food combinations than counting carbohydrates.” Counting carbohydrates is the gold standard for predicting blood sugar levels after food consumption.
A handful of companies analyze data related to biological systems, such as gene regulatory networks and metabolic pathways, using computational methods and artificial intelligence to provide personalized food recommendations. The more data they collect, the more precise the recommendations become.
Start-up company Zoe is funding a series of large-scale studies called the Personalized Responses to Dietary Composition Trial (PREDICT) program to boost the data that underlie its algorithms for personalized diet recommendations. The PREDICT studies involve thousands of participants and are led by scientists at Massachusetts General Hospital, King’s College London, Stanford Medicine, and the Harvard T.H. Chan School of Public Health.
The first PREDICT study enrolled 1,002 twins and unrelated adults in the UK (Nat. Med. 2020, DOI: 10.1038/s41591-020-0934-0). The results showed that data from the gut microbiome are better than genetics for predicting metabolic responses, such as high levels of glucose or triglycerides in blood, after a meal.
The PREDICT studies investigate how much variability there is in people’s responses to food in terms of blood sugar and fat levels after meals and what is determining the variability, says Sarah Berry, a nutritional researcher at King’s College London and lead nutrition scientist of the PREDICT program. “We see huge interindividual variability in how we respond not just to food but a whole host of different diets and lifestyle interventions,” Berry says. “We realize that taking the population mean, as we have traditionally done in nutrition research, is perhaps quite short sighted,” she adds.
Zoe offers personalized food recommendations based on tests of the gut microbiome, blood sugar, and blood fat. Consumers collect a stool sample and mail it to a laboratory that sequences bacterial DNA in the sample. They also wear a continuous glucose monitor for up to 14 days to measure their blood sugar responses to carbohydrate-rich food in real time. And they do a finger-prick blood test to determine blood fat responses and identify biomarkers of inflammation after eating specially formulated muffins.
Six weeks later, they get a report comparing their results to those of thousands of other people. Users also receive a personalized gut health report that includes a score based on the prevalence of 15 good and 15 bad bacteria linked to metabolic health, as well as a list of foods to enhance good bacteria and foods to reduce bad bacteria.
For an extra fee, consumers can get a personal Zoe coach that provides one-on-one support. That premium plan includes video coaching sessions and daily support.
Viome is another company taking a systems biology approach to personalized nutrition and using artificial intelligence to make food recommendations from data from hundreds of thousands of samples. The company started out in 2016 examining messenger RNA (mRNA) in stool to understand the activity in certain metabolic pathways in a person’s gut. Viome now offers kits with blood and stool collection devices for mRNA testing. Stool provides information about microbiome activity, and blood provides human gene expression data. “We look at the interaction between the two, the host-microbe interaction,” says Guru Banavar, Viome’s chief technology officer.
Viome recommends foods on the basis of specific metabolic pathways’ activity and answers to a questionnaire. For example, particular bacterial species and enzymes in the gut are key to eliminating oxalate, one of the primary components of kidney stones, says Eric Patridge, head of computational systems biology at Viome. If a person’s oxalate-elimination pathways aren’t very active, Viome would advise the consumer to not eat spinach and other foods high in oxalate.
Viome also recommends supplements, probiotics, and prebiotics, which it will send to the consumer for a monthly fee. The supply is “enough for a month to be able to get you back into what we consider to be a balanced state,” Banavar says. Prebiotics can feed beneficial microbes and activate pathways such as the production of butyrate, which is important for energy, he says. Probiotics can replace microorganisms that are missing.
“Ideally, we would like people to retest every 6 months so they can see the progress in their underlying biology after having followed the recommendations,” Banavar says.
Scientists say it is unclear how many data points companies have and whether the amount of data is enough to make personalized nutrition predictions. “I think that there’s a lot that’s still at that basic science level that we don’t yet understand about these diet-microbiome relationships,” says Abigail Johnson, a registered dietitian and nutrition scientist at the University of Minnesota Twin Cities. “Personally, I don’t think we’re at the point where if you gave me your microbiome sample, I could tell you what you should eat,” she says.
Johnson and her colleagues have been working to untangle how food consumption shapes the composition of the gut microbiome and how those bacterial communities change over time. Their work shows correlations between consumption of specific food groups and the presence of certain bacterial species in the gut (Cell Host Microbe 2019, DOI: 10.1016/j.chom.2019.05.005). But the correlations are inconsistent from person to person. “I might eat dark-green leafy vegetables and see a bloom of a specific bacteria, while you may eat dark-green leafy vegetables and that same bacteria could go down,” Johnson says.
Johnson predicts that personalized nutrition will improve over time as the science evolves. In the next 5 years, she expects to see more-complete databases of metabolites—in foods and in human blood and fecal samples. “I think we’ll get to the point where it could be feasible for somebody to say this is your microbiome, this is where we want your microbiome to be, and these are the steps we think you need to take,” she says. But that is probably 10 years away, she adds.
Personalized nutrition will get more precise, but “it will only get better if it’s more equitable, if everybody can have access, and if everybody can afford it,” Abrahams says. “Otherwise, we’re always going to sit with this biased data set of people who have access to the internet and digital tools and can afford whatever is recommended to them,” she says. A systems biology approach to personalized nutrition is “the ideal way to go,” she says, but it is “way out of most people’s budgets.”
“There’s plenty of hype, and lots of people already making money off” personalized nutrition products, the CSPI’s Lurie says. The question is how to regulate those products appropriately, he says.
Personalized nutrition products fall under several categories that are underregulated by the US Food and Drug Administration, according to Lurie. Those products include direct-to-consumer laboratory tests and dietary supplements. “In the absence of regulation, the market continues unabated,” he says.
“We are in an information-rich environment, where this explosion of biology gives many opportunities to give either truthful or misleading information that’s available in real time, anywhere in the world,” Robert Califf said during an August workshop on personalized nutrition hosted by the National Academies of Sciences, Engineering, and Medicine. Califf, head of clinical policy and strategy at Verily Life Sciences and Google Health, is President Joe Biden’s nominee to lead the FDA.
The ability to integrate massive amounts of information “is profound,” Califf said during the August workshop. “It does raise a number of questions about how to regulate such a complex interplay of findings and claims that might be made,” he added.
“What we really care about is the clinical end point. Is someone living longer, functioning better, or feeling better?” Califf said. “We need to be cautious about taking these intermediate biomarkers and making claims that somehow we are affecting health in a predictable and reliable way,” he said. Califf noted that he worries that certain claims “lead people to buy products thinking that they’re improving their health when there’s absolutely no evidence that such is the case.”
Underresourced regulators are already facing more claims than they can investigate, particularly when it comes to dietary supplements, Lurie says. The problem will only get worse as the personalized nutrition industry grows, he predicts. Abrahams expects the number of personalized nutrition companies to explode next year, in part because the COVID-19 pandemic caused some businesses to delay plans this year.
Big food companies are also investing in personalized nutrition research. General Mills, which funded much of Johnson’s research at the University of Minnesota, is interested in whether different types of dietary fiber are more beneficial for a healthy gut microbiome than a single source of fiber. “If we find that single sources of fiber are less beneficial,” then manufacturers can reformulate and improve food products by adding different fiber types, Johnson says. If some people benefit more than others from consuming multiple fiber types, such products can target those consumers.
Large companies are “planting the seed” now in personalized nutrition and engaging consumers with simple surveys, Abrahams says. Dutch firm DSM invested $100 million in the launch of personalized nutrition company Hologram Sciences earlier this year. Bayer purchased vitamin and supplement firm Care/of for $225 million in 2020. Nestlé purchased Persona, a personalized vitamin and supplement subscription service, for an undisclosed sum in 2019.
It is unclear what direction these companies will take as the science evolves, but consumer advocates hope the personalized nutrition industry will ultimately benefit consumers. “The question is all about the translation” of the science, Lurie says. Will consumers benefit from personalized nutrition from a clinical point of view, he asks, or “will they experience it in a way that separates them from their wallets?”