Are Personalized Diets Ready for Prime Time?

Debbie Koenig wrote . . . . . . . . .

When Howard Wolinsky was diagnosed with type 2 diabetes, he expected to kiss bagels goodbye — too many carbs. But a personalized diet based on his own gut microbiome offered a pleasant surprise: “It turns out those little bugs in my guts seem to like bread, if it’s combined with fats and proteins,” he says.

Wolinsky’s diet came from DayTwo, a company that uses research from the Weizmann Institute of Science in Israel to create customized advice for people with diabetes. From his home in suburban Chicago, Wolinsky, 71, sent the company a stool sample and a completed questionnaire, and he got back guidance about precisely which foods would spike his blood glucose and which would keep it steady. He was also taking an oral medication for his diabetes.

“I could have a bagel, with cream cheese and lox,” he says. “That combination got a really good rating on the DayTwo scale.” He was amazed to find that when he followed DayTwo’s advice, his blood sugar remained within a normal range. It didn’t spike the way it would for foods outside their recommendations.

News Flash: Diets Aren’t One-Size-Fits-All

DayTwo has plenty of company in the personalized diet business. At least a dozen outfits offer nutrition advice customized to your body, based on DNA or blood tests, microbiome profiling, or a combination of those. Several promise weight loss, while others focus on specific conditions or just general “wellness.” Each uses its own proprietary process, and for some, the science behind it gets murky. Costs range from under $100 to nearly $1,000 for different services. DayTwo, for example, charges $499 for a microbiome testing kit, personalized app, orientation call with a registered dietitian, and microbiome summary report.

Earlier this year, a new study about personalized diets made headlines. Called the Predict Study, it found that different people respond to exactly the same food in different ways — even identical twins, who have almost the same genetic makeup. So, a muffin that spikes one person’s blood glucose might not affect someone else’s. The study captured data by closely monitoring how 1,100 people, more than half of them twins, responded to various foods, including prepared items provided to them. Researchers tracked details like blood sugar, insulin, and triglycerides (fat) as well as sleep patterns, activity levels, and gut bacteria. Using that data, they began to create a model to predict how anyone might respond to a particular food, based on their own microbiome and DNA.

The Weizmann Institute’s research took a similar approach, analyzing the blood sugar responses of 800 people after more than 45,000 meals. They found wide variations in their glucose levels after eating, even when meals were standardized.

Eric Topol, MD, a cardiologist and author of Deep Medicine: How Artificial Intelligence Can Make Healthcare Human Again, tried a version of the Weizmann test. He provided a stool sample and for 2 weeks wore a glucose sensor. He monitored his food, sleep, and physical activity. “Certain foods gave me prominent spikes in my glucose, and I’m not a diabetic,” says Topol, editor-in-chief of Medscape, WebMD’s site for health care professionals. “A lot of my favorite foods were incriminated, while others that I’d never think of eating were recommended, things like bratwurst or cheesecake. I tried cheesecake just to see, and sure enough, my glucose didn’t budge.”

These discoveries go against conventional advice like the federal Dietary Guidelines for Americans and most popular diet plans. Instead of broad rules about food groups, the results suggest that each of us could be eating foods to support the specifics of our own bodies. Still, even if evidence mounts that personalized diets significantly help people identify “ideal” foods, those who eat a well-balanced diet have also been found to have improved health, decreased diabetes, heart disease, etc.

“We’re so driven by this dull idea that everyone has the same needs, that there’s a perfect proportion of carbs and fats for everybody,” says Tim Spector, MD, a professor of genetic epidemiology at King’s College London. Spector was the principal investigator of the Predict Study and is co-founder of Zoe, the company funding the research. “You have to tear up the rule book and start again.”

Enter the Gut Microbiome

Your microbiome is made up of trillions of tiny organisms called microbes that live in and on your body. Each of us has a unique mix of microbes in our guts, and the balance affects your risk of conditions like obesity and diabetes. That’s one reason scientists are focusing on the gut for custom-made diets.

A personalized diet aims to steer you toward foods that encourage the right mix in your unique microbiome.

“We believe the microbiome plays a role, because out of all the things we measured in identical twins, what differed most were the microbial species and what they did,” says Spector. “The other differences that aren’t due to genes or microbes, we’re still trying to tease apart.”

Wolinsky’s experience has him convinced. “It seems so strange that making microbes in my gut happy can affect my health and my weight, but I do believe it helps,” he says.

The Genetic Component

What we eat has an effect on our genes — there’s an entire field of study devoted to it, called nutrigenetics — but does that mean we should eat or avoid specific foods based solely on our DNA?

Right now, numerous companies claim to provide a diet made just for your DNA. But the Predict Study shows that genes alone don’t create a full picture. Using identical twins and their matching DNA allowed Spector and his colleagues to account for the effect of genetics. Even when they ate the exact same meals, twins often had wildly different responses. “Yes, genetics plays a role,” Spector says. “But it’s a very small role, compared to the things that make us individual.”

Topol agrees. “There isn’t anything proven yet with DNA. So let’s be clear about that,” he says. “The only real breakthrough in recent years has been capturing all of a person’s data, including their gut microbiome data.”

Conflicting, Confusing Results

Differing approaches to the kind of testing and the data being collected led to advice that can be hard to follow. In addition to consulting DayTwo, which focuses on helping people with diabetes manage their blood sugar, Wolinsky also got a personalized diet from Viome, a company that promises to help you “optimize” your microbiome for increased energy and well-being. The results were often at odds with each other: DayTwo gave butter, duck, and tuna an A+ score for Wolinsky, while Viome suggested he avoid those foods.

“It seems your microbiome should be your microbiome. But it’s not that simple,” he says. “So I was dubious.” He could confirm DayTwo’s recommendations with a finger-stick blood glucose test, and its program is targeted toward people with diabetes. He stuck with DayTwo’s advice.

Topol points out that because DayTwo is so focused on blood sugar, the results may not be promoting overall health. Remember that his results recommended bratwurst? “As a cardiologist, I still can’t go near that,” he says.

What We Don’t Know

While experts say the research is promising, the era of personalized diets has barely begun. Numerous questions remain. The biggest: Is it worth it?

“What we don’t know is whether we should live our lives like this. Should we radically change our diets to avoid glucose spikes? It’s intuitive that we wouldn’t want to have them, but we need more proof that this will make a difference,” says Topol.

The second phase of Spector’s research, Predict 2, aims to expand the database by collecting data from at-home volunteers in the United States. Participants of different races, ages, and lifestyles will be tested and tracked for 10 days to enrich the data — and the at-home aspect means the results will reflect real life. Ultimately, he hopes to create a commercial app through Zoe that will allow users to get up-to-the-minute advice about what they should eat.

But we’re nowhere near understanding the long-term effects of following a personalized diet. “It’ll take years to see its effect on weight reduction or heart disease. Nobody knows yet that reducing glucose peaks will do this,” says Spector. “Once we’re into the hundreds of thousands of participants, it’ll be easy to track.”

Another unknown is how practical such detailed diet plans will be. If your report says you should stay away from, say, steak, but your spouse’s says the opposite, does that mean cooking two dinners? Eating for your specific microbiome may require changing the way you approach family meals and socializing.

“Plus, we already have a pretty good sense of what constitutes a healthy diet: lots of fruits, vegetables, and whole grains with minimal red meat,” says Joe Schwarcz, PhD, director of the McGill University Office for Science and Society. “What’s the point of adding more info when people aren’t even following what we know to be true?”

Should You Try It?

At this point, none of the personalized diets on the market gather enough information about you to pinpoint what you should eat for overall health — you’ll only get a partial picture. And there’s no consensus about what they should be gathering.

“I find the genetic factors and the microbiome effects too confusing at this point to make any solid recommendations,” says Schwarcz. “People are putting the cart before the horse.”

Source: WebMD

What Does Telomere Testing Tell You about Aging and Disease Risk?

Patricia Opresko and Elise Fouquerel wrote . . . . . . . . .

Over the past few years direct-to-consumer genetic tests that extract information from DNA in your chromosomes have become popular. Through a simple cheek swab, saliva collection or finger prick, companies offer the possibility of learning more about your family tree, ancestry, or risk of developing diseases such as Alzheimer’s or even certain cancers. More recently, some companies offer tests to measure the tips of chromosomes, called telomeres, to learn more about aging.

But what exactly are telomeres, what are telomere tests, and what are companies claiming they can tell you? Age based on your birthday versus your “telomere age”?

Telomeres play a big role in keeping our chromosomes and bodies healthy even though they make up only a tiny fraction of our total DNA. The Greek origins of the word telomere describes where to find them. “Telo” means “end” while “mere” means “part.” Telomeres cap both ends of all 46 chromosomes in each cell, and protect chromosomes from losing genetic material. They are often compared to the plastic tips at the ends of shoelaces that prevent fraying.

We are molecular biologists studying how chemicals, agents from the environment and metabolism damage telomeres and affect their lengths and function, and how damaged telomeres affect the health of our cells and genome. The idea of offering telomere length as part of a genetic test is intriguing since telomeres protect our genetic material. But equating telomere length with something as complex as aging struck us as tricky and overly simplistic.

Link between telomere length and human diseases

Telomeres are important for human health and despite their protective function, they are not indestructible. Telomeres shorten every time a cell divides and shorten progressively as we age.

When telomeres become too short or lost, the chromosome tips are left unprotected and become sticky. This can cause chromosomes to fuse. To prevent further chromosome shortening and fusions, the cells enter senescence, a state in which they can no longer divide. Although they lose the ability to rejuvenate tissues, senescent cells can still promote inflammation and secrete factors that favor growth of nearby pre-cancerous or cancerous cells.

Unfortunately, our lifestyle can actually accelerate the shortening. Environmental exposures such as sunlight, air pollution, cigarette smoke and even inflammation or poor diet can damage cell components, including DNA. They do this by generating unstable oxygen molecules, or free radicals. Telomeres are particularly susceptible to damage by free radicals.

In collaboration with chemist Marcel Bruchez, we developed a new tool that damages only the telomeres. Using this tool we discovered that oxidative damage to telomeres is sufficient to not only accelerate their shortening but also to cause telomere loss.

In previous laboratory experiments, scientists found that eliminating senescent cells from mice led to the delay or prevention of diseases and conditions associated with aging including heart disease, diabetes, osteoporosis and lung fibrosis. This has led to the pursuit of new drugs called senolytics that could eliminate senescent cells in humans.

Is longer better?

Since short telomeres cause cells to senesce, this makes them interesting targets for healthy, disease-free aging. Also, since telomeres shorten with age, regardless of exposure to toxins this led to the notion that telomere length may provide information about a person’s “true” biological age.

Commercial tests typically measure telomere lengths or amounts of telomeric DNA in a blood sample. Companies compare your telomeres to telomeres from people of similar age to try to determine the biological age of your blood cells.

However, just as individuals of the same age vary in height and weight, so do telomeres. If a child falls in the 40th percentile for height, this means compared to 100 girls her age she is taller than 40. For this reason, charts similar to growth charts for children have been generated for telomeres.

Individuals with telomere lengths below the first percentile are at risk for developing specific diseases including anemia, immunodeficiency and pulmonary fibrosis, likely due to a gene mutation that impairs telomere maintenance

At the other extreme, individuals with gene mutations that lead to very long telomeres above the 99th percentile are at greater risk for developing inherited forms of melanoma and brain cancers. Longer telomeres allow a cell to divide more times, and with every division there is a chance that an error during genome duplication produces a mutation that promotes cancer. In a way, telomeres follow the Goldilock’ principle. Telomeres that are too short or too long are not optimal.

Can telomere length predict health outcomes?

But what about telomere lengths in between the extremes? Large studies involving hundreds to thousands of participants show general associations of shorter telomeres with increased risk for some diseases of aging, including heart disease, whereas longer telomeres are associated with increased risk for some types of cancers.

But translating these population studies to predictions about individual life spans and health is difficult. For example, as a group, men are taller than women, but that does not mean all men are taller than women. Similarly, some people with shorter telomeres do not develop heart disease in these population studies. More studies are needed to fully understand what an individual’s telomere length means for their health and aging.

While large population studies show a healthy diet is associated with longer telomeres, published reports about specific supplements that claim to support telomere health are lacking.

If such a product could extend telomeres, would it be safe? Or would it increase one’s risk for developing cancer due to long telomeres? Can protecting telomeres or slowing their shortening promote disease-free aging? We do not have the answers to these questions yet.

Given the uncertainty and risk of wrong interpretation, should you have your telomeres measured? Maybe, if the results motivate healthy lifestyle changes. For now, a surer bet for healthy aging would be to spend the money on exercise programs and nutritious foods instead.

Source : The Conversation


Today’s Comic

Ireland First With New DNA Food Scanning Tool

The Food Safety Authority of Ireland (FSAI) revealed that it now has a new DNA scanning tool to identify the entire DNA content of a food. The new analytical tool can proactively identify all the ingredients and their biological sources in a food, which will aid regulators in protecting consumers in relation to potential food fraud and/or misleading labelling. The FSAI worked with a commercial laboratory (Identigen) over the past two years in adapting a relatively new DNA sequencing technology known as “next generation sequencing”, so that it could be used as a DNA scanning tool in food. The idea is to compare the actual ingredients in a food, identified by their DNA profile, with those declared on the label. Up to this, DNA testing of food required analysts to know what they wanted to look for specifically and then test for it – such target information is no longer a pre-requisite.

According to Dr Pat O’Mahony, Chief Specialist, Food Science and Technology, FSAI this applied use of next generation sequencing is unique in a regulatory context and will be a significant new asset for regulators to identify exactly what is contained in a food and if that matches what is stated on the product’s labelling. It is now possible to scan the entire DNA content of a food without any prior knowledge or suspicion of what may or may not be present in that food.

“Even with the restriction of having to target the DNA of certain plant or animal species in previous studies, the FSAI has been able to detect food allergens and GMOs, and demonstrate the mislabelling of fish products. Of course targeted DNA analysis was also the method used by the FSAI in discovering horsemeat in beef products, which ultimately brought the global awareness of food fraud to a new level.”

The restrictions imposed by the need to target only specific species and ingredients in products led the FSAI to look for new innovative ‘non-targeted’ screening methods. Next Generation DNA Sequencing (NGS) is the basis of the new DNA food scanning tool and has been applied successfully by the FSAI to screen 45 plant-based foods and food supplements from Irish health food shops and supermarkets. It looked for the presence of all plant species in the selected products and identified 14 food products of interest that may contain undeclared plant species.

Of the 14 products selected for further investigation, one was confirmed to contain undeclared mustard at significant levels. Mustard is one of the 14 food allergenic ingredients that must be declared in all foods under EU and Irish food law. Another product (oregano) was found to contain DNA from two undeclared plant species, one at significant levels. A third product was found to have no DNA from the plant species declared on the label, but instead rice DNA was identified. All three products are under further investigation.

“Our two year project has proved that next generation sequencing has the capacity to screen a variety of plant-based foods for the presence of undeclared plant species. It is important to understand that any results of the initial scan will always need to be corroborated by more established analytical techniques. Being able to scan the entire DNA content of a food means that it will be difficult to substitute or hide an ingredient of biological origin without it being detected. The plan is that in the future, the FSAI will apply the same technology for the screening of meat, poultry and fish products,” concluded Dr O’Mahony.

Source: Food Safety Authority of Ireland

Genomic Study Brings Us Closer to Precision Medicine for Type 2 Diabetes

Leah Eisenstadt wrote . . . . . . . . .

Most patients diagnosed with type 2 diabetes are treated with a “one-size-fits-all” protocol that is not tailored to each person’s physiology and may leave many cases inadequately managed. A new study by scientists at the Broad Institute of MIT and Harvard and Massachusetts General Hospital (MGH) indicates that inherited genetic changes may underlie the variability observed among patients in the clinic, with several pathophysiological processes potentially leading to high blood sugar and its resulting consequences.

By analyzing genomic data with a computational tool that incorporates genetic complexity, the researchers identified five distinct groups of DNA sites that appear to drive distinct forms of the illness in unique ways.

The work represents a first step toward using genetics to identify subtypes of type 2 diabetes, which could help physicians prescribe interventions aimed at the cause of the disease, rather than just the symptoms.

The study appears in PLoS Medicine.

“When treating type 2 diabetes, we have a dozen or so medications we can use, but after you start someone on the standard algorithm, it’s primarily trial and error,” said senior author Jose Florez, an endocrinologist at MGH, co-director of the Broad’s Metabolism Program, and professor at Harvard Medical School. “We need a more granular approach that addresses the many different molecular processes leading to high blood sugar.”

It’s known that type 2 diabetes can be broadly grouped into cases driven either by the inability of pancreatic beta cells to make enough insulin, known as insulin deficiency, or by the inability of liver, muscle or fat tissues to use insulin properly, known as insulin resistance.

Previous research attempted to define more subtypes of type 2 diabetes based on indicators such as beta-cell function, insulin resistance, or body-mass index, but those traits can vary greatly through life and during the course of disease. Inherited genetic differences are present at birth, and so a more reliable method would be to create subtypes based on DNA variations that have been associated with diabetes risk in large-scale genetic studies. These variations can be grouped into clusters based on how they impact diabetes-related traits; for example, genetic changes linked to high triglyceride levels are likely to work through the same biological processes.

Early efforts to do so used a “hard-clustering” approach, in which each genetic variation was assigned to only one cluster. However, this failed to produce patterns that made biological sense.

Miriam Udler, an endocrinologist at MGH and postdoctoral researcher in the Florez lab, took another approach. She teamed up with Gaddy Getz and Jaegil Kim of the Broad’s Cancer Genomics team to apply a “soft-clustering” approach known as Bayesian non-negative matrix factorization, which allows each variant to fall into more than one cluster.

“The soft-clustering method is better for studying complex diseases, in which disease-related genetic sites may regulate not just one gene or process, but several,” said Udler.

The new work revealed five clusters of genetic variants distinguished by distinct underlying cellular processes, within the existing major divisions of insulin-resistant and insulin-deficient disease. Two of these clusters contain variants that suggest beta cells aren’t working properly, but that differ in their impacts on levels of the insulin precursor, proinsulin. The other three clusters contain DNA variants related to insulin resistance, including one cluster mediated by obesity, one defined by disrupted metabolism of fats in the liver, and one driven by defects in the distribution of fat within the body, known as lipodystrophy.

To confirm these observations, the team analyzed data from the National Institutes of Health’s Roadmap Epigenomics Project, a public resource of epigenomic data for biology and disease research. They found that the genes contained in the clusters were more active in the tissue types one would expect.

To further test whether each cluster had been assigned the correct biological mechanism, the researchers gathered data from four independent cohorts of patients with type 2 diabetes and first calculated the patients’ individual genetic risk scores for each cluster. They found nearly a third of patients scored highly for only one predominant cluster, suggesting that their diabetes may be driven predominantly by a single biological mechanism.

When they next analyzed measurements of diabetes-related traits from high-scoring subjects, they saw patterns that strongly reflected the suspected biological mechanism and distinguished them from all other patients with type 2 diabetes – for example, patients who fell into the obesity-mediated cluster were indeed found to have increased body-mass index and body fat percentage.

The results appear to reflect some of the diversity observed by endocrinologists in the clinic. For example, people who scored high on the lipodystrophy-like cluster were likely to be thinner than average but have insulin-resistant diabetes, similar to a rare type of diabetes in which fat accumulates in the liver, which is a fundamentally different process from insulin resistance that results from obesity.

“The clusters from our study seem to recapitulate what we observe in clinical practice,” said Florez. “Now we need to determine whether these clusters translate to differences in disease progression, complications, and response to treatment.”

In addition to paving the way to clinically useful subtypes, the work sheds light on the diverse pathophysiology underlying type 2 diabetes and offers a model for unraveling the heterogeneity of other complex diseases.

“This study has given us the most comprehensive view to date of the genetic pathways underlying a common illness, which if not adequately treated can lead to devastating complications,” said Udler. “We’re excited to see how our approach can help researchers make steps towards precision medicine for other illnesses as well.”

Source: Broad Institute


Today’s Comic

Nestlé Is Using DNA to Create Personalized Diets in Japan

Chase Purdy wrote . . . . . . .

The world’s largest food company is experimenting with people’s DNA to build and sell personalized nutrition plans that, it says, will extend lifespans and keep people healthy.

Nestlé is rolling out these new products in Japan first. Some 100,000 people are taking part in a company program there that gives consumers a kit to collect their DNA at home. The program also encourages them to use an app to post pictures of what they’re eating. Nestlé then recommends dietary changes and supplies specialized supplements that can be sprinkled on or mixed into a variety of food products, including teas, according to Bloomberg.

For years Nestlé been positioning itself to straddle the line between pharmaceuticals and food. In December 2016, then-chairman, Peter Brabeck-Letmathe made the case to Quartz that personalized, fortified foods would be the future. The dream, according to Brabeck-Letmathe, is to invent a new suite of food products that could prevent diseases from occurring. Pizzas that can ward off Alzheimer’s disease, for instance.

Brabeck-Letmathe has since retired from the company, but his vision is intact. It’s setting Nestlé apart from its food industry peers

The world’s largest food manufacturers have spent the last several years trying to regain footing with consumers in America and Europe, who lost faith in many packaged goods products because of its artificial flavors and coloring, sugar, and salt content. Nestlé, in particular, saw sales in its US frozen-foods plummet. General Mills and Kellogg’s watched as their breakfast cereals became less popular. And Coca-Cola and Pepsico both saw consumers drift away from sugary sodas, opting instead for healthier teas and flavored waters.

The shift in purchasing habits sparked companies to reformulate products to persuade consumers back into buying their foods. For Nestlé, that meant changing the ingredient lists on a whole host of well-known brand’s products, including California Pizza Kitchen, Hot Pockets, and Digiorno’s Pizza. The company sold off its US candy unit earlier this year, and recently announced a $7.15 billion licensing deal with Starbucks that will allow it to sell the Seattle-based coffee maker’s teas and coffees around the world.

Customizing meals via DNA analysis takes this recent mentality to a new level, and it’s complimenting its food efforts with investments in medical research. Since 2007, Nestlé has spent billions acquiring firms such as Novartis Medical Nutrition, Atrium Innovations, Vitaflo, Prometheus Laboratories, a minority stake in Accera, and Seres Therapeutics, Inc., to name a few.

Japan may wind up informing how Nestlé will rolls out the program in other places around the world. Until then, people will just have to wait for their personalized wonder pizzas.

Source: QUARTZ