Celeste McGovern investigates three critical nutrients you may never have heard of and why you absolutely need them
Most of us assume that if we’re eating reasonably well and our blood tests come back “normal,” we’re probably doing fine nutritionally. No red flags. No deficiencies.
We may feel less than brilliant—tired, foggy, slower to recover, maybe less able to cope with physical or emotional stress than we used to be. But our doctors aren’t worried if our test results are reassuring.
At the same time, troubling trends persist at the population level. Birth defects have not disappeared. Children today suffer from far more chronic illness than their grandparents did.
Inflammatory disease is epidemic. Infertility continues to rise worldwide. More people are anxious and depressed than ever before. Dementia is a huge crisis, and cancer has not been beaten.
If we’re so well fed and our healthcare is the best in the world, why are so many of our bodily systems failing?
A new wave of research is turning to an old group of unsung nutrients the body uses every day—not just to avoid deficiency but to keep our cells energized, our brains sharp and our metabolism running smoothly as we age. These compounds are rarely tested for and often slip under the radar in modern diets. Here we’ll look at three of them: choline, taurine and glycine.
They aren’t household names, and they’re seldom mentioned in a routine doctor’s visit, yet they play critical roles in everything from pregnancy and brain development to liver health, stress resilience and cellular repair. As our diets have shifted toward convenient, carb-heavy foods and away from traditional staples like bone broth, eggs and dairy, we’ve ended up with enough nutrition to get by—but not always enough to thrive.
Choline is one of the clearest examples of a critical nutrient that most people have never heard of. We absolutely need it to develop healthy babies and for brain and liver function. Scientists are now investigating whether it boosts long-term cognition and can reduce the risk of Alzheimer’s disease.1
Yet public health authorities know that many people, if not most, don’t get enough essential choline in their diet. The obvious potentially serious health consequences include fatty liver and impaired metabolism—both epidemic in the West.
Still, there are no public health campaigns to raise awareness about choline, and it’s rarely ever discussed, or tested for, at a routine medical checkup.
Ironically, public health advice of the past several decades has driven the choline shortfall in diets. In their campaigns to steer people away from cholesterol, public health vilified foods like meat and eggs, which became synonymous with heart attack, and told people to replace real butter with fake, highly processed margarine. It was advice that also steered people away from the richest food sources of choline, a loss that has largely gone unnoticed.
“Since the 1960s and ’70s, when people were told to avoid foods like eggs and liver, we’ve created a problem that we weren’t designed for,” says Dr Steven Zeisel, professor emeritus of nutrition and pediatrics at the University of North Carolina at Chapel Hill, whose work established choline as an essential nutrient.
Back in the early 1990s, when choline was still considered a nonessential amino acid because our bodies can make it, Dr Zeisel’s research team at UNC conducted human feeding studies.2 They removed choline from the diets of healthy men to test the assumption that it was not necessary to eat additional choline.
The assumption was wrong, it turned out, and the men became sick within weeks. Their livers became full of fat, elevated liver enzymes leaked into their blood and in many cases their muscles began to break down.
Remarkably, when they began eating choline-rich foods again, their conditions reversed to health. The research established that “essential” choline must be eaten in addition to what the body is able to make.
Subsequent studies into the 2000s demonstrated how choline affects women differently than men and how hormones, especially estrogen, upregulate certain genes in some women, providing a protective mechanism that reduces the quantity of choline needed to maintain health.
As women enter perimenopause and menopause, estrogen is depleted and internal choline production wanes. That means they need to be eating more choline just when many of them begin consuming less of it.3
Genetics complicate the picture even more. Common genetic mutations involved in choline metabolism (including PEMT, MTHFD1, CHDH and MTHFR) set up biochemical “roadblocks” that significantly increase choline requirements and vulnerability to deficiency, says Dr Zeisel. This helps explain why two people eating the same foods might have very different outcomes, including choline levels, and why choline deficiency often goes unrecognized.4
Choline is indispensable at the biochemical level, but our bodies can’t make enough of it. We need to eat it to make phosphatidylcholine. This lipid is a major component of cell membranes, fats and the neurotransmitter acetylcholine, which is involved in muscle activation, memory and autonomic nervous system regulation. Choline also donates methyl groups through its metabolite betaine, linking it to one-carbon metabolism, DNA methylation and homocysteine regulation.5
Choline deficiency doesn’t come on urgently—it works quietly at the cellular level. The liver is where the trouble becomes most obvious. To export fat, the liver must package it into tiny transport particles; choline provides the molecular “wrapper” that makes this possible.
Without enough choline, fat can’t be shipped out and it builds up inside liver cells, setting the stage for nonalcoholic fatty liver disease (NAFLD)—now estimated to affect one in four adults globally. “There’s a lot of fatty liver out there,” says Dr Zeisel.
Although it’s crucial, most adults don’t get nearly enough choline. Population surveys in the United States, Canada and Europe show that most people consume less than the government-recommended minimums, which range from 200 mg/day for toddlers to 550 mg/day for grown men. Adult women, who should be consuming at least 425 mg/day (450 mg/day if they are pregnant and 550 mg/day if they are breastfeeding), are most likely to be missing the mark.
“Large portions of the population (i.e., approximately 90 percent of Americans), including most pregnant and lactating women,” are falling short of these guidelines, the researchers state in a review of the “under-consumed and underappreciated nutrient.”6
As we’ve moved away from choline-rich foods such as egg yolks, liver, shellfish and red meat—often in response to outdated cholesterol guidance or the promotion of low-fat and plant-based diets, choline consumption has nosedived.
The answer is not to just megadose choline, however. “Too much choline isn’t good for you, either,” Dr Zeisel says. “It increases problems with heart disease.” He points to a US Department of Agriculture database on choline content of common foods that can raise serum choline levels.7
You don’t want to get more than 5 g/day, he cautions. If you have one of the genetic roadblocks for choline production, however, the standard minimum intake recommendations are not enough.
As the one who coined the term precision nutrition, Dr Zeisel thinks it’s best for women who are planning to have children to test for genetic mutations relevant to the use of choline and other nutrients in the body and supplement accordingly. He helped to found Genate SNP Therapeutics (genate.com), which offers a cheek swab test to analyze the genetics relevant to nutrition and then supplement accordingly.
“Seven in 10 moms-to-be have genetic variations that impact how they process nutrients critical for early fetal development,” he says.
Public health agencies have yet to clearly educate people about the importance of choline—perhaps it’s still uncomfortably close to their anti-cholesterol campaigning. But in the US, Dr Zeisel points to positive changes in the 2025–2030 food guidelines, which basically turn the old food pyramid upside down. It previously recommended copious grain consumption as its base and minimal animal protein but now emphasizes meat, eggs and cheese (see WDDTY March 2026).
It will take a long time to undo the damage of the public health campaigns against choline-rich foods. “People are still afraid of cholesterol,” says Dr Zeisel. Perhaps they should be more afraid of choline deficiency.
Another quietly missing ingredient in modern diets is taurine, a sulfur-containing amino acid generating a major research boom. PubMed lists more than 50,000 taurine-related papers, and the number is still climbing.
Attention first turned to taurine in the 1970s through an unlikely source: cats. During the 1950s, when pet food became industrialized, veterinarians noticed rising obesity and diabetes followed by something more disturbing. Cats were going blind, bumping into walls and failing to grow normally.
In 1975 researchers found the cause: processed pet foods were missing a single essential nutrient—taurine—that dogs can make to some degree, but cats cannot. Without it, they developed severe retinal damage and stunted growth.8
The pet food industry was slow to respond. More than a decade later, a 1987 Los Angeles Times investigation revealed that thousands of cats were dying from dilated cardiomyopathy, a fatal weakening of the heart muscle.
One veterinarian had noticed a cat with this condition was also blind and began testing these patients for taurine deficiency. All 50 of the first cats tested were deficient.9
The cat story triggered a wave of research into taurine’s role in human heart health—and beyond.
Unlike protein-building amino acids, taurine is a “conditionally essential” free amino acid. It’s not built into muscle or tissue proteins, but it circulates freely and concentrates in organs including the heart, brain and eyes, where it performs a long list of functions. It’s a critical building block in cell membranes and a key player in the construction of mitochondria, the energy factories of cells and the body.
Like choline, taurine is critical to prenatal development, and newborns have more of it than adults. Taurine regulates the balance of electrolytes including calcium. It’s key to metabolic health, the central nervous system, vision and, as new research shows, cardiovascular health.
Also, like choline, taurine has been sidelined in most modern diets. It’s most abundant in foods like shellfish, dark meats and organ meats, while foods promoted as “lean” or plant-based provide virtually none.
Given taurine’s wide-ranging biological roles and its gradual disappearance from modern diets, researchers started asking a bigger question: Does taurine affect how we age?
A study published in the journal Science in 2023 ignited a storm of interest around that question. Researchers measured circulating taurine levels in worms, mice and monkeys and reported that taurine declined with age in all three species. When they supplemented taurine in midlife, the results were striking.
In worms (Caenorhabditis elegans), taurine extended both median and maximum lifespan in a dose-dependent way. In mice, it increased median lifespan by 10–12 percent and improved health markers in multiple systems.
In monkeys, it extended health span but not lifespan. Multiple markers, including for bone density, muscle function, metabolism and immune health, improved compared with controls.
The paper framed taurine deficiency as a “driver of aging,” and public interest surged.10
Then, in 2025, a large study by the US National Institutes of Health (NIH) tracked taurine levels over time in humans, monkeys and mice rather than comparing different age groups. It found no consistent age-related decline.
In humans and monkeys, levels often remained stable or even increased in later life. Taurine also failed to correlate with established aging markers like muscle strength or physical function. The authors concluded that taurine is unlikely to be a useful biomarker of aging.11
But the story didn’t end there. “It’s an evolving picture,” says Vijay Yadav, the Rutgers Health researcher who led the 2023 Science study. “Taurine’s function is vast. It’s associated with so many functions from head to toe.”
Yadav points to decades of evidence establishing taurine’s importance in fetal development, glucose control, brain function, bone density, vision and heart health—and to mounting research that, much like restoring choline intake, restoring taurine intake can affect physiology (see What taurine can do, below).
Dr Yadav’s group looked only at “middle-aged” animals, younger than the human equivalent of about 75 years, so the NIH study showing high taurine in some individuals in their 90s was surprising. But he’s not convinced it means taurine isn’t critical in aging. To explain why, he points to new research that looks at taurine levels in relation to frailty, a clinical measure of physiological resilience.12
In adults across a wide age range, taurine levels were not consistently linked to chronological age but instead tracked closely with frailty status. The pattern was nonlinear. Robust older adults tended to have higher taurine levels, while those in a prefrail state—an early stage of declining resilience—had the lowest levels.
Frail individuals showed intermediate levels, suggesting taurine metabolism is disrupted early in the aging process and partially compensated for later. This finding indicates taurine may be more relevant as a marker of biological resilience than of aging itself.
“I think taurine’s role in resilience and aging will come back into focus,” Yadav says. “We’ll have more data soon.”
Taurine’s closest metabolic “cousin” is glycine, another underappreciated amino acid that performs endless critical roles with respect to mitochondrial function, digestion, detoxification, nervous system calming and—most importantly, perhaps—regulation of inflammation in the body.
Glycine is the simplest amino acid. For most of human history, it arrived in the diet daily and abundantly in the form of bone broths, slow-cooked meats, connective tissue, skin, cartilage and even bones.
But today people want lean muscle meat, and the gristly glycine-rich offcuts are chucked in the bin. The deficiency that results doesn’t trigger disease outright, but it takes an inflammatory toll.
Preventing inflammation, as it turns out, may be glycine’s most underappreciated role.
Glycine is not just a building block of protein. It’s a precursor of glutathione, the master antioxidant and detoxifier. It’s also a regulator of metabolism and especially a signaling molecule for the immune system.
Research over the past few decades has shown that immune cells, particularly white blood cells and other frontline responders at sites of infection and injury, produce glycine receptors. When glycine binds to them, it alters calcium signaling in the cell and shuts down an inflammatory cytokine storm. Glycine is the controller deciding whether immune cells escalate a situation to immune assault or stand down.
This idea is championed by Joel Brind, professor of human biology and endocrinology at Baruch College, City University of New York, and author of The Glycine Miracle: The Science of Living Long and Free from Inflammation (The Oaklea Press Inc., 2024). Brind has been researching amino acid metabolism and endocrine signaling for decades.
His theories about glycine are built on the work of the late Dean Thurman and researchers at the University of North Carolina, who used models to show that glycine could suppress inflammatory injury in cases of shock, restricted blood flow (as in a stroke), and toxic insult.13 Brind realized not just that glycine reduces inflammation but that it appears to be the main controller of immune system response.
Burns, bruises, sun damage and blunt trauma are not infections, but sometimes the immune system responds like they are. It stokes inflammation that causes swelling, pain, tissue breakdown and long recovery time, or scarring that leads to a cycle of inflammation.
“Inflammation is not an appropriate response to injury—only to infection,” Brind says, a claim that sounds radical until you examine the cellular signaling behind it.
“Macrophages are the immune system’s first responders,” he says. They show up on the scene of injury or infection and, like police, are equipped to start shooting at the threat, or they can call in other immune system players to help deal with it.
These macrophages are studded with glycine receptors. When there is enough glycine around to saturate the receptors, they lean toward peaceful resolution: clearing debris, stabilizing tissue, and promoting repair.
But when glycine is deficient (as in modern Western diets), the balance shifts toward assault and prolonged inflammatory signaling. It can mean the difference between a quick-healing injury and a painful, swollen, maybe even chronic injury (see Heal fast with glycine, below).
Glycine’s role as the immune system’s top cop becomes especially relevant as we age. Chronic, low-grade inflammation that ages our cells, also called inflammaging, is now seen as a driver of heart disease, insulin resistance, neurodegeneration, cancer, arthritis and frailty.
The amino acid’s levels drop with age, and research has linked higher glycine status to a lower risk of metabolic disease, better mitochondrial function and improved longevity markers. What’s more, glycine supplementation reduces oxidative stress, improves insulin sensitivity and turns down inflammatory signals.14
The modern diet works against us here. Muscle meat is a really high source of methionine but poor in glycine. Every excess molecule of methionine that the body has to clear uses up two molecules of glycine to do the job.
So, while traditional diets supplied methionine and glycine in balance via whole-animal consumption, today’s diets are low in glycine for starters. Then they drive glycine demand up with exceptionally high methionine from muscle meat.
Glycine is also synthesized endogenously—but not enough of it to meet modern metabolic and inflammatory demands, particularly under stress, illness or aging. The gap between what the body needs and what it receives widens silently over time.
Looked at this way, glycine is not a niche supplement. It’s a foundational signal that tells the immune system when to fight and when to heal. Its disappearance from the diet may help explain why inflammation is so excessive and so stubborn to resolve.
The impact of choline stretches across the lifespan, but demand for it soars during pregnancy because it is critical to fetal development. An active choline shunt develops from a mother to her unborn baby, who has choline concentrations 15 times that of a grown adult during brain development, membrane formation and more.
Ongoing studies from Cornell University’s Choline Cognition Research Group show just how critical choline input is to brain development. In one experiment, pregnant women were randomized to receive either 480 mg/day (about the current recommendation) or 930 mg/day of choline throughout the third trimester of pregnancy. Infants born to mothers in the higher-choline group showed faster information processing speed (a key early marker of neurocognitive function) when tested between four and 13 months of age.1
A follow-up of these same children at age seven found those in the higher-choline group showed better visual memory and better sustained attention than children in the lower-choline group. Sustained attention—especially maintained performance across a challenging task—is a strong predictor of later cognitive and academic functioning.2
Dr Zeisel’s research showed how critical choline is to infant brain development and how intravenously fed infants without sufficient choline rapidly developed liver disease. His work led to the addition and regulation of choline in infant formulas.
Choline deficiency effects are still widespread, however. Dr Zeisel believes at least part of the 25 percent of neural tube defects in newborn babies that persist today despite folate replacement programs for pregnant women could be attributed to choline deficiency. Chinese researchers agree in a 2026 paper.3
It’s not just neural tube defects that have been linked to low choline consumption in pregnancy but autism, depression, schizophrenia, and more.4
A 2025 Chinese study found that women with the highest consumption of choline during the third trimester of pregnancy had the lowest risk of preeclampsia. Each additional 25 mg of choline they consumed (about the amount in half an egg) lowered the risk by 11 percent.5
Last year, a meta-analysis of 34 randomized controlled trials found that taurine supplementation improved fasting blood glucose and insulin sensitivity, lowered blood pressure and total cholesterol, and reduced inflammatory markers linked to cardiometabolic disease.1
This confirms earlier research:
“Glycine is the trigger lock on the immune system,” says Joel Brind. He arrived at this conclusion after experimenting on himself. After decades of studying amino acids in the lab, he began supplementing 10 g of glycine daily in 2008, figuring that at the very least it could do no harm. “I don’t believe you can overdose on glycine,” he says.
About two years into this experiment, he went to an open-air New York Yankees baseball game in full sun in 2010. Since the Yankees were winning, Brind didn’t realize until the fifth inning that his skin was bright red with sunburn.
Based on past experience, he expected days of pain followed by blistering, crinkling and peeling skin. None of that happened. The redness faded. The skin tanned. There was no pain, no sloughing, no inflammation-driven aftermath.
A few months later, he fell hard onto a cement floor while unloading supplies at a hardware store. The impact produced a dramatic bruise across his lower back.
But apart from the first minute of excruciating pain after the fall, he felt fine. He went dancing that night. No lingering soreness. No stiffness. No inflammatory cascade.
Brind didn’t think these were coincidences. They were what he had been researching for years: Glycine isn’t just a player in repair—it’s the governor deciding whether inflammation is triggered in the first place.
Some nutrients, like these amino acids, don’t come with well-defined deficiency diseases or dramatic symptoms, which partly explains why they’ve flown under the radar. Researchers do have a ballpark idea of how much we tend to need and how to get that amount.
Choline: 425–550 mg/day
Pregnant or menopausal women need more, as do those with specific genetics (see main story). Egg yolks are the easiest source—just one delivers 125–150 mg—followed by liver, beef, chicken, fish and dairy. Beans, soy and vegetables contain only very small amounts.
Higher doses of 4–6 g/day risk side effects such as fishy body odor, sweating, digestive upset and low blood pressure. Choline bitartrate is more likely to cause side effects as well and can raise the risk of blood clots and blocked arteries.1
Another choline supplement is citicoline, which crosses into the brain more efficiently. Phosphatidylcholine (lecithin), often derived from sunflower or soy lecithin, is a food-like supplement form that is gentle on digestion.
Suggested dosage: 1,200–3,600 mg/day phosphatidylcholine (split with meals)
Taurine: 500–3,000 mg/day
The body can make a little taurine, so there’s no formal requirement, but diet matters a lot. A typical mixed diet supplies 50–400 mg/day, but plant-based diets provide virtually none; the major food source is animal protein.
Supplemental L-taurine comes as powder or capsules, but it’s easier to get higher doses with powder in water or tea. Taurine has been studied at doses up to 3 g/day without major safety concerns.
Suggested dosage: 500–2,000 mg/day as supplement, plus taurine-rich foods
Glycine: 3–10 g/day
It’s technically nonessential, but most of us are not eating enough glycine in connective tissue, bone broth, gelatin and collagen. The amount we need is hard to swallow in capsules, so glycine powder is ideal. Though it won’t make you drowsy, some people take it before bed for better sleep.
Dr Brind, who recommends 8 g/day, developed Sweetamine (sweetamine.com), a pure L-glycine powder in 8 g sachets. It naturally sweetens any drink like sugar without the cooling effect of xylitol or the aftertaste of stevia.
Suggested dosage: 5 g USP food-grade 100% L-glycine powder twice daily
Also see Healthy shopping: Choline, taurine and glycine supplements.
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