Despite decades of research, the evidence for omega-3 supplements is murky.In 1970, two Danish researchers traveled to Greenland to investigate a nutritional paradox: The Inuit people living in the region consumed foods very high in fat, yet reportedly had very low rates of heart attacks.That observation flew in the face of nutrition dogma at the time, which held that eating fatty foods — like whale and seal meat and oily fish — would clog your arteries and cause heart disease.The Inuit on Greenland, a Danish territory, had lower levels of blood cholesterol and triglycerides than people back in Denmark, the researchers reported. The reason, they hypothesized, was that the Inuit diet was rich in omega-3 fatty acids — particularly EPA and DHA, which are concentrated in fish and the animals that eat them.These findings sparked decades of scientific and commercial interest in the role omega-3 fatty acids play in heart health, even after later studies suggested that, in fact, the Inuit had rates of heart disease similar to those found in Europe, the United States and Canada. Today, omega-3 supplements are among the most popular in the United States, surpassed only by multivitamins and vitamin D. Among U.S. adults 60 and older, about 22 percent reported taking omega-3s in a 2017-2018 survey.Unlike most other supplements, fish oil has been rigorously studied, said Dr. JoAnn Manson, a professor of medicine at Harvard Medical School. But the results of those studies have been mixed, leaving researchers and doctors still debating whether fish oil is beneficial for heart health. They have also revealed that taking fish oil is linked to a slightly greater risk of developing atrial fibrillation, a type of irregular heartbeat.Here’s where the evidence for both the benefits and risks of fish oil stands today.A boatload of studies, but unclear benefitsAfter reading the dispatches from Greenland, researchers began looking at people elsewhere in the world and finding, in study after study, that those who consumed fish at least once per week were less likely to die from coronary heart disease than those who rarely ate fish. In animal experiments, they found that fish oil helped keep electrical signaling in heart cells functioning properly, said Dr. Dariush Mozaffarian, a cardiologist and director of the Food is Medicine Institute at Tufts University.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

We’ve learned plenty about eating well. Here’s the advice we’ll carry with us into 2024.As a health reporter who’s been following nutrition news for decades, I’ve seen a lot of trends that made a splash — and then sank. Remember olestra, the Paleo diet and celery juice?Watch enough food fads come and go, and you realize that the most valuable nutrition guidance is built on decades of research, in which scientists have looked at a question from multiple perspectives and arrived at something like a consensus.Here are 10 science-backed pearls to carry you into the new year.1. The Mediterranean diet really is that good for you.Decades of research support the Mediterranean diet — which is centered on fruits and vegetables, whole grains, legumes, olive oil, nuts, herbs and spices — as one of the healthiest ways you can eat. Its heart-health benefits are numerous, and it has been linked to a lower risk of Type 2 diabetes, cognitive decline and certain types of cancer.If you’re interested in adopting the Mediterranean diet but aren’t sure where to start, stay tuned. Starting Jan. 15, we’ll be sharing a week of practical guidance and recipes for Mediterranean-style eating in the Well newsletter, which you can sign up for here.2. It’s OK to drink coffee on an empty stomach.Some people may experience heartburn, but there’s no evidence that drinking coffee on an empty stomach can damage your gastric lining or otherwise harm your digestive system, experts say. And there are reasons to feel good about your morning brew: Drinking coffee has been linked to a longer life and a lower risk of heart disease and Type 2 diabetes.3. Start your day with a healthy breakfast.Mornings can be hectic, and it may be tempting to grab a quick muffin or skip breakfast altogether. But nutrition experts say it’s worth prioritizing that morning meal — especially if it contains a balanced mix of protein, fiber and healthy fats. It will fuel your day, and studies have found that those who eat breakfast tend to enjoy a range of health benefits, including a lower risk of cardiovascular disease, Type 2 diabetes and obesity.4. Take good care of your gut.Keeping your digestive system healthy and running smoothly can protect you from life’s discomforts — like heartburn, bloating and constipation — as well as lead to better overall health. Unsurprisingly, the best way to care for your gut is to feed yourself (and by extension, your gut microbes) well, by prioritizing fiber and consuming a variety of plant-based and fermented foods.5. You probably don’t need protein bars.They’re often marketed as a health food or as essential fuel for athletic performance, but most protein bars are loaded with sugar. You’re better off meeting your protein needs with whole foods like yogurt, nuts, beans or eggs, experts say.6. Go easy on the dark chocolate.File this as one of the saddest nutrition news stories of 2023. Dark chocolate has some of the highest levels of lead and cadmium (heavy metals that can harm the body) when compared with other foods. Fortunately, you don’t have to give up your dark chocolate habit entirely. Enjoying it in moderation — no more than about an ounce per day, experts say — will keep your risk low.7. Blending fruits and veggies won’t destroy their nutrients.Puréeing fruits and vegetables in a blender won’t strip them of their vitamins, minerals or fiber. And, somewhat surprisingly, several small studies suggest that sipping your fruit in blended form won’t spike your blood sugar any more than when you eat it whole. So go ahead — enjoy your smoothie. And check out our tips for making yours more nutritious.8. Cottage cheese is back.You might associate cottage cheese with fad diets from the 1970s, but it’s a food that has stood the test of time. Cottage cheese was a breakout hit on TikTok this summer, and for good reason. You can eat it plain or use it as a versatile ingredient in both sweet and savory snacks, and it offers an impressive array of nutrients including protein, calcium, selenium and more.9. Tofu really is good for you, too.In past decades, people have worried that tofu and other soy foods might be linked with cancer or fertility problems because they contain estrogen-like compounds. But studies have put those fears to bed, scientists say. In fact, research suggests that eating soy-based foods may reduce your risk of heart disease and even some types of cancer.10. It’s challenging to separate nutrition myths from facts.Myths about nutrition tend to linger in American culture and in our minds, leaving us confused and sometimes even anxious about our eating decisions. We asked 10 nutrition experts which myths they wished would disappear like plate of fresh cookies at a holiday party.

It’s the beef in your stew and the fish in your tacos; the eggs in your omelet and the beans on your nachos. Protein-rich foods play a starring role in any satisfying meal. And for good reason: Protein is essential for every function in your body.But how much protein do you really need? What are the best food sources? And how can you be sure you’re getting enough?Take this quiz to see how much you know.

A dentist shares five tricks for managing treats.Dr. Apoena Ribeiro is a pediatric dentist and microbiologist at the University of North Carolina at Chapel Hill. She’s also a parent.When her daughter was little and growing up in Brazil, Dr. Ribeiro encouraged her to enjoy a holiday called the Feast of Saints Cosmas and Damian, which involves children collecting large bags of candy. But she also had some strategies for keeping the dental dangers at bay.Here’s what she did back then, and still does today, to protect her family’s oral health on a candy-laden holiday.She minimizes grazing.One sugar-filled night won’t sabotage your oral health, Dr. Ribeiro said — so when her daughter was young, she allowed her to collect and enjoy as much candy as she wanted on sweet-heavy holidays.Once she’d had her fill, Dr. Ribeiro would ask her daughter to sort her candy into two piles: One for her favorites, which she called her “treasures,” and another for the rejects, which they would donate.The “treasures” would be stashed away in a cardboard “treasure box” that could only be opened once or twice a week (though once per day is also OK, Dr. Ribeiro said). When the box was open, her daughter could eat as much candy as she wanted. But once she was done eating and it was closed, she would be cut off from the candy until the box was opened again. Then it was time to brush her teeth.These rules prevented Dr. Ribeiro’s daughter from grazing on candy throughout the day, which could give the cavity-causing bacteria in her mouth more opportunities to feed on sugars and create an environment that could lead to tooth decay. “Free access to the candy is the main problem,” Dr. Ribeiro said.But if the bacteria can only consume the sugar once a day or once every few days, “they will starve,” she said.She times candy eating with meals.The best time to have candy is with or just after a meal, Dr. Ribeiro said. At that point, the bacteria in your mouth may have already filled up on any carbohydrates from the meal, so they’re less able to take advantage of the sugar in the candy. And you produce more saliva when you eat, which helps to rinse the sugar from the candy off your teeth. It also neutralizes acids made by the bacteria that can wear away at your tooth enamel.For most families, having candy with dinner makes the most sense, since all members are likely to be at home and can brush their teeth just after, she said.Giacomo BagnaraShe emphasizes proper brushing right after eating candy.At least twice per day, Dr. Ribeiro brushes her teeth for at least one minute with toothpaste containing fluoride, and she flosses before brushing at night. Two minutes of careful brushing, which is what’s recommended by the American Dental Association, is even better than one, Dr. Ribeiro said.Ideally, Dr. Ribeiro tries to brush her teeth right after she has candy, and always brushes before bedtime.Children should follow the same rules: brushing twice per day — and after they’ve had candy, if possible — and always flossing and brushing before bed.For children under 5 or 6, she said, parents should brush their teeth for them, and parents should supervise the routine until their children are 8 or 9.She takes extra care with the worst candies.Any sticky, gooey or chewy candies that lodge into the grooves and crevices of your teeth can do serious damage. A caramel, for instance, can create a “banquet” for the bacteria in your mouth, Dr. Ribeiro said. And sour candies can increase the risk of damage by making your mouth more acidic, she added.Chocolate is Dr. Ribeiro’s favorite, in part because it’s less likely to linger on teeth. She still enjoys the gooey and chewy candies, but she makes sure to have them with meals, and she brushes and flosses right after to ensure their remnants don’t stick around.She makes Halloween a teachable moment.Dr. Ribeiro knew it would be futile to forbid her daughter from having candy on holidays or at any other time of the year.It’s more helpful to use Halloween as an opportunity to explain to children how sugar from candy or other popular sources like soda or juice can contribute to tooth decay, and how they can protect their teeth while still enjoying special treats, Dr. Ribeiro said.This is knowledge that they’ll carry with them beyond Halloween, she said, adding that good dental habits could improve the health of your teeth in the long run.“This is a concept for life,” she said.

Q: I’m in my 50s, and I’ve heard that it’s normal to burn fewer calories as I get older. Is this true?You can think of burning calories as “Step 1 of being alive,” said Herman Pontzer, a professor of evolutionary anthropology at Duke University. Food gives your body the fuel it needs to stay healthy, he said.Your age — among several other factors — can have a big effect on how many calories you need to maintain your body’s weight and basic functions, Dr. Pontzer and other experts said.Here’s what to know.How your age affects the calories you burnThe size of your body is the most important factor that affects your calorie requirements, Dr. Pontzer said. “The bigger you are, the more calories you need.”But your life stage is also crucial, he added.Babies and children, for example, require fewer calories than adults simply because they are smaller. But when you calculate how many calories they use relative to their body size, it’s actually more than what adults use because they are growing and developing, Dr. Pontzer said.Being more physically active also increases the number of calories you burn, said Anna Maria Siega-Riz, a nutrition professor and the dean of the School of Public Health and Health Sciences at the University of Massachusetts Amherst. She was the lead author of a 2023 report from the National Academies of Sciences, Engineering and Medicine that estimated the calorie needs of people in the United States and Canada.According to that report, an inactive, 200-pound, 40-year-old man would need about 2,700 calories per day to maintain his weight and basic bodily functions. But if he were an athlete training for a couple of hours each day, he would need about 3,500 calories per day.The same report estimated that starting around age 19, calorie requirements “drift down” a bit each year — to the tune of about 11 calories annually for men and seven for women, said Susan Roberts, a senior associate dean of foundational research at the Dartmouth Geisel School of Medicine.A 170-pound woman who walks for 60 to 80 minutes each day, for example, would need 2,450 calories per day at age 20 — at age 60, however, that would drop to 2,150, and at 80 it would be 2,000.This age-related drop in calorie burn is usually most noticeable in your 60s and beyond, Dr. Roberts said, possibly manifesting in weight gain or a less robust appetite. As you age, you tend to lose muscle and gain fat, which burns fewer calories, she said. And your brain — the body’s most metabolically active tissue — naturally shrinks in size and requires less energy, she added.It’s also common for people to become less physically active as they age, further reducing the number of calories they burn each day, Dr. Siega-Riz said.You can estimate your own calorie requirements using an online calculator. Just keep in mind that such calculators can provide only a general picture of what you should consume. Your actual needs will vary according to your daily activities, genetics and other factors, Dr. Siega-Riz said.If you’re wondering whether you’re consuming the right amount, the best way to check is to weigh yourself every so often, Dr. Siega-Riz said. If your weight is relatively stable, then you’re eating an appropriate number of calories.But for some people, a hyper-focus on the scale can create or worsen anxieties about food and weight, Dr. Siega-Riz said, so weigh yourself only as often as you’re comfortable.What burning fewer calories means for your eating habitsThe good news is that you probably won’t need to do much calorie counting as you age, because your appetite should naturally ebb to match your needs, Dr. Pontzer said.But as you get older, it’s important to make sure you’re getting the right balance of nutrients, Dr. Roberts said.For instance, research suggests that beginning in your 50s, your body needs more of certain nutrients such as calcium, vitamin B6, vitamin D and protein, even though you’re likely eating fewer daily calories overall.Because of that, Dr. Siega-Riz said, you’ll need to dedicate more of your daily calorie budget to foods that give you a bigger bang for your buck nutrient-wise, like fruits, vegetables, whole grains and lean sources of protein.Dr. Roberts agreed. When you’re in your 20s and 30s, she said, “you can still have calories left over for chocolate or beer or a piece of cake.” But if you’re in your 80s and consuming only about 1,500 calories per day, there’s less room for treats, she said.Dr. Roberts thinks it’s wise for older adults to take a multivitamin supplement to help fill in any nutritional gaps. But even then, a good diet is still necessary to ensure you’re getting other important nutrients like protein, fiber and healthful plant-based compounds, she said.Do you have a health question? Ask Well

The process of updating the healthy eating recommendations has become more transparent in recent years, but conflicts persist.It is a long-running concern of government watchdogs: Some of the experts responsible for helping to craft the U.S. dietary guidelines also take money from big food and drug companies.A report published Wednesday by the nonprofit U.S. Right to Know makes those concerns plain. Nine of the 20 experts on the 2025 Dietary Guidelines Advisory Committee have had conflicts of interest in the food, beverage, pharmaceutical or weight loss industries in the last five years, the report found.Gary Ruskin, the executive director of the nonprofit, said the finding “erodes confidence in the dietary guidelines,” which provide recommendations on how people can eat a healthier diet. The guidelines are widely used by policymakers to set priorities in federal food programs, health care and education — and questions about industry influence could damage the public’s trust that the recommendations are based in science rather than reflecting corporate interests, Mr. Ruskin said.What the new report foundFor the report, Mr. Ruskin and his colleagues scoured publicly available records and identified financial relationships with industry groups and for-profit food and pharmaceutical companies. Those relationships included research funding from infant formula companies, the U.S. Egg Nutrition Center and the California Walnut Commission; paid consulting positions with companies that manufacture weight loss drugs; and advisory board roles at WeightWatchers and the National Dairy Council.One committee member, for example, received a $240,000 grant from Eli Lilly, one of the top insulin manufacturers, to research better ways for diabetes patients to manage their blood sugar through their diets. The current committee members have far fewer industry ties than those in years past, said Marion Nestle, a professor emerita of nutrition, food studies and public health at New York University who served on the 1995 committee and is a frequent critic of the guidelines. The U.S. Department of Agriculture and the Department of Health and Human Services, which jointly revise the dietary guidelines every five years, appointed the current committee members. The members reported their financial disclosures to the agencies, who released a combined list of conflicts for the group — but not for individuals — in June.Why conflicts of interest are a concernWhen committee members receive funding from certain industry groups or organizations, it raises the concern that they may be biased toward them, Dr. Nestle said. “Part of the problem is the influence is unconscious,” she said. “People don’t recognize it,” she added, and will often deny it.Even if such relationships do not influence the experts, Mr. Ruskin said, they can create the appearance that they do — which can seed doubt about how independent the committee’s recommendations actually are.Christopher Gardner, a professor of medicine at Stanford University and a current member of the dietary guidelines committee, said it would be difficult to find enough nutrition experts for the 20-member committee who had not taken money from industry groups. Federal funding for nutrition research is limited, he said, and many researchers accept industry grants for research studies so they can keep their jobs in academia. “We have to publish or perish,” Dr. Gardner said.The Right to Know report identified one major conflict of interest for Dr. Gardner: a research grant from Beyond Meat, which makes plant-based meat alternatives.Despite that conflict, Dr. Gardner said he believed he could remain objective in his committee duties, which will include reviewing the relationship between what people eat and the risk of various diseases. And, he said, the way the committee evaluates questions of diet and health, including by rigorously reviewing scientific evidence and holding committee discussions and public meetings, would prevent one person’s bias from swaying the committee’s decisions. “I have full faith that this group is going to very objectively consider all the evidence for every question,” he said.Even with significant conflicts among members of the 2020 Dietary Guidelines Advisory Committee, Dr. Nestle said they did a “pretty good job” of evaluating the evidence. Yet industry influence can still creep in later in the process, she said, when the U.S.D.A. and the H.H.S. produce the final guidelines based on the committee’s advice. The 2020 guidelines, for example, disregarded the committee’s recommendation for stricter limits on sugar and alcohol. And the 2015 edition omitted the committee’s advice on limiting the consumption of red and processed meats after intense lobbying by the meat industry.Why the Dietary Guidelines are importantThe Dietary Guidelines for Americans influence federal policies and food programs, physician guidance and how nutrition is taught in schools. They are also used for meal planning in schools, the military, prisons and hospitals.“You can’t overestimate how important they are,” Dr. Nestle said.The current committee is evaluating the research on a number of issues, including on the health effects of ultraprocessed foods, which include most packaged foods and drinks.That is a topic Dr. Nestle said she would follow with interest, given her concerns that the foods are harmful to people’s health.

Q: I routinely drink three or four cups of coffee per day, but often wonder if this is too much. Should I consider cutting back?Coffee can be many things: a morning ritual, a cultural tradition, a productivity hack and even a health drink. Studies suggest, for instance, that coffee drinkers live longer and have lower risks of Type 2 diabetes, Parkinson’s disease, cardiovascular conditions and some cancers.“Overall, coffee does more good than bad,” said Rob van Dam, a professor of exercise and nutrition sciences at the Milken Institute School of Public Health at George Washington University.But between your breakfast brew, lunchtime latte and afternoon espresso, is it possible to have too much? And if so, how can you tell?We asked experts to give us the unfiltered truth.The consequences of overdoing itCoffee contains thousands of chemical compounds, many of which may influence health, said Marilyn Cornelis, an associate professor of preventive medicine at Northwestern University Feinberg School of Medicine.But coffee is also the largest source of caffeine for people in the United States, and that’s where most of the risks associated with coffee consumption come from, she said.Having too much caffeine can cause a racing heart, jitteriness, anxiousness, nausea or trouble sleeping, said Jennifer Temple, a professor of exercise and nutrition sciences at the University at Buffalo.It can also lead to headaches, acid reflux and, at high enough doses, even tremors or vomiting, said Dr. Adrienne Hughes, a medical toxicologist and an assistant professor of emergency medicine at Oregon Health and Science University.But “most people are kind of well tuned with their response to caffeine,” Dr. Cornelis said, and when they begin to experience even mild symptoms of having too much, they cut back.As such, it’s rare to experience dangerous side effects from drinking coffee, Dr. Hughes said. Caffeine overdoses typically result from taking in too much caffeine from concentrated forms, such as powders or supplements, in a short period of time, she said. And in most cases, you would need to consume at least 10,000 milligrams of caffeine — or the equivalent of about 50 to 100 cups of coffee, depending on the strength — for it to be potentially fatal, Dr. Hughes said.Caffeine can cause a short-term increase in your blood pressure and heart rate, particularly if you don’t consume it regularly, she said. But this isn’t usually harmful. Studies show that habitual coffee drinking does not seem to raise blood pressure or the risk of an abnormal heart rhythm in the long run.That said, if you’re prone to abnormal heart rhythms, or if you notice palpitations after having caffeine, you may be more sensitive to its effects and should not consume more than you’re used to, or ingest large doses from concentrated sources, like supplements or energy shots, Dr. Hughes said.And having too much caffeine while pregnant is associated with an increased risk of miscarriage, Dr. van Dam said.Know your limitsMost adults can safely consume 400 milligrams of caffeine — or the amount in about four eight-ounce cups of brewed coffee or six espresso shots — per day, according to the Food and Drug Administration. If you’re pregnant, the American College of Obstetricians and Gynecologists recommends no more than 200 milligrams.Keep in mind that cup sizes and coffee strengths can vary. A typical eight-ounce cup has about 80 to 100 milligrams, according to the F.D.A. But at Starbucks, a “tall” (12 ounce) medium-roast brew contains around 235 milligrams of caffeine — about the same amount as a triple shot of espresso.Caffeine can also be found in certain teas, sodas, dark chocolates, headache medications and some energy and sport supplements.That being said, the 400 milligram guideline is reasonable for most adults, Dr. van Dam said. It also fits in with the research on how much you should consume to reap the health benefits while avoiding unpleasant side effects. Two to four cups per day is “kind of a sweet spot,” he said.But people break down caffeine at different rates, Dr. van Dam said; 400 milligrams may feel like way too much for some, while others can routinely have more without any side effects. Depending on your genetics, Dr. Cornelis said, it could take anywhere from two to 10 hours to clear half of a dose of caffeine from your blood. If you fall on the longer end of that spectrum, a midafternoon espresso may lead to trouble sleeping, whereas if you metabolize caffeine faster, you may not be bothered.Smoking tobacco can also speed up your rate of caffeine metabolism significantly, which is why those who smoke may need to consume more caffeine to feel alert. And being pregnant or taking oral contraceptives can slow it down, Dr. van Dam said.At the end of the day, “you just kind of have to listen to your body,” Dr. Temple said. “If you’re starting to feel nauseous or jittery or anxious, maybe cut back,” she said. “If it’s affecting your sleep, cut back.”

After enduring severe nausea and vomiting in pregnancy, the geneticist Marlena Fejzo made finding the cause of her condition, hyperemesis gravidarum, her life’s work.Taped above a tidy wooden desk in the corner of her bedroom, right at eye level, is a piece of paper that Marlena Fejzo has saved for 24 years.It’s a portrait of Dr. Fejzo at age 31 during the worst ordeal of her life. Her face and body are drawn in the gaunt greens and yellows of illness; her hollowed cheeks are marked with tears. The colored pencil drawing, made by her sister in 1999, is the only image she has held on to from that time. The few photos her mother took “were too horrible” to keep, said Dr. Fejzo, now 55.A little nausea and vomiting in pregnancy were normal, she knew. But she experienced weeks of debilitating illness when she was pregnant with her son, and when expecting her second child, Dr. Fejzo was so ill that she couldn’t move without vomiting.She couldn’t go to work or care for her little boy, or swallow so much as a teaspoon of water, let alone a bite of toast or a prenatal vitamin. Her empty gastrointestinal tract would spasm so violently and for so long that she couldn’t breathe.“Every living moment was torture,” she said.For at least a month, Dr. Fejzo couldn’t keep down any food or drink, and she received fluids through an IV. Her weight dropped to 90 pounds from an already slight 105, after which she grew too weak to stand on a scale.“I was starving,” she said, “and the doctor just kept trying higher doses of drugs and different drugs, and nothing helped.”Finally, her doctor agreed to deliver liquid nutrients through a catheter running into a large vein near her heart, but Dr. Fejzo believes this step came too late. Fifteen weeks into her pregnancy, the fetus’s heart stopped beating.Dr. Fejzo was devastated. “All that incredible suffering for nothing,” she said.Dr. Fejzo, who was then a postdoctoral fellow at the University of California, Los Angeles, is now a faculty researcher in the department of obstetrics and gynecology at the University of Southern California Keck School of Medicine.During her pregnancy, she suffered from hyperemesis gravidarum, a condition whose hallmark symptoms include nausea and vomiting so severe and relentless that it can cause dehydration, weight loss, electrolyte imbalances and hospitalization.The complication is rare, affecting about 2 percent of pregnancies, but its consequences can be devastating. In surveys, women have described their experiences with the condition in harrowing terms: “I was depressed and bedridden for 20 weeks. I wanted to die,” one wrote; “I am terrified to experience another pregnancy,” another said.Some wrote of feeling “miserable, with no hope”; or lonely and abandoned, with references to suicide. “I sobbed when I awoke in the mornings because I realized, I was still alive.”In a recent survey of more than 5,000 hyperemesis patients, 52 percent had considered — and 5 percent had gone through with — terminating a wanted pregnancy; and 32 percent reported contemplating suicide.Maggie Shannon for The New York TimesYet despite the gravity of hyperemesis, as it’s colloquially called, doctors are often slow to treat it. Sometimes, they dismiss it as a temporary discomfort, or even a psychological disorder, said Dr. Jone Trovik, a gynecologist and a professor of clinical science at the University of Bergen in Norway.“My doctor pretty much thought it was all in my head,” Dr. Fejzo said. He told her that women make themselves sick during pregnancy to gain the sympathy of their husbands, and later, that her illness was a ploy for attention from her parents, who were helping with her medical care.That her doctor would blame her suffering on her own psyche infuriated Dr. Fejzo. So she made it her life’s work to find the condition’s true cause.“It was so devastating what happened to me that I don’t want that to happen to anyone else,” she said.Career interruptedMarlena Fejzo grew up a few miles from her current home in the affluent Brentwood neighborhood of Los Angeles, one of four siblings in a household humming with cousins and friends. It was a charmed California childhood, Dr. Fejzo said, with regular trips to ski at Mammoth Mountain, hike in Yosemite National Park and vacation in Palm Springs.She graduated near the top of her high school class from the prestigious Harvard-Westlake School (then known as the Westlake School for Girls), and then studied applied math at Brown University.During her third year at Brown, an introductory genetics class captivated her, and she decided to pursue a doctorate in the field at Harvard University — a surprise to her family of lawyers, language scholars and musicians.As a graduate student at Harvard, Dr. Fejzo discovered two genes involved in the development of uterine fibroids, and she received national recognition for her research from the American Society of Human Genetics.It was a rare honor for a young scientist, particularly one working on a health problem that didn’t affect men, said Cynthia Morton, a professor of obstetrics, gynecology and reproductive biology at Harvard Medical School and Dr. Fejzo’s doctoral adviser.“She was a hard worker and dedicated to the work,” Dr. Morton said. “She could do anything.”In 1995, Dr. Fejzo began a postdoctoral fellowship in breast cancer genetics at the University of California, San Francisco, setting her sights on a tenure track faculty position and a career researching the genetics of conditions that affect women. But first, she and her husband wanted to start a family.Within a few weeks of becoming pregnant with her first child in 1996, she was hit with constant nausea and vomiting — similar to the symptoms that would afflict her second pregnancy, though not as severe. Still, she could barely eat and was unable to work for eight weeks, and she twice needed IV fluids for dehydration.About 70 percent of pregnancies come with some degree of nausea and vomiting, but health care providers can be slow to differentiate between regular “morning sickness” and hyperemesis, and to offer treatment for it.Maggie Shannon for The New York TimesThis was Dr. Fejzo’s first experience with hyperemesis, though her doctor at the time never told her the name of her condition or offered medication to treat it.By her second trimester, she felt well enough to return to work, and the rest of her pregnancy was normal. “When my son was born, I was ecstatically happy, and it was all great, which is why you do it again,” Dr. Fejzo recalled.Dr. Fejzo’s second pregnancy came two years later, in 1999, after she moved back to Los Angeles and began a second postdoctoral position at U.C.L.A. That was when, she said, she experienced the worst ordeal of her life, leading to 10 weeks of severe illness and her miscarriage.Dr. Fejzo’s sister, Melanie Schoenberg, now 45, a public defense lawyer for Los Angeles County, remembered seeing her at the end of her ordeal. She was in a wheelchair, too weak to walk and wrapped in a blanket, sobbing and shaking with grief.“She looked like a ghost,” Ms. Schoenberg said. “Like a pile of bones.”An under-researched conditionAt age 31, as Dr. Fejzo regained her strength, she made two life-altering decisions. First, she said, she wouldn’t try another pregnancy; her twin daughters would later be born with the help of a surrogate. Second, she was determined to find the cause of hyperemesis.She scoured the medical literature for clues. Why had she gotten so sick when most pregnancies had far milder symptoms? “Nothing was known,” she said. “There was so little research.”Hyperemesis has long been under researched and under recognized, in part because about 70 percent of pregnancies come with some degree of nausea and vomiting, which is usually not dangerous, Dr. Trovik said. Health care providers can be slow to differentiate between the more common “morning sickness” and the rarer but more severe hyperemesis, and to offer treatment, including medications and nutrition, she said.“It was so devastating what happened to me that I don’t want that to happen to anyone else,” Marlena Fejzo said of her experience with hyperemesis, and of her doctor’s dismissal of the condition as being all in her head.Maggie Shannon for The New York TimesBefore IV fluids became routinely available in the 1900s, hyperemesis killed pregnant women often enough that medical literature listed excessive vomiting as a reason to induce abortion because of the danger it posed to the mother’s life. Some experts believe that the death of the author Charlotte Brontë in 1855 was most likely caused by hyperemesis, not tuberculosis, as was listed on her death certificate.Today, deaths from hyperemesis are rare, but they do occur, as do serious complications.Electrolyte imbalances caused by excessive vomiting and dehydration can bring about heart arrhythmias and cardiac arrest. Malnutrition and deficiency in the B vitamin thiamin can lead to a brain disorder called Wernicke’s encephalopathy, which can result in miscarriage, brain damage and death.Hyperemesis is also linked with a higher risk of pregnancy complications including preterm birth, pre-eclampsia and blood clots.In a recent survey of more than 5,000 patients with hyperemesis in the United Kingdom, 52 percent had considered — and 5 percent had gone through with — terminating a wanted pregnancy; and 32 percent reported contemplating suicide. A 2022 study found that hyperemesis is one of the main predictors for postpartum depression.Most babies born from hyperemesis pregnancies are healthy, but recent studies have shown that they have a small increase in risk of having low birth weight, and of having cognitive, mental health and behavioral difficulties in childhood — effects that could be caused by malnutrition and stress in the womb, researchers hypothesize.Over the last century, physicians have claimed, without evidence, that hyperemesis is a subconscious attempt at “oral abortion,” as if trying to throw up a pregnancy; a rejection of femininity; a product of sexual frigidity; a strategy for taking a “time out” from stressful household responsibilities; or a bid for attention, as Dr. Fejzo’s doctor had told her.As a result, women have often been blamed and punished for their own illnesses. In the 1930s, hospitalized hyperemesis patients were “denied the solace of the vomit-bowl” and forced to lie in their own vomit.To this day, patients hospitalized with the condition are sometimes isolated in a dark room and prohibited from having visitors or access to their cellphones. This treatment has been based in part on the theory that hyperemesis is caused by a woman’s subconscious rejection of pregnancy, and that isolation would make her accept it, said Dr. Philippe Deruelle, a professor of obstetrics and gynecology at the University of Strasbourg, via email.The practice is “misogynist” and “indefensible,” he said, but it still occurs at least occasionally in France and elsewhere in Europe. In 2022, the College of French Gynecologists and Obstetricians issued new guidelines that included a statement condemning it.Dr. Fejzo was haunted by the dismissal of her illness as having a psychological cause, and by the lack of effective treatments to help her. Nothing would change as long as the condition’s true cause was unknown, she thought.A decade of FridaysWhen Dr. Fejzo returned to her lab at U.C.L.A. after her miscarriage, she told her boss, the chair of the genetics department, that she wanted to find the cause of hyperemesis. “She just laughed at me,” Dr. Fejzo said, “like it was a joke.”Unable to find a mentor interested in hyperemesis, Dr. Fejzo took a job studying ovarian cancer at the university, a position she stayed in, mostly part-time, for 20 years. But she began piecing together research on hyperemesis during her evenings and weekends and on Fridays when she wasn’t working in the lab.Her younger brother, Rick Schoenberg, 51, a statistician at U.C.L.A., helped her create an online survey of hyperemesis patients, and the Hyperemesis Education and Research (HER) Foundation offered collaborators and small grants to fund her work. In 2005, Dr. Fejzo also began partnering with obstetrician-gynecologists at the University of Southern California.Tallying survey responses, “I saw right away that it was running in families,” Dr. Fejzo said. “The answers kept coming in where people were like, ‘Yeah, my sister has it; my mom has it.’”In 2011, Dr. Fejzo and her collaborators published their findings in the American Journal of Obstetrics and Gynecology. Women who had sisters with hyperemesis, they found, had a 17-fold higher risk of developing the condition than those who didn’t, providing some of the first clear evidence that the condition could be passed down from parents.Dr. Fejzo knew that DNA analysis would be crucial to understanding the genetics of hyperemesis. So in 2007, she began collecting saliva samples from people who had experienced the condition and those who hadn’t.Every Friday for 10 years, she called study participants — more than 1,500 in all — to request their medical records and consent to participate, and mailed them saliva collection kits from her home.But Dr. Fejzo wasn’t sure how she would pay for the genetic analyses. Her grant proposals to the National Institutes of Health were rejected. Since 2007, the agency has funded only six hyperemesis studies, totaling $2.1 million.That amount is small in comparison with the economic burden of the condition, said Kimber MacGibbon, executive director of the HER Foundation. (Amy Schumer, who publicly documented her struggles with hyperemesis, is on the foundation’s board of directors.)Hyperemesis hospitalizations are thought to cost patients and insurers about $3 billion per year, she said, and then there are the expenses of medications, home health care, lost work and complications like postpartum depression. “The costs of it are just astronomical,” she said.‘This is it’Without funding to analyze the saliva samples accumulating in the lab freezer, Dr. Fejzo discovered an alternative strategy when her older brother gave her a 23andMe DNA testing kit for her 42nd birthday.After registering her kit, she received a standard email giving her the option of participating in the company’s research studies by completing an online survey and consenting to the use of her genetic data.“I saw what they were doing, which I thought was brilliant,” she said.She asked 23andMe if they would include a few questions about nausea and vomiting in pregnancy on their customer survey, and they agreed. A few years later, she worked with the company to scan the genetic data of tens of thousands of consenting 23andMe customers, looking for variations in their DNA associated with the severity of nausea and vomiting during pregnancy. The results were published in the journal Nature Communications in 2018.A handful of gene mutations were flagged as significantly different, but the most striking was for one that makes a protein called growth differentiation factor 15, or GDF15. Dr. Fejzo had never heard of it, but as soon as she started reading about it, “I was like, ‘Oh my God, this is it,’” she recalled.GDF15 acts in a part of the brainstem that suppresses appetite and sets off vomiting, and it had already been shown to cause appetite and weight loss in cancer patients. Blood levels of the protein are naturally increased in pregnancy and have since been found to be even higher in those with severe nausea and vomiting.Researchers speculate that GDF15 may have evolved to help pregnant women detect and avoid unsafe foods that might harm fetal development early in gestation. But in hyperemesis, this normally protective mechanism seems to run in overdrive, at least in part because of too much GDF15, said Stephen O’Rahilly, director of the metabolic diseases unit at the University of Cambridge, who now collaborates with Dr. Fejzo on GDF15 research.In a study published in 2022, Dr. Fejzo and her colleagues confirmed the link between hyperemesis and GDF15 in the patients she had enrolled over a decade of Fridays. The analyses were conducted without charge by the biotechnology company Regeneron.When that study was published, Dr. Fejzo wrote on Twitter, “My life’s work is out.”But she isn’t done. She’s watching closely as several pharmaceutical companies have begun testing GDF15-based drugs that aim to reduce nausea and improve appetite in cancer patients, with promising early results.A smaller number are working on similar medications for hyperemesis, Dr. Fejzo said. Among them is a newly formed company called Materna Biosciences, which recruited Dr. Fejzo as chief scientific officer.There are significant hurdles to testing new medications in those who are pregnant, Dr. Fejzo said, but if done carefully, this step could improve treatment options for hyperemesis patients and definitively prove that GDF15 is the condition’s primary cause.And, Dr. Fejzo hopes, it could finally put to rest the idea that the condition is psychological.“I would be devastated to see my daughters go through this without having tried everything in my power to make things better,” Dr. Fejzo said. “If I don’t keep going, who will?”

At my grocery store, the bread selection stretches across an entire aisle. And among those amber waves of bread loaves, bagels and buns are a few gluten-free options, which can cost about twice as much as their wheat-based counterparts. Are they a more nutritious choice?As is often the case with nutrition questions, the answer will depend on your individual circumstance, said Jerlyn Jones, a spokeswoman for the Academy of Nutrition and Dietetics and a registered dietitian in Atlanta. But for most people, choosing a gluten-free bread instead of a wheat-based bread is not an inherently more nutritious option, she added. And, gluten-free breads can be harder on your wallet, she said, since they are often more expensive and have a shorter shelf life.Gluten is a protein found in the grains of wheat, barley and rye. In traditional bread made from wheat flour, gluten forms a protein network that makes dough cohesive and stretchy and gives bread that quintessentially satisfying, chewy texture.But gluten or other components of wheat can cause health problems in some. For the estimated 1 percent of people worldwide who have celiac disease, a serious autoimmune condition triggered by eating gluten, the protein causes intestinal damage that can impair nutrient absorption and lead to symptoms like diarrhea, weight loss, fatigue, anemia and a blistery, itchy rash. The only effective way to manage celiac disease is strict and lifelong gluten avoidance.For others with milder wheat-related sensitivities, eating the grain doesn’t cause the intestinal damage found in celiac disease, but can cause gastrointestinal discomfort and symptoms like fatigue and headache that usually go away when wheat is avoided. It’s not clear how many people have this condition, called non-celiac wheat sensitivity, but it may be more common than celiac disease.A third, much less common wheat-related condition is a wheat allergy, which can cause allergic reactions like diarrhea, vomiting, facial swelling or difficulty breathing within minutes to hours after eating wheat.If you have celiac disease, wheat sensitivity or a wheat allergy, going with a gluten-free bread is clearly the better choice. But in a 2017 survey of 1,000 people in the United States and Canada who purchased gluten-free groceries — conducted by the food and beverage ingredient supplier Ingredion — 46 percent said they bought those products for reasons other than a medical condition. Among their top motivations: wanting to reduce inflammation or consume fewer artificial ingredients, believing that gluten-free products were healthier or more natural, and thinking that such products would help with weight loss.However, none of these beliefs are true, said Anne R. Lee, a registered dietitian and an assistant professor of nutritional medicine at the Celiac Disease Center at Columbia University Medical Center. “Typically, the gluten-free products are higher in fat, higher in sugar, higher in salt and lower in fiber and your B vitamins and iron,” she said.Making bread without gluten is a technological challenge, and manufacturers tend to rely on ingredients like refined rice, potato or tapioca flours, which contain much less protein and fiber than wheat flours, Dr. Lee said. Most of the refined wheat flours used in the United States are enriched with iron and the B vitamins folic acid, niacin, riboflavin and thiamin, while the flours used in gluten-free products generally don’t contain these added nutrients.Gluten-free bread manufacturers also often add sugar, fat and salt to their products to make them taste better, Dr. Lee said. And in part because gluten-free breads tend to contain more water, fat and refined starch than wheat-based breads, they spoil and become stale more quickly.Aileen Son for The New York TimesFor these reasons, going gluten-free is not always a better choice. “If you think you have an intolerance to gluten, before you take it out of your diet, go see a gastroenterologist and really be tested appropriately,” Dr. Lee said. An added benefit: Celiac disease is more difficult to diagnose in people who have already eliminated gluten.There’s also quality of life to consider. Restricting your diet can make you more anxious in social situations or make you more reluctant to try homemade foods at family meals, Ms. Jones said. Food “is not only fuel for our bodies, but it also gives us enjoyment, too. You don’t want to miss out on enjoyment, especially nowadays,” she added, referring to those who avoid gluten without a medical reason.For her patients who need to eliminate gluten, Dr. Lee advises focusing less on packaged gluten-free products and more on whole foods like fruits, vegetables, beans and gluten-free whole grains and seeds like amaranth, buckwheat, quinoa, teff and millet. “If you do a gluten-free diet where you’re using foods that are naturally gluten-free, like all these wonderful grains, then your diet can be incredibly healthy,” she said.But if you’re craving a sandwich, you’ll need bread. The good news is that gluten-free products have improved — “they’re better than they were even five years ago,” Dr. Lee said. Many manufacturers have started to include more gluten-free whole grains in their products, which can boost fiber, protein and some vitamins and minerals. Just as wheat-based breads can range widely in nutritional quality, from highly processed white bread to whole grain loaves, the same is now true of gluten-free options, Dr. Lee said.To identify better gluten-free breads, Dr. Lee recommended comparing their nutrition labels with those from whole wheat breads. Check for similar levels of fiber and protein and minimal added sugar, and look for a bread with whole grains among the first few ingredients, which are listed in descending order by weight, so that the first ingredient is always present in the largest amount. “If your first ingredients are water and tapioca starch, put the bread back on the shelf,” Dr. Lee said.Alice Callahan is a health and science journalist.