Latest news with #DariushMozaffarian
BBC News
5 days ago
- Health
- BBC News
Are seed oils really bad for you?
Seed oils like canola and sunflower oil have attracted controversial claims about harmful effects in recent times. Is there any truth to them? You might have a bottle of sunflower oil or canola (rapeseed) oil stashed away in a kitchen cupboard somewhere. Whether you cook with them or drizzle them over salads, seed oils are popular across the world. But these unassuming seed oils have become the centre of a heated debate online. In recent years, seed oils have become the target of countless social media posts, with people claiming that they are "toxic", "poisonous" and, ultimately, are damaging our health. Critics have nicknamed some seed oils 'the hateful eight' – referencing eight popular seed oils, canola, corn, cottonseed, grapeseed, soy, rice bran, sunflower and safflower – and blame them for causing heart disease and type 2 diabetes. Are seed oils really the enemy, or is the antagonism towards them unjustified? Are seed oils connected to heart health? Much of the recent criticism of seed oils focuses on their high omega-6 fatty acid content. Omega 6 fatty acids are essential fatty acids, which means we need them, but can't produce them ourselves. In recent years some scientists have argued that omega 6 can cause chronic inflammation (which can increase the risk of developing diseases including heart disease and cancer). But controlled trials have found that omega-6 fatty acids do not increase inflammation, says Dariush Mozaffarian, professor and director of the Food is Medicine Institute at Tufts University in Massachusetts in the US. "New research shows that omega-6 fatty acids give rise to unique natural molecules, like lipoxins, that have powerful anti-inflammatory effects in the body," says Mozaffarian. Recent research studied the diet and health of over 200,000 people in the US for around 30 years. The researchers found that people who consumed more plant oils (including seed oils) were less likely to die from cardiovascular disease or cancer over the course of the study. On the other hand, those with a higher intake of butter were more likely to die during the same period. There are numerous observational studies looking at how omega 6 effects our heart health – where scientists look at data on diet and health, and find associations between the two. But some observational studies rely on people's own accounts of what they eat, says Matti Marklund, assistant professor of human nutrition at Johns Hopkins Bloomberg School of Public Health in the US. And this, he adds, can be problematic because people may misremember, or even be dishonest, about their dietary habits. Another way to measure omega 6 intake is to measure the average amount in the individual components and ingredients in a person's diet. However, Marklund adds, it can be difficult to translate what people say they have eaten into certain quantities. Numerous studies investigating the effects of omega 6 on our health focus on linoleic acid, an omega 6 fatty acid found in high amounts in seed oil, that has been found to lower the 'bad' LDL cholesterol in our blood. In a 2019 study, Marklund instead focused on the levels of fatty acids in the blood of participants from around 30 observational studies – some which followed people for up to 30 years – and looked at how many developed cardiovascular disease and died from it. He found that those with the highest levels of linoleic acid in blood had the lowest risk of developing cardiovascular disease. There is some confusion regarding omega 6 and heart health, says Christopher Gardner, director of nutrition studies at the Stanford Prevention Research Center in the US. This partly stems from omega 6's role in the process of blood clotting, which Gardner says people mistakenly only associate with strokes and heart attacks. Omega 3, he says, tends to be more blood-thinning. "If you had a wound in your hand, you'd want it to clot," he says. "You need balance." Meanwhile, scientists concluded in a 2019 analysis of 30 studies that people with higher amounts of linoleic acid in their blood were 7% less likely to develop heart disease. "Linoleic [acid] might improve cholesterol to reduce the risk of cardiovascular disease, and also improve glucose metabolism, which reduces the risk of type 2 diabetes," Marklund says. Seed oils and the 3:6 ratio Another common accusation levelled at seed oils is that eating too much omega 6 compared to omega 3 is harmful. In the Western world, omega-6 fatty acids account for around 15% of our total energy intake. The average person's ratio of omega 3 to omega 6 can be up to 50:1. However, it should be more like 4:1 to reduce our risk of cardiovascular disease, according to one study. A 2022 World Health Organization review and meta-analysis reported that a higher omega 6:3 ratio was associated with a greater risk of cognitive decline and ulcerative colitis, a chronic inflammatory bowel disease. On the other hand, a higher omega 3:6 ratio was also linked to a 26% reduced risk of depression. Overall, the scientists involved in the WHO study concluded that a high intake of omega 6 fatty acids from seed oils is unlikely to increase your risk of death and disease – but say that more high-quality research is needed. But while some scientists argue that you shouldn't have too much omega 6 compared to omega 3, Marklund says it's better to up your intake of omega 3 rather than consume less omega 6, as both are associated with health benefits. How seed oils are processed Unlike other oils, seed oils are extracted from the seeds of plants. There are some concerns that seed oils are extracted with hexane – a chemical made from crude oil – but there is little evidence so far suggesting that this process can cause issues. While some evidence suggests hexane could be linked to several health conditions, after being extracted, the oil is then deodorised and bleached to remove and additives. "Scientists will say hexane extract is normal in food processing, and the deodorising and bleaching removes potentially harmful compounds," says Gardner. Cold-pressed seed oils avoid this process entirely, as it involves squeezing the seeds to extract the oil – but this results in a more expensive product. Can seed oils fuel tumour growth? Despite an abundance of research showing the potential benefits omega 6 might have to our health, researchers have recently found that this fatty acid can fuel the growth of a specific type of breast cancer. The findings may have implications for the impact of omega 6 consumption on other diseases, too. Cancer cells use nutrients as fuel to grow and multiply, but until now, there was limited research looking at the role omega 6 fatty acids play. But a study published in March this year found a mechanism by which linoleic acid, an omega 6 fatty acid, helps cancer cells to grow and multiply in patients with triple negative breast cancer (TNBC). This is the most aggressive sub-type of the disease, and one that doesn't respond well to targeted therapies. Previous studies suggest there is no association with omega 6 fatty acids, or a small increase in risk, says Nikolaos Koundouros, postdoctoral associate at Weill Cornell Medicine research centre in New York. But these studies, he says, haven't taken into account that there are multiple sub-types of breast cancer, and that they all differ in terms of a patient's survival and prognosis, and how they might respond to targeted therapy. TNBC seems to respond the most to omega 6 linoleic acid, Koundouros says. Along with a team of researchers, Koundouros discovered in the lab that, when fed omega 6, TNBC cells activate a protein complex linked to tumour growth and progression. Another protein, which is found in larger amounts in TNBC tumours compared to other breast cancer subtypes, is known to take fatty acids and lipids throughout the body and within cells to exactly where they need to be. Koundouros explains that these proteins, along with omega 6, may also be relevant in other chronic diseases, such as obesity and type 2 diabetes. This research could potentially inform treatment options for TNBC patients, but it doesn't necessarily have wider implications for everyone, Koundouros says. "It's important to remember omega 6 fats are essential for a reason; if you completely cut them out, you could have detrimental side effects," he says. Which seed oil? Some seed oils – such as canola oil and soybean oil – have been studied more than others, so have a more rigorous evidence base. "These each provide a balanced combination of healthy fats, including monounsaturated fats, omega-6 polyunsaturated fats, and omega-3 polyunsaturated fats," Mozaffarian says. Canola oil, Mozaffarian adds, has similar anti-inflammatory effects and produces better improvements in blood cholesterol levels than olive oil, which has long been hailed the healthiest of all oils. One meta-analysis of 27 trials found that canola oil was found to significantly reduce LDL cholesterol compared to sunflower oil and saturated fat, while another found that it dramatically reduced body weight, especially in in those with type 2 diabetes. "Canola oil produces excellent benefits for blood cholesterol levels, and also modestly reduces body weight. The healthy fats in canola oil, especially the omega 6 polyunsaturated fats, also improve blood glucose, insulin resistance, and insulin production," says Mozaffarian. Soybean oil has also been found to improve cholesterol levels compared to saturated fats. One study found that people who consumed more soybean oil had lower risk of death from all causes; a 6% lower risk for every 5g they consumed daily. Which seed oil is healthiest? "Seeds are one of nature's most nourishing gifts; a package of beneficial healthy fats," says Mozaffarian. That something so well studied within nutrition science has had such a backlash has been a source of confusion for some scientists. But this misunderstanding may come from a "misplaced combination of partial truths", Mozaffarian says. For instance, some people may link seed oils to ultra-processed foods (UPFs), which often contain seed oils, particularly canola, corn, soybean, and sunflower oils. In recent years there has been a huge focus on the health risks of consuming too many UPFs, including increased risk of developing type two diabetes and heart disease. More like this:• What is the healthiest cooking oil?• The truth about saturated fat• Cod liver oil: The fishy fix that was surprisingly healthy "But these dangers arise from too much starch, sugar, and salt, loss of natural intact food structure and dozens, or even hundreds, of artificial additives," Mozaffarian says. Some people have also drawn a correlation with increased consumption of seed oils in recent years and the rise in obesity and diabetes. "But if you want to draw parallels with people eating more seed oils and unhealthy outcomes, it's because we're eating food that tends to contain a lot of sugar and sodium," Gardner suggests. He says there are many ways to consume seed oils at home that don't involve UPFs, such as with a salad or stir-fry. "I'd hate to see people tossing out seed oils because of this seed oil war," says Gardner. Ultimately, while some scientists call for more rigorous trials looking into the effects of seed oil consumption on our health, others, including Marklund, argue that there is already a wealth of good quality trials showing benefits on blood cholesterol, blood glucose and insulin levels for the general population. "Omega-6 fatty acids are excellent for health," says Marklund. "They have been linked to lower onset of heart disease, stroke, diabetes, and even death from all causes." -- For trusted insights into better health and wellbeing rooted in science, sign up to the Health Fix newsletter, while The Essential List delivers a handpicked selection of features and insights. For more science, technology, environment and health stories from the BBC, follow us on Facebook, X and Instagram.
6 days ago
- Health
Food and fitness make or break success on weight loss meds, report finds
Drugs like Wegovy and Zepbound -- GLP-1 medications typically used to treat obesity -- can lead to impressive weight loss. But a new joint advisory from four major medical groups warns that without proper nutrition and lifestyle support, people may face muscle loss, weight regain, and high long-term costs once they take themselves off GLP-1 medications. Experts from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society contributed to the report, which noted that only about half of users continue taking their GLP-1 medication after one year and only about 15% remain on treatment after two years. Many people stop taking GLP-1 medications due to side effects, cost or disappointing results -- and when they do, they often regain weight, making long-term success depend on consistent use and a healthy diet, the report stated. The report aims to guide both clinicians and patients on nutrition and lifestyle changes to improve long-term outcomes while taking a GLP-1. "We really wanted to bring in four major societies together that focus on nutrition, lifestyle, [and] obesity and come with a consensus statement on how nutrition should be thought about when prescribing these drugs," Dr. Dariush Mozaffarian, a cardiologist, director of the Food is Medicine Institute at Tufts University, and the report's lead author, told ABC News. Mozaffarian explained that for someone to achieve success on a GLP-1, they need to commit to comprehensive lifestyle changes. "The FDA says these drugs are approved for use as an adjunct to lifestyle therapy," he said. "In fact, they are prescribed the other way around with lifestyle therapy being the adjunct if being thought about at all. Doctors are not following either society guidelines or FDA guidelines if they are prescribing [GLP-1s] without lifestyle therapy." Before starting GLP-1 medications, the report recommended that patients work with their doctors to set goals that focus on overall health, not just weight loss. It's also important to check for any stomach or bone issues that could lead to side effects like nausea, vomiting, or muscle and bone loss, the report stated. "Registered dietitians can play really key roles in comprehensive obesity care by providing medical nutrition therapy to support GLP-1 therapy," said Emily A. Callahan, registered dietitian nutritionist and director of policy strategy for the Food is Medicine Institute. "The evidence space is growing that shows when registered dietitians deliver medical nutrition therapy, it has been associated with improvements in body weight, waist circumference, blood pressure and glycemic control." People should usually start GLP-1 medications at the lowest dose and slowly increase as needed, the report said. Patients should also be aware that nausea is common when taking these drugs and this may trigger cravings for sugary, high-calorie comfort foods that work against weight loss. To stay on track, the report recommended eating small, frequent meals and focusing on minimally processed, nutrient-rich foods. The report called for exercising special caution for anyone following an intermittent fasting diet or a low-carbohydrate "keto diet" that limits foods like breads, pastas and fruit to put the body into a state called ketosis, where it burns fat for fuel instead of carbs. These individuals might be especially vulnerable to gastrointestinal side effects, the report said. The report also advised people who may not be getting enough nutrients to consider taking supplements like vitamin D, calcium and multivitamins, while increasing protein intake by 50-100% from foods such as fish, eggs, nuts and seeds. This is especially important for those eating less while on GLP-1s, since lower food intake can make it harder to get all the nutrients the body needs. The report also underscored the importance of maintaining muscle mass and bone density while losing weight. Since weight loss can also lead to muscle loss -- especially in older adults -- the report advised doing a full body strength training routine at least three times a week and getting 150 minutes of moderate cardio each week. Focusing on nutrition, physical activity and other healthy lifestyle habits should give GLP-1 users a greater chance of achieving their goals, the report concluded. "GLP-1s have the best chance of helping people achieve and sustain lasting weight reduction when they are paired with strong nutrition guidance and lifestyle support," said Callahan.
New York Times
17-02-2025
- Health
- New York Times
Is Fake Meat Better for You Than Real Meat?
You've probably heard these two bits of nutrition advice: Eat more plants, and cut back on ultraprocessed foods. So where does that leave fake-meat burgers, sausages, nuggets and other products sold by companies like Beyond Meat and Impossible Foods? They are made from plants like soybeans and peas, but they are also highly processed. If you ask the companies, they will tell you that their products are good for you. Nutrition experts say that there may be benefits, too. But while it's clear that eating red meat and processed meat is associated with health risks like heart disease, some types of cancer and earlier death, we really don't yet know how fake-meat alternatives might affect our health in the long term. How do their nutrients compare? The nutrient profiles of fake-meat products can vary widely, but two scientific reviews, both published in 2024, suggest a few patterns. Compared with regular meat like ground beef, pork sausages and chicken, the plant-based versions typically have fewer saturated fats (a category of fats that have been linked to heart disease) and similar or slightly lower levels of protein. A four-ounce burger made with 85 percent lean ground beef, for instance, contains 6.5 grams of saturated fat. An equivalent size Impossible Burger has a little less than that (six grams of saturated fat), and a Beyond Burger has a lot less (just two grams). On the other hand, a Gardein Ultimate Plant-Based Burger has nearly 40 percent more saturated fat (nine grams) when compared with ground beef. When it comes to protein levels, the burgers are a lot more similar: The beef patty has 21 grams of protein, while the three plant-based versions have between 19 and 21 grams. Plant-based meat products also typically contain some fiber — a nutrient associated with reduced risks of Type 2 diabetes, colorectal cancer and heart disease. An Impossible Burger has five grams, a Beyond Burger has two grams, and a Gardein patty has one gram. Real meat lacks fiber entirely. The main nutritional downside of plant-based meats is that they tend to contain far more sodium than uncooked and unprocessed meats like ground beef, pork chops and chicken breast, said Dr. Dariush Mozaffarian, a cardiologist and professor of medicine at Tufts University. Of course, most people add at least some amount of salt to raw meat before they cook it, a spokeswoman for Beyond Meat said in a statement. The company's current burger and beef products contain less sodium than previous versions, she said, and they now use avocado oil instead of coconut oil, which has reduced saturated fat levels. Fake-meat products generally have a better nutritional profile than red meat, said Dr. Frank B. Hu, a professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health. 'The products are evolving very rapidly,' he said, adding that he hopes they keep getting better. How might fake-meats affect health? In two small studies that investigated the health effects of replacing real meat with plant-based alternatives like those from Beyond Meat and Impossible Foods, Dr. Hu said, researchers reported mixed results. One study, published in 2024, found that when 40 people in Singapore ate 2.5 servings of plant-based burgers, sausages or chicken per day for two months, they were no healthier than the 42 other participants who had similar amounts of real meat during the same time period. The researchers used fake meat products from Impossible Foods, Beyond Meat, OmniMeat (based in Hong Kong) and The Vegetarian Butcher (based in Britain). That study was funded by an agricultural research firm in Hong Kong that did not have a vested interest in the outcome, the study's lead author said. In another study — this one funded by Beyond Meat and published in 2020 — researchers found some benefits associated with plant-based meats. Thirty-six healthy adults consumed about 2.5 servings of real meat per day for two months, and about 2.5 servings of plant-based products from Beyond Meat per day for another two months. At the end of the plant-based phase, the participants had lower cholesterol — and were a few pounds lighter — compared with the end of the real meat phase. Christopher Gardner, a nutrition scientist and professor of medicine at Stanford University who led the 2020 study, acknowledged that people may be skeptical of its findings because it was funded by Beyond Meat. Industry-funded nutrition research tends to end up with results that are more favorable to the industry than research without industry funding. But with limited federal dollars for nutrition research, it's often the only way such studies are conducted, Dr. Gardner said. He tried to minimize bias, such as by having outside statisticians analyze the data and by not allowing Beyond Meat to review the results of the study until it was accepted for publication. The different findings from the two studies could have been related to differences in the participants, food products or study design, added Dr. Hu, who said the Stanford study was 'well designed and carefully executed.' Regardless of these conflicting results, the data are 'promising,' Dr. Hu added. They suggest that the plant-based products may be beneficial for health — or at least not worse than meat. But, he said, 'we need much larger and longer-term studies' with independent funding sources to confirm that. What about the processing? One added complication is that fake-meat products typically fall into the ultraprocessed food category, which has generally been linked with greater risks of cardiovascular disease, Type 2 diabetes and other health issues. It's difficult to make products that replicate the tastes and textures of real meat without using highly processed ingredients, experts said. But it's not clear that all ultraprocessed foods are harmful, said Samuel Dicken, a research fellow at University College London who studies ultraprocessed foods. We need more and better evidence to tease out how different ultraprocessed foods affect health. Given the available data, Dr. Dicken said plant-based meats were not the ultraprocessed foods he was most worried about. (Sugary drinks and processed meats were.) The Bottom Line If you enjoy the tastes and textures of meat but want to eat less of it, fake-meat products can be a helpful 'steppingstone to a more plant-forward diet,' Dr. Hu said. They may have some benefits for health, he said, and major benefits for the environment. Even better, all of the experts agreed, is to shift your diet away from red meat and processed meat, and toward more whole food or less processed sources of plant protein like beans, lentils, tofu and tempeh. Swapping plant-based foods like legumes and whole grains for meat, for instance, has been clearly linked to reduced risks of heart disease and Type 2 diabetes. These foods are typically cheaper, too, Dr. Gardner said. 'Beans, peas and lentils, hands down, over the Beyond Burger,' Dr. Gardner said. You can also try fish and chicken as healthier alternatives to red meat and processed meat, Dr. Mozaffarian said. Or, he added, use a portobello mushroom for your burger patty instead of ground beef. 'That's a real alternative,' Dr. Mozaffarian said.
