Are seed oils really bad for you? 1 day ago Share Save Jessica Bradley Getty Images
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?
Advertisement 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.
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.
Advertisement Getty Images Oilseed rape is used to make a canola oil, one of the most common cooking oils (Credit: Getty Images)
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.
Advertisement
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.
Another common accusation levelled at seed oils is that eating too much omega 6 compared to omega 3 is harmful
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."
"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.
Getty Images Seed oils are extracted from the seeds of plants, but the process is often industrial in scale and uses chemicals (Credit: Getty Images)
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.
Advertisement
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.
Researchers have recently found that omega 6 can fuel the growth of a specific type of breast cancer
"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.
Alamy Completely cutting out omega 6, which is found in some cooking oils, could have a detrimental effect on health, scientists say (Credit: Alamy) Advertisement
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.
Advertisement
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.
Getty images Seeds like sunflower seeds have been proven to contain many of the crucial nutrients needed to live a healthy life (Credit: Getty Images) Advertisement
"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.
"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.
"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.
"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.
Advertisement
"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.
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.
For farm-raised salmon, most health experts suggest limiting intake to 1–2 servings per week due to potential contaminants like PCBs (polychlorinated biphenyls) and dioxins, which tend to be higher in farmed fish compared to wild.
Why Limit Farm-Raised Salmon?
Higher contaminants: Farmed salmon are often fed processed feed that can accumulate toxins. Omega-6 imbalance: Some farmed salmon have more omega-6 fatty acids (which can be pro-inflammatory in excess) compared to wild salmon. Use of antibiotics: In some countries, farmed salmon are treated with antibiotics, which raises additional concerns.
Safe Guidelines
1–2 servings (3.5–6 oz each) per week is a safe and balanced amount. Try to choose farmed salmon from trusted sources (like Norway, Canada, or U.S. Atlantic farms with good sustainability practices), which tend to have stricter regulations.
Eating salmon regularly is generally healthy, but too much of it can pose risks, mostly due to:
1.
Mercury and Other Contaminants
Wild salmon (especially from Alaska) is lower in mercury and contaminants than farmed salmon. Farmed salmon may have higher levels of PCBs and other pollutants, depending on where it’s from.
2.
Omega-3 Overload
Omega-3s are great, but in excess (especially via supplements), they can increase bleeding risk or interfere with some medications.
General Guidelines
According to health authorities like the FDA and the American Heart Association:
植物油的优缺点?用那种油好或者不好?
https://www.bbc.com/future/article/20250530-are-seed-oils-really-bad-for-you
Are seed oils really bad for you? 1 day ago Share Save Jessica BradleySeed 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?
Advertisement 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.
AdvertisementThere 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.
AdvertisementIn 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.
Another common accusation levelled at seed oils is that eating too much omega 6 compared to omega 3 is harmfulThere 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.
Advertisement"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 ratioAnother 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.
AdvertisementOn 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 processedUnlike 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.
Researchers have recently found that omega 6 can fuel the growth of a specific type of breast cancerWhile 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.
Advertisement"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.
AdvertisementThis 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.
AdvertisementFor 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.
Advertisement"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.
感觉这些文章读多了只能饿死。
牛油果油是cold pressed 吗?
这篇主要讨论的是菜籽油Conola oil的优缺点。说Omaga 6 fatty acid可能助长一类breat cancer growth。但是又说总体来说植物油是好的食用油。
橄榄油的问题是燃点低。
高温非常不好,我家是老公做饭,喜欢让油冒烟,怎么劝都不听
偶尔香油
娃从小都是在外面吃,除了偶尔包饺子吃一些,不知道吃什么长大的
紫苏油或橄榄油凉拌。紫苏油omiga 3含量高。我最近买不到野生三文鱼,吃三文鱼的量小了,就加大牛油果和紫苏油的摄入。借此机会问一下,这里同学都在哪里买野生三文鱼?有网购的吗?
的养殖的三文鱼,这个更好吃
是食材多样性,鱼类和纳豆?
啥事都是融会贯通。真的没错。
想想真是饿死算了
打一杯kale+胡萝卜+blueberry+keifer酸奶的奶昔,里面会加flaxseeds和chia seeds各一勺。假如烤燕麦果仁枣片牛奶蛋糕,里面也会加一勺chia seeds。吃酸奶时加磨碎的flexseeds和烤熟的黑芝麻。我需要严格控制坚果的总摄入量。因为坚果热量高。
主要吃argentine red shrimp,野生的
出门买菜前看到有亲妈给闺女过广告想着自己家的熊娃上高中以后我就基本放养,于是自惭形秽;买完菜后看到大家这么热烈的讨论买菜用什么油,对比自己刚刚买了一堆预制菜……
我以后尽量不来紫檀了,有时间都用来想着怎么帮娃推娃和给娃做新鲜的饭菜吃。今天先立个flag
For farm-raised salmon, most health experts suggest limiting intake to 1–2 servings per week due to potential contaminants like PCBs (polychlorinated biphenyls) and dioxins, which tend to be higher in farmed fish compared to wild.
Why Limit Farm-Raised Salmon?
Safe Guidelines
Eating salmon regularly is generally healthy, but too much of it can pose risks, mostly due to:
1.
Mercury and Other Contaminants
2.
Omega-3 Overload
General Guidelines
According to health authorities like the FDA and the American Heart Association:
我把一开始的标题换了啊。本来就是问那种炒菜油好?听了兔妈的建议换个标题,否则很快被咔嚓。lol 我就是想问到底听谁的啊?每天做饭必须得用油啊。
日本料理的缺点:
生吃,重鹹、愛吃醃漬物: 这可能日本胃癌胃癌發生率超高的原因。
缺钙 (日本人似乎没有像老中那样喜欢用大骨头熬汤): 到日本旅游, 看到很多驼背的老人(特别是女性)。
只是少吃一点就好了。平常做菜什么的用橄榄油更健康。