这种流行的食用油可能会悄悄地破坏你的肠道健康

加州大学河滨分校的研究人员发现，富含大豆油的饮食会损害肠道健康并增加……

　　

加州大学河滨分校的研究人员发现，富含大豆油的饮食会损害肠道健康，增加患炎症性肠病的可能性。

这种油的主要成分亚油酸会滋养有害的大肠杆菌，同时消耗有益的肠道细菌。它还会削弱肠道屏障，导致毒素渗入血液。研究小组建议限制大豆油的摄入量，并多食用橄榄油或鳄梨油等更健康的脂肪。

大豆油不仅与肥胖和糖尿病有关

过量摄入大豆油已被证实与肥胖和糖尿病等疾病有关，还可能与自闭症、阿尔茨海默病、焦虑症和抑郁症有关。研究人员现在将溃疡性结肠炎（一种以大肠持续炎症为特征的炎症性肠病 (IBD)）也列入了可能引发疾病的名单。

加州大学河滨分校的科学家对喂食富含大豆油饮食长达24周的小鼠的肠道健康状况进行了研究。他们的研究结果显示，有益菌数量下降，有害菌数量上升（特别是粘附性侵袭性大肠杆菌），而这些有害菌已知会导致结肠炎。

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 肠道微生物群破坏
 <p>大豆油是美国消费最广泛的食用油，在巴西、中国和印度等其他主要国家也越来越受欢迎。美国大规模种植大豆始于20世纪70年代，主要用于动物饲料，而大豆油则成为一种丰富的副产品。由于大豆价格低廉且易于种植，其用途迅速扩大。p>
 <p>“我们的研究挑战了几十年来的观念，即许多慢性疾病源于摄入过量的动物产品中的饱和脂肪，相反，植物中的不饱和脂肪必然更健康，”微生物学和植物病理学系助理专业研究员、该研究的共同通讯作者 Poonamjot Deol 说，该研究发表在开放获取期刊<em>《肠道微生物em>》上。p>
 
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  重新思考“健康”脂肪
  <p>Deol 表示，主要担心的是大豆油的关键成分亚油酸。p>
  <p>“While our bodies need 1-2% of linoleic acid daily, based on the paleodiet, Americans today are getting 8-10% of their energy from linoleic acid daily, most of it from soybean oil,” she said. “Excessive linoleic acid negatively affects the gut microbiome.”p>
  <p>Deol and her colleagues discovered that diets high in soybean oil promote the growth of adherent invasive <em>E. coliem> in the gut. This bacterium uses linoleic acid as a carbon source to fuel its growth. At the same time, several beneficial bacterial <span>speciesspan> are unable to tolerate linoleic acid and die off, allowing harmful bacteria to thrive. In humans, adherent invasive <em>E. coliem> has been linked to IBD.p>
  <p>“It’s the combination of good bacteria dying off and harmful bacteria growing out that makes the gut more susceptible to inflammation and its downstream effects,” Deol said. “Further, linoleic acid causes the intestinal epithelial barrier to become porous.”p>
  
  <h>
   When the Gut Barrier Breaks Down
   <p>The barrier function of the intestinal epithelium is critical for maintaining a healthy gut; when disrupted, it can lead to increased permeability or leakiness. Toxins can then leak out of the gut and enter the bloodstream, greatly increasing the risk of infections and chronic inflammatory conditions, such as colitis. The researchers note that the increase in IBD parallels the increase in soybean oil consumption in the U.S. and hypothesize the two may be linked.p>
   <h>
    Rethinking the “Good Fat” Narrative
    
Toxicologist Frances M. Sladek, a professor of cell biology and a co-corresponding author on the research paper, recalled that heart disease was linked to saturated fats in the late 1950s.
    
“Since studies showed that saturated fats can be unhealthy, it was assumed that all unsaturated fats are healthy,” she said. “But there are different types of unsaturated fats, some of which are healthful. For example, the unsaturated fat fish oil is well known to have many beneficial health effects. People, therefore, assumed that soybean oil is perfectly safe and healthier to consume than other types of oils, without actually doing a direct comparison as we have done.
    
Sladek noted that linoleic acid is an essential fatty acid. The soybean oil the researchers used in their experiments had 19% linoleic acid. The American Heart Association recommends 5 to 10% of daily calories be from omega-6 polyunsaturated fatty acids, such as linoleic acid, in order for the heart to remain healthy. Many seed oils – safflower and sunflower, for example — are sources of linoleic acid. Animal fat can also be a source.
    
     The Double-Edged Role of Linoleic Acid
     
“Every animal has to get linoleic acid from the diet,” Sladek said. “No animal can make it. A small amount of it is needed by the body. But just because something is needed does not mean a lot of it is good for you. Several membranes in the body, in the brain, for example, require linoleic acid for the cells to function properly. If all we ate was saturated fats, our cell membranes would become too rigid and not function properly. Future studies are needed to determine the tipping point for how much daily linoleic acid consumption is safe.”
     
According to Sladek and Deol, olive oil, which has lower amounts of linoleic acid, is a healthier oil to consume.
     
“Olive oil, the basis of the Mediterranean diet, is considered to be very healthy; it produces less obesity and we have now found that, unlike soybean oil, it does not increase the susceptibility of mice to colitis,” Sladek said.
     
     
      Olive Oil vs. Soybean Oil
      
James Borneman, a professor of microbiology and plant pathology at UCR and a co-corresponding author on the paper, is an expert on the gut microbiome. He has collaborated at UCR with several groups on research projects, including studies investigating how gut microbes prevent obese people from losing weight. For the current study, he teamed up with Deol and Sladek to examine the gut microbes of the mice that were fed a high soybean oil diet.
      
“Adherent invasive E. coli contributes to IBD in humans, and the fact that we find this E. coli in these mice is concerning,” he said. “Sometimes, it can be unclear how research done in mice translates to humans, but in this study it is fairly clear.”
      
The research team was also surprised to find that the mice fed on a high soybean oil diet showed a reduction in the gut of endocannabinoids, cannabis-like molecules made naturally by the body to regulate a wide variety of physiological processes. At the same time, the gut showed an increase in oxylipins, which are oxygenated polyunsaturated fatty acids that regulate inflammation.
      
      
       Surprising Molecular Shifts
       
“We previously found that oxylipins in the liver correlate with obesity,” Deol said. “Some oxylipins have also been found to be bioactive in colitis studies. The bottom line of our current study is that a soybean oil-enriched diet similar to the current American diet causes oxylipin levels to increase in the gut and endocannabinoid levels to decrease, which is consistent with IBD in humans.”
       
Most processed foods in the U.S. contain soybean oil, perhaps explaining why many Americans have more than the recommended daily allowance for linoleic acid. Further, most restaurants in the U.S. use soybean oil because it is relatively inexpensive.
       
        Soybean Oil in Everyday Foods
        
“Try to stay away from processed foods,” Sladek advised. “When you buy oil, make sure you read the nutrition facts label. Air fryers are a good option because they use very little oil.”
        
The researchers use olive oil for cooking and salads. Other healthy options for cooking, they said, are coconut oil and avocado oil. They cautioned that corn oil, on the other hand, has the same amount of linoleic acid as soybean oil.
        
“We recommend keeping track of the soybean oil in your diet to make sure you are not consuming excessive linoleic acid,” Deol said. “That is our take-home message.”
        
         Editor’s Note (October 17, 2025)
         
This story covers a 2023 UCR study in Gut Microbes (DOI: 10.1080/19490976.2023.2229945) showing that high-soybean oil (linoleic-acid–rich) diets made mice more susceptible to colitis by disrupting the gut microbiome and weakening the intestinal barrier. As of October 2025, the core findings remain relevant: subsequent animal research generally supports microbiome disruption and inflammation with high linoleic-acid intake, while human data are still mixed and observational. Experts emphasize overall diet context (especially the omega-6 to omega-3 balance) and moderation rather than eliminating any single food. Practical takeaway: limit ultra-processed foods, be mindful of high-linoleic-acid oils, and consider lower-linoleic options like olive oil alongside a varied, whole-food diet.
         
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