长期与不平衡的肠道微生物组有关：现在该知道什么

长期未知的确切原因

Long COVID is a condition that involves persistent symptoms for weeks or months after initial infection with SARS-CoV-2, the coronavirus that causes COVID-19.

疲劳，呼吸急促，胸痛，气味丧失和“脑雾”是一些最常见的症状。

This condition is not limited to people who have had severe COVID-19. It can also occur in those who had mild symptoms initially, including children and adolescents.

尚不清楚漫长的互联物的确切原因 - 为什么有些人可能面临更高的发展风险。

Several possible explanations have been proposed for this condition, including an exaggerated immune response, ongoing inflammation, cell damage, and physiological effects of severe illness.

此外，最近 学习 确定了可能引起长期相互交联的四个因素 - 2型糖尿病，体内爱泼斯坦 - 巴尔病毒的重新激活，错误攻击人细胞的抗体的存在以及血液中冠状病毒RNA的存在。

Mahmoud A. Ghannoum, PhD, director of the Center for Medical Mycology at University Hospitals Cleveland Medical Center, said earlier research — such as a study published last year in肠- 还将肠道微生物组连接到Covid-19的严重程度。

在这些研究中,患者更严重COVID -19 tend to have a decreased microbial diversity in the intestines, he said.

In addition, he said they often have a reduction in beneficial microbes that help support the immune system and an increase in pathogenic microbes, those that “cause trouble.”

“What this [new] study did is extend this observation to say that the changes in the composition of the microbiome could affect how we respond to long-term [after COVID-19],” said Ghannoum, also a professor of dermatology and pathology at the Case Western Reserve University School of Medicine.

In the new study, Hong Kong researchers looked not only at the link between the gut microbiome and long-COVID symptoms, but also the connection with the types of symptoms people experienced and the severity of their initial illness.

该研究包括106人在Covid-19中住院。其中大多数患有轻度至中度的疾病，尽管有些人患有更严重的COVID-19。

Researchers asked people 3 and 6 months after their initial illness whether they were experiencing any long-COVID symptoms. Over 80 percent said yes at both time points.

Fatigue, poor memory, hair loss, anxiety, and difficulty sleeping were the most common symptoms reported by people at 6 months.

The researchers also analyzed the gut microbiomes of 68 of these people using stools samples. Fifty of these people had long-COVID symptoms.

Some of the 68 people also completed a 6-minute walk test at their 6-month follow-up visit to assess their aerobic capacity and endurance.

At 6 months, there were no significant differences in other factors that could impact the microbiome, such as age, gender, underlying health conditions, use of antibiotics or antiviral drugs, and COVID-19 severity, between people with and without long COVID.

In addition, for a comparison group, researchers recruited 68 patients who hadn’t had a coronavirus infection. They analyzed the gut microbiome for some of these individuals.

Dr. David StrainBMA科学委员会和临床高级讲师兼荣誉顾问主席，埃克塞特大学医学院说statement这项研究很有趣，但是需要更多的研究来确认这些发现是否适用于其他群体。

“This finding is consistent with several existing hypotheses that long COVID may be associated with a small quantity of residual virus in the immuno-privileged tissue (i.e., the regions of the body such as the gut, that the protection of our antibodies doesn’t reach),” Strain said.

“It is important to clarify that there are some substantial potential confounders in this study,” he added. “Notably that this is in a Hong Kong population that have a significantly different diet to the U.K. population and are have been demonstrated to have substantial differences In their dominant gut species.”

Balanced gut microbiome was beneficial

研究人员发现，一个人的初始病毒载荷与是否继续发展长期相互作用之间没有任何联系。他们还发现肠道微生物组与一个人疾病的严重程度之间没有联系。

However, they did find that people with long COVID had “distinct” differences in their gut microbiome than individuals who hadn’t had a coronavirus infection.

长卵巢患者的肠道微生物组比非杂化患者的多样化。在6个月的时间里，长期有兴趣的人的“友好”细菌和没有COVID-19的人的“友好”细菌和更多的“不友好”细菌。

Ghannoum说，这项研究表明，“如果您有一个不平衡的微生物组（我们称之为营养不良的人），那么出现这些症状的可能性就会更高。”

In contrast, people who didn’t develop long COVID had fewer changes in their gut microbiome, and this “recovered completely by 6 months,” the authors found.

In fact, the gut microbiome of people who didn’t develop long COVID was similar to the non-COVID patients.

Ghannoum说：“如果您一开始就有更平衡的微生物组，您将能够抵抗这些症状，否则您至少会更快地恢复。”

他说：“因此，[这项研究]告诉我们，拥有平衡的微生物组确实是一个优势。”

Researchers also looked at whether the composition of the gut microbiome was associated with different categories of long-COVID symptoms, such as respiratory, neurological, gastrointestinal, muscle- and joint-related, and fatigue.

他们写道，结果表明“不同的[肠道]微生物模式可能有助于发展不同的[长期旋转]症状。”“因此，微生物组有可能成为预测特定急性后共证症状的发展的代表。”

For example, they found that higher levels of certain “unfriendly” microbes were linked with persistent respiratory symptoms. People with long COVID also had lower levels of several bacteria species that the authors say are known to be beneficial for immunity.

In addition, several “unfriendly” bacteria species were more common in people with long COVID who performed poorly on the 6-minute walk test.

This is an observational study, so it can’t show whether long-COVID symptoms are the result of the gut microbiome changes or the other way around.

Ghannoum said the study also had several limitations, including its small size and that researchers didn’t measure other factors that could impact the gut microbiome, such as diet, lifestyle, and other medications.

保持肠道微生物组健康的方法

尽管需要更多的研究，但Ghannoum表示，这项研究提醒了肠道微生物组对我们的健康的重要性，包括我们如何应对病毒感染。

“The fact that having a balanced gut microbiome resulted in less [long COVID] highlights that we should take the necessary steps to ensure that we have a balanced microbiome,” he said.

Microbiome research has already identified several ways in which people can improve their gut microbiome — all things that can also improve overall health.

A key one, said Ghannoum, is eating ahealthy diet, one that is high in fiber, plant polyphenols (found in berries, nuts, vegetables, coffee, and tea), and unsaturated fats such as olive and sunflower oils.

此外，人们应该避免吃量过多的饱和脂肪，精制糖和人造甜味剂。

“In addition to diet,” said Ghannoum, “you have to follow a lifestyle which helps balance your gut, including exercise, sleep, and reduction of stress.”