新研究发现：肚子越大，脑子越小

我们都知道，大肚腩的人容易得心脑血管病、脂肪肝、糖尿病，但是你大概想不到，肚子大还和脑容量有关系。研究人员发现，大腹便便的肥胖者平均脑灰质含量更低，而脑灰质和记忆力等大脑功能息息相关。

Belly fat has long been thought to be particularly bad for your heart, but now, a new study adds more evidence to the idea that it may also be bad for your brain.

长期以来，人们都认为腹部肥胖对心脏特别不好，但现在一项新研究提出的新证据表明，它可能还对你的大脑有害。

The study, from the United Kingdom, found that people who were obese and had a high waist-to-hip ratio (a measure of belly fat) had slightly lower brain volumes, on average, compared with people who were a healthy weight. Specifically, belly fat was linked with lower volumes of gray matter, the brain tissue that contains nerve cells.

英国的这项研究发现，肥胖者以及腰臀比（腹部脂肪衡量指标）高的人比起那些体重健康的人来说，平均的脑容量要稍微小一些。具体来说，腹部肥胖和脑灰质含量低有关。脑灰质是含有神经细胞的脑组织。

"Our research looked at a large group of people and found obesity, specifically around the middle, may be linked with brain shrinkage,” lead study author Mark Hamer, a professor at Loughborough University’s School of Sport, Exercise and Health Sciences in Leicestershire, England, said in a statement.

该研究报告的第一作者、英国莱斯特郡拉夫堡大学的运动、锻炼及健康科学学院的教授马克·哈默尔在一项声明中表示：“我们的研究调查了一大群人，然后发现肥胖，尤其是腰腹部肥胖，可能和脑部萎缩有关。”

Lower brain volume, or brain shrinkage, has been linked with an increased risk of memory decline and dementia.

该研究指出，脑容量更小，或者说是脑部萎缩，和记忆衰退以及痴呆的风险增加有关联。

The new findings, published Jan. 9 in the journal Neurology, suggest that the combination of obesity (as measured by body mass index, or BMI) and a high waist-to-hip ratio may be a risk factor for brain shrinkage, the researchers said.

这些新发现1月9日发表在《神经学》期刊上。研究指出，肥胖加上高腰臀比可能是脑部萎缩的一个风险因素。研究人员通过身体质量指数来衡量一个人是否肥胖。

However, the study found only an association between belly fat and lower brain volume, and cannot prove that carrying more fat around the waist actually causes brain shrinkage. It could be that people with lower volumes of gray matter in certain brain areas are at a higher risk of obesity. Future studies are needed to tease out the reasons for the link.

不过，这项研究只是发现了腹部脂肪和脑容量小之间的关联，并不能证明肚子上的肉会导致脑部萎缩。也可能是脑部特定区域灰质较少的人更容易肥胖。要梳理出这个关联的前因后果，还需进行更多研究。

Dangerous fat 危险的肥肉

Belly fat, also called visceral fat, is fat that’s stored deep within the abdominal cavity. It’s tied to greater health risks than subcutaneous fat, or fat that’s stored just under the skin. Previous studies have linked visceral fat with a higher risk of heart disease (including heart attack and stroke), Type 2 diabetes, high blood pressure and premature death, according to the Mayo Clinic.

腹部脂肪也被称为“内脏脂肪”，是堆积在腹腔内部深处的脂肪。它们比皮下脂肪的健康风险还要高。梅奥医学中心指出，先前的研究已经发现了内脏脂肪和更高的心脏疾病（包括心脏病发作和中风）、二型糖尿病、高血压和早逝风险之间的关联。

visceral['vɪsərəl]: adj. 内脏的

subcutaneous[,sʌbkjʊ'tenjəs]: adj. 皮下的

Some previous studies have also found a link between visceral fat or a high waist-to-hip ratio and lower brain volume, but these studies tended to be small and did not look at the combined effect of BMI and waist-to-hip ratio.

先前的一些研究也发现了内脏脂肪或高腰臀比和脑容量小之间的关联，但是那些研究规模都比较小，而且也没有考虑身体质量指数和腰臀比的混合效应。

In the new study, the researchers analyzed information from more than 9,600 people living in the United Kingdom, with an average age of 55. Participants had their BMI and waist-to-hip ratio measured, and underwent an MRI to determine their brain volumes.

在这项新研究中，研究人员分析了生活在英国的9600多名平均年龄为55岁的参与者信息。研究人员测量了参与者的身体质量指数和腰臀比，然后通过核磁共振成像测量了他们的脑容量。

The study found that people with both a high BMI and high waist-to-hip ratio had the lowest brain volumes, compared with people who had just a high BMI (but not a high waist-to-hip ratio) and people of a healthy weight.

研究发现，和身体质量指数高但腰臀比不高的人以及体重正常的人相比，身体质量指数和腰臀比都高的人脑容量最小。

Specifically, people with both a high BMI and high waist-to-hip ratio had an average gray matter volume of 786 cubic centimeters, compared with 793 cubic centimeters for people with a high BMI but not a high waist-to-hip ratio; and 798 cubic centimeters for people of a healthy weight.

详细来说，身体质量指数和腰臀比都高的人平均脑灰质体积为786立方厘米，而身体质量指数高但腰臀比不高的人平均脑灰质体积为793立方厘米，体重健康的人平均脑灰质体积为798立方厘米。

The findings held even after researchers took into account other factors that can affect brain volume, including age, smoking and high blood pressure.

即使在研究人员考虑了年龄、吸烟和高血压这些会影响脑容量的其他因素之后，这一发现依旧成立。

Though the study didn't look at potential mechanisms linking visceral fat and brain shrinkage, one hypothesis is that this type of fat is thought to produce inflammatory substances that may play a role in brain atrophy, the researchers said.

研究人员说，虽然本研究没有探索内脏脂肪和脑部萎缩关联的潜在作用机制，但是有一项假说认为这种脂肪据说会产生炎症物质，可能会导致脑萎缩。

hypothesis[haɪ'pɑθəsɪs]: n. 假设

inflammatory[ɪn'flæmə'tɔri]: adj. 炎症性的

atrophy['ætrəfi]: n. 萎缩，萎缩症

Dr. Gayatri Devi, a neurologist at Lenox Hill Hospital in New York, who was not involved with the study, agreed with the findings. "Brain gray matter shrinkage...seems to be associated with obesity and with increased visceral fat,” she said.

未参与该研究的纽约勒诺克斯山医院神经学家嘉亚特里·德维医生表示认同这一发现。她说：“脑灰质的萎缩似乎和肥胖以及内脏脂肪增多有关联。”

"All this goes to show that good general health is very important for good brain health," Devi told Live Science.

德维告诉趣味科学网说：“这些都表明了良好的总体健康对良好的脑部健康十分重要。”