Beware the Beer Belly
By Nicholas Bakalar

A beer belly is a dangerous thing.

A new analysis of data from a large national study has found that carrying fat around the middle of the body greatly raises the risk for heart disease and death, even for those of normal weight.

Doctors usually determine obesity by body mass index, or B.M.I. — calculated from height and weight — but the calculation does not distinguish between fat and lean muscle weight. Measuring waist-to-hip ratio presents a different, and possibly more accurate, picture because it accounts for central obesity, or visceral fat, the fat stored around the internal organs.

Waist-to-hip ratio is waist measurement divided by hip measurement. According to the World Health Organization, a ratio higher than .90 for men or .85 for women defines central obesity.

It has been known for some time that having an “apple” shape increases the risk for disease and death. But the new study found that a man of normal B.M.I. with an abnormally large belly has an 87 percent higher risk for death than a man with the same B.M.I. but a normal waist-to-hip ratio. Pot-bellied women of normal B.M.I. have a 48 percent higher risk than women with normal B.M.I. and normal belly fat.

Researchers used data on 15,184 men and women older than 18 who were examined at mobile examination centers. They followed them for an average of more than 14 years, during which there were 1,404 deaths from cardiovascular diseases. The association of waist-to-hip ratio with increased risk persisted even after controlling for smoking, history of heart attack or diabetes, race, poverty, blood lipid levels and other factors.

The study, in Annals of Internal Medicine, found that people with normal weight and central obesity have worse long-term survival than anyone of any weight with normal fat distribution. For example, compared with an overweight or obese man with normal waist-to-hip ratio, men of normal weight with central obesity were at more than twice the risk for death, which may help to explain the “obesity paradox,” in which obesity seems to protect against heart disease in some people.

“People with normal weight according to B.M.I. can’t be reassured that they don’t have any fat-related health issues,” said the senior author, Dr. Francisco Lopez-Jimenez, a professor of medicine at the Mayo Clinic. “Having a normal weight is not enough. It’s good only if the distribution of fat is healthy.”

啤酒肚致死風險 比肥胖多2倍

以後看醫生可能就像去找裁縫師一樣，量腰圍變成很重要的一環，因為你的啤酒肚可能暗藏殺機。

新的研究報告指出，即使你身體其它部位都很瘦，過多的肚皮脂肪仍可能比肥胖或過重帶來更大的風險。一般人都知道肥胖會升高心臟病、中風、糖尿病或罹癌的機率，卻不知啤酒肚的風險更大。

以往，控制肥胖的重要指標是依據身高、體重計算體脂肪得出的身體質量指數（BMI）。但現在，即使你有「健康的」BMI，小屁股、瘦瘦的手臂和大腿，但是褲頭卻不太容易扣緊，還是得留意一下體重。

明尼蘇達梅約醫院的心臟病醫師羅培茲吉梅尼斯最近在「內科年鑑」發表的研究報告指出，凡是有大肚腩的病人都應該多吃花椰菜並增加運動時間，還要釋放壓力，例如深呼吸或做瑜伽。

他說：「有些BMI指數正常的病人常會問我：『既然我的BMI正常，我為什麼還得運動？我不胖，應該可以隨心所欲地吃喝。』」

他的報告檢視逾1.5萬人的病歷，研究人員估計，有啤酒肚男子的致死風險是僅有過重或肥胖因子男子的兩倍，大肚皮女性的死亡風險也升高1.5倍。

早先的研究顯示，腰臀比值高的人，得糖尿病、中風、冠狀心疾和其它心臟病的風險會跟著升高，新的報告則首度將致死風險加以量化。

為什麼肚腩脂肪會格外要命呢？原因之一是肚腩脂肪和腰側的脂肪不同，懸在胃部區域外的脂肪可能深入體內，裹住重要器官。而且，肝臟會變得貪婪，不斷借用這裡的脂肪轉換成膽固醇，再溜進血液，附著在動脈血管的管壁。膽固醇升高後，動脈就開始硬化，中風或心臟病發的機率自然飆高。

深層脂肪也是身體產生胰島素抗性的禍首，可能變成第二型糖尿病，或導致發炎，成為許多慢性疾病根源。且這類脂肪會升高葡萄糖含量，降低能夠保護心臟的肌肉質量。

原文參照：
http://well.blogs.nytimes.com/2015/11/10/beware-the-beer-belly

2015-11-12．聯合晚報．A6．國際焦點．編譯陳澄和