燕麦：
燕麦中富含的水溶性纤维可以“阻止”肠道吸收过多的胆固醇，改变血液中脂肪酸浓度，降低“坏胆固醇”和三酸甘油酯。每天摄取水溶性纤维5-10克，就可使“坏”胆固醇的吸收率降低5%。其他富含水溶性纤维的食物还有：四季豆、苹果、桃子、瓜类、菇类、海带、黑白木耳、紫菜等。
坚果：
杏仁、花生、胡桃、腰果、栗子等坚果含有多不饱和脂肪酸，可以降低胆固醇，还能维持动脉血管的健康和弹性。但坚果唯一的缺点就是热量太高。专家建议不妨每周吃两次，每次吃8克，大约握在手心松松一把的量，即可获得丰富的不饱和脂肪酸和抗氧化剂。
黄豆：
黄豆饱和脂肪量低，不含胆固醇，用大豆蛋白取代动物蛋白，可降低血液中总胆固醇、“坏”胆固醇、三酸甘油酯，而又不影响“好”胆固醇的含量。此外，黄豆所含的大豆异黄酮和纤维素也能降低胆固醇。每天摄取20-50克大豆蛋白质，约可降低4%—8%的“坏胆固醇”和三酸甘油酯。除了黄豆，大豆蛋白质制品还有豆腐、豆浆等。
深海鱼：
其中的欧咪伽—3脂肪酸可以通过影响血脂，降低三酸甘油酯浓度、减缓血液凝集速率、发挥保护心血管的作用，减少冠心病的发病。深海鱼有鲑鱼、鲔鱼、鲭鱼、秋刀鱼、海鳗等，每周最好至少吃两次。
橙汁：
其中的植物甾醇是一种和胆固醇结构类似的化学物质，可以和胆固醇在肠道里竞争吸收通道，进而减少人体对胆固醇的吸收。最近有研究指出，每天摄取植物甾醇2-3克，可降低6%-15%的“坏”胆固醇，而不影响“好”胆固醇。除了橙汁，含植物甾醇的还有坚果、种子、黄豆油、花生油、有的植物奶油里也添加了植物甾醇。
Monday, October 30, 2006
Wednesday, October 11, 2006
Paleontology - Earth wobbles linked to extinctions
LONDON, England (Reuters) -- Wobbles or variations in the Earth's orbit and tilt are associated with extinctions of rodent and mammalian species, Dutch scientists said on Wednesday.
They studied rodent fossil records in central Spain dating back 22 million years and found that the rise and fall of mammal species was linked to changes in the Earth's behavior which caused cooling periods.
"Extinctions in rodent species occur in pulses which are spaced by intervals controlled by astronomical variations and their effects on climate change," Dr Jan van Dam, of the Utrecht University in the Netherlands, said.
The researchers found two cycles corresponding to the disappearance of rodent species. One lasts 2.4 million years and is linked to variations in the Earth's orbit. The other is a 1.2 million year cycle relating to shifts in the tilt on the Earth on its axis.
The cycles are associated with lower temperatures, changes in precipitation, habitats, vegetation and food availability which are the main factors influencing the extinction peaks, the study published in the journal Nature said.
"Rodents are very sensitive to seasonal changes because they have such a short lifespan," said Van Dam, adding that they represent one of the best mammal fossil records.
At the moment, the Earth is at the beginning of a cycle but the planet's climate system has changed so much in the past 3 million years that it is difficult to predict what will happen in the future.
"The environment is responsible to what happens to species," said Van Dam. "Biological factors are secondary, according to our results."
Copyright 2006 Reuters. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.
They studied rodent fossil records in central Spain dating back 22 million years and found that the rise and fall of mammal species was linked to changes in the Earth's behavior which caused cooling periods.
"Extinctions in rodent species occur in pulses which are spaced by intervals controlled by astronomical variations and their effects on climate change," Dr Jan van Dam, of the Utrecht University in the Netherlands, said.
The researchers found two cycles corresponding to the disappearance of rodent species. One lasts 2.4 million years and is linked to variations in the Earth's orbit. The other is a 1.2 million year cycle relating to shifts in the tilt on the Earth on its axis.
The cycles are associated with lower temperatures, changes in precipitation, habitats, vegetation and food availability which are the main factors influencing the extinction peaks, the study published in the journal Nature said.
"Rodents are very sensitive to seasonal changes because they have such a short lifespan," said Van Dam, adding that they represent one of the best mammal fossil records.
At the moment, the Earth is at the beginning of a cycle but the planet's climate system has changed so much in the past 3 million years that it is difficult to predict what will happen in the future.
"The environment is responsible to what happens to species," said Van Dam. "Biological factors are secondary, according to our results."
Copyright 2006 Reuters. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.
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