Monday, November 06, 2006

Be cool, live long

I had earlier written about Calorific restriction (eating less) and living longer. This wasn’t about starvation, but just by eating less in terms of calories (but still getting enough essential nutrients) led to substantially longer and healthier life spans (in everything from the humble yeast to mammals, and likely, us). Now, the New York Times has an article chronicling the same story, but perhaps written in a more entertaining style.

But that is not what this post is about. That’s old news. This one is cool.

Literally.

It is widely believed that body temperature acts in concert with calorific restriction in increasing life span, as calorific restriction does seem to lower body temperature.

The normal body temperature is 98.6 F (or 37 degrees Centigrade). That’s what we all know. We also believe that this temperature is the optimal temperature for survival and life. This body temperature is controlled by a region of the brain, the hypothalamus, where a complex network of different types of neurons interact to maintain and control body temperature. By directing blood flow to shift to cutaneous blood vessels (that reach the skin), heat can be spent, while directing blood flow to deep blood vessels retains heat.

Researchers decided to test the cool-body temperature- long lifespan theory, and to do that they made use of this central temperature controlling system. Cells have a certain organelle, the mitochondria, which convert organic material in to energy (in the form of ATP) that the body uses. Now, mitochondria also have a protein called UCP (with two forms, 1 and 2) that uses up this energy and results in the release of heat. In this study, the researchers cleverly decided to take advantage of the central temperature controlling region of the hypothalamus to modify the core body temperature itself.

What they did was to engineer mice to over express this UCP protein (UCP-2) exclusively in the hypocretin region of the hypothalamus. This excess of UCP-2 slightly increased the heat in that small region alone. This effectively fooled the hypothalamus in to thinking that the entire body was too hot, and resulted in a lowering of the core body temperature of the mice, resulting in a lowering of temperature by 0.3-0.5 degrees centigrade.

The engineered “cool” mice were then fed the same amount of food as wild-type (normal) mice, and were monitored. Due to their lowered body temperature, these engineered mice ended up gaining more weight (compared to the normal mice), even though they ate the same amount of food. This was somewhat expected, since maintaining a lower body temperature would require less energy.

One would imagine that this weight gain (which is normally known to adversely affect lifespan) would result in a lowered life span. But surprisingly, what the researchers observed was exactly the opposite.

What they saw was that the engineered mice with slightly lower body temperature on average increased their life span by about 8% (in human terms that would be an increase in lifespan of about 8 years!). To push the question further, both the normal as well as the lower body temperature mice were fed on a fat diet. The engineered mice ate normally, and ended up surviving longer than the normal mice.

Now, what was earlier known was that calorific restriction would result in lower body temperature as well as longer lifespan. But here, the results suggested that lower body temperatures actually increase lifespan, independent of calorific restriction.

This study raises some really interesting questions. Would it be desirable to decrease body temperature slightly, and therefore live longer? Body temperatures are tightly regulated, and have evolved over millions of years to be where they are today. So, even if a slightly lower body temperature results in a longer lifespan, could there be other adverse side effects on behavior, or psychology or reproduction or something else? Calorific restriction appears to lead to healthier longer lives. Will just lowering of the body temperature do the same?

As always, more questions, each as fascinating as the other.

(You can read the complete article here (Science Vol. 314. no. 5800, pp. 825 – 828), or a short comment here)

9 comments:

Anonymous said...

Most interesting indeed. While on the topic of body temperature, the Eastern concept of 'body heat' is what comes to mind immediately. It's something that hasn't found much credibility among Western scientists or doctors, but I have observed that it seems to work.

The concept is that due to various factors, such as dietary and sleeping habits, the body can get 'heated' up. This heating up is thought to cause various problems, ranging from ulceration, to sore throats and even colds!

Excessive rheum ('sleep' or 'eye booger') formation is considered a symptom.

There are several remedies prescribed for this problem. Castor oil is considered a great 'coolant', and its application is thought to alleviate the symptoms quickly. Coconut water and buttermilk are also thought to be coolants, and they are often consumed to combat 'body heat'.

This concept is traditionally known across India and China, and I suspect it's prevalent in other parts of East Asia as well. What's interesting is that although there's no measurable difference in body temperature, many of the remedies successfully alleviate the symptoms, so there must be something to it.

Sujatha Bagal said...

Hmmm, heat is on my mind as well.

But why are the mice eating more if their lower body temperature requires less calories? I thought eating more than required was learned behavior, not instinctual.

Also gaining weight beyond a certain point cannot be good. It'll probably lead to a strain on the body's mechanism (heart, lungs, etc.) to keep a heavier body functioning and therefore generation of more heat in the body (body working harder = more heat), ultimately leading back to shorter life spans. Am I way off base or only slightly?

Sunil said...

Witnwisdumb....there is certainly something to the concept of 'body heat' that is described in eastern medicine. Even with massages and the like, there are special oils depending on the person. And there is definitely a slow acceptance of these Eastern body concepts in western medicine. This is really influenced by the gaining popularity of yoga in the west. A professor of mine teaches a very popular "mind-body-medicine" course, combining aspects of yoga etc in the course.

Sujatha....the mice are not eating more, they are eating exactly the same amount as the normal mice. This is a controlled experiment where the food for each mouse can be exactly controlled. The mice are not "wild" or foraging, but get exactly what you give them. And these are not obese mice. Their weight gain was 5-10% more than the normal mice (as would be expected with lower body temperatures), but they certainly were not too fat. That is certainly not good, nor is even this weight gain really probably good. But the remarkable observation was that inspite of gaining weight, the low-body temperature mice still lived longer. It is already known that combining calorific restriction with low temperature does lead to substantial gains in lifespan.

Anonymous said...

interesting ... all of my grandparents are either still alive in their 90s or died in late 80s or 90s. I've always had a problem with putting on weight easily, even when apparently eating/Exercising the same as others.
Today I happenned to measure my body temperature for the first time I can remember (probably did it as a a sick kid). Voila - 36.1C. I seem to fit the theory. And here I was stressing about having to go on a low calorie diet to live forever! :-)
When you think about it, it makes sense. If the cells are generating less heat, they are likely also generating less pollutants such as free radicals, which means fewer issues caused by their damaging effect and on average a longer life.

Anonymous said...

black mold exposure,
black mold symptoms of exposure,

wrought iron garden gates,
your nest iron garden gates, here,

hair styles for fine thin hair,
search hair styles for fine thin hair,

night vision binoculars,
buy, night vision binoculars,

lipitor reactions,
lipitor reactions,


luxury beach resort in the philippines,
beach resort in the philippines,

homeopathy for baby eczema.,
homeopathy for eczema learn about it.,

save big with great mineral makeup bargains,
companies marketing mineral makeups,

Anonymous said...

美容課程專業彩妝網化妝課程健康瘦身減肥健康飲食瘦身瘦身減肥飲食常識營養理論營養飲食指導新娘化妝化妝美容瑜伽常識來也匆匆,去也匆匆飲食健康新新數碼的生活英語學習新突破飲食文化
快樂比較多愛,永無止境愛情哲理人生哲理我的激情人生我的數碼生活語言學習美味生活生活點滴人生成長生活隨筆一生的等待成長歷程新科技視野一片面包,一杯牛奶品味下午茶親情無價哲理美文人生歷程輕松減肥

Anonymous said...

美容課程專業彩妝網化妝課程健康瘦身減肥健康飲食瘦身瘦身減肥飲食常識營養理論營養飲食指導新娘化妝化妝美容瑜伽常識來也匆匆,去也匆匆飲食健康新新數碼的生活英語學習新突破飲食文化
快樂比較多愛,永無止境愛情哲理人生哲理我的激情人生我的數碼生活語言學習美味生活生活點滴人生成長生活隨筆一生的等待成長歷程新科技視野一片面包,一杯牛奶品味下午茶親情無價哲理美文人生歷程輕松減肥

Anonymous said...

中古DVD

中古DVD

アダルトDVD

ヒップホップ

Anonymous said...

(法新社倫敦四日電) 英國情色大亨芮孟的成人公司昨天說色情,芮孟a片下載日前部落格去世,享壽八十二歲;成人網站這位身價上億的房地產開情色電影發商,曾經a片在倫敦推出av女優色情一場脫色情衣舞情色表演。


芮孟的財產估計達六億五千萬英色情影片鎊(台幣將近四百億),由日本av於他名a片下事業大多分布部落格在倫敦夜av生活區蘇活區成人電影,因此擁有「蘇活之王」的稱號。sex


他的公司「保羅芮a片孟集團」旗下發行多種情色雜誌情色視訊,包括「Razzle成人影片」、「男性世界」以及「Mayfair」。av女優


成人光碟芮孟a片下載本名av女優a片福瑞成人影片av安東尼.奎恩,父成人影片親為搬運承包商。芮孟十五歲離開學校,矢言要在表演事業留成人網站AV片,起先表成人網站演讀心成人術,後來成為巡迴歌舞avdvd雜耍表演的製作人。
情色電影

許多評論家認為,他把情色表演帶進主流社會,一九五九年主部落格持破天荒的av脫衣舞表演,後來更靠情色著在蘇活區與倫敦西區開發房地成人電影產賺得大筆財富。av


有人形容芮孟是英國的海夫納色情a片,地位等同美國的「花花公子」創辦人海夫納。