AP Biology class blog for discussing current research in Biology

Tag: longevity

Kombucha: More Than Just a Trend

With its bitter flavor, supposed health benefits, vague origin, and aesthetic presentation, Kombucha has become the nation’s latest trend. In Williamsburg on a sunny day, you are bound to see someone sipping on this beloved probiotic tea. While hipsters, health nuts, and myself have all jumped on the Kombucha bandwagon, it seems that science is not too far behind. Researchers at McGill University have found that a combination of probiotics and an herbal supplement called Triphala led to 60% prolonged life expectancy in fruit flies.

This study suggests evidence that the gut microbiome and health may be intertwined, a notion widely believed in the practice of holistic health. Senior author of the study, Satya Prakash, stated “Probiotics dramatically change the architecture of the gut microbiota, not only in its composition but also in respect to how the foods that we eat are metabolized”.

Fruit flies have 70% similarity to humans in regard to their biochemical pathways, making the study promising for fellow Kombucha drinkers! The authors of the study cite the “gut-brain axis” , a communication system between the brain and microorganisms of the gut, as an explanation for their findings.

While Triphala may be hard to come by, some foods with a high probiotic content include sauerkraut, kimchi, kefir, yogurt, and of course, my personal favorite– Kombucha. So while it seems science may catch up, you and I can be well ahead!

Evolution of Human Lifespans


(Locutus Borg, Wikimedia Commons)

Humans have started living longer and healthier lives. According to research conducted by various international teams, the last two centuries have had a greater percent increase in human lifespan than the past millions of years did.

The research teams compared the average lifespan of the most developed societies to the average lifespan of modern-day hunter-gatherer populations, which most closely resemble the lifespan and lifestyle of early humans. The researchers found that developed countries, such as Sweden, have average lifespans of eighty years now (an increase from the mid-thirties range it was in 200 years ago). On the other hand, hunter-gatherer populations such as the Hadza in Tanzania live only ten to twenty years longer than wild primates.

Such drastic improvements in human longevity are attributed to the advent of several post-industrial era features, including modern medicine and supermarkets. However, males trail behind females in terms of lifespan by at least three to four years– something that has not changed since the beginning of primate history.

The exact reason for the lifespan gender gap is unknown. Some hypotheses propose that males are more at-risk because they carry one X-chromosome and one Y-chromosome, as opposed to the females’ two X-chromosomes, which makes males more susceptible to disease. Another possible explanation centers around harmful male-related behavior, such as fighting. What do you think is the most likely reason for the gender gap?

Is There a Limit to How Old Humans Will Get?

In the 1900s, the life expectancy for humans in the United States was approximately 50 years. Since then, the age to which humans can live has only grown. In 1997, a woman by the name of Jeanne Calment died at the age of 122- an astounding increase from the life expectancy less than a hundred years ago. A new study written about in the New York Times explains that Dr. Vijg, an expert on aging at the Albert Einstein College of Medicine, feels that we have now reached our “ceiling. From now on, this is it: Humans will never get older than 115.” Dr. Vijg and his graduate students published their pessimistic study in the journal Nature, presenting the evidence for their claim.

For their study, Dr. Vijg and his colleagues looked at how many people of varying ages were alive in a given year. Then they compared the figures from year to year, in order to calculate how fast the population grew at each age. For a while, it looked as though the fastest-growing group was constantly becoming older; “By the 1990s, the fastest growing group of Frenchwomen was the 102-year-olds. If that trend had continued, the fastest-growing group today might well be the 110-year-olds.” (NY Times Article). Instead, the increases slowed and eventually stopped, leading Dr. Vijg and his colleagues to conclude that humans have finally hit an upper limit to their longevity. Further research into the International Database of Longevity seemed to validate their findings; No one, except in rare cases like Ms. Calment, had lived beyond the age of 115. It appears as though human beings have hit the ceiling of longevity.

There was a varied mix of responses to the study. Some, like Leonard P. Guarente, a biology professor at MIT, praised it, saying “it confirms an intuition he has developed over decades of research on aging.” Others, like James W. Vaupel, the director of the Max-Planck Odense Center on the Biodemography of Aging, called the new study a travesty and said, “It is disheartening how many times the same mistake can be made in science and published in respectable journals.”

This study is by no means conclusive. It is simply one more piece of research in the ongoing debate over whether human beings will continue to live longer, and will continue to be debated by many experts in the field.

However, one must wonder whether living longer should be the goal. After all, as Dr. Vijg pointed out, “aging is the accumulation of damage to DNA and other molecules. Our bodies can slow the process by repairing some of this damage. But in the end, it’s too much to fix. At some point, everything goes wrong, and you collapse.” While morbid, he makes a valid observation: Humans can only go so long until necessary bodily functions begin to break down. Rather than worrying about whether we will live to an extraordinary age such as Ms. Calment, I concur with Dr. Vijg; the focus should be on living the most amount of healthy years and taking care of our bodies. While it may seem like a great idea to live to the age of 125, what good would that do if you aren’t able to continue with the activities you enjoy because your body is breaking down?


Other Relevant Articles:

In Depth Explanation of Longevity:

A brief summary of Dr. Vijg’s findings (a bit shorter than the NY Times article):

An interesting article about an entrepreneur’s quest to make people live even longer:


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