The Role of Free Radicals in Human Life Spans

 

In Psalm 90:10 of the King James Version of the bible it clearly says:

"The days of our years are threescore years and ten; and if by reason of strength they be fourscore years yet is their strength labour and sorrow; for it is soon cut off, and we fly away". 

“You do not know what will happen tomorrow. For what is your life? It is even a vapor that appears for a little time and then vanishes away” (James 4:14).

A list of 10 of the oldest people mentioned in the Bible were:

1. Methuselah: He is often regarded as the longest-lived person in the Bible, living for 969 years according to the Book of Genesis (Genesis 5:27).
2. Jared: Jared, the father of Enoch, lived for 962 years (Genesis 5:20).
3. Noah: The famous ark builder lived for 950 years (Genesis 9:29).
4. Adam: The first man in the Bible, Adam, lived for 930 years (Genesis 5:5).
5. Seth: Seth, the son of Adam and Eve, lived for 912 years (Genesis 5:8).
6. Kenan (Cainan): Kenan, also known as Cainan, lived for 910 years (Genesis 5:14).
7. Enosh: Enosh, the son of Seth, lived for 905 years (Genesis 5:11).
8. Mahalalel: Mahalalel lived for 895 years (Genesis 5:17).
9. Lamech (father of Noah): Lamech, the father of Noah, lived for 777 years (Genesis 5:31).
10. Shem: Shem, one of Noah's sons, lived for 600 years (Genesis 11:10-11).

Despite that, I often read claims by people that we can avoid old age and death through healthy lifestyles such as good nutrition, exercise, rest and sleep besides avoidance of smoking and alcoholism and obesity promotes good health and extends human life span through the absence of diseases. This may be true in limited ways though we may have limited scientific knowledge and evidence to show that. There is also a limit on how long we can live.

Nevertheless, in 1935, a scientist named Clive McCay published a startling discovery that rats with severely restricted diets lived up to 33% longer than previously known possible. Over the last few decades, similar experiments have been carried out on countless species, from worms to rodents and even primates. 

The specifics vary from study to study, but many show results just as surprising as those that McCay discovered so many years ago. The exact manner by which calories are reduced changes across studies, but the animals’ calorie intakes are generally reduced by as much as half their normal levels. Depending on the species, the most promising results have shown lifespan extensions between 50 and 300%.

If these results hold water, then they could have important implications for our own longevity. However, these studies are not without controversy. Many scientists are concerned that calorie restriction will not benefit humans, or that it could even result in long-lasting harm. Is calorie restriction a silver bullet against aging, or something that should be kept in the laboratory? 

At first glance, calorie restriction is a counter-intuitive way to approach longevity. Here, we use this term to refer to up to a 50% reduction of calories from a normal diet, not simply a lack of overeating. Consuming so much less food than a normal diet seems like it should reduce your lifespan, not extend it. To better understand where this idea comes from, it’s necessary to first understand how aging – the process by which our bodies function less well over time – works. There are two classic theories that could potentially shed some insight into this process: the rate of living theory, and the free radical theory.

The rate of living theory arose from the observation that larger animal species tend to have longer lifespans than small ones. One way to explain this observation is through the concept of metabolic rate, which refers to how quickly an animal expends energy for the body’s day-to-day functioning. This includes energy needed for processes like breathing, maintaining body temperature, and circulating blood. Since larger animals have also been observed to have lower metabolic rates, this theory suggests that slower metabolic rates – i.e., slower “rates of living” – are associated with longer lifespans to quote a source from the Internet.

This is only the second theory on life spans. But we have another more interesting theory to offer.

In chemistry a molecule is made up of more than one atom. Each atom in a molecule is attached to other atoms by a pair of electrons. Thus, a carbon atom may be attached to four different hydrogen atoms by four different hydrogen atoms by four different electron pairs, under some circumstances a hydrogen atom may break free taking its electron with it. What is left of the original molecules is a carbon atom with only three hydrogen atoms. Where the fourth hydrogen atom should be is a single electron unattached to anything.

A molecular fragment containing that single electron is a radical. That single electron is very active, tending to tear strongly at other molecules in order to grasp an atom with which it can make up an electron pair again. This happens so rapidly that a radical, even if formed does not last long and may just snatch up the atom that broke loose before it can quite get away. Nevertheless, if a radical can last long enough to wander about a bit and seize an atom from some other molecule, it is spoken of during its brief existence as a ‘free radical’.

Free radicals can form within living cells. Energetic radiation such as cosmic rays, X-rays or ultraviolet light from the Sun can produce them. So can certain chemicals. These free radicals can last long enough to damage neighborhood molecules. When these damaged molecules happen to be proteins, enzymes, or worse of all, the deoxyribonucleic acid (DNA) molecules in the genes, the cells suffer. Some portions of the cell machinery may be knocked awry.

The body has ways of preventing or correcting damage by free radicals. Substances such as vitamin C and vitamin E can give up electrons easily, and in so doing they can satisfy the appetite of the free radicals and prevent them from taking other molecules. The body also has corrective mechanisms that can repair molecules damaged by free radicals.

Nonetheless, not all free radical damage can be averted or repaired. This means that as life goes on, injury to the cells does take place and it does add on. With the years, more and more cells are crippled, and various necessary portions of the body machinery become more and more rickety and ineffective.

There are some scientists who think it is this accumulating damage that causes old age that makes it certain we all die in the end, even in the absence of disease, infection, and accidents.   

If this is so, then we might live longer if we could find some more powerful means than the body itself for preventing free-radical damage. For instance, there are some plants such as the creosote bush that have an unusually long-life span. The creosote bush (Larrea tridentata) is called chaparral as a medicinal herb that contains a plentiful supply of the compound nordihydroguaiaretic acid (NDGA). This can short -circuit free radicals by handing them an electron and perhaps does this more efficiently than vitamin C and E do.

A biochemist at the University of Louisville, John P. Richie, Jr. has tested this possibility by feeding NDGA to female mosquitoes. Such mosquitoes normally live for an average of 29 days, but with NDGA they lived for an average of 45 days. That’s an increase of 50 percent. If this worked similarly on human beings, it might increase our average lifespan from 75 years to 113 years.

It is unlikely that anyone will try to feed human beings NDGA as a nutrition-medical experiment, but Richie’s observation seems to support the free radical theory of aging.

 There may be other less problematic ways of preventing free radical formation or encouraging their removal so that human life span can significantly be extended.

But the question that we must face is whether we want to do this even if this is possible. Any extended life span will obviously increase the population, which will make it necessary to lower the birth rate than would be advisable. Mankind will end up with an ageing population that no country would desire. This means there will be fewer and fewer young people. Governments, business, and all the machinery that runs society will need to be conducted for longer and longer periods by older and older people and what young people that are left will have to wait for longer and longer periods of time to take over. Does this matter and make sense?

It probably does. It would not be just young people, but they are new people who are biologically, economically and socially better people with better brains who might just be in a better position to tackle problems in new and creative ways. Society in command by long-lived oldsters with a declining infusion of the young and new might tend to decay and become static. In truth it might well be that oldsters give way to the young and new for the survival of the fittest of the human species. The advantage that we may gain by living longer could be paid for by the decline of humanity.  It is just one of the biological rules in evolution on the survival of the fittest.