On My Youngest Daughter Ai Hsing (Front) Graduation Day

On My Youngest Daughter Ai Hsing (Front) Graduation Day

Monday, July 9, 2018

Fasting, Caloric Restriction and Longevity

A question from Ms. Josephine Wong was posted to me on a video claim that frequent eating with short intervals between meals is more health-protective and contributes towards longevity than those who eat less and less often.

Thank you for your question.

Caloric Restriction and Longevity:

First of all I want to quote a very famous study by Clive McCay of Cornell University as far back as in 1935 that when rats were put on a caloric restriction diet, it considerably prolongs their life span.

This study was repeated many times on other animals showing the same result. Even before all these well-established studies, Hippocrates of Kos, circa460 – c.370 BC, now considered the Father of Medicine and Nutrition, and later Galen have all advocated eating less.

Avicenna c.980 1037) a Persian physician, astronomer, thinker and writer of the Islamic Golden Age also taught the same advice  that we should eat less for longevity and freedom from disease.

Let me now elaborate on their thinking as well as giving probable explanations what modern scientists found when we eat little, and less often. We will begin by seeing what happens when food is consumed  

However, we will not go into the physiology of food consumption, its digestion, absorption, transportation and distribution as discussion on these are very lengthy, unnecessary, and irrelevant within the scope of answering your enquiry.

We will instead go straight away into metabolism of food using simple biochemistry  and the role of the liver and kidneys as these are the only two organs that have to deal with the nutrients absorbed (the liver), and the chemical fate of the nutrients (metabolism), and the kidneys that has to deal with the metabolic wastes like urea.


Once food has been digested, absorbed and transported to the liver by the portal vein, the nutrients are either metabolized or stored. The body is continuously undertaking a series of complicated chemical reactions called metabolism to empower the body to continue to exist, provide the energy the body needs, and the cells to divide and grow.

Metabolic reactions are divided into catabolism by obtaining energy derived from the nutrients, and anabolism for the development of new cells that necessitates energy from the catabolism.

There are hundreds of thousands of chemical reactions going on and their pathways in the body at any moment in time, but we shall not deal with biochemistry here.  

In order to keep this answer short and neat and within the scope of the question, we shall only give some examples of major sources of energy the body derives from the metabolism of nutrients. These are:

1.   Glycolysis which is the oxidation of glucose that empowers  the synthesis of energy-rich ATP

2.   Krebs' cycle or citric acid cycle (CAC), sometimes also called the tricarboxylic acid cycle (TCA) is a chain of chemical reactions used by the body to release stored energy through the oxidation of acetyl-CoA acquired from carbohydrates, fats, and proteins.  

Acetyl-CoA is a molecule that participates in many biochemical reactions involving protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for energy production.

They then give off carbon dioxide and the release of chemical energy and other intermediary products. The Kreb’s Cycles requires the B group of vitamins to proceed.

The oxidative phosphorylation encompasses the disposal of the electrons released by glycolysis and citric acid cycle. Much of the energy released in this activity is subsequently stored as adenosine triphosphate (ATP), an energy-rich phosphate bond.

The discharge of electrons in a metabolic or in any chemical reactions generates destructive free radicals to the cells, tissues and body systems, and more crucially to the DNA. We shall deal with this later.

3.   The pentose phosphate pathway is the synthesis of pentose, and the release of reducing energy needed for anabolic reactions

4.   The urea cycle comprises of the disposal of NH4+ in less toxic forms

5.   Fatty acid beta-oxidation activates fatty acids breakdown into acetyl-CoA. This then enters into the Krebs' cycle once again.

6.   Gluconeogenesis that involves in glucose synthesis is used by the brain for energy.

The Liver:

One of the major functions of the liver is the maintenance a fairly balanced concentration of glucose in the blood. This is accomplished through gluconeogenesis and glycogen synthesis and degradation. It synthesizes ketone bodies when acetyl-CoA is adequate.

It is also the site of urea synthesis. There are hundreds if not thousands of chemical reactions and various pathways taking place in the liver. But we shall not go into all the liver chemistry

It is estimated the liver has to deal with over 500 – 700 functions. Many of these include assimilating and storing fat-soluble vitamins, producing bile, filtering blood, metabolizing fats, proteins, and carbohydrates, and endogenous hormones, dealing with wastes, and detoxifying  alien chemicals,  toxins and drugs, changing ammonia into urea through the urea  or ornithine cycle.
The liver also syntheses blood proteins, depositing nutrients like glucose into glycogen, as well as storing fat soluble vitamins, and minerals.

The Liver and Free Radicals:

Since the liver is the site of most of the synthesis and metabolic breakdown, and since these biochemical reactions involve the transfer of elections; either to lose or to capture them, it generates free radicals.  Any atoms, molecules or molecular fragments that lose an election become a highly destructive free radical.

The simplest free radical is an electron. A hydrogen atom is also the simplest free radical

A hydrogen molecule has an electron pair, and hence, it is not a free radical. But when hydrogen is irritated with UV light without oxygen, a hydrogen molecule (H-H) may be fragmented evenly (homolytic cleavage) it produces two hydrogen atoms or two free radicals:

H2 2H

A very good example of a free radical production in chemical reactions in the liver, or elsewhere in the body, and in the environment outside the body, is production of the hydroxyl radical (HO•)

Since free radicals are highly unstable chemically they can only exist for just a fraction of a second in the presence of an electron recipient   

However even their very short existence is long enough to cause untold damage to the DNA, cells, tissues, organs and systems of the body. We shall go more into free radicals a little later, and how they can damage the DNA in the body.

Unfortunately, the more food we eat, the more toxic wastes and metabolites we produce, and the more destructive free radicals are generated in the process of anabolism and catabolism. After the liver have broken down the toxic waste of metabolism, most of them are handed over to the kidneys for excretion 

The Kidneys:

The kidneys besides being an excretory organ can also carry out gluconeogenesis to release glucose into the bloodstream.  But its main role is the excretion of urea, electrolytes, and other excretory metabolites.

There is a condition called metabolic acidosis that occurs when the body produces excessive amounts of acid or when the kidneys are not clearing sufficient acid from the body.

However, metabolic acidosis may be increased during the ornithine (urea) cycle, since urea synthesis executed in the liver uses HCO3-, and in so doing further lowers the blood pH. Under these conditions, nitrogen may be removed by the combined action of kidney and liver.

Any surplus nitrogen is first integrated in glutamine by glutamine synthetase. The renal enzyme glutaminase then splits glutamine in glutamate NH3, which the kidneys directly excrete. This procedure permits nitrogen excretion without affecting blood bicarbonate levels.  

This process involves lots of excretory products of metabolism from the food consumed giving neither the liver nor the kidneys physiological or biochemical rest 

Hormone Regulator:

Hormone regulations are principally performed through the action of two hormones synthesized by the pancreas via its insulin and glucagon.

Insulin is released by the beta cells in the pancreas when blood glucose levels are elevated primarily after food.  Insulin stimulates glucose uptake by the muscle, glycogen synthesis, and triglyceride production by the adipose tissue.

Insulin blocks gluconeogenesis and glycogen degradation. Glucagon is then released by the pancreas when blood glucose levels drops significantly.

This biochemical event is the reversal of the action of insulin.  In the liver, glucagon excites glycogen breakdown, and the absorption of amino acids. It inhibits glycogen synthesis and stimulates the release of fatty acids by adipose tissue.

All these biochemical events snowballed when more and more food are consumed at libitum. More and more excess nutrients are stored, old cells including cancer cells and tissues cannot be disposed of until the excess sugars, triglycerides (fats) and amino acids (proteins) from over eating are metabolized (burnt)  first.

Once again keep in mind free radicals are produced in all these above metabolic process.

However, if the body is put on a caloric restricted diet, or on a prolonged and frequent fasting,  it  will start to break down its stored sugars (glycogen) first,  than the body stored fats, and lastly its own  body tissues and muscle to supply it with energy. That is where a biological event called autophagy kicks in by digesting its own old and unwanted cells first.


Autophagy is a normal physiological function the body performs in the destruction of old and degenerated cells in the body. Its function is to maintain a homeostatic check and balance for normal cellular functioning by inducing protein degradation for the birth of new healthy cells.  

During cellular stress and trauma such as attacked by free radicals released in metabolic pathways, and in their breakdown, the rate of autophagy is increased.  Autography is also increased in prolonged fasting

Autophagy hence can be achievable through intermittent fasting or by longer fasts. This biological event is initiated when liver glycogen is depleted. This takes place around 12-16 hours into a fast. Studies showed the rate of autophagy peaks during this period, and then fall off after about 2 days.

This also takes place when cells in a healthy human body are continuously being damaged as a normal part of metabolic processes.

However, as we age, or endure any kind of physiological, psychological or chemical stress such as from the food and medicine we take, we have to  deal with more and more free radical damage, resulting in more and more cellular damage  at an increased rate.

Autophagy also comes in by clearing damaged and senescent cells that serve no more functional role in the body. The reason why it is so important to remove senescent and damaged cells is because they can trigger damaging inflammatory pathways that contribute to various diseases including cancers.

Autophagy and Longevity:

It is only in very recent animal studies that researchers have shown how autophagy can promote longevity by conferring benefit to the nervous and immune systems, as well as the cardiovascular system.

Naturopathic (Natural) Medicine:

While scientific research only over the last two decades has demonstrated the medical and health benefits of autophagy or autophagocytosis induced during fasting, this piece of evidence is not new.

Doctors of naturopathic medicine have already known this, and have put this principle into their clinical practice or the science of clinical autophagy through physiological fast on fruit juice. They have already practiced this on their patients for almost 10 decades already.

Prize in Medicine or Physiology:

It was only in 2016 that a Japanese medical researcher Dr. Yoshinori Ohsumi won the prestigious Nobel Prize in Medicine or Physiology for his work on the mechanism of autophagy when doctors of naturopathic medicine have already put that mechanism into their practice almost 100 years earlier.

Autophagy is a non-specific term for the degradation of cytoplasmic components within lysosomes as shown by several workers (Cuervo 2004; Levine and Klionsky 2004; Shintani and Klionsky 2004; Klionsky 2005, 2007; Mizushima and Klionsky 2007).

This process is quite separate from endocytosis-mediated lysosomal degradation of extracellular and plasma membrane proteins.

There are actually three types of autophagy (macroautophagy, microautophagy, and chaperone-mediated autophagy). We shall not go into all of them. However, “autophagy” usually signifies macroautophagy.

Autophagy is mediated by a unique organelle called the autophagosome. Organelles are specialized cellular parts such as lysosome, mitochondrion, chloroplast, or nucleus inside a cell.  

As autophagosomes swamp around a portion of cytoplasm, autophagy becomes part of a nonselective degradation system.

Its role can be beneficial or bad. For instance it can switch on tumor suppressors to prevent the onset of cancer, but it can also promote cancer cell survival among many other pathophysiological functions.

Recent Studies:

However, recent studies have clearly demonstrated that autophagy has a greater function other than its pathophysiological roles of destroying old, damaged and non-functional cells.  They are also mediated during starvation adaptation, intracellular protein and organelle clearance, development of new healthy cells, anti-aging function, the destruction  of pathogens and microorganisms,  promotes cell death, cancer suppression, and antigen production among others (Mizushima 2005).

Nonetheless, its mechanisms can be very complex such as its role in cancer suppression or promotion or in cell death.  Autophagocytosis is thus a double-edged sword much like the double personalities of Dr. Jekyll and Mr. Hyde.

Autophagocytosis Fasting:

The  best and easiest way to induce autophagy or sometimes called autophagocytosis  (meaning "self-devouring")  is through intermittent fasting  using plain drinking water with added minerals, or on fruit juice to maintain fluid and electrolyte balance. This is recently termed as autophagocytosis fasting or physiological fasting has already been put into clinical practice as one of the therapeutic modalities by doctors of naturopathic medicine.

Free Radicals and Cellular Damage:

The human body is mainly made up of 65 % oxygen, 18 % carbon and about 10 %hydrogen. The presence of carbon with other elements made up the organic compounds.  Hence the body consists mainly of organic compounds.  Most of the biochemical reactions in the body involve organic molecules such as sugars, amino acids, fatty acids, enzymes and hormones

In almost all chemical reactions, free radicals are generated during the transfer and exchange of electrons from one atom to the other among the donor and recipient molecules. These are free radical reactions. This type of reactions occurs very often in organic reactions.

Free radicals are highly reactive when molecules lose their electrons. They become highly unstable, and in order to stabilize themselves, they snatch an electron from the next molecule or molecular fragment such as a DNA, damaging it and causing it to be unstable.

The amount of damage done to the body by free radicals by excessive eating is horrendous. This has already being earlier explained in our brief discussions of metabolisms and the role of the liver and kidney.

Even at rest and on fasting, free radicals are also continuously being generated by untold number of chemical reactions of metabolism throughout the body. The more we eat, or the more frequent we eat in between meals, the more free radical reactions occur to process the excess nutrients. This event causes a lot of damage to the cells which the body tries to repair or replace. In doing so we do not even allow a chance for the body to have bowel, physiological and biochemical rest. We treat it like whipping a tired horse.

Cellular Repairs:

Normally cells will try to repair themselves. But when a cell cannot be repaired, the body will substitute it with stromal connective tissue to maintain tissue and organ function 

Metabolic activities and environmental factors such as radiation resulting in free radicals can also cause DNA damage, and there may be about as many as 1 million individual molecular lesions per cell per day.

Many of these lesions initiate structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes.

Other lesions generate potentially unsafe mutations in the cell's genome. This affects the survival of its daughter cells after it undergoes mitosis. As an after-effect, the DNA repair process is continuously active as it responds to damage in the DNA structure.

The rate of DNA repair is dependent on various factors, including the cell type, the age of the cell, and the extracellular environment.  

A cell that has amassed a large degree of DNA damage, or one that can no longer effectively repair the damage to its DNA, it then enters into one of four possible events:

1.   Go into senescence which is an irreversible state of dormancy
2.   Induce autophagocytosis
3.   Commit apoptosis or programmed cell death which is cellular suicide
4.   Uncontrollable cellular dissection which may lead to the formation of a cancerous tumor

Number of Cells in the Body:

Scientists are not very sure how many cells are there in the human body, because this depends on the age, the  body weight, growth rates, aging, degenerations of old cells, etc.

Our current estimate is at 37 to 38 trillion. This number fluctuates over time and varies from individual to individual, but about 37.5 trillion cells should be a close estimate for an average adult.

Cellular Molecular Damage:

Within the structure of each cell, untold numbers of molecular lesions occurs at any point in time each day, and as already estimated, it could be as many as 1 million individual molecular lesions per cell per day.

Even if we put the number of cells of a small child at just ten million, million (1013) the child would have been bombarded with tens of thousands of DNA lesions per day

Scientists estimate the human body is injured by no less than 1 million individual molecular lesions per cell per day even during physiological and metabolic rest.

Many of these lesions cause structural damage to the DNA and can change or eliminate the cell's ability to transcribe the gene that the affected DNA encodes.

Other lesions induce potentially injurious mutations in the cell's genome, which affect the survival of its daughter cells after it undergoes mitosis.

All these destructive factors affect human health, the onset of degenerative diseases and cut short life span

All these destructive biochemical events cause a lot of stress to the liver and other organs brought about by free radicals generated during the exchange of free elections in their chemical reactions, causing uncountable damage to all the cells involved. All these events are the result of over eating or eating too often.

We estimate there are about  37 thousand billion,  billion chemical reactions per second taking place in the human body at any moment in time, and this biochemical scenarios occurs throughout 24 hours even when we are at rest or sleeping.

This is chemically a disaster by shortening our programmed longevity drastically through damaging lifestyle and over nutrition that promote these destructive chemical events.


In summary we can see the benefits of intermittent fasting to allow autophagocytosis to take its course through bowel rest and metabolic clearance via the liver and kidneys

This would be contrary to a video claim you sent to me for comment  that frequent eating  is more health protective than a longer delay between small feeds. I do not know where that American lady in her U-tube video claim got that belief from?

Best of all to my understanding, to ensure a disease-free life and longevity go on regular physiological fasts on low-sugar fruit or vegetable juice, or go on a  caloric restricted diet as demonstrated in countless studies, subsequent to the famous and classical study of  Clive McCay of Cornell University in 1935

Thank you once again Ms. Josephine Wong for your question. I hope my brief and easy to understand explanation helps

Lim ju boo

Wednesday, May 30, 2018

Does Garlic Cause Cancer When Heated

I write this comment below to a request and question via Whatsapp on a video narrated  in Chinese Mandarin. It was sent to me for advice by a friend called Sister Sonia Soon from Bahhma Kimaris on behalf of her sister and someone else from a cancer society (CanSurvive) in Malaysia

They solicited my opinion that garlic when overcooked causes cancer

Dear sister Soon

Thank you sister Soon for soliciting my personal view once again on this video claim

This video in Chinese Mandarin emphasizes on overheating the garlic (Allium sativum) that it claims can cause cancer, but it says garlic is cancer-protective if eaten uncooked.

If you were to solicit my opinion on this, let me tell you a lot of foods containing complex starches such bread when toasted, cakes, traditional kuih, coffee (after roasting its beans), potatoes chips, pop corns, fried rice, fried mee, fried rice noodles and any foods containing starches (almost all foods do) when cooked above 120 degrees Celsius produces  this acryloyl group called acrylic amide or acrylamide or prop-2-enoyl  in short

We are not too clear on the mechanism how this substance is formed when almost all starchy foods,  not just garlic alone, are heated to above 120 0 C. Food scientists  think this may be a by-product of Maillard reaction.

Maillard reaction:

Maillard reaction is a chemical reaction between amino acids and reducing sugars that gives food its brown colour and distinctive flavor when foods like bread, buns, and cakes are heated at a high temperature. It is a non-enzymic browning reaction, a very well-known reaction in food chemistry.

This reaction does not occur when starchy foods are boiled such as in boiled potatoes and rice. But in fried or baked goods, acrylamide may be produced by the reaction between asparagine (an amino acid from protein) and reducing sugars (fructose, glucose, etc.) or by reactive carbonyls at temperatures above 120 °C.

Unfortunately some later studies  showed that  acrylamide was also present  in black olives, prunes, dried pears for reasons not clear to us.

The Decomposition of Acrylamide:

However, we also know that acrylamide decomposes in the presence of acids, bases, oxidizing agents, iron, and iron salts. This means that even if starchy foods are baked, acrylamide may not be present if they are cooked at high temperatures in the presence of vinegar (acetic acid), lime juice (citric acid) or if baking powder (sodium bicarbonate, a mild alkaline) has been added.

The baking powder itself will decompose into carbon dioxide and sodium carbonate which is even more alkaline than baking powder. This may block the formation of acrylamide, but we need studies to show this.

But even if acrylamide is present, this compound can decompose even without heating into ammonia, and with heat, it decomposes into carbon monoxide, carbon dioxide, and oxides of nitrogen after some time. Again we need to conduct studies on this.

Discovery of Acrylamide:

Acrylamide was discovered in April 2002 by a scientist in Sweden when she found the chemical in starchy foods, such as, French fries (potato chips), and bread that had been heated higher than 120 °C, but  was not found in food that had been boiled or in foods that were not heated.
The discovery of acrylamide in some cooked starchy foods provoked worries about the cancer-causing effects of these foods.

However as today (Friday, June 1, 2018), food scientists, nutritionists, toxicologists, and medical scientists are still uncertain whether or not acrylamide in foods put us all at risk of developing cancer.

Tumors in Experimental Animals:

In experimental animals, exposure to acrylamide was shown to causes tumors in the lungs, thyroid, adrenal glands, and testes.

This concern is not just through ingestion, since acrylamide can easily be absorbed by the skin and distributed throughout the body.

It was demonstrated that the highest levels of acrylamide after exposure were found in the blood, non-exposed skin, liver, the kidneys, in the testes, and spleen.

The mechanism how the carcinogenicity of glycidamide is triggered in animal models is through a gene called cytochrome P450 which transfers its metabolism into a genotoxic metabolite called  glycidamide.

However, people who worked in food manufacturing industry and were exposed to twice the average level of acrylamide do not exhibit higher cancer rates. 

Detoxification of Acrylamide:

Interestingly, acrylamide and glycidamide can also be detoxified by conjugation with glutathione (an antioxidant produced by the body) to form isomeric glycidamide-glutathione conjugates, and these  are subsequently  metabolized to mercapturic acids and excreted harmlessly in the urine.

Neurotoxic Effect:

Acrylamide has also been found to have neurotoxic effects in humans who have been exposed. Animal studies also show the same neurotoxic effects.

Nonetheless, we cannot translate experimental results based on animal studies into human.  First of all, human life span is far longer than smaller animals like rats, rabbits and guinea pigs.

Secondly, the dose normally given to animal models are far higher and fed continuously than those consumed unintentionally by human in their daily diet.

What we are unsure of is the accumulative effects of acrylamide in humans even at low doses, but over a long period of our  life span. So far we have no evidence on its correlation with cancer in humans


Thirdly, how our human body reacts to acrylamide and other substances may not necessary be the same as those in animals. There are a lot of other factors such as nutrigenetics to be considered.

Nutrigenetics is a sub-specialization of the science of nutrition on how nutrients have variations in  genetic responses, and thus the onset of disease and their outcome such as cancer.

Food substances such as acrylamide may influence gene expression and gene behavior and also their epigenetics. The branch of molecular medicine called epigenetics refers to external modifications to DNA that turn genes "on" or "off."

These modifications do not change the DNA sequence, but may trigger off disease like metabolic syndrome and cancers, and the way we respond to acrylamide or other poisons are different from individuals to individuals, not just among human or among animals, but even among individual humans.

In short, you and I are entirely different even though we share almost exactly the same genome, and we respond to disease, their treatment including cancer and their outcome differently.

Absorption through Skin:

Acrylamide has been found to be a skin irritant. Thus being a chemical irritant, this may act as a tumor initiator on skin tissues, giving an increased risk to skin cancer. Clinical presentations of acrylamide exposure include dermatitis in the exposed area, and subsequent peripheral neuropathy.

But what we are concern is not so much  the presence of acrylamide in heated garlic, but by the loss of a lot of valuable suphur-containing allicin and other functional active components in garlic,  one of the most important medicinal principle is ajoene when garlic is cooked at home,  or processed into pills by other means through food technology

Allow me to briefly explain  this in a simple language for the benefit of my gentle lay readers.


Ajoene has medicinal properties. It is an antioxidant that is able to block the formation of free radicals like superoxide. Ajoene also acts as an antithrombotic agent that prevents platelets in the blood from forming blood clots. This means that regular consumption of raw garlic reduces the risk of heart disease and stroke in humans due to blood clots

Ajoene processes anti-viral properties against a number of viruses such as those that cause vesicular stomatitis, para-influenza, vaccinia virus, human rhinovirus, and herpes simplex.

It was shown that when cells are infected by a human immunodeficiency virus (HIV), ajoene in garlic was able to block the integrin-dependent processes as shown by Tatarintsev AV, et al.

Ajoene also exhibits broad-spectrum antibacterial and antifungal properties, and garlic has been used traditionally as a natural antibiotic and fungicide against many types of infections since ancient times by all civilizations for thousands of years.


The mechanism how ajoene acts as natural antibiotics is its ability to inhibit genes expression controlled by quorum sensing.  Quorum sensing is a communication system used by pathogenic bacteria like Pseudomonas aeruginosa to synchronize the expression of specific genes involved in pathogenicity.

Cancer therapeutics:

In cancer therapeutics too, ajoene has been found to exhibit anti-leukemia properties against acute myeloid leukemia and it was found to decrease basal-cell carcinoma tumor size by inducing apoptosis (induced cell suicide)

This was shown that ajoene was able to effectively inhibit tumor cell growth by targeting the microtubule cytoskeleton of cancer cells and through other phyto-pharmaco dynamics.
Like its action against pathogenic microorganisms, in cancer management where gene expression, epigenetic, and nutri-genetic are of paramount importance to our understanding on the biology of malignant growth and their spread, garlic and other natural medicines are of current interest to  scientists in their search for cancer treatment.

Garlic Pills vs. Raw Garlic:

Unfortunately this extremely useful cancer fighting and cardio-protective sulphur-containing ajoene in garlic was found to be absent in all 20 brands of garlic pills manufactured by 20 different countries

This strongly suggests to us that when foods are processed by extraction, heating, cooking or by other means, a lot of valuable nutrients and medicinal properties are lost.

Hence, as a general rule, wherever, and whenever possible, bearing in mind hygiene, digestibility, toxicity and other factors when some foods are consumed raw, plant-based foods generally are best consumed raw or lightly cooked such as in blanching of vegetables where most of the nutritive, medicinal and health-protective properties are retained

By lim ju boo

Tuesday, May 15, 2018

Speed of black ants

Just fancy this:

This morning I was eating breakfast in my kitchen, and for a long time as usual, noticed red or black ants crawling over certain areas in the kitchen especially along the white-tiled wall that was just right in front where I was sitting

I then wondered as I always do about tiny creatures, how fast black ants “crawl” since I often notice they actually move quite fast for their small size.

I then decided to conduct a very small and very informal post-breakfast study on their speed similar to a research paper.  But here I make it very simple, very informal and friendly to read for non-scientists, and non-researchers

Materials and method:

I marked out exactly 2 meters on the white wall along the path of the black ants, and made 12 measurements on their velocity across these two points.

The ants were then killed by a sweep of  the flame from a  blow torch lasting less than one second on each point along the line of sweep to minimize contraction of the ants’ size due to crinkling of the ant’s protein molecules when subjected to heat.

The ants’ sizes were then measured under a low power (50 X) microscope fitted with a measuring scale on the eye piece and their natural sizes corrected for magnifications

Here are the results:

Measured Data:

Size of kitchen black ants (cm): 3.6, 3.5, 3.0, 3.2, 3.4, 3.6,
3.2, 3.7, 3.1, 3.3, 3.2, 3.4, 3.3, 3.3, 3.5, 3.4

Sampling Technique: Randomized:

1.       Sampling size (n): 16
2.       Mean size:  3.375 mm (3.375 x 10-3 meter)
3.       Sample Standard Deviation: +/- 0.195
4.       Time taken to “crawl” 2.0 meters was 10.2 seconds (mean of 12 measurements)
5.       Velocity of crawl in a straight line: 19.6 cm per second = 0.7058 km per hour

Results and Discussion:

Olympic 100 Meters Sprint Record:

The current Olympic men’s world record for a 100 meter sprint is 9.58 seconds. This was set by Jamaica's Usain Bolt in 2009. This translates to 37.57 km per hour over a short distance.  He was 1.95 m tall compared to the ants which were just 3.375 mm in size.

He was thus 577.77 times larger than the size of the ants

Had the black ants in my kitchen reached the size of Usain Bolt, my ants would have run 407.79 times faster than Usain Bolt. This truly would be far outside this world’s record.  

Now let us compare with a latest version of the AirBus jet plane. One of the latest models made by AirBus is the A350-1000. It is 73.88 meters long, or 21,890 times longer than the black ants.

Its new wing design allows it a cruising speed of Mach 0.89 or 1,098.97 kph

If those ants crawling along my kitchen wall were to reach the size of A350-1000, their velocity would be 15,450 kilometers per hour. This is more than 14 times faster than the latest model of this commercial jet plane.

Mr. Atom Ant:

The Earth radius is 6378.1 kilometers. This translates to 40,075 km in circumference (calculated or measured). The velocity of Space Shuttle is 27,870 km/h orbiting the Earth at a minimum height of 304 kilometers above sea level or 6,682 from the center of the Earth. This means its minimum circuit is 41,984 km round above the Earth.

This also means the Space Shuttle will go round the Earth once every 90.38 minutes.

Should my kitchen black ants be now be bloated up to also the same size as an A350-1000 AirBus jet, and then decide to go up into space to the same height as the Space Shuttle, it would be able yo circle the Earth once every 2.717 hours or 163 minutes, making the Space Shuttle 1.8 times faster. Still, that is  an awesome speed for Mr. Black Ant 

Of course we are fully aware that ants cannot fly like a plane, nor can they hurtle into space and circle the Earth like a space craft. Furthermore, we are only assuming that when the ants were bloated up to the size of a man or to a  plane its speed will be magnified proportionally. That may not be true. In all probability their speed may slow down tremendously instead because of an increased mass, let alone we need to consider the aerodynamic shape of the ants as their speed increases, causing a drag, loss of energy and slowing down a body considerably

Of course we are just discussing this under a hypothetical scenario just for academic interest far from being practical. I understand that very well.

Yet we always describe ants as “crawling” on the wall and floor. This very simple and informal study shows they “fly” far faster than a jet plane,  not ”crawl”

Do we make sense when describing small creatures?  Think this over.

Thank you for reading

-          Lim jb

Tuesday, April 17, 2018

The Physiological Role of Lutein in Vision and Disease

BSc Post Grad Dip Nutr MSc MD PhD FRSPH

Royal Society of Medicine

Chemistry of Vision:

Rhodopsin or visual purple is a sensory protein-containing pigment found in the rod cells of the retina requiring retinol or vitamin A for its synthesis.

In the event of vitamin A or carotene  deficiency (carotene is a precursor of retinol or vitamin A), the synthesis of rhodopsin is compromised, resulting in night blindness, and in severe cases lead on to xeropthalmia and keratomalacia and total blindness.

Hence the importance of an adequate intake of vitamin A or fruits and vegetables containing carotene which can be converted into retinol (vitamin A) by the body

However, retinol is not the only nutrient that ensures good vision in the dark in particular.

Lutein and Carotenoids:

There are other carotenoids that are also involved in good vision in both in the day and at night , one of which is lutein, the other zeaxanthin.

Lutein is a one of the carotenoids that acts as an antioxidant responsible for protecting the eyes. This phytochemical is found abundantly in most brightly colored fruits and leafy vegetables and in plant-based foods that have deep orange or yellow colours.

Many colorful fruits and vegetables such as kale, spinach, broccoli, water cress, kangkong, sayur manis, including mangoes, water melons, citrus fruits, in fact in most tropical fruits, and even egg yolk are rich not just in carotenes, the precursor of retinol, but are also abundant  in lutein and zeaxanthin.

Green tea too contains lutein and zeaxanthin in good amounts besides the catechins, a subgroup of the flavonoids, as well as  vitamins C and E,

So does a Chinese herb called Gou Qi Zi (Wolfberries) which has very high levels of zeaxanthin, lutein, polysaccharides and polyphenols, all of them  have been shown to improve eyesight, prevent macular degeneration and diabetic retinopathy.

Their rich presence in most colorful fruits, vegetables, teas, berries and herbs protects the eyes from oxidative stress and vision loss.

Like retinol, lutein and zeaxanthin cannot be synthesized by the human body and hence they must be obtained by the consumption of plant-based foods rich in these sources. However, lutein may also be  giving by lutein supplements.

Although it is best to source lutein naturally through foods rich in them,  other antioxidants supplements or fortified foods may also be used to help increase levels of lutein, zeaxanthin and carotene levels in order to confer the full potential of lutein in terms of disease prevention, bioavailability, metabolism and dose-response relationships

When foods rich in lutein or lutein supplement is consumed, scientists and nutritionists believe this is easily transported throughout the body, especially to the parts of the eyes called the macula and the lens where it is wanted most. Nutritional and food scientists know that there are more than 600 different types of carotenoids found in nature, but only less than two dozen find their way into the eyes.

Of these, approximately 20, lutein and zeaxanthin are the only two left that are deposited in high quantities into the macular portion of the eyes.  The macula is the central area of the retina which is the light sensitive, and it is in this area that lines the inner portion  of the eye that  gives us the ability to see an optimal “20/20”vision  and visualize the full range of colours.

Oxidative Radical Damage:

Furthermore, the antioxidant properties of lutein to block off free radical damage caused by blue light from smart phones or from other sources have been reported in the journal Nature.

A diet lacking lutein and other carotenoids may increase the risk of developing age-related vision loss or disorders related to macular degeneration and cataracts formation

Nutritionists and medical researchers are aware that lutein protects healthy cells like rods and cones in the eyes and skin cells, and its ability to arrest the growth of malignant cells.

One of the most important parts of the eye is the lens. The function of the lens is to collect and focus light onto the retina. This is exactly why the lens has to remain clear and transparent for light to enter. It has to be free from the cloudiness which is indicative of the formation of cataracts.

Energy of Light:

The main reason why the lens becomes cloudy is due to oxidation of the lipids in the lens by ultraviolet light and blue light which are shortwave ends of the light in the electromagnetic spectrum.

The shorter the wave length or the higher the frequency, the greater the penetrating and destructive powers of the electromagnetic spectrum including light as given in the Max Planck equation:

E = hv

where,  E = energy delivered, h = Max Planck constant, and v = the frequency

Thus blue light and ultra violet of the Sun can energize molecules in the eyes, the skin  and other tissues liberating highly destructive free radicals to the cells, especially the DNA, initiation molecular lesions on the sites where the light or radiation is turned on.

However the presence of antioxidants like lutein and zeaxanthin is able to block off these highly distractive free radicals that may ultimately lead to vision impairment, both to the lens and to the retina.

Even for those who may, or may not have existing eye and vision problem other than short or long sightedness, including plenty of lutein in their diet or in supplements can prevent  vision impairmemt Thus it is important to ensure we have adequate lutein intake.

Preventative measures are the best ways to ensure that our vision and eyes remain  intact and healthy even till old age. It is thus strongly advised that both the young and the old should ensure adequate consumption of foods rich in lutein, or the use of supplements so as to minimize the risk of oxidative damage to the eyes.

Cancers and Heart Disease:

Even though lutein, zexanthin and other carotenoids are extremely crucial for vision and the eyes, their benefits is also extended to other areas of the body.

For instance, lutein is also used in the prevention of skin disorders, several types of cancer including colon or breast cancer, type 2 diabetes as well as minimizing risk factors associated with coronary heart disease.

Macular Degeneration:

Lutein may be considered a natural treatment for macular degeneration (AMD), which is probably the most common cause of blindness among older adults in countries where vitamin A intake is adequate but where lutein is deficient.  

Estimates show that more than 25 million people worldwide are affected by age-related macular degeneration or cataracts, especially people aged 55 and older living in areas where exposures to ultra violet rays of the sun is highest such as in snow covered mountains of Tibet or in the tropical sun like in Malaysia.

For instance, the incidence of AMD in the United States is predicted to triple by 2025 according to the American Optometric Association

Mechanism of Action:

Lutein protects the eyes by blocking off a portion of the short-wavelength UV light or blue light that have the most damaging effects on the most delicate parts of the eyes such as the retina and the macula.

Researchers at Harvard University have found that supplementing with 6 milligrams daily of lutein can lower the risk for macular degeneration by an average of 43 percent.

Cataract & other Studies:

Similarly, other studies have demonstrated that a higher dietary intake of lutein and zeaxanthin along with vitamin E is associated with a significantly decreased risk of cataract formation. While the research is still in its early stages, it is suggested that taking lutein three times weekly for up to two years may confer an improvement in vision in older people who already have cataracts or at risk.

Other benefits of lutein intake or its supplements include a reduction in  eye fatigue, glare and light sensitivity especially those who plays with their smart phones constantly especially in the dark. It assists the lens and retina to remain intact while strengthening the eye tissues.

Individual Variations:

However, the requirements of lutein like for all other nutrients differ from individual to individual.  No one person is biologically the same. It’s likely that even for those with a relatively high intake of antioxidant-rich foods, their blood levels might be correspondingly high in the various nutrients, and yet their levels in the tissues within their eyes and at retinal levels may still be too low.

Scientists have now devised ways of measuring macular pigment levels of lutein in the eyes to determine the risk for retinal disease. By determining the macular pigment optical density test (MPOD), nutritionists and specialist doctors can now formulate more precise dietary recommendations for lutein and other protective nutrient requirements based on individual responses, genetic predisposition and lifestyle requirements

Skin Cancers:

It was shown that carotenoids including lutein and zeaxanthin are not just present in the eyes, but also in the skin. It is postulated that lutein may be able to filter out high-energy wavelengths of visible light such as blue light and ultraviolet radiation by slowing down the rate of free radical damage and oxidative stress. A few animal studies have shown that lutein provide significant protection against light-induced skin damage, such as signs of aging, the loss of skin elasticity, and potentially skin cancer.

Lowers risk of diabetes:

It was also demonstrated in some animal studies that high levels of lutein and other carotenoids within the blood are associated with a better control of blood sugar. This may be translated to a lower risk of diabetes and its complications.

For instance, a 2000 study conducted on diabetic rats found that oral supplementation with lutein and omega-3 fatty acid or DHA was able to normalize all diabetes-induced biochemical lesions in the experimental group.

Compared to the control of rats not given lutein and DHA, diabetic rats taking the supplements showed   lower oxidative stress rates and less damage to the retina of the eyes, even though they were under hyperglycemic conditions.

Lowers Risk of Cancer:

There was some evidence that people who obtain more lutein in their diet have lower rates of breast, colon, cervical and lung cancers. However, we do not know exactly how lutein and cancer formation is linked currently, even though correlational studies have shown that adults with higher levels of lutein in the blood experience a reduction of developing several forms of common cancers.

Thus it may be possible lutein could offer as a part of a natural cancer treatment because of the fact that foods rich in lutein such as broccoli,  kale, spinach,  leafy green vegetables and all highly colored fruits  with high antioxidants scores  can  lower inflammatory diseases due to oxidative stress.

But more research is still needed to help us fully understand the role lutein and other carotenoids have on cancer, immune response, hormonal and cardiovascular functions, independent of other nutrients and phytochemicals that are found in fruits and vegetables.

One possibility is their epigenetic influence on how genes express themselves in the presence of lutein and carotenoid-rich foods.

Cardiovascular Protection:

A few  observational studies have demonstrated  that xanthophyll carotenoids including lutein can reduce the risk of cardiovascular events and  coronary heart disease and stroke However as in previous studies that show potential cancer-protective effects of lutein, we are not quite  sure as yet at this moment in time how lutein could be cardiovascular protective?  

One such possibility is lutein anti-inflammatory and antioxidant properties may inhibit inflammatory response which currently scientists and cardiologists believe is the primary cause of heart and vascular diseases.  This hypothesis is currently replacing the out-of-fashion high cholesterol theory.

Studies conducted at the University of Southern California suggest that low levels of lutein within the blood might contribute to the thickening of artery walls. This elevates the risk for arteriosclerosis development and clogging of the carotid arteries that can result in cerebrovascular accident or stroke.

The USC’s observational studies show that populations with the highest levels of lutein in the blood experience less plaque formation in their arteries, as opposed to the other group with lower levels of blood lutein.   It was shown that the lesser lutein-rich plant foods they consumed, the more clogged their arteries. Perhaps more studies are needed to confirm this observation.

Another interesting observation is that after the researchers tested effects of lutein on human arteries that were surgically removed, there were fewer white cells present within the arteries after lutein supplementation was added compared to the controls. We know that the presence of white cells is suggestive of   an inflammatory response, and a subsequent blockage of the arteries which has no link to high or low blood cholesterol levels.

This may suggest the actions of free radical damage prior to atherosclerotic plaques and lesions.