I received this information from Ms
Violet Ho, an old schoolmate of mine. I quote what she sent to me in a WhatsApp
chat group:
“How does the A1C test measure your
blood glucose levels over the last 3 months instead of what it was at the time
blood was drawn?
A1C”, also often called “HbA1c”, is short for “glycated haemoglobin”, a
haemoglobin (Hb) protein with a glucose molecule permanently stuck to it.
Glucose is a valuable source of energy in the body because its molecular
structure holds lots of energy within it that can be used by our cellular
energy-management machinery. It is also a risky molecule to have around,
because it is reactive and can easily use its energy to attach itself to
unintended structures like haemoglobin proteins.
Glucose and haemoglobin are both present in the bloodstream, and some amount of
glucose will always attach to haemoglobin forming HbA1c. The amount of glucose
that attaches to haemoglobin is dependent on the blood glucose level; the
higher the glucose level, the more HbA1c that will form. And once the HbA1c
forms, it does not separate. The glucose-haemoglobin attachment is permanent
for the lifespan of the haemoglobin (now HbA1c) protein.
Haemoglobin is the protein that makes up about one-third of the volume of red
blood cells. (It is the protein that picks up oxygen (O2) in the lungs and
carries it to all the tissues of our muscles, brain, and other organs and
structures where it releases the O2 and carries the metabolic waste product
carbon dioxide (CO2) back out to the lungs for release.) Red blood cells are
constantly being produced in the body to replace worn-out old ones; they have
an average lifespan of about four months. Some wear out faster than that, some
last a few weeks longer, but the average is four months.
Since haemoglobin only lasts as long as the red blood cells that carry it and
since once a haemoglobin protein is glycated to HbA1c it never loses the
stuck-on glucose molecule, the percentage of haemoglobin that is glycated to
HbA1c is an indicator of the average blood glucose level over almost the entire
lifespan of a red blood cell: three months”.
We have been using glycated
haemoglobin (HbA1c) to diagnose diabetes for a very long time already instead
of merely looking at blood sugar levels alone as this fluctuates hour to hour,
day to day, hence looking at blood sugar level even randomly may not be
reliable. So, we use HbA1c which is more stable for at least 3 months to diagnose
diabetes. Normal human red blood cells have an average life span of about 90 -
120 days. I knew about this “new” diagnostic test for diabetes in the
early 1970’s when I started my professional career as a Senior Medical Research
Officer at the Institute for Medical Research in Malaysia in 1968. So, this
HbA1c as part of our haematological profiling in a patient is not really new to
us.
Glycated haemoglobin (HbA1c)
is a useful backdated marker for blood glucose control over the previous 3
months. The HbA1c value is determined by at least a 3-month lifespan of a red
blood cell, hence we can trace back what the sugar level was in the past 3
months. Although the recommended HbA1c target for most people with diabetes is
≤7.0%, this target can be individualized.
Prior to this test, clinicians use
another method at looking for diabetes mellitus. It is valid at that point in
time when the test was carried out. We call it the "glucose tolerance
test" (GTT) where fasting blood sugar levels are taken initially. Then we
give 50 to 75 gm of glucose dissolved in 250 water to the patient to drink
before blood for sugar level is taken again at one-hour intervals till 2.5
hours, preferably longer till it returns to baseline sugar levels. The
glucose tolerance test is given to determine the rate glucose is cleared
from the blood. It also gives us not just the diagnostic test for diabetes, but
also insulin resistance, impaired beta-cell function, reactive hypoglycaemia,
acromegaly, and other disorders of carbohydrate metabolism.
GTT though a better assessment of
diabetic status at the point in time of the day the test was carried out, it is
a little longer as the patient needs to remain in the lab for at least 3 hours
for blood to be drawn and tested, whereas for the A1C we need take the
blood from the vein only once to look indirectly at what the blood sugar was in
the last 3 months.
I would personally suggest another
alternative to look at blood sugar status that is even better in real life
situations over the entire day without even needing to go to see a doctor or go
to a pathological lab to waste time and money there for HbA1c or GTT. This we
can do in the comfort of our home, and we can monitor our blood sugar levels
ourselves if we have a home glucometer. This is how it is done, my suggestion.
First, fast overnight. First thing
on waking up is to test the blood sugar level. It requires only one drop of
blood on the finger prick.
Then take a usual normal breakfast.
An hour later, take the blood sugar level again. Repeat every hour throughout
the day, before and after every meal till the last meal for the night.
You may repeat this every 2 -3 days
over the next one week. Collect all your data, and if you are familiar with
statistical analysis, a mathematical treatment of data we use extensively in
medical research, calculate out the mean or the average reading and determine
the standard deviation (SD). A
high standard deviation means that the values (sugar levels) are generally far
from the mean, while a low standard deviation indicates that values are
clustered close to the mean. Generally, it is better to have all your reading
within normal range with a low SD. If you are not trained or familiar with
biomedical statistics, never mind, just look at all your readings and the
average reading will do. We cannot process the data more than taking the
average readings and the SD, because we have no other groups to compare such as
in RCT (randomized clinical trials) where we can analyze and compare data from
various groups to determine if there was a ‘statistical significance’ among
various groups. Here we are only studying ourselves for diabetes.
My personal recommendation here is
not only cheap, reliable but even more real and reliable as it is real life
situations catering every moment of our day-to-day living at home or in our
workplace as we live, than all those glucose tolerance test, HbA1c where we
need to go to a doctor’s office only once or twice. This gives us a false sense
of our actual glucose status spread over 24 hours for several days into weeks.
Diabetes is a lifestyle disease as
with cardiovascular diseases like stroke, obesity, metabolic syndrome, chronic
obstructive pulmonary, most of them caused by overeating and sedentary
lifestyle. Try to minimize eating. I personally eat only once, maximum twice a
day.
My advice to everyone who likes to
eat excessively all day long, is to eat as little as possible to allow bowel,
metabolic, liver and kidney physiological and biochemical rest, and also to
prevent cellular, tissues, organ and all systems damage from free radicals
generated through the stress of overeating, free radicals generated during the
metabolism of food.
However, ensure we drink at least
1.5 litres of water a day to prevent dehydration, and to ensure healthy renal
functions. We can go on an intermittent physiological fast on unsweetened fruit
or vegetable juice.
As far back as in 1930 Clive McCay at Cornell University has shown that caloric
restrictions result in longevity. Subsequently, over the years till the
present, more than 100 studies conducted in animals as well as in limited human
studies have consistently shown exactly the same results that food and caloric
restrictions prolongs life, not just longevity, but disease-free long life.
Of course that does not mean we
should not nourish ourselves with a balance diet rich in proteins, vitamins and
minerals else we may land up with nutritional deficiency diseases like
marasmus, kwashiorkor, from energy and protein deficiency, night blindness,
Bitot spots to the potentially blinding stages of corneal xerosis,
ulceration and necrosis (keratomalacia) from retinol (vitamin A) deficiency,
beriberi from thiamine (vitamin B1) deficiency, ariboflavinosis (riboflavin or
vitamin B2 deficiency) resulting in skin disorders, hyperaemia and oedema
of the mouth and throat, angular stomatitis (lesions at the corners of the
mouth), cheilosis (swollen, cracked lips), photophobia, oculo-orogenital syndrome in deficiency of vitamins B2 and
B6, hair loss, reproductive problems, itchy and red throat, niacin
(vitamin B3) deficiency causing pellagra presented as the 4 Ds - dermatitis,
dementia, diarrhoea, and death, Casal collar, and butterfly lesion, and in vitamin B6 deficiency associated with
microcytic anaemia, electroencephalographic abnormalities, dermatitis with
cheilosis (scaling on the lips and cracks at the corners of the mouth) and
glossitis (swollen tongue), depression and confusion, and weakened immune
function, etc, etc, vitamin 12 deficiency and folate deficiency resulting
in Addisonian and pernicious anaemia, neurological disorders, rapid
breathing or shortness of breath, palpitation, loss of appetite, diarrhoea, photophobia,
vision loss, numbness, muscular weakness, psychological disorders from mild
depression or anxiety, to confusion and dementia or problems with balance and
coordination, pins and needles and incontinence, etc, etc, or from vitamin C
deficiency as in scurvy, presented as irritability and anorexia,
dermatological problems such as poor wound healing, gingival swelling and
bleeding with loss of teeth, purpura and mucocutaneous petechiae,
ecchymosis, and hyperkeratosis, not to mention simple iron deficiency anaemia,
etc, etc, etc…on and on.
We can go on, and on writing,
running into chapters on nutritional diseases, onwards into other fields and
aspects on nutrition that would occur in several dozens of thick volumes of
books with tens of hundreds of thousands of research papers and references. We
shall not go into them as it would be completely outside the scope of this
short article on the diagnosis of diabetes mellitus.
What is important for all to be
aware of is, when all kinds of incurable diseases like diabetes, cardiovascular,
liver and kidney diseases begin to creep in due to harmful lifestyle, in
particular dietary and nutritional lifestyles, then we would start to go to a
doctor who would only be interested in prescribing all kinds of Big
Pharma chemical "medicines" to "cure" all these intractable
disorders until we begin to take medicines all day long as our daily food. My
very strong advice is to limit our daily food intake, but ensure it is a
balanced diet rich in fruits, vegetables, adequate proteins and vitamins of
various types inclusive of minerals and trace elements.
By the way, Hippocrates never said, 'let medicine be thy food' He only advised
proper food and nutrition as our medicine.
Think this over. I hope this short article serves its purpose not just for
longevity, but disease-free longevity.
Thank you for reading.
Lim ju boo
No comments:
Post a Comment