Blood group and personality type: myth busters

Profile on @Quora for Asher Nitin, Physician, artist, athlete, student of Christian theology.

When I looked at the answers to this question, I was surprised to find people writing about how blood groups determine a person’s personality. I now find myself forced to answer this question because whoever created this question tagged it under scientific research. So I’m going to answer this using scientific research.

The blood typing systems that pseudoscience proposes can be used to type people into various personalities are the ABO system and Rh system. These systems use markers on the surface of RBCs to determine blood type.

These is an RBC (red blood cell).

This is the surface of the red blood cell via an electron microscope.

Chemically, this is what the surface looks like.

It comes down to basically carbon, hydrogen, oxygen and nitrogen atoms.

Now, embedded within this surface are the protein markers that determine blood type. Proteins are basically folded chains of amino acids. Amino acids are mostly made of C, H, O, N and S. These protein markers determine how RBCs of one person’s blood will interact with the serum of another person’s blood.

Now, this is the human brain.

You see that thin clingy film around it? That’s part of three physical barriers that wrap around the brain. And there are chemical barriers too.

In fact, there are three organs here:
the blood,
the cerebrospinal fluid (CSF)
and the brain.

So this area has three chemical barriers:
a blood-brain barrier,
a blood-CSF barrier,
and a brain-CSF barrier.

One of the effects of this intricate multilayered physical and chemical barrier is this: red blood cells never touch the neurons in the brain! Never. So it is impossible for RBCs to physically influence neural traits.

What about genetics then? What if the same genes that code for blood groups also code for personalities?

They don’t. We know the exact location of the genes that code for blood groups on the human genome. And we know the exact location of some of the genes that code for human personality. But more importantly, genes are not the only determinant of personality. They are not even the primary determinant of personality. They place a slightly bigger role in some rare conditions like psychosis or mania, but that’s it.

A person’s personality is affected by his IQ, EQ, dietary deficiencies, embryological development, early childhood experiences, cultural cues, religious beliefs, chemicals ingested (alcohol, caffeine, ecstasy, PCP), physical contact, atmospheric oxygen content, traumatic brain injury and more.

We take all these into account in neurology and psychiatry. Believe me, if blood groups were relevant, we would use this information. We don’t.

A person’s blood group has close to zero relevance to his personality and mindset. Most of this superstition arose the same way astrology arises: confirmation bias, self-fulfillment and lack of statistical analysis.

The proof lies in the links people will attach to prove the blood group personality theory. They will all be links to naturopathic or independent websites.

Just because a website says something doesn’t mean it’s true. On the other hand, if it was a link to a medical website (scientific medicine) citing a randomized double-blind study, then it might be real science.

But none of those links will ever direct you to anything with verifiable data. Just claims and talk of studies. And numbers that will look like data.

Additional point: as Raghuraj S. Hegde pointed out in the comments section below, RBCs undergo enucleation early in their life. That is to say, they discard their nucleus. The nucleus holds all the genetic material that is transmitted. So it is simply impossible for them to carry are the similarities of people having the same blood group? 

~by Asher Nitin


What to prioritize:food habit or exercise

Well the answer is a bit difficult as food habits and exercise both go hand in hand in controlling the BMI and all round growth- development of a child. Exact Healthy bmi is not achievable without proper food habit and outdoor activities.

Now let’s take a look that what exactly consists of a balanced diet specially of a growing child, as we all know nutritional requirements of a growing male and female child is widely different, not to mention the variety among pre pubescence and puberty age group.

with the advancement of our Modern era the habit of outdoor games has almost diminished, videogame, PC games, Android games, Internet surfing, playing in tablet has replaced the need to go out of the bedroom and play in the soil and dirt. No! it has not improved our quality of life rather it has decreased the much needed interaction of children with outside organisms required to build the very basis of immunity making them more vulnerable to certain pathogens.

Health consequence:-Thus now a days children are more and more susceptible to infectious diseases and also their sedentary Lifestyle, from the very beginning of their life, causing them to be prone to non infectious diseases too. If we look at a chart of how the number of young population affected by diabetes , CAD , hypertension has increased exponentially it will made us think that what exactly is the cause of such misery!

the answer is known, it is basically a result of increased lifestyle stress!coronary artery diseases, heart diseases, diabetes, diseases related to lipids metabolism ,infertility,hypertension.Interestingly, most of the causes are rooted in the childhood itself . It is a lack of parental guidance on what food to eat and not what is easily available or to let the children go out and play under the sun rather than just sit at home and play in the damn phone . It is also worth mentioning that this increased body fat causes a variety of endocrinological problem and exposes a child to various disease process.apart from the consequences we already discussed females face an array of gender specific disorders, for example~metromenorrhagia, anovulation, metabolic syndrome, PCOD and not to mention infertility

psychological consequences:- children unwittingly become victim of bulimia ,anorexia nervosa,some develop bipolar disorder, generalized anxiety disorder, borderline personality disorder, suicidal tendencies.


Not just diet or exercise alone, rather a healthy and improved approach towards food and combined with properly guided exercise is the best measure to fight the dreaded consequences of childhood obesity, which should be started early in the childhood.

School health programs are immensely important as a holistic approach through schools can actually give an all-round idea about students’ physical and psychological status as well as nutritional assessment and help us secure our citizens of tomorrow.

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How to crack a seat in medical ug entrance

Hard work

Smart study

Unsettling determination

Allow me to elaborate the second point, as I believe anyone appearing for NEET ,AIIMS and Other Entrancexams at Ug Level. Have idea about first and third point.

Smart study:- what is it?

As someone have already pointed out in the answer section selection in NEET PG is less than 1%! so it is very important to sort out in which subject you are strong and in which points you are weak and to focus on them separately so if you are having a study schedule of 12 hours solid everyday, at least 6 hours should be focused on your weak points, where your concepts are not strong! 2 hours for revision and the rest of the time to strengthen your strong subjects. Also along with it you need to check yourself frequently with the ever changing question patterns of neet; it will be very helpful if you enroll for a mock test or schedule a mock test on your own at home. It is not necessary to always join Kota or other coaching institutes but it is obviously necessary to reach out your weak points and to provide your hard work where it is needed most, that is to strengthen your weak areas, where you make repetitive mistakes, when you first appear for mock test your scores maybe as low as 20% or lower, but it is up to you how you are going to use one full Year’s preparation to make that 20% into more than 98% score ! Only then if your dreams keep you awake only then you will achieve what you deserve!

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Why you feel sleepy after a sufficient 6-7 hrs ) good night sleep!

It’s not always how long you sleep, sometimes it’s about the quality of sleep and when exactly you wake up, Or to be more specific in which sleep phase!

Sleep in medical science is broadly divided into two phases

  1. NREM(non rapid eye movement)
  2. REM (rapid eye movement)

Now NREM is further divided into N1,N2,N3. Together NREM+REM takes approximately 90minutes in adults though varies in different age groups.

During the total sleep awake cycle (Circadian Rhythms ) there are four kind of Electroencephalography waves generated in our brain

  • Alpha wave
  • Beta wave
  • Delta wave
  • Theta wave
  1. Beta is seen when we are awake and again at REM. It’s fascinating how our brain is so active during REM , arguably the deep sleep phase, also dreams and nightmares are mostly seen in this phase.
  2. Alpha, at the beginning of sleep, when we are lying awake eyes closed, also in N1.
  3. Theta, usually seen in N2 as we progress to more deep in sleep
  4. Delta, in N3

There are not lined demarcation and waves as well as sleep phases and they do overlap. For the best quality of sleep or should I say to wake up refresh a person usually needs N1,N2,N3,REM in exact sequential order .also four to six of such cycle is needed in daily basis preferably at one go.

Now here is the tricky part, considering you are sleeping 6hours straight without any waking up , the duration of REM will increase in every 90minute cycle, and the best time to wake up is during the transition phase from REM to N1. Waking up at any other sleep phase will leave you feeling tired and sloppy to some extent, mostly if it’s during REM phase itself!

So, I’ll suggest wake up in accordance with REM cycle, there are multiple online calculators available for that, also no tea/coffee before bedtime, limit intake of any caffeinated product or nicotins or any addictive substance atleast 3_4 hours before going to sleep. Have a light dinner , relax yourself as much as possible , and hola! You just earned yourself a goodnight sleep.

All the best.


  1. Sleep – Types and Stages of Sleep – Non-REM (NREM) Sleep
  2. Basics on Sleep
  3. Sleep
  4. The 4 different stages of sleep (NREM Stages 1-2-3, REM Sleep)

Image credit – all images downloaded from imagesearch app. No copyright infringement intended. All materials belong to developers and respective site owners. Used here for educational purposes only.

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