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Questions to rouse our Brain on Glucose

A birds' brain session one afternoon. 

This post is very much a set of questions for medical researchers (and those want to be).

**Do you know how the brain works?. 
We can find some interesting data like -- in humans, the brain accounts for about 2% of the body weight, but it consumes ~20% of glucose (this means the brain consumes vastly more energy than other organs) and, puzzlingly, it remains a fuel-guzzler even when its neurons are not firing. [https://scitechdaily.com/brain-drain-scientists-solve-puzzling-mystery-of-why-neurons-consume-so-much-energy-even-when-at-rest/] says -- synaptic vesicles - neurotransmitter molecules consumes chemical energy  inherently very leaky, about 50% when not active, there are about 100 Trillions of synaptic vesicles in the human brain (so the brain idles at high rev like racing cars ready to take off --the brain idles at high ready state so able to response/transmit quickly. This is probable because humans have evolved to depend on the brain. Readiness means faster responses/reactions to changes in situations -- for survival. ==Does this link 'meditation' as a way to reduce energy loss from 'useless' thinking?==)

**The energy needs of the brain
A normal weight adult requires 200 g of glucose per day, two-thirds of which (about 130 g) is specifically needed by the brain to cover its glucose needs. The brain competes with the rest of the body for glucose when levels dip very low — such as during starvation. [Glucose and The Brain: Improving Mental Performance https://www.eufic.org › whats-in-food › article › glucose...]. If this information can be doubly checked and confirmed, we can see that we need a lot of fuel (food) to keep up with the running of the brain -- 130g of ==glucose== per day. [## Sugar is not all 'glucose'. Fructose (fruit sugar), lactose (milk sugar) and Sucrose (cane sugar, น้ำตาลอ้อย) are usually lumped together under 'sugar'. But our body differentiates 'glucose' from other sugars and processes 'glucose' differently.##]. Many studies say that though brains need glucose, too much of glucose can be bad. This is an issue of regulating blood sugar level (ie. diabetic issues)]. ==Most foods (meats, fruits, vegetables, beans and nuts, ...) contain some glucose. Honey has some 35% glucose; dried fruits some 30%; sugary soft drinks 7%; most fruits and vegetables around 5%.== [Refined] Sugar that we buy from a shop contains 50% glucose and 50%  sucrose. --carbohydrates, like bread, potatoes, and fruit. As you eat, food travels down your esophagus to your stomach. There, acids and enzymes break it down into tiny pieces. During that process, glucose is released.

Glucose in our body comes from from diet/food, and from stored glycogen -- proteins and fats in our own body in a tightly regulated system of 2 processes 'gluconeogenesis' (breaking down fats, proteins or non-carbohydrates into ketones then to produce glucose - not using insulin) and  'glucogenolysis' (using insulin to change glucose into glucogen then to store in liver and muscle cells). [Normally, approximately 50% of the glucose released into the circulation is the result of hepatic glycogenolysis; the remaining 50% is due to gluconeogenesis (30% liver; 20% kidney)]. In adult humans, there are about 18 g of glucose, of which about 4 g are present in the blood. Approximately 180-220 g of glucose are produced in the liver of an adult in 24 hours. ==1 g of glucose raises blood sugar level by 4 mg/dl (or 0.28 mmol/l) -- varying with body size.== (A warning: สมาคมโรคไตเผยอาหารกึ่งสำเร็จรูป ‘โซเดียมสูงปรี๊ด’ กินมากเสี่ยงเกิดโรค NCDs. --so, some foods ain't food!)

**The brain also needs 'oxygen'
The brain's oxygen demands are enormous; despite comprising only 2 percent of the body, our brains consume 20 percent of the body's oxygen supply. (Lack of oxygen in the brain is called  'Brain Hypoxia' affects balance, memory, speech, dizziness, possible links to Parkinson's disease, Alzheimers disease, Dementia, ...).

Our Liver also takes 20% of Body Oxygen (at rest) with the flow rate between 1L/m - 2L/m. Our liver is a 'control filter' removing toxins, breaking down and balancing nutrients in blood into non-toxic readily usable forms. (Our kidneys are also filters for other fluids in our body.)

Both glucose and oxygen are delivered to the brain in 'blood streams'. (the brain is served by 3 major arteries (vertebral and carotid which divide into anterior and middle cerebral arteries). Here we have issues of 'blood pressure', cholesterol, and diabetes and external environment (air pollution, temperature, threats, and other stimulants -- drugs, alcohol, smoking,...). Suffice to say that keeping our brain healthy needs to have many factors (foods, environment and mental conditions) 'right'.

The normal average cerebral blood flow (CBF) in adult humans is about 50 ml/(100 g min), with lower values in the white matter about 20 ml/(100 g min) and greater values in the gray matter about 80 ml/(100 g min). (The 'gray matter' is again taking more than proportional share or resources. There tests like Trans-cranial Doppler (TCD) ultrasound test, and Computed tomography (CT) perfusion imaging for blood flow to brain.)

**There is a lot of data on our brain and body. We can spend many nights digesting the data. Please do so for your own learning and I do encourage sharing the data and your own understanding of the data.**

**The questions
We know that World Health Organization (WHO) and many other authoritative recommend:
"an added-sugar limit of no more than 100 calories per day (about 6 teaspoons or 24 grams of sugar) for most women and no more than 150 calories per day (about 9 teaspoons or 36 grams of sugar) for most men." -- in plain languages, we say less than
7 sugar cubes or teaspoons per day.

How do these recommendations compare to the brain needs (130 g per day) for glucose?
Remember 100 g of sugar only contains 50 g of glucose and other sugars are handled differently in our body (as we noted earlier). So our brain must get glucose from elsewhere other than our diet/food. That is from our stored fats and proteins (muscles?)

On one hand we would ask if WHO (et al) want us to be lean or 'stupid' or unhealthy (not able to use our brain)? 
On another hand, we ask if we can reduce our body fats by thinking a lot or using only our brain (no physical exercises)?  [Edited 2 Mar 2565BE: https://www.science.org/content/article/scientist-busts-myths-about-how-humans-burn-calories-and-why  says we can by using Math problems to create (mental) stress. ]
On the side, we can ask if reducing our brain activities by 'meditation' would reduce the need for glucose by the brain?
Can we improve our brain functions/abilities (or reduce mental disability) by increasing glucose supply to the brains?
What can do about this 'conflict' of brain and diabetic health? ==Note that our liver can produce about 200g/day of glucose==, presumably with our normal liver functioning and daily diet. And the brain only needs 130g a day==.
 
Your turn to ask questions. Your questions may solve some of the present days problems (obessity, diabetes, memory loss, ...)

;-)