Friday, March 3, 2017

Water physiology


Water physiology
Drinking water (without some electrolytes and glucose-not simple sugars) alone for me is un-physiological.
This was the basis of formulation of rehydration fluid by our (National Formulary-Headed by Professor Senaka Bible) yesteryear physicians.
I may be wrong but Pediatrician Prof. Sanath Lamabadusuriya PhD thesis in London was (somewhat) related to Rehydration Fluid.
This formula has saved millions of sick people including children.
This is not an attempt to revisit that history but to pen down water metabolism (physiology) in a few lines.
I looked at all my physiology and medical books (huge volumes) and I could not find a succinct account on water metabolism.
As a last resort I browsed the web (content reproduced below) and it was no better except the lively web discussion.
No human can (rats in the desert can live longer) survive threee days without water.
There are centers in the brain that drive thirst and make somebody to crave for water if deprived of water completely.
That is also not my point of view here.
All these people who for political stunts (reasons) fast are scoundrels who cheat gullible masses and drink lot of sugary drinks and man can go on for three months of (absolute) starvation of solid food.
Let me come to the statement that drinking water alone is unphysiological.
There is only one place in the gastrointestinal tract that can absorb pure water (without electrolytes).
That is anatomically situated, not in the top end but in the bottom end.
It is the large intestine and rectum.
That is why rectal enema is saline based and never water.
In an old sick patient water enema can kill and cause water intoxication.

Water intoxication
Water intoxication can occur in a variety of different clinical settings but is generally not well recognized in the medical literature. The condition may go unrecognized in the early stages when the patient may have symptoms of confusion, disorientation, nausea, and vomiting, but also changes in mental state and psychotic symptoms. Early detection is crucial to prevent severe hyponatraemia, which can lead to seizures, coma, and death.
However, it is almost impossible to become water intoxicated by drinking water unless one is psychotic.
Many moons ago when I was working abroad I had a similar case.
The first thing I do when working abroad is, to find a difficult case generally neglected by the majority (patient is expected to die) and solve it on my own accord.
In this case very old gentleman 80 plus and supposed to have pneumonia.
Treated adequately with antibiotics but almost unconscious.
Generally old people present with confusion (not unconscious) with ill defined infection but this case had been adequately treated.
I ordered a repeat X-ray and it was all clear.
Looked at the basic biochemistry to see water intoxication (with hyponatraemia) with a saline drip running.
I asked the relatives what I should do?
They wanted their grandpa home.
I said give me two weeks and asked the nurse to take the drip down and leave the cannula.
They were hesitant but I said you have to follow my instructions.
Asked them to repeat blood chemistry twice a day and nothing by drip or mouth for two days.
In two days he woke up from slumber but still dazed.
Biochemistry marginally improved but not isotonic.
I told the nurses, he will ask for something to drink tomorrow give him a strong cup of coffee or tea and call me if he vomits.
In five days he recovered but disorientated.
I got friendly with him and the entire family and he went home in six weeks.
On the Christmas day he was admitted with broken hip.
I immediately transferred him by plane to the regional center where he had the hip replacement.
Mind you he broke his other hip within three months.
This was the only case who had bilateral hip replacement in my tenure in there.
He was doing OK when I left but he could not remember me (the family was very close to me) very well with all these medical misadventures. 
Coming to my bone of contention back; 
If one drinks large amount of water without food (it does not matter drinking water before or after a meal) one has to spend extra energy to absorb it and excrete the excess by the kidneys.
That is my bone of contention.
However, it may lower the risk of stone formation in the kidney.
All these physiological processes (water conservation or water excretion) need potential energy and we call it homeostasis.
What I am trying to say is if one is not feeling thirsty, do not drink water as a drill but always associate drinking water with food that helps digestion in many ways. 
It does not matter one drinks water soon before or soon after a meal or with the meal.
What I am against is drinking water as a drill which stresses the intestinal physiology (needs potential energy to excrete the excess of water).
Of course, if the water is retained that means there is water deficit to begin with but we cannot do that mental arithmetic ourselves but the the brain (pituitary does it automatically for us) does it for us.

Both hunger and thirst are physiological reactions to body's deficit in sugar or water.
No volition is implied here.

Little Physiology and Anatomy

The top end, the oesophagus cannot absorb anything including water.
The stomach, is the reservoir of food until partial digestion is carried out and has to secrete large amount of digestive secretions.
Upper intestine (duodenum and jejunum) also secrete large amount of digestive enzymes.
Lower intestine (about 22 feet in length -I could remember without referring) does most of the absorption including water (80%) and the digested food.

The small intestine in adults is a long and narrow tube about 7 meters (23 feet) long. The large intestine is so called because it is wide in diameter. However, it is shorter than the small intestine — only about 1.5 meters (5 feet) long.
Large intestine absorb 400 ml of water (20%).

Below is an interesting web interaction reproduced.

Water absorption occurs primarily in the
A. duodenum.
B. jejunum.
C. stomach.
D. large intestine.
E. mouth.

I thought small intestine can absorb water but Kaplan says large intestine is the right answer.
Can someone check this for me?


Yup. the small intestine absorbs sugars fats and protein.

The large intestine does the water absorption and K+ ions and B16 it think. But here are some notes I threw together from EK.
Hope it Helps.

My human physiology power power slides say it can also absorb water XD.

I don't know which one to follow.

The Large intestines main function is water absorption and electrolyte absorption. Remember that in the small intestine primarily the in the duodenum ( I forgot how to spell it) the body will absorb amino acids and sugars through the enterocytes directly into the blood stream. While the fatty acids will get absorbed into the enterocytes and then will be modified in the smooth ER where they are incorporated into chylomicrons (water soluble globules).


There really isn’t much water absorption in small intestine ... it was a question on my bio final... so I'm assuming.


A.. yes large intestine's main role is water absorption but it's only absorbing what's left over from small intestine. My whole class argued over this one.. so I remember this very well.


I'm pretty sure its the large intestine. The main function of the large intestine is to absorb the water from the material that comes in from the small intestine and make solid waste (feces).


Vitamin K and Water are absorbed within the LARGE intestine! Small intestine is primarily involved in absorption of nutrients.


Site of compaction = large intestine, so I think it's large intestine. If the small intestine was the answer..way too easy I think. 
 
Small intestine (jejunum). We JUST had a quiz on this today and that's the right answer.

Large intestine is the first answer that comes to mind.

Although my Physiology power points tell me that the small intestine reabsorbs 8500ml of water compared to 400ml in the small intestine.

Yeah, small intestine.
Note the difference between the two choices:
While most water is absorbed in the small intestine, that's not its primary function. The large intestine's primary function is water absorption, but it doesn't do the majority of that during the digestive process.

Also, if you look at the diagram, it looks as if the part where 8500 ml is being reabsorbed, it looks like that would be the jejunum.


I'm almost 100% sure that the discussion could have ended with this post.
Main function of Colon is water reabsorption, but most of water reabsorption is done in the small intestine.
Therefore its a major fuction of the large intestine.

Water ingested              2000 ml per day
Saliva                           1500 ml per day
Gastric Juice                 2000 ml per day
Bile                              500 ml per day
Pancreatic Juice           1500 ml per day
Upper Intestinal sectretions 1500 ml per day

Lower intestinal absorption 8500 ml per day
Colonic absorption              400 ml per day
Feacal Excretion                 100 ml per day

Water Metabolism
Chemical reactions take place in cells. Collectively these reactions together are called metabolism, i.e. all the chemical and physical processes within a cell. The chemicals involved are called metabolites. Water is a metabolite in many reactions, either as a reactant or as a product of reaction. For example, it's involved in photosynthesis, digestion and aerobic respiration.
Metabolic water refers to water created inside a living organism through their metabolism, by oxidizing energy-containing substances in their food. Animal metabolism produces about 100 grams of water per 100 grams of fat 42 grams of water per 100 g of protein and 60 grams of water per 100 g of carbohydrate.
Some organisms, especially xerocoles, animals living in the desert, rely exclusively on metabolic water. Migratory birds must rely exclusively on metabolic water production while making non-stop flights. Humans, by contrast, obtain only about 8-10% of their water needs through metabolic water production.
In mammals, the water produced from metabolism of protein roughly equals the amount needed to excrete the urea which is a byproduct of the metabolism of protein. Birds, however, excrete uric acid and can have a net gain of water from the metabolism of protein.



Straight Back Response to American Dietary recommendations


Straight Back Response to American Dietary recommendations


Skip this part and read the conent below if YOU are not a vegetarian.
 

Straight Back Syndrome of Mine

This description has no relationship to the medical conditions stated below.

Fortunately my initial are also S.B. and I am known to be a genetically predisposed be having a straight back aggravated by my early childhood sports activities.
It started to dawn on me that, I have had several minor spinal stress fractures.
They started affecting me in my internship.
As a kid I could touch my toes with hands by bending (while keeping the back straight).
I have long legs particularly suitable for short distance running and jumping.
I noticed that I was losing this ability gradually while in the university.
I did lot of long jump and hop step and jump as part of my training ending with military drill around the university track daily.
I never practiced short distance running in the track.
I did that with my dog around the lake of Kandy.
My dog was my trainer.
I could never beat him and I had the leash to restrain him when I needed to catch my breath and rest.
On the days (over the weekend) I wasn't in the campus, I did my running with the dog. My dog was perfect companion and sporting match and wizard. Unfortunately, dog died tragically when I went away for my internship. I should have taken him with me.
I won't tell you the story, I was told about its death.
I still believe it was cooked up story to pacify my anger.
He died due to his separation from its dearly loved master companion.
There was nobody to take him round the lake.
I did not have a dog for nearly 25 years after this episode.
My campus dog (called the lone ranger) and roommate of course lasted the full life cycle since I handed over the dog to Nicholus Uncle who was our physiology technician.
He was there even when I returned from UK, in good condition.
My Straight Back Syndrome started affecting me in my internship with constant back pain. I did not give up sporting activity but continued on badminton and table tennis and never running and long jump.
Over time with heat treatment (we did not have warm hydrotherapy) and constant alert and avoidance of further damage, I was without pain in about four years.

But my back became straight and I cannot touch my toes as I used to do as a kid.

This gave me an added advantage and good stead. 

I never bend down even to a politician. 
Also I never go with bended knees like an average Sri-Lanka. 

When, I went abroad, it was very useful.

All Asians, who are vociferous in front of the local voters go bended back and knees when in Western countries. 
I always kept my back straight in front of white men well over 6 foot 6 inches and most of them thought, I was smart and I never told anybody, I had a stiff back probably due to spinal fractures or the straight back syndrome. 
 But I regularly went for hydrotherapy which was available free in hospitals, there. Now my back does not bend to even monks of BBS. leave alone, the politicians. Below are medical explanations.

Flat Back Syndrome

Spinal Curvatures
The human spine has natural curvatures.
When you look at a back from behind, the spine should be straight and centered over the pelvis. However, when you look at the spine from the side, the curves are designed to maintain balance as the spine is behind organs in the chest and abdomen.
The spine has two alternating curves to create an “S” like shape.
In the neck and low back there is normally an inward curvature or sway back known as lordosis.
In the thoracic spine and sacrum there is an outward curvature known has kyphosis or hunchback. These curves normally balance out each other so that when the patient stands they are well balanced with their head straight above their hips when viewed from the side.
Standing in this position minimizes the effect of gravity and allows the patient to stand with the best posture and use the least energy when moving or walking.
Flat back syndrome is an abnormal condition where the spine loses its natural low back curve to become flat. The spine becomes imbalanced and the patient leans forward. Patients with flat back syndrome typically notice troubles standing upright or have ongoing back or leg pain. Symptoms usually worsen as the day goes on and the patient feels they lean further and further forward the longer they try to stand upright. The severity of the symptoms usually depends on the amount of curvature present and difficulties with standing erect.
In patients with flat back syndrome, a loss of normal lumbar curvature causes an imbalance of the spine. The patient’s head begins to lean forward, away from the body and they may have trouble standing upright. This imbalance can cause muscle fatigue and pain.
Today, the term flat back syndrome has been broadened to include any patient with a decrease in lumbar lordosis causing symptoms.
As such, flat back syndrome can occur as a result of any condition that shortens the front portion of the spine, causing the patient to lean forward.
Flat back syndrome may develop as the result of the following causes:
Degenerative Disc Disease,
Lumbar Post Laminectomy Syndrome,
Compression Fractures,
Ankylosing Spondylolitis.

Degenerative Disc Disease:
For some patients, progressive degeneration of the intervertebral discs or the shock absorbers of the spine may lead to a loss of height in the front part of the spine. As discs degenerate the spine begins to lean forward and lumbar lordosis decreases.
The patient may develop pain as a result of the degenerative disc disease or as a result of the spinal imbalance.
Lumbar Post Laminectomy Syndrome:
Lumbar flat back syndrome may develop in patients previously treated with a laminectomy or other lumbar surgery to decompress the spinal nerves to treat stenosis.
These procedures can lead to a decrease in lumbar lordosis and in some cases spinal instability.
Vertebral Compression Fractures:
Compression fractures are often the result of weak spinal bones due to osteoporosis. A fracture can lead to loss of height of the bone in the thoracic and lumbar spine. This may occur in one bone or in multiple bones throughout the spine, resulting in flat back syndrome.
Ankylosing Spondylitis:
Ankylosing spondylitis (AS) is a chronic inflammatory disease that causes stiffness and arthritis throughout the entire spine. Some patients with AS notice an increasing forward posture of the spine, including an increase in thoracic kyphosis or decrease in lumbar lordosis.
This can lead to symptoms of lumbar flat back syndrome.

Straight back syndrome (SBS)
Straight back syndrome (SBS) is a thoracic deformity characterized by loss of the normal upper thoracic spinal kyphosis. This deformity leads to a reduced antero-posterior diameter of the chest causing a compression or “pancaking” of the heart and great vessels so as to appear enlarged. This is accompanied by a leftward displacement of the heart, resulting in cardiac murmurs1, chest pain and tracheal compression.
Mitral valve prolapse (MVP) has been reported in 64% of patients.
Misdiagnosis of straight back syndrome as pericardial absence has also been cited.
A study investigating the relationship between SBS and MVP showed echocardiograms to be normal in 36% of patients diagnosed with SBS; however, 58% of these patients demonstrated mitral valve prolapsed.
Despite the fact that this syndrome has been recognized for over 50 years, it is not commonly considered as a differential diagnose and thus the incidence is unknown.
However, given that this syndrome is often associated with heart symptoms, it is important that health care practitioners are made aware of SBS and consider it as a differential diagnosis in a patient presenting with symptoms that can appear to be cardiac in nature.
This is especially true in cases of atrial septal defect which can resemble the symptom picture of SBS.

Reproduction

This is from American Cardic association.

My question is why there was a delay in reporting associated research?

The plant-based diet

Whole food plant-based dietary patterns are becoming increasingly popular because of a variety of reported health benefits.
A vegan dietary pattern is devoid of all animal products, whereas a vegetarian diet is typically a nonmeat diet, but can include milk products and eggs.
All plants contain protein, but in variable amounts. Pound for pound (dry weight), vegetable protein-rich foods, such as legumes, contain as much or more protein than most animal foods, without the sodium or fat.
One cup of cooked lentils contains 18 g of protein (and no fat or sodium). For comparison, an average 6-oz steak may have up to 40 g protein, but also has 12 g of SFAs, which is nearly two-thirds of the recommended daily allotment.
It is not necessary to intentionally combine or “complement” plant foods to obtain adequate protein.
I do not agree with the aove phrase.
Additionally, I recommend our 4 G snack bar (with or without additional chocolate flavour- only five ruppies up) from Samaposa 20 ruppies a bar.
Although the quantities of essential amino acids vary from 1 food to another, nearly all plant-derived foods contain most of the essential amino acids.
Including foods from a variety of plant sources can provide adequate quantities with careful diet planning.
This sentence goes against the higlighted sentence.
Epidemiological studies and RCTs indicate that plant-based diets are associated with improvement in ASCVD risk factors and a decreased risk of ASCVD.
Studies have been conducted both for the prevention and treatment of CVD with plant-based diets, often in conjunction with other heart-healthy lifestyle behaviors.
In the European Prospective Investigation into Cancer and Nutrition, 44,561 men and women were followed for 11.6 years. Of the participants, 15,151 (34%) were vegetarians (consuming no meat or fish).
Vegetarians had a lower mean BMI, lower non-HDL-C, lower systolic blood pressure, and a 32% lower risk of developing CHD.
In the United States, vegetarian dietary patterns are associated with lower prevalence of T2DM and metabolic syndrome .
Meta-analyses have also shown that, compared with omnivorous dietary patterns, vegetarian dietary patterns are associated with healthier body weight and blood pressure.
In a systematic review and meta-analysis of 8 studies with a Seventh Day Adventist population (n=183,321), there was a reduced risk of CHD events (RR: 0.60; 95% CI: 0.43 to 0.80 vs. RR: 0.84; 95% CI: 0.74 to 0.96) and cerebral vascular disease events (RR: 0.71; 95% CI: 0.41 to 1.20 vs. RR: 1.05; 95% CI: 0.89 to 1.24) in vegetarians compared with nonvegetarians. Furthermore, populations consuming a predominantly plant-based diet are reported to rarely develop CVD. These include the Okinawans, the Papua Highlanders of New Guinea, the rural Chinese, central Africans, and the Tarahumara of northern Mexico.
Clinical trials have also demonstrated benefits of plant-based dietary patterns in patients with CHD.
In 1983 and 1990, RCTs using a lifestyle medicine intervention of a whole foods, low-fat, vegetarian diet, moderate exercise, social support, and stress-management training documented significant reversal in CHD, as measured by improvements in ventricular function using radionuclide ventriculography, a 400% increase in myocardial perfusion by cardiac positron emission tomography, regression in coronary atherosclerosis using quantitative coronary arteriography, and 2.5 times fewer cardiac events when compared with a randomized control group.
There was a dose-response correlation between adherence to this lifestyle intervention and changes in percent diameter stenosis. Two demonstration projects showed significant improvements in all risk factors, a >90% reduction in angina within weeks, decreased need for medications, and a 77% reduction in the need for revascularization.
Additionally, in 1995 and 2014, a whole food plant-based diet intervention was shown to result in prevention of coronary artery disease progression and angiographic disease reversal.
On this basis, it appears that a whole food, plant-based diet may halt progression of coronary atherosclerosis and achieve evidence of angiographic disease regression.
Most recently, a large prospective cohort study of U.S. health care professionals described the association between animal versus plant protein intake and mortality outcomes.
This study showed increased all-cause and CV mortality with high animal protein intake (including processed red meat, unprocessed red meat, and eggs).
High plant protein intake was inversely associated with mortality rates. These findings are consistent with recommendations to increase plant protein intake and substitute plant protein for animal protein.

Plant-based diets and ASCVD: the bottom line

Evidence indicates that a diet that is predominantly plant based is associated with improved ASCVD risk factors, reduced CHD progression, and beneficial effects on ASCVD.
A whole food, plant-based dietary pattern plays an important role in ASCVD risk reduction.