WATER, WATER EVERYWHERE - NOT A DROP TO DRINK

Prof. B.M.Hegde

Water is the elixir of life. Life depends on water to a great extent, like oxygen. The common man never appreciates the great significance of water in day-today life. People drink water only when they are thirsty. That is, of course, the right thing to do; but most of us, who claim to be educated, drink artificial sweetened drinks when we are thirsty. Some of us drink tea or coffee to quench our thirst. All these, except pure water, are good diuretics trying to send more water out of the system when one drinks them. The end result is more water depletion than water balance. This is more marked in a pressurized cabin of long haul jet aircraft. To cap it, if one drinks alcohol, the dehydration gets worse. Alcohol is a diuretic in its own right.

In addition, the sweetened drinks, being hypertonic, would draw water from the stomach wall cells into the cavity of the stomach upsetting the lining cell function. If one drinks water after a heavy meal of hypertonic liquids like paayasam (Indian special meals) the withdrawal of water from the cells is so great that one gets the feeling of bloating in the tummy after that for quite sometime. This is misinterpreted as `gas’ in the stomach; to correct that good amount of antacids are routinely used.

Sixty to seventy percent of the body weight is made up of water. Every part of the body, including the bones, have to have water. Drying of the cells of the brain could lead to coma. Man could live without food for long times but not without water for longer than a day or two, at the most. Water is needed for the following important functions of the body:
*Chemical reactions of digestion and metabolism.
*Carry nutrients and oxygen to the cells through blood flow.
*Keep the body cool and the body temperature constant under varying conditions by perspiration etc.
*To lubricate our joints.
*To have the best consistency for the stools for regular bowel motion.
*To regulate fat content of the body.
*To regulate muscle tone and size.
*To maintain proper weight. If weight losers do not drink enough water the body finds it difficult to metabolize fat properly.
*For digestive efficiency.
*To beat exhaustion after heavy work, especially in hot weather.
*To clear all the waste products from the body through the kidneys. One good example is Diabetes Mellitus. In the latter disease the high blood sugar makes the blood so thick that it can not be correctly filtered in the very thin minute kidney nephrons. The body’s intelligence then draws lot of water from various parts of the body to dilute the blood in the kidneys producing dehydration-resulting in thirst, poly-urea (lots of urine), and fatigue. In extreme cases it could even cause coma. Similar is the situation in physiological states where there is excess production of protein waste in the body; the body needs plenty of water to clear the metabolic end products of protein.
*To avoid kidney stones in hot weather.

Healthy human being needs about eight glasses of water per day, in addition to his normal food intake. These should not be taken in the form of coffee, tea, sweetened drinks, or milk etc. It should be cool water (ice water intake makes the body spend some energy to warm it to the body temperature). Minimum water for ordinary activity should be at least 30 ml per Kg. body weight. For heavy exercise in hot weather it is 40 ml per Kg. body weight. One must compensate for a glass of tea or coffee with a glass of water that will be lost because of the diuretic properties of the former. It is better to distribute the water intake over the whole day.

Unfortunately, this message does not go down well with many; doctors and health educators do not think it is important to let the common man know about this. They would much rather spend more time advertising the new high powered kidney stone pulverizing machines than to tell people to drink enough water to avoid the stones in the first place. I have never seen any message in our media on the good effects of water, but have seen many times talks and glossy advertisements about kidney stones, their treatment and what have you.

We, in the medical fraternity, are learning our lessons everyday. We have blindly believed in the Starling’s laws of fluid balance in the body, for centuries. Recent work has shown that the laws are very badly flawed. To give one simple example it is believed that the small blood vessels, called the capillaries, have two ends on either side. They connect the high-pressure arterial end to the low-pressure (no pressure) venous end to complete the cycle of blood circulation. In a manner of speaking, the capillaries are the swimming pool, holding all the blood. The heart, arteries, and the veins are like the cleaning pump of the swimming pool. The heart is the pump that pumps blood into the arteries first; they, in turn, push blood through the capillaries onto the veins, in its onward journey back to the heart. How do the nutrients in the blood reach the tissues? The nutrient containing water has to be pushed out of the tight knit blood vessel compartment at the arterial end of the capillaries. The latter have the capacity to selectively leak water. The water then bathes the tissues and is supposed to be collected by the venous end of the capillaries by a mechanism labeled osmotic pressure. The osmotic pressure was thought to be the most important function of the colloids inside the blood vessels.

This in mind, doctors were giving colloids like albumin (Rs.4000 per injection) in some disease states with shock. Poor Starling did not realize the monetary potential of his theories when he propounded them. But a lot of stars (medical) have made money in the bargain. New knowledge has shown that the Starling’s laws are badly flawed and the extra albumin that is given leaks as much into the tissues from the blood vessels in those situations making the condition of the patient still worse. If he survives he is lucky. The mistake in the Starling’s law was the idea that water could be drawn back into the blood vessels to keep up the blood pressure inside the vessels in such critical times. The truth seems to be that the leaked-out water at the arterial end of the capillary comes back to the heart only through the lymphatics; the osmotic pressure having very little role to play.

Water is the key to many of our bodily functions. Keep drinking enough water to keep going. If one drinks more than the usual need for the body he does not have to worry, as the normal kidneys are very good in keeping the water balance. One passes extra urine. Regularly keep passing urine if you drink plenty of water. Do not believe in the civilized society’s rules and taboos to keep the extra water in the bladder for a long time. If one is suffering from heart, kidney, or liver diseases (any disease) one has to follow his doctor’s advice regarding water intake. Water, water everywhere only to drink.