Human Digestive System - Digestive Enzymes - and Drinking Cold Water after Meal

Drinking Cold Water after Meals

Why shouldn't you drink cold water after eating food? This is one question that seems to raise very many contradicting answers. There are people who agree that drinking cold water immediately after meals is not good for digestion of food. There are other people who think all is well with drinking cold water after eating food.

Slow Down Digestion

It is very refreshing to drink a glass of cold water after a meal – and it’s your body that is telling you that. Ideally, it would look like if you drink cold water immediately after your meal, the cold water will help solidify the oily food you have just eaten and slow down digestion. And that the oily sludge will line the intestine walls and block the villi that absorb nutrients. Now, this is not true because our bodies are such that they immediately give up internal body temperatures to neutralize the low temperatures of food or drinks we may swallow.

Digestive Enzymes Optimum Temperature of 37°C to 42°C

Why all this confusion? The digestive enzymes in human works best at the optimum temperature of between 37°C and 42°C. This is the temperature range where the rate of food digestion is the maximum. When you eat food it enters the stomach at a temperature of between 37°C and 42°C, and if not, it’s regulated by the body to that temperature range. For example: The enzyme pepsin in the stomach degrades food proteins into peptides at the optimum temperature of between 37°C and 42°C and optimum acidic environments of pH of 1.5 to 2. The body has sensors with memory, or it’s linked to the brain, and immediately it sense the food in the stomach has temperatures and pH outside the optimum range, it uses the energy and acids stored in the body to regulate the right conditions for the optimum digestion. Once the digestion is up and running, it uses the food to immediately replace the backup that has initially been used. This would therefore mean there should be no problem whether you drink cold water, warm water or warm soup after the meal.

Digestive Enzymes Optimum Temperature of 37°C to 42°C
Digestive Enzymes Optimum Temperature of 37°C to 42°C

It’s Safe to Drink Cold Water after Meals

The thing is: when you hear your body telling you to drink cold water because it will be refreshing, give it cold water.

Definition of cold water for drinking: "Cold water" in this article does not mean icy cold water. "Cold water" in this article does not meant that if the room temperature is 30ºC, and the water is at 30ºC, the water is "cold water". "Cold water" is water with a temperature of 60ºF (15.5ºC) +/- 2 degree Celsius. The temperature of 60ºF (15.5ºC) +/- 2 degree Celsius is selected because it is the temperature of water that a person of average body build, in good health, wearing work clothes and a life preserver could be expected to survive in/on that water for about eight/ten hours. The temperature of 60ºF (15.5ºC) +/- 2 degree Celsius is cold enough but still friendly to your teeth.

But there is an exception to this rule of taking cold water. And you may want to ask, how do cold temperatures supposedly give us the common cold? If you are sick, keep away from cold water because if you drink or wash with cold water you will get sicker.

Why Do Cold Temperatures Give Us The Common Cold?

It works this way: your blood has white blood cells which are the body soldiers which fight infections. If you are sick, say you have a cold, at normal temperatures of the stomach, the body will be diverting a lot of blood to the sick areas of your body to keep the infection virus and bacteria at a control. Then, all of a sudden, the report comes that the temperatures are very low at the stomach and that solving that problem is a priority. Now, the blood and white cells will abandon the infecting virus and bacteria and will be diverted to solving the problem of raising the stomach temperature to the optimum range. The infecting virus and bacteria will take this opportunity to multiply themselves into millions and within hours you will be sicker. If say you had malaria, you will find yourself having to see a doctor sooner than you would have because malaria is a dangerous disease that kills very fast.

If You Are Sick Take Warm Water after Meals

So, when you feel your body telling you to drink cold water because it will be refreshing, give it cold water, unless you are sick. If you are sick take warm water, hot coffee or warm soup.

Human Digestive System

Perhaps it may help if we can discuss the process of human digestive system. Digestion is the breakdown of large food particles into smaller molecules that are easy to absorb into the blood stream. The digestion processes is both mechanical and chemical.

In the mouth, food is chewed using teeth. That is a mechanical process. What follows next is mastication which is chemical processes that breaks food using saliva that is produced by salivary glands.

Digestion of Food in the Stomach

In the stomach, the gastric glands secrete pepsinogen, and pepsinogen is then converted in presence of hydrochloric acid to an enzyme called pepsin. The pepsin then digests the larger proteins into smaller proteins called peptides. In humans, this process takes about 1 to 2 hours in the stomach before the resulting thick liquid called chime goes into the small intestine.

Human Digestive System. Image Credit:Mariana Ruiz + LadyofHats Via Wikimedia Commons
Human Digestive System. Image Credit:Mariana Ruiz + LadyofHats Via Wikimedia Commons | Source

Digestion of Food in the Small Intestine

From the stomach, food moves to small intestine which has internal layer of small, finger-like structures called villi which are covered by even smaller hair-like structures called microvilli to help improve the surface area for faster absorption of nutrients. The small intestine is divided into duodenum, jejunum and ileum. In duodenum, intestinal enzymes and enzymes from the pancreasbreaks nutrients into simpler forms that can be absorbed. The enzymes amylase digest starch, maltase digest maltose, sucrase digest sucrose and lactase digest lactose. The main enzymes for digestion of proteins are chymotrypsin and trypsin. Trypsin and chymotrypsin are secreted by the pancreas. Pepsin is secreted by the stomach. These enzymes break down food proteins into polypeptides that are then broken down by the enzyme erepsin into amino acids. Fats are also digested here by bile which is produced by liver (bile is stored in gall blander). The enzyme for digesting fats is called lipase. Most of nutrients absorption into the blood stream happens in the jejunum. Ileum is the part where the final absorption takes place. Any food that is not absorbed here proceeds to the large intestines.

Nutrients Processing In the Liver

Once nutrients are absorbed through the villi and microvilli into the blood, the blood containing the absorbed nutrients goes to the liver for filtering, removal of toxins, and nutrients processing. The liver is one organ that has a wide range of functions than any other organ. The liver is responsible for detoxification, plasma protein synthesis, glycogen storage, decomposition of red blood cells, and production of biochemicals used in digestion.

Appendix - Has Lost Most of Its Original Functions

At the junction of the small intestine and the large intestine lies the appendix. The appendix in humans is a vestigial structure which means that an appendix in humans has lost all or most of its original functions through evolution of humans. But still, some scientists are of the opinion that the human appendix harbors and protect bacteria that are beneficial in the function of the colon.

Digestion of Food in the Large intestine

The large intestine is also known as colon and is composed of ascending, transverse, and descending parts. When the food that has not been absorbed in the small intestine enters the colon, it is stored there. Water is absorbed and other residues are eliminated. Whatever remains is called feaces which is stored in rectum, and eventually removed out as feces, feaces, faeces, excrement, stool, or poopoo.

There are many enzymes involved in the digestion of food. Most enzyme in the stomach functions best in acidic environments of pH of 1.5 to 2 and optimum temperature range of between 37°C and 42°C. Below is a listing of digestive enzymes in human body.

Digestive Enzymes in Humans

1. Amylase useful in digestion of complex carbohydrates
2. Bromelain is a protein enzyme that also digests proteins
3. Cellulase useful in digestion of fibers from soluble sources
4. Lactase useful in digestion of Lactose or dairy sugars
5. Lipase useful in digestion of fats and denatured fatty oil
6. Maltase useful in digestion of disaccharides to mono saccharides
7. Protease useful in digestion of protein into amino acids
8. Sucrase useful in digestion of complex sugars and starches

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Comments 5 comments

rasta1 profile image

rasta1 4 years ago from Jamaica

Room Temperature water is the best or lukewarm based on your information.


StephanieBCrosby profile image

StephanieBCrosby 4 years ago from New Jersey

Thanks for the collection of information. Very useful.


JCielo profile image

JCielo 4 years ago from England

I'm guessing though that, even although the body's 'system' can regulate the temperature of food or liquid in the stomach, it'll still be better to drink water at room temperature because then the body doesn't have to work so hard to bring it to the optimum temperature?


ngureco profile image

ngureco 4 years ago Author

Thank you, Rasta1, StephanieBCrosby, and JCielo, for your comments. I would like to add that by “cold water” I do not mean icy cold water. “Cold water” in this article does not mean that if the room temperature is 30ºC, and water at 30ºC, the water is “cold water”. “Cold water” is water with a temperature of 60 degree Fahrenheit (15.5 degree Celcius) +/- 2 degree Celsius. The temperature of 60 degree Fahrenheit (15.5 degree Celcius) +/- 2 degree Celsius is selected because it is the temperature of water that a person of average body build, in good health, wearing work clothes and a life preserver could be expected to survive in/on that water for about eight hours. The temperature of 60 degree Fahrenheit (15.5 degree Celcius) +/- 2 degree Celsius is cold enough but still friendly to your teeth.


the rawspirit profile image

the rawspirit 18 months ago from Hutchinson Island, FL - Aruba - Carlsbad, CA - Myrtle Beach, SC - Gilbert, AZ

Good article... I wish you had more resources. I come from the Dr. Ann Wigmore school, where we only drink water at room temperature and never with our meals. thanks s0 much. I have written an article on food enzymes if you are interested. Thanks again.

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