Digestion in Mammals

Digestion in Mammals

Definition of terms

Digestion is the process by which food materials are changed from a solid or semi- solid state into simple, soluble diffusible and usable molecules by the body.

-          Digestion in man involves two breaks down processes: mechanical and chemical breakdown.

Mechanical breakdown

-          It involves the breakdown of large particles of food into small particles by chewing to make it easier to swallow.

-          It also increases the surface area of the food for enzymes to act on it during chemical digestion.

Chemical breakdown

-This process involves the breakdown of large, complex food molecules into small, simpler molecules that can be absorbed by the body.

- The process starts from the month and continues in the stomach and small intestine.

- In that process carbohydrates are finally changes into fructose, galastose and glucose, proteins are changed into amino acids, and fats and oils are changed into fatty acids and glycerol.

The products of digestion

Complex food molecules	Simple, soluble, breakdown products
Carbohydrates	Simple sugar e.g. glucose, galactose and fructose
Fats and oils	Fatty acids and glucerol
proteins	Amino acids

   

 Absorption

This is the process by which soluble end products of digestion diffuse into the blood system (stream)

Assimilation

This is the utilization of the absorbed molecules by the body to provide either energy or material to be incorporated into the body.

This is the incorporation of products of digestion into the cell metabolism.

Ingestion

This is the taking in of food through the mouth.

Egestion

This is the process by which undigested food particles sure removed from the body through the anus.

DIGESTIVE SYSTEM IN MAN

-          The digestive system in man is made of alimentary canal (gut) and associated organs such as pancreas and liver

Function of digestive system

(i)                 Digestion.

(ii)               Absorption.

The alimentary canal is along hollow tube that runs from the mouth to the anus.

It is a special tube when digestion takes place and it is also known as gut or digestive tract.

The human digestive processes

The process of digestion starts in the mouth and continues as the food passes along the alimentary canal

Digestion in the mouth

In the mouth, food is broken down into small particles by a mechanical process called chewing

Why chewing is necessary?

a.       It breaks down large pieces of food into small pieces for easy swallowing.

b.      It mixes the food with saliva making the food slippery for easy swallowing.

c.       It makes it easy for the digestive enzymes contained in saliva to penetrate the food.

Saliva

Saliva is a watery secretion containing the mucus, enzymes salivary amylase and lysozyme, and various mineral salts, including chloride ions which speed up the enzymes.

Saliva is produced by three salivary glands. These includes;

a.      Parotid salivary gland

-          It consists of serous cells and thin watery secretion rich in enzymes and antibiotics.

b.      Sublingual salivary gland

-          Have mucous secretory cells and produce viscid secretion.

c.       Submandibular  salivary gland

-          It contains both, serous and mucous secretory cells and produce secretion of intermediate consistency.

-          Not all salivary glands produces enzymes, it is only the parotid gland.

-          About  of saliva are produced daily.

                           Composition of saliva

1.      Water – over 99% of saliva is water.

2.      Salivary amylase – A digestive enzyme which hydrolyses starch to maltose.

3.      Mucin – A sticky material which helps to bind food particles together and lubricates them to assist swallowing.

4.      Mineral salts (.e.g. sodium hydrogen carbonate ) and other electrolytes i.e. potassium ions (), chloride ions (), Phosphate ions (), Nitrate ions ( )

-The sodium bicarbonate it helps to maintain a pH of around 6.5 – 7.5, which is the optimum for the action of salivary amylase.

 5.  Lysozyme helps to kill bacteria, which are potentially harmful, by catalyzing the break down of their cell walls.

- The enzymes acts in an alkaline medium which is provided by chlorides, carbonates of sodium and other electrolytes.

Roles of saliva

(a)    Water acts as a solvent for dissolving food substances.

(b)    Mucin lubricates the food for easy swallowing.

(c)    Salivary amylase contains in saliva catalyses the hydrolysis of cooked starch into maltose

            

               Starch            Water                Maltose

d.      Mineral salts help to maintain a pH of around 6.5-7.5, which is the optimum for the action of salivary amylase and lysozyme

e.       Lysozyme helps to kill bacteria, which are potentially harmful, by catalyzing the breakdown of their cell walls.

-Also the amylase and lysozyme enzymes in saliva digest particles of starch which remain between the teeth after swallowing. This helps to prevent tooth decay.

Lingual lipase

Secretion of lingual lipase in mouse, rate, rabbit, guinea pig, baboon and humans

-          The lingual lipase is secreted from serous (Von Ebner) glands of the tongue which is active between pH of 3.0-6.0.

-          This enables to digestion of lipids- in particular the triacylglycerol (triglyderides) to diacyl glycerol and free fatty acids.

-          Because lingual lipase can tolerate acid environment, it can continue the breakdown of lipids-especially triglycerides for a considerable time after food reaches the stomach.

The process of swallowing

After food has been chewed it is rolled by the tongue into small balls called boli(singular bolus).

-          In this form food is ready to be swallowed

-          Swallowing is the process by which food is pressed against the roof of the mouth and the muscular action of the tongue pushes the food into the pharynx-a cavity bevind the mouth.

Epiglottis

Is the structure that closes the opening of the trachea (the glottis), to prevent food from entering during swallowing.

Soft palate

The opening of the nasal cavity is closed by soft palate

-Since trachea is closed during swallowing breathing and swallowing cannot occur simultaneously.

Oesophagus

The oesophagus is a muscular tube connecting the pharynx with the upper part of the stomach. The boluses move down the oesophagus by a process known as peristalsis

Peristalsis

Is a wave of muscular contraction which causes constriction of the oesophagus behind the bolus. This constriction passes along the oesophagus it pushes the bolus before it, down the stomach. This process continues throughout the alimentary canal.

Cardiac sphinter

Is a ring of muscles at the junction between the oesophagus and the stomach. When food reches it automatically relax to allow entrance of food into the stomach.

Role of cardiac sphinter

This prevents the movement of food back into the oesophagus.

Digestion in the stomach

The stomach has muscles, which contract and relax producing movement that mixes the contents of the stomach. This mixing is called churning.

Chyme

A creamy semi-liquid formed when food is mixed with hydrochloric acid and gastric juice.

The production of gastric juice

The foldings of the stomach form up the gastric pits which are lined with secretory cells. These produce gastric juice.

Composition of gastric juice

Water

The bulk of the secretion is water in which are dissolved the other constituents.

Hydrochloric acid

This is produced by oxyntic cells and with the water form a dilute solution giving gastric juice its pH of around 2.0.

Roles of Hydrochloric acid

• It helps to kill bacteria brought in with the food.
• It activates enzymes pepsinogen and prorennin.
• It also initiates the hydrolysis of sucrose and nucleoproteins.
• Provides a suitable acidic medium for enzymes to work best.

Pepsinogen

This is produced by the zymogen or chief cells in an inactive form to prevent it from hydrolyzing the proteins of the cells producing it. One in the stomach it is activated to pepsin by hydrochloric acid.

Role of pepsin

It hydrolyses protein into polypeptides.

Prorennin

It is also produced by zymogen cells in an inactive form, and then activated to rennin.

Roles of Rennin

Is an enzyme which coagulates milk by converting the soluble caseinigen into insoluble casein. This enzyme is abundant in young sucking mammals than in adults.

Mucus

This is produced by goblet cells and forms a protective layer on the stomach wall, thus preventing pepsin and hydrochloric acid from breaking down the gastric mucosa (i.e. Prevent autolysis)

If the protection is not effective and gastric juice attacks the mucosa, an ulcer results. Mucus also helps lubricate movement of food within the stomach.

Note

The chime from any one meal is released gradually over a period of 3-4 hours. This enables the small intestine to work on a little material at a time and provides a continuous supply of food for absorption throughout the period between meals.

Digestion in the duodenum

The duodenum is small portion of the small intestine just after the stomach. There are two juices entering the duodenum.

Ø  Bile juice

Ø  Pancreatic juice

Bile juice

Bile juice is a complex green fluid produced by the liver. It is then stored in the gall bladder and then entering the duodenum via the bile duct. It contains no enzymes but possesses two other substances important to digestion.

1.      Mineral salts (e.g. Sodium hydrogen carbonate).

These help to neutralize the acid chime from the stomach and so create a more neutral pH for the enzymes of the small intestine to work in. 

2.      Bile salt-sodium and potassium glycocholate and taurocholate.

Roles of Bile salts

·         They emulsify lipids, breaking them down into minute droplets. This is a physical, not chemical change, which provides a greater surface area for pancreatic lipase to work on. The break down of lipids into droplets is known as emulsification.

·         Bile salt neutralizes the acidic chyme from the stomach.

·         It provides an alkaline medium for enzymes to work best.

Pancreatic juice

It is secreted by the pancreas which is situated below the stomach. The pancreatic juice contains sodium bicarbonate and enzymes.

Roles of pancreatic juice

(i)                 Mineral salts (e.g. sodium hydrogen carbonate)

-          Help to neutralize acid chime from the stomach

-          Provides more suitable pH in which the intestinal enzymes can operate.

(ii)               Proteases

-          It contains trypsinogen which, when activated by enterokinase from the intestinal wall form trypsin.

-          Role of trypsin is to catalyses the hydrolysis of proteins into peptides

-          It also contains chemotrypsinogen which is activated by trypsin to form chemitrypsin. The chemotrypsin it coverts proteins into peptides.

(iii)             Pancreatic amylase-completes the hydrolysis of starch to maltose which began in the mouth.

(iv)              Pancreatic lipase- it breaks down fats and oils into fatty acids and glycerol.

(v)                Nuclease-converts nucleic acids into their constituent nucleotides.

NB: The resulting food mixture in the duodenum is known as chyle.

Digestion in the ileum

The ileum is the small intestine connecting the duodenum and the large intestine. The intestinal wall secretes an intestinal juice ( succus entericus juice).

Description of the intestinal wall

      At the base of the villi the epithelium folds in places to form narrow tubes called Crypts of Liebercuhn.

      It is here that new epithelium cells are made to replace those which are constantly being shed from the villi.

      The cells of the crypts also secretes a slightly alkaline fluid which contains water and mucus

      Paneth cells at the base of the crypts secrete lysozyme, the antibacterial enzyme.

      Goblet cells are the special epithelial cells throughout the small intestine which secretes mucus.

      Enzymes are produced by the breakdown (lysis) of cells at the tip of the villi.

Composition of intestinal juice

(i)                 Mucus- helps to lubricates the intestinal walls and prevent autolysis

(ii)               Mineral salts(e.g. sodium hydrogen carbonate)

-          Secreted by cells of the crypts in order to neutralize the acidic chyme from the stomach.

-          It provides more suitable pH for the action of enzymes in the intestine.

(iii)             Protease (Erepsin)

Erepsin is a mixture comprising several protein-digesting enzymes. It catalyses the hydrolysis of the remaining peptides into amino acids

Acids

Amino acids are the end products of protein digestion.

(iv)              Enterokinase

A non-digestive enzyme which activates the trypsinogen produced by the pancreas

(v)                Maltase –catalyse the hydrolysis of maltose to glucose.

      

(vi)              Sucrase – catalyse the hydrolysis of sucrose to glucose and fructose.

           

(vii)            Lactase- catalyses the hydrolysis of lactose to glucose and galactose

           

           Glucose, fructose, and galactose are the end products of carbohydrate digestion.

(viii)          Lipase

Catalyses the hydrolysis of some of the remaining fats and oils to fatty acids and glycerol

(ix)             Nucleotidase-converts nucleotides into pentose sugar, phosphoric acid and organic bases

Summary on enzymes contained in the intestinal juice

The end products of digestion are simple molecules that are soluble in water, diffusible and therefore absorbable.

Enzyme	Substrate	Produs
Enterokinase	Trypsinogen	Trypsin
Maltase	Maltose	Glucose
Sucrase	Sucrose	Glucose and fructose
Erepsin	Peptides	Amino acids
Lipase	Fats and oils	Fatty acids and glycerol
Lactase	Lactose	Glucose and galactose
nucleotidase	nucleotides	Pentose sugar, phosphoric acid and organic base

Absorption

Absorption is the process by which the soluble end products of digestion (glucose, amino acids, fatty acids and glycerol) diffuse into the blood stream.

Absorption takes place mainly in the small intestine. Things like alcohol, some water, soluble vitamin B and C, soluble salts are absorbed in the stomach.

Process of absorption

The digested food materials are being absorbed into the body by diffusion and active transport

-Digestion results in the formation of relatively small, soluble molecules which, provided there is a concentration gradient, could be absorbed into the body through the intestinal wall by diffusion.

-If the epithelial lining were permeable to molecules such as glucose, it could just as easily result in it diffusing out of the body when the concentration in the intestines was too low. For these reasons most substances are absorbed by active transport.

Active transport

It is the process by which the molecules of the materials move against their concentration gradient using the energy derived from ATPs. The materials tend to move in the form of mass flow.

 Absorption of amino acids and glucose

Amino acids and glucose are absorbed into the blood stream through the process of active transport while other simple molecules of food are absorbed by simple diffusion.

-The material diffuse into the blood capillaries are drained into the hepatic portal vein. That vessel takes the blood with the dissolved materials to the liver and then joins the general body circulation.

Fatty acids glycerol

These are absorbed in the lacteal of the villi. They then drained into the lymphatic vessels which form up lymphatic system and finally join the general body circulation at the vena cava.

Adaptations of the small intestine (ileum)

-          This is the only part of the alimentary canal where the absorption of food materials already digested are taking place, substances like glucose, fatty acids and glycerol, amino acids are absorbed.

-          This part of the small intestine is highly specialized for absorption and has the following

adaptations.

(i)                 It is very long (4-6)m in human and up to 45m in cattle so as to increase the surface area for the absorption of the soluble digested food materials.

(ii)               Its walls are folded to provide internal projections. This helps to increase surface area for the absorption of the food.

(iii)             It has numerous fingers like projections called villi which increase the surface area. The epithelial all linings the villi are covered with menute projections called microvilli.

(iv)              The inner lining is very thin (made up by single cell layer), so as to facilitate absorptions.

(v)                The ileum is highly supplied by large number of blood capillaries so as to ensure enough blood supply during absorption of food.

(vi)              The cells of the ileum contain large number of mitochondria so as to release high energy for the process of absorption.

(vii)            The ileum is made by soft muscles (involuntary muscles) therefore contraction and relaxation during absorption is self controlled (not under man’s will)

Note ; All these aims to increases the surface area for absorption of materials, thus most substances are absorbed by active transport rather than diffusion and this is because.

a)      Diffusion is slow while the active transport is fast

b)      Diffusion could be wasteful; this is because diffusion provides two ways traffic which depends on the concentration gradient. Thus it could easy result into the substances diffusing out of the body when the concentration on the epithelium cells of the intestinal is low.

-Active transport on the other hand is unidirectional therefore it ensures the unidirectional flow of materials from the lumen of the small intestine to the tissue beneath the epithelium.

Assimilation

This is the utilization of the absorbed molecules by the body to provide either energy or material to be incorporated into the body.

Assimilation occurs as follow;

Glucose

·         Some is oxidized during respiration to produce energy (ATPs)

·         Some is stored as glycogen in the liver and muscles.

·         Some is converted to fats and stored as adipose tissue beneath the skin.

Amino acids

·         Some is used in the synthesis 9formation) of proteins.

·         Some is used in growth and repair of worn out cells.

·         In absence of glucose and fats, they may be oxidized to release energy during respiration.

Fatty Acids and Glycerol

·         Oxidized to release energy during respiration

·         Stored as adipose tissue beneath the skin. This helps in insulating the body.

The Caecum and Appendix

The caecum and appendix have no function in man. In herbivores such as rabbits the caecum and appendix contain bacteria that secretes cellulose enzyme that digests the cellulose to glucose.

Colon

The undigested and indigestible materials pass through the large intestine (colon) by peristalsis.

There are no digestive enzymes in this part of the alimentary canal.

Functions of the colon

·         It concerned with the re-absorption of water from the undigested food materials and indigestible materials to reduce chances of dehydration. The lining of the colon is folded so as to increase surface area for the re-absorption of water.

·         It makes sure that the undigested and indigestible materials are passed into the rectum.

Rectum

This is the last part of the alimentary canal where faeces are temporary stored and then later removed from the body through the anus. When the rectum is full a person feel the urge to empty it, this is known as defaecation or egestion.

Study Questions

1)      Write an essay on role of ileum in human digestion and absorption.

2)      Define the following terms as they are applied in digestion,

(i)                 Digestion

(ii)               Assimilation

(iii)             Absorption

(iv)              Emulsification

3)      (a) Complete the table bellow

Food digested	Enzyme	products
maltose	(i)	(ii)
(iii)	pepsin	(iv)
(v)	(vi)	Fatty acids and glyerol

     

      (b) Write down the function of the following food nutrients in the body.

(i)                 Carbohydrates

(ii)               proteins

4)      James was turning upside down and the he was given the banana by his friends, amazingly he was able to swallow it without any problem. Explain what was happened in the oespphagus during swallowing process enabling the bolus to move in zero gravitation to the stomach.

5)      Explain the role of bile in human digestion.

6)      Why the enzymes that digest proteins in the stomach and duodenum are secreted in inactive form?

Summary of digestion in the human digestive system

Part of alimentary canal	Source of enzymes	enzymes	Food digested by enzymes	Product(s)
Mouth	Salivary gland(parotid salivary gland)	Salivary amylase(ptylin)	starch	glucose
	serous (Von Ebner) glands	lingual lipase	Fats and oils	Fatty acids and glycerol
Stomach	Gastric juice which are seceted by gastric glands found in the stomach walls	(a) pepsin	proteins	peptides
		(b)Rennin	Soluble milk proteins (caseinogen)	Insoluble milk proteins (casein)
Duodenum	Pancreatic juice which are secreted by pancreas	(a) pancreatic amylase	Starch	Maltose
		(b) pancreatic lipase	Fats and oils	Fatty acids and glycerol
		(c)Trypsin	Proteins	Peptides
			Chemotrypsinogen	chemotrypsin
		(d) chemotrypsin	Proteins	peptides
Ileum	Inetstinal juice which are secreted by secretory cells found in the intestinal walls	(a)   Erepsin	peptides	Amino acids
		(b)   Maltase	maltose	Glucose
		(c)    Lipase	Fats and oils	Fatty acid and glycerol
		(d)   Sucrase	Sucrose	Glucose and fructose
		(e)    Nucleotidase	Nucleotides	Pentose sugar, phosphoric acid and organic base
		(f)Enterokinase	Trypsinogen	trypsin

Digestive system of Ruminants

·         Ruminants are the animals that have a rumen. A rumen is an extension of the oesophagus where food is stored temporary by ruminants before it is taken back to the mouth for further chewing.

·         The ruminants are the animals such as cattle, goats and sheep because they have a rumen. So not all herbivores are the ruminants that mean some of them such as donkey and rabbit are the herbivore but do not possesses a rumen.

·         The ruminant has two additional extension of the oesophagus called reticulum and the omasum, which act as false stomachs (they does not secretes gastric juice)

·         The ruminants have a “true” stomach, the abomasum, which secretes gastric juices containing enzymes.

The Digestive Process in Ruminants

·        The digestive process in ruminants begins when the food is partly chewed and then swallowed.

·        The swallowed food goes into the rumen and reticulum chambers, where it is acted upon by bacteria.

·        The bacteria break down proteins, polysaccharides, fats and most importantly cellulose. These bacteria they help in production of cellulase enzyme which brings about hydrolysis of cellulose to glucose.

·        When the animal is resting it regurgitates the coarse food from the rumen for further chewing.

Rumination or ‘Chewing the cud’  

It is the process by which food is regurgitated and thoroughly re-chewed, then swallowed again. The thoroughly chewed food material is swallowed again, but instead of passing into the rumen it passes through the reticulum and proceeds into the omasum.   

·         In the omasum chamber the food material is churned and some water is reabsorbed from it.

·         The food is then passed into abomasums, in this chamber food is acted upon by gastric juices.

·         The hydrochloric acid from the gastric juice kills the bacteria which were in the food. Many of the dead bacterial cells are digested with the rest of the food.

·         Digestion then continues as in human. Note that some herbivores such as rabbit and donkeys, which are not ruminants, the digestion of cellulose is carried out by bacteria in an enlarged caecum.

The differences between the digestive system of ruminants and human

Ruminants	Humans
1.      Have a four chambered stomach	Have only one stomach
2.      Are able to digest cellulose through enzyme cellulose	Have no cellulose enzyme to digest cellulose.
3. Ruminant chew cuds	No chewing of cuds
4. Have relatively long alimentary canal	Have relatively short alimentary canal

Common diseases and Disorders of the Human Digestive System

Common diseases and disorders associated with the human digestive system includes;

·         Heartburn

·         Ulcers

·         Constipation

·         Flatulence

·         Indigestion

·         Dental caries

1.      constipation

Is a condition by which the faces become drier, harder and more difficult to move and expel from the anus.

Cause

·         Constipation is caused by eating poor diet, lack of fruits, green vegetables, natural fibres or roughage in the diet causes constipation.

·         Food with lo fibre content moves slowly through digestive track than food with high fibre content.

·         Low fibre contents means that the food material moves through the gut more slowly. This allows more time for the re-absorption of water and the greater likelihood of constipation.

Prevention/ control measures

Drinking more water and eating foods with more fruits, natural fibre, cassava, carrots, pumpkins and sunflower seeds will help to prevent constipation

2.      Heartburn

This is a burning sensation which occurs in the upper part of the digestive track (oesophagus)

Cause

Heartburn is caused by excess acid in the stomach which leaks to the oesophagus causing discomfort or a burning feeling.

      Control Measures

(a)    Avoid all acidic and greasy food as much as possible

(b)   Too much coffee and alcohol should be avoided too.

(c)    Milk helps to reduce the strength of the acid causing heartburn.

(d)   Antacid tablets such as Actal, Magnesium etc help to neutralize the acid in the stomach.

(e)    If the heartburn gets worse especially at night when lying flat, try sleeping with the upper body somehow raised.

3.      Flatulence

This is an uncomfortable feeling caused by too much gas in the stomach.

Cause

·         Flatulence occurs when one eats gas inducing foods such as beans, green vegetables, etc. These foods result into production of large quantities of gas.

·         The trapped gas causes the gut to be distended and results in discomfort or pain.

·          The discomfort and pain are lessened when the gas is released either from the stomach or from the anus.

 Control measures

 Flatulence can be controlled by avoiding gas, inducing foods such as green vegetables and beans.

-Eating slowly

-Avoiding milk if you are lactose intolerant.

                                                                                                            

4.      Indigestion

This is the discomfort or pain in the stomach caused by eating too much food. It occurs most commonly after eating too much rich, oily, spicy food and can be worse if it is accompanied by alcohol.

Control

Indigestion can be avoided by eating the right amount of food at set time in course of the day. Also the meal times should be arranged so that there is enough time for each meal to be eaten in a relaxed way.

5.      Ulcers

An ulcer is an open sore that may occur in the skin or intestinal mucus membrane of the body.

This occurs as a result of the action of enzymes and acid on the epithelial membrane lining of the stomach and duodenum walls. Stress may stimulate acid production and contribute to ulcers. Ulcers can be also inherited. Examples of digestive system ulcers are:

(i)                 Peptic ulcers

(ii)               Gastric ulcers

(iii)             Duodenal ulcers

A peptic ulcer is an eroded area in the first part of duodenum (duodenal ulcer). Gastric ulcers are caused by a combination action of pepsin and hydrochloric acid in the digestive juice of the stomach.

·        Ulcers are due to an alteration in the protective action of the stomach juice from digesting the stomach itself.

·        Individual with an inherited tendency to get ulcers are more likely to develop the ulcers.

Symptoms and signs

• Pain in the abdomen
• Deep ache accompanied by feeling of hunger and nausea
• Sometimes the exist materials from the stomach via the pyloric sphinter may be absorbed. This condition is known medically as pyloric sterosis.
• Vomiting, sometimes with blood
• Dark, black stool may be produced.

Prevention and treatments

(i)                 Avoiding drinking of coffee, tea and drinks with (which) contain caffeine

(ii)               Avoid smoking and drinking alcohol

(iii)             Have stress reduction programs.

(iv)              Changing diet and take meal on time.

(v)                Take milk or ant acid drugs.

(vi)              In severe cases surgical operation may be necessary. The surgery which include cutting the vogues partial and gastrectomy removal of  the duodenum and the stomach

6.      Dental Caries

This is the dental disease in which the teeth decay and also holes are formed in them. The decay is caused by acids produced by the action of bacteria on sugary food left between the teeth.

Cause

This disease is caused by a number of factors including;

v  Lack of hard food

v  Too much sweet food. Sweet food tends to encourage growth of bacteria.

v  Lack of calcium in the diet

v  Lack of vitamin D

v  Lack of cleanliness.

v  General ill-health

Prevention

 Fluoridation, the artificial addition of fluoride compounds to drinking water for the purpose of protecting teeth against dental caries (tooth decay).

Fluoridation:  recent research has shown that fluoride salt in the drinking water may have some effect in reducing dental caries.

-Also cleaning the teeth using toothpaste three times per day it help to reduce dental caries