Many people worldwide, especially in countries where people often eat foods containing added sugar, suffer from tooth decay and gum disease.
Dental caries is the name given to tooth decay.
Periodontal disease is the name given to gum disease.
Teeth form in the jaws long before they come through the gum and the covering enamel is 96% made of minerals (mainly calcium, and phosphorus).
When food is eaten, a white, sticky substance called plaque forms on the surface of the teeth, especially next to the gum. Plaque is mostly micro-organisms, plus some water and polysaccharides. When sugar is eaten, it is turned into acid.
pH is a measure of acidity. Plaque normally has a pH of 6.8, but when sugar is eaten it can fall as low as pH 4.5 within seconds. Below pH 5.5, the mineral part of tooth enamel dissolves. It cannot be replaced, and leaves a weak spot, which gets larger.and deeper until a cavity (hole) is made in the tooth (this is sometimes called 'acid attack'). If unchecked, the decay will continue until the whole tooth is affected and has to be removed.
Dental plaque also causes periodontal disease. This is where the gums become irritated and infected by micro-organisms in the plaque. The infection is called gingivitis. The gums swell, become inflamed and sore, and bleed easily. Eventually, the ligaments and bone that hold the teeth in place are destroyed and the teeth become loose and fall out. Bad breath is another symptom of periodontal disease.
| tooth teeth | |
| decay | , |
| gum | |
| to add | |
| to suffer from | |
| jaw | |
| to cover | |
| enamel [i'nxmql] | |
| % - per cent | |
| sticky | , |
| plaque [plRk] | , |
| surface | |
| measure | , |
| to dissolve | |
| spot | |
| cavity, hole | , |
| to affect | |
| to irritate | |
| gingivitis ["GinGi'vaitis], | |
| to swell swelled - swollen | |
| to inflame | |
| to sore | |
| ligament ['ligqmqnt] | |
| bone | |
| to hold held held | |
| loose | , |
IV. .
- What is the other name of gum disease?
- What is the covering enamel made of?
- What is plaque?
- What is a measure of acidity?
- How is a cavity made in the tooth?
- Describe the causes and symptoms of periodontal disease.
. - : must, have to, be to, should, ought to, can, may.
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have to must, , , , .
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| Our scientists had to solve many complicated practical problems in the construction of the first atomic power-plant. | . |
be to , .
| The new bottling line is to be commissioned next spring. | . |
s should ought to , , , .
| You should lower the voltage in the circuit. | . |
| He ought to know properties of this mixture. | . |
can , , .
| Man can subdue atomic energy. | . |
may , , .
| You may touch the wire as the circuit is open. | , . |
I. .
1. Most monosaccharides can exist as both open-chain and cyclic structures.
2. The protection of consumers rights should be regulated by a separate legislative act.
3. Proposals for legislation on labeling food products have to be addressed to ensure that they are practical and enforceable.
4. Pregnant women must not fast for more than 6-8 hours.
5. At what stage of production ought these farm products to be certified?
6. Scientists and environmentalists are to forecast correctly the possible development of the situation and to work out preventive measures.
7. The principle of substational equivalence may be the reason for the conflict with trade issues regulated by the FAO (Food and Agricultural Organization) standards.
II. .
1. , , .
2. , , , 1600 .
3. , .
4. .
5. , .
6. , .
7. , .
.
1. All countries must be aware of the problems associated with food irradiation even if not engaged in research problems.
2. In order to kill spoilage agents the food should be heated to 1600 F.
3. You cannot keep milk without sterilizing it.
4. The canned food may store for a very long time,
5. The method you read about is to be used for egg preservation.
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6. We had to freeze meat to store it for a long period.
7. We should eat to have energy.
IV. DIETS
A
I. , .
vegetarians ["veGi'tFEriqn], reason ['rJzqn], yogurt ['jOgqt], vegan ['vJgqn], polish ['pOliS], soya ['sOiq], tablet ['txblqt], synthetically [sin'Tetikqli], anemia [q'ni:miq]
II. , , .
to object [qb'Gekt] () objection; diet ['daiqt] () dietary; to like to dislike; to believe () belief; health () healthier the healthiest; little () less the least; directly () indirectly
III. .
TEXT A. VEGETARIANS
Vegetarians are people who will not consume animal food, for which an animal has to be slaughtered or has suffered in any way. There are several reasons why a person may become a vegetarian, including:
1. Religious beliefs.
2. Objection to the slaughter of animals, because it is considered to be cruel, or economically wasteful (rearing animals is expensive and uses a lot of land).
3. Dislike of animal flesh.
4. Dietary reasons.
5. Belief that a vegetarian diet is healthier than a carnivorous (meat-eating) diet.
In recent years the number of vegetarians has increased. There is some evidence that a vegetarian diet is better for long-term health, and that vegetarians may suffer less from diseases such as cancer and heart disease. There are two main types of vegetarian:
lacto-ovo vegetarians
vegans (strict vegetarians).
Lacto-ovo vegetarians will not eat meat, or meat products, poultry, fish, lard, suet, fish oils, or gelatine, because producing these involves slaughtering the animal or fish.
However, they will eat food products from animals, such as free-range eggs, milk, cheese, butter, cream, yogurt. The animal is not slaughtered to produce these.
Vegans will not eat any food that is made directly or indirectly from an animal, even if the animal has not been slaughtered for that purpose. They also refuse to use products such as soaps, cosmetics, and polishes, which involve the use of animal oils or fats.
With careful planning, vegan meals can be made appetizing and good to eat; and with knowledge of the value of foods, they can be nutritionally well balanced. There are several important points that must be taken into consideration when planning vegan diets:
1 Protein is found in relatively small amounts in plant foods, so a large bulk may have to be eaten. The richest sources are: soya beans, cereals, nuts.
2. Extra vitamins and minerals can be taken in the form of tablets and drops, providing that they are made synthetically and do not come from animals. Vitamin B is only found in animal foods. Vegans may be at risk of developing anemia and may need to take it in tablet form to avoid this.
| vegetarian ["veGi'tFEriqn ֽ] | |
| to consume | , |
| to slaughter | , () |
| to suffer | |
| belief | |
| objection | , |
| wasteful | |
| to rear | , |
| flesh | |
| carnivorous [kR'nivqrqs] | |
| evidence | , |
| cancer | , |
| vegan [´vJgqn] | |
| poultry | |
| lard | |
| suet ['sjHit] | |
| polish | |
| to take into consideration | |
| bulk | , |
| providing | , |
| anemia [q'nJmiq] | , |
IV. .
1. What are the main reasons for becoming a vegetarian?
2. What is the difference between a lacto-ovo vegetarian and a vegan?
3. Suggest suitable meals for each.
