SCURVY

Definition

Scurvy is a condition caused by a lack of vitamin C (ascorbic acid) in the diet. Signs of scurvy include tiredness, muscle weakness, joint and muscle aches, a rash on the legs, and bleeding gums. In the past, scurvy was common among sailors and other people deprived of fresh fruits and vegetables for long periods of time.

Description

Scurvy is very rare in countries where fresh fruits and vegetables are readily available and where processed foods have vitamin C added. Vitamin C is an important antioxidant vitamin involved in the development of connective tissues, lipid and vitamin metabolism, biosynthesis of neurotransmitters, immune function, and wound healing. It is found in fruits, especially citrus fruits like oranges, lemons, and grapefruit, and in green leafy vegetables like broccoli and spinach. In adults, it may take several months of vitamin C deficiency before symptoms of scurvy develop.

Currently, the recommended dietary allowance (RDA) for vitamin C is 50-60 mg/day for adults; 35 mg/day for infants; 40-45 mg/day for children 1-14; 70 mg/day during pregnancy; and 90-95 mg/day during lactation. The body's need for vitamin C increases when a person is under stress, smoking, or taking certain medications.

Causes and symptoms

A lack of vitamin C in the diet is the primary cause of scurvy. This can occur in people on very restricted diets, who are under extreme physiological stress (for example, during an infection or after an injury), and in chronic alcoholics. Infants can develop scurvy if they are weaned from breast milk and switched to cow's milk without an additional supplement of vitamin C. Babies of mothers who took extremely high doses of vitamin C during pregnancy can develop infantile scurvy. In children, the deficiency can cause painful swelling of the legs along with fever, diarrhea, and vomiting. In adults, early signs of scurvy include feeling weak, tired, and achy. The appearance of tiny red blood-blisters to larger purplish blotches on the skin of the legs is a common symptom. Wound healing may be delayed and scars that had healed may start to break down. The gums swell and bleed easily, eventually leading to loosened teeth. Muscle and joint pain may also occur.

Diagnosis

Scurvy is often diagnosed based on the symptoms present. A dietary history showing little or no fresh fruits or vegetables are eaten may help to diagnose vitamin C deficiency. A blood test can also be used to check the level of ascorbic acid in the body.

Treatment

Adult treatment is usually 300-1,000 mg of ascorbic acid per day. Infants should be treated with 50 mg of ascorbic acid up to four times per day.

Prognosis

Treatment with vitamin C is usually successful, if the deficiency is recognized early enough. Left untreated, the condition can cause death.

Prevention

Eating foods rich in vitamin C every day prevents scurvy. A supplement containing the RDA of vitamin C will also prevent a deficiency. Infants who are being weaned from breast milk to cow's milk need a supplement containing vitamin C.

CALCIUM AND VITAMIN D

Calcium and Vitamin D are nutrients that have received much attention in recent years because they work together to prevent several chronic diseases. One of the best sources of calcium and Vitamin D is milk, but there are other sources. This post can help you understand why adequate amounts of these nutrients are needed for overall health and prevention of disease. You will also learn ways to meet the recommended intakes of each nutrient.

Where Is Calcium Found In The Body?

About 99% of the calcium in the body is in the bones and teeth and 1% is in the blood, muscles, and other soft tissues (such as the nerves, organs, etc.) This 1% plays a major role in our health.

Calcium is a very important mineral because it...

• Combines with phosphorus to form bones and teeth, making them hard and resistant to breaks and decay. Children need to get enough calcium for their bones and teeth to develop normally. Getting enough calcium early in life helps bones remain strong later in life.
• Helps muscles to contract normally. A deficiency can cause muscle spasms and cramps.
• Helps blood to clot normally, when you get a cut or wound.
• Is essential for nerve messages to be passed along the nervous system from the brain to other parts of the body and vice versa.
• Helps regulate blood pressure. Low calcium intake has been associated with high blood pressure. People with high blood pressure should make sure they consume the recommended amount of calcium (1000 to 1500 mg per day). African-Americans have a higher rate of high blood pressure than other groups and tend to have low calcium intakes.
• Calcium may help prevent colon cancer, one of the most common forms of cancer. Calcium may reduce cancer risk in two ways: (a) by binding fat and bile acids in the large intestine, keeping them from causing harm and (b) by preventing the excessive growth of cells in the intestines, which could otherwise lead to cancer.

Vitamin D is a fat soluble vitamin that ...

• Must be present for calcium to be absorbed and used. For this reason, milk that is rich in calcium and fortified with Vitamin D is a good choice.
• Is essential for calcium to be used for building bones and teeth and for other roles in the body.
• May help prevent colon cancer by working with calcium to slow the growth of intestinal cells that could otherwise lead to cancer.

Other Important Facts About Vitamin D:

• Vitamin D is called the "sunshine vitamin" because it is formed in the skin by the action of ultraviolet rays from the sun. For fair skinned individuals, 15 minutes of sunlight will produce enough Vitamin D to last for several days, even when wearing light clothing. However, it takes 3 hours or more for this to happen with dark-skinned people.
• Clouds, smoke, and window glass also prevent penetration of ultraviolet rays
• Use of a sunscreen lotion of 8 SPF or higher will prevent the formation of Vitamin D in the skin. When sunbathing, just wait 15 minutes before applying sunscreen lotion (i.e. if you are fair skinned).
• Vitamin D is also present in fish oil and some types of saltwater fish and shellfish (salmon, halibut, herring, tuna, oysters, and shrimp).
• Other Vitamin D sources are fortified milk (400 IU per quart) and some cereals. Check nutrition labels of cereals to see which ones contain Vitamin D.

What Is Good Bone Health?

• Throughout life, calcium continuously moves in and out of the bones. During childhood and the teen years, bones grow in size and density. Calcium goes into the bones faster than it comes out.
• Between ages 20 and 30 years, the bones do not grow anymore in size, but they become more dense and hard if you are taking in enough calcium and Vitamin D. Therefore, the first 30 years (first third of life) is called the "bone building stage."
• After age 40, calcium begins to move out of the bones faster than it goes back in. This is called the "bone losing stage." It is very important to reach this age with the strongest, most dense bones possible to minimize the effects of calcium loss.
• "Good bone health" means reaching adulthood with the most dense, strong bones possible, and then keeping the bones strong by doing the things discussed in this pamphlet.
• On the other hand, if too little calcium is stored in the bones before age 30, or calcium is drawn out too fast in later life, you will be at risk for getting a disease called osteoporosis.

What Is Osteoporosis?

• Osteoporosis (OSS-tee-oh-pore-OH-sis) is a disease, occurring mostly in older adults, due to a loss of bone density and a break down of bone structure. The bones become porous, thin, and brittle. Osteoporosis is a major health problem in the U.S.
• One cause of this disease is getting too little calcium in early life and reaching age 30 with too little calcium in the bones. It can also result from calcium being drawn out of the bones too fast due to several conditions (risk factors) discussed below.
• As the bones in the spine lose calcium, they become more thin and soft and can no longer support the body, causing the person to stoop forward. Eventually, this becomes very serious because the lungs and organs may not have enough room to work properly.
• Bones also break easily, especially those in the hips, legs, and arms. Falls may cause a bone to break, or a bone might give way causing the person to fall.

Risk Factors for Osteoporosis

• Being female: 80% of people with osteoporosis are women. Females have smaller bones and tend to take in less calcium than males. On average, U.S. adult females consume only 450 - 550 mg of calcium per day, which is only half the recommended amount of 1,000 mg.
• Race: Whites and Asians are at greatest risk for osteoporosis, but African-Americans and Hispanics also have some risk.
• Having thin bones and a small frame: If you start out with smaller bones, then lose calcium and bone due to other risk factors, the effect will be more serious.
• Family history of osteoporosis: There is a tendency for osteoporosis to run in families.
• Being underweight or constantly dieting to lose weight: Heavier people tend to have more dense bones. This is one advantage of being overweight. People who constantly stay on a diet to lose weight often do not take in enough calcium.
• Post-menopause: After menopause (i.e. menstrual periods have stopped) women have much lower levels of estrogen, which causes a loss of calcium from the bones.
• Inadequate physical activity: Getting too little physical activity leads to a loss of calcium from the bones.
• Low calcium/Vitamin D intakes: If you do not get enough calcium and Vitamin D early in life, your bones will be less dense and smaller. When you start losing calcium after age 40, the bones will rapidly show the effects of calcium loss.
• Excessive intakes of sodium and protein: Eating excessive amounts of sodium (in salt) and protein (in meat), while not taking in enough calcium, causes the kidneys to excrete more calcium from the body.
• Smoking: Smokers tend to have a lower bone density, partly because smoking decreases calcium absorption.
• Alcohol intake: Excessive intake of alcohol causes a loss of calcium from the body.
• Certain medications: Long-term use of corticosteroids, anticonvulsants, and antacids, as well as excessive levels of thyroid hormones, may either reduce calcium absorption or cause increased loss of calcium from the bones. If you take any of these medications, talk with your doctor about your possible need of a calcium supplement.

A major health concern is that many children and teenagers are not taking in enough calcium. One culprit may be the increased drinking of soft drinks. Health experts fear that many children will develop osteoporosis later in life, due to low calcium intakes during childhood and the teen years.

Ways to Prevent Osteoporosis

If you have any of the above risk factors, you should take the following actions to protect your bones. This is even more important if you have several risk factors.

1. Avoid fad or very restrictive diets to lose weight. If you are trying to lose weight, follow a balanced eating plan with at least a minimum of two cups of low-fat milk or other low-fat milk products. It is best not to go below 1500 calories. If you cannot lose weight at this level, you may need to increase your physical activity.
2. If you have gone through menopause or think you are near menopause, talk with your doctor about hormone replacement therapy (HRT) or estrogen replacement therapy (ERT).
3. Participate in regular physical activity, including at least 30 minutes of activity on most days of the week. Stretching and weight-bearing activities, such as walking, can increase bone density and help bones remain strong throughout life. Weight lifting exercises are also beneficial to bones, balance, and overall health. Be sure to check with your doctor before starting any new physical activity or greatly increasing your level.
4. Don't smoke. If you already smoke, try to stop, or at least cut down.
5. Eat a wide range of foods by selecting a variety from each group of the Food Guide Pyramid. Several nutrients are needed to build strong bones and teeth. Eat a variety of foods to get all of them.
6. Eat more calcium-rich foods. Milk and foods made with milk are the best sources of calcium. Fluid milk also contains Vitamin D. Cheese and other foods made from milk may not contain the same level of Vitamin D as fluid milk.
7. Limit salt and meat intake to moderate levels. Recommended intakes are 2400 mg sodium (1 teaspoon or less of salt) and 2 servings (total of 6 ounces) of meat per day.
8. Eat low-fat milk products. When trying to lose weight, or to reduce blood cholesterol, don't cut out milk. Instead, drink skim milk, 1% milk, or buttermilk, or eat low-fat cottage cheese (with added calcium) and yogurt.
9. If you drink alcoholic beverages, limit the amount to no more than one per day for women and two per day for men (one drink = 12 ounces beer, or 5 ounces wine, or 1 1/2 ounces liquor).
10. Have a bone density test, especially at age 65 and every 2 years thereafter. If you have 2 or more risk factors for osteoporosis, ask your doctor about having a bone density test at a younger age. The machine that measures bones in the entire body is referred to as a DEXA (dex-za) machine

Meeting Your Calcium Needs

The National Research Council has set up recommendations for the amount of calcium people need at different ages. These are called Dietary Reference Intakes or DRIs.

DRIs for Calcium At Different Ages and Amount of Milk Needed

Age Group	Calcium Needs	Milk to Provide Most of Calcium*
1 - 8 years	500 - 800 mg	2 to 3 cups
9 - 18 years	1300 mg	4 cups
19 - 50 years	1000 mg	3 cups or more
Women, 51+ (with **HRT) and Men, 51+	1200 mg	3 to 4 cups
Women, 51+ (without **HRT)	1500 mg	4 cups or more
Pregnant or Breastfeeding	1200 mg	3 to 4 cups
*1 cup (8 ounces) of Milk contains about 300 mg of Calcium. The above amounts of milk will not provide all the calcium needed, but there are other foods that can help meet calcium needs. **HRT = Hormone Replacement Therapy

What Are the Best Sources of Calcium and Vitamin D?

• The Milk, Yogurt, & Cheese Group of the Food Guide Pyramid is the best source of calcium and Vitamin D. It is very difficult to get enough calcium without drinking milk. One cup (8 ounces) of milk equals one serving and gives about 300 milligrams (mg) of calcium.
• Foods made with milk, such as cheese, yogurt, pudding, custard, ice milk, ice cream, and cream soups, are included in this group.
• Foods that are the lowest in calories, but contain the highest amount of calcium, are skimmed and low-fat fluid milk, buttermilk, and low-fat yogurt. Low-fat cottage cheese with added calcium is also an excellent choice. Plain, low-fat yogurt is especially high in calcium with 415 mg per cup.
• Cheeses contain varying amounts of calcium. The more firm the cheese, the more calcium it contains. For example, Swiss and Parmesan cheese are excellent sources of calcium, whereas softer cheeses (American, Farmers, Mozzarella, and Provolone) have lower amounts of calcium. Cream cheese is not a good source of calcium.
• Some cheeses are made with low-fat or skim milk and are lower in fat, cholesterol, and calories than regular cheese. Check "Nutrition Facts" labels to see how much fat and calcium you are getting in a serving. On the label, calcium is shown as a percent of the daily need of 1000 mg. To determine the milligrams of calcium in a serving, remove the % sign and add one 0. A food that provides 20% of calcium need in one serving will contain 200 mg of calcium.
• Canned fish, such as sardines and salmon, are good sources of calcium, if the bones are eaten.
• Tofu and soymilk are good sources of calcium if made with calcium.
• Almonds, dried beans and peas, and dark green leafy vegetables are fair sources of calcium.
• Due to their acid and Vitamin C content, some fruit juices increase the absorption of calcium.

Drinking orange or grapefruit juice with added calcium is a good way to meet calcium needs.

When substituting other calcium sources in place of milk, care must be taken to eat enough of these foods to equal the calcium in the milk that is replaced. The following foods provide about the same amount of calcium as 1 cup of milk (300 mg).

• Very Firm Cheeses (Swiss, Parmesan) - 1 ounce
• Less Firm Cheeses (cheddar, American, mozzarella and provolone) -1 1/2 ounces
• Regular Cottage Cheese - 2 cups
• Calcium-enriched Cottage Cheese - 3/4 cup
• Plain Ice Milk or Frozen Yogurt - 1 cup
• Plain Yogurt - 3/4 cup
• Pizza (2 slices) - 1/4 of a 12" pizza
• Tofu (cubes) - 1 cup
• Soybeans (cooked) - 2 1/3 cups
• Navy Beans (cooked) - 1 1/4 cups
• Pork N¹ Beans - 1 3/4 cups
• Salmon (canned with bones) - 5 1/3 ounces
• Turnip Greens - 1 1/2 cups

Contrary to previous belief, calcium from plant sources is well absorbed. One exception is the calcium in spinach, which is not well absorbed due to compounds called oxalates.

Lactose Intolerance

If you have a problem called "lactose intolerance," you may have trouble drinking regular milk. This is because some of the milk sugar "lactose" may not be digested due to a deficiency of the enzyme, lactase. This may result in excess gas, diarrhea, and nausea after drinking milk.

Cheese, yogurt, and buttermilk may not cause this problem since much of the "lactose" has already been broken down. Also, you may be able to drink smaller amounts of milk at one time (1 cup or less) without symptoms. Lactaid tablets (from a drug store) can be added to milk to reduce the lactose.

Do you need to take a calcium supplement?

If you do not get enough calcium from food, because you don't like milk or have lactose intolerance, you may need to take a calcium supplement. Postmenopausal women, if not on hormone replacement, may need a calcium supplement. The recommended intake of calcium is 1500 mg per day, which is difficult to meet without a calcium supplement.

Here are some things to consider, if you take a calcium supplement:

• Not all calcium supplements are equally well absorbed in the body. Calcium Carbonate and Calcium Citrate are fairly well absorbed. These are available in most drug stores without a prescription.
• Calcium Citrate is well absorbed under most conditions, but is best taken on an empty stomach. Calcium Carbonate needs acid to be absorbed, so it is best taken with a meal or soon thereafter when stomach acid is highest. Stomach acid may be low in older adults (called achlorhydria), causing reduced calcium absorption. Thus, Calcium Citrate might be the best choice for older adults.
• How much calcium should you take at one time? No matter what type of calcium supplement you take, limit the amount to no more than 500 mg at a time (calcium in food + supplement). This is all that the body can absorb at once. Some cereals provide 1000 mg calcium in a serving, which overloads the body's ability to absorb all of it.
• Do you also need a Vitamin D supplement? If you have dark skin, or are in the sun very little, you may need a calcium supplement that contains Vitamin D. Only 5 to 10 micrograms (200 to 400 IU) of Vitamin D are needed each day, but be sure to keep your intake below 50 micrograms (2,000 IU) per day. A daily intake higher than this can be very harmful.

NUTRITION PART 7: MALNUTRITION

MALNUTRITION
Malnutrition may be due to people not taking enough food or taking too much food and not in the right proportion.

In the underdeveloped nations, malnutrition takes many forms:

• Starvation leading to marasmus (lack of energy food and protein) and kwashiorkor (lack of protein).
  
• Eating disorders like anorexia and bulimia.
• Overweight and obesity due to too much consumption of saturated fats.
• Constipation (not enough dietary fibres in the diet)
  

WHY ARE SO MANY PEOPLE SUFFERING FROM MALNUTRITION?
There is no simple answer to this question as there are many factors which can combine to create the problem. Some of these are:

• OVERPOPULATION - The population of many countries has been rising faster than food production.
  
• FAMINE - Famine is an extreme shortage of food. Industrialised nations have agricultural surplus due to their advances in technology and their high yielding crops. This results in an unequal distribution of food. The farmers of industrialised nations expect a return for their labour in producing surplus food. They sell the surplus food to the highest bidder - the industrialised consumer countries. underdeveloped and developing countries with no means to pay fo the expensive food face famine when their food production is insufficient.
  
• FLOODS - Floods may occur when rivers overflow their banks. Heavy rainfalls during monsoon season, tidal waves and collapsed dams, all cause widespread destruction of the agricultural land and the crops themselves. Farm lands destroyed by tidal waves are no longer suitable for farming.
  
• DROUGHT - This brings about extreme crop damage and the destruction of farm animals. Severe climatic changes have also contributed to a world wide shortage of food.
  
• POOR SOIL - To grow good crops, the soil has to contain nutrients. If the same soil is used year after year, the nutrients are all gradually removed, leaving the soil unable to support life.
  
• PESTS - A single locust swarm contain millions of insect which can eat in one day an amount of food which would feed hundreds of people for a year.
  

WHAT CAN BE DONE TO OVERCOME PROBLEMS OF WORLD FOOD SUPPLIES?

• Enhanced food yields can be obtained using new strains of wheat, maize and rice - called the green revolution.
• Farming the sea by culturing fish, lobsters, prawns and crabs has been done successfully. Seaweed and algae could be grown and harvested for food as well.
• Genetically modified food has shown promising results in food production. Plants and animals have had their genes altered to improve quality. Genetically modified food is being hailed as the potential solution to a growing world population and dwindling food supplies.
• Improve the distribution of food from countries with surplus to overpopulated third world countries. This has been successfully implemented bu the World Red Cross organisation. Surplus wheat from USA has been distributed to famine stricken nations.
• Developing farming technology has been effective in improving the output from farms. Modern day farm machinery and the use of fertilisers has helped farmers increase output.
• By enriching food, most basic foods such as bread have nutrients added to them to improve the quality of food and help prevent malnutrition. Vitamins and minerals are added to benefit the health of consumers.
• Using better methods of pest control could reduce the quantity of food lost during storage.
• Increasing the land under cultivation can increase food production. With modern technology, arid, semi-arid and deserts can be irrigated for farming.
  

NUTRITION PART 6: BALANCED DIET

WHAT IS A BALANCED DIET?
A balanced diet is a diet which contains the right amount of carbohydrates, fats, proteins, vitamins, minerals, water and roughage to meet the daily requirements of the body. A balanced diet for one person may not be suitable for another person because the amount of each type of food to be taken depends on factors like climate, body size, age, sex, health and occupation.

WHAT IS BASAL METABOLISM?
It is the amount of energy needed to carry on vital processes of the body when it is in complete rest. Therefore, our daily energy requirement depends on our basal metabolism and the physical activities we perform. So it means that, the more active we are, the higher will be our basal metabolic rate and the more energy is needed (therefore, more food should be taken).

FACTORS AFFECTING BASAL METABOLIC RATE
A. CLIMATE

• People living in colder climate tends to lose more heat.
  
• They generally have higher basal metabolic rate compared to those living in the warmer places.
  
• So, to maintain their body temperature (remember they tend to lose more heat faster), they need to take in their diet, more energy giving food (like carbohydrates) to generate more heat thus compensating the heat lost earlier.
  

B. BODY SIZE

• People with bigger body size (despite the same age and sex) have higher basal metabolic rate than those with smaller body size. They lose heat more than those with smaller body size.
  
• Therefore, they should take in more energy giving food like carbohydrates.
  

C. AGE

• Young children usually have higher basal metabolic rate than adults because they need more energy for growth. Since they are growing, they also need protein rich food as well as food rich in vitamin D and Calcium for bones and teeth formation and development.
  
• The basal metabolic rate in adults, tends to decrease slowly throughout their life. Therefore, adults need to be very careful with their intake of energy giving food. The intake must match with their physical activities.
• Older adults also need to take in more Calcium and vitamin D since they are more prone to bone-related problems.
  

D. SEX

• Male, being generally more muscular and having less fatty tissue in their body than female have higher basal metabolic rate despite their body size and age.
• This means that male lose heat easily. Therefore, to compensate this heat loss, male must take in more energy giving food than the female.
  

E. HEALTH

• Thyroid gland produces thyroxine (hormone) which controls the basal metabolic rate of a person.
• The more it is produced, the higher the basal metabolic rate.
• Some people may have under-active thyroid glands, thus thyroxine production becomes less and this will in turn lower down the basal metabolic rate.
• Those having over-active thyroid glands will produce more thyroxine which increases their basal metabolic rate.
  

F. OCCUPATION

• Those working in an air-conditioned offices, sitting infront of the computer may not need as much energy giving food as those working outdoor under the scorching hot sun.
• Therefore the more active you are the higher your basal metabolic rate. Therefore the more energy giving food must be taken.

SPECIAL REQUIREMENTS
A. PREGNANCY

• Pregnant ladies need to eat for two? Not necessarily!!!
• For the healthy development of the fetus as well as for their health throughout their pregnancy, they need to take in food rich in protein, calcium, vitamin D and iron.
• Protein is needed for making the baby's tissues ( hence for growth).
• Calcium and vitamin D are needed for the baby's proper bone formation and development.
• Iron is needed of making the baby's haemoglobin in its blood.
  

B. LACTATING MOTHER

• Lactating mother need to increase the intake of proteins, vitamins and calcium to produce milk of adequate quality and quantity for the baby.
• Protein is needed for the baby's growth.
• Vitamin D and calcium for the baby's proper bones and teeth formation and development.
• Vitamin C for proper development of the connective tissues.
• Iron for making haemoglobin.
  

C. GROWING CHILDREN

• Growing children needs a diet very rich in protein, calcium, iron, vitamins D and C.
• Girls who have gone through puberty must take in more iron in their diet especially during menstruation to replace the iron they lose.
  

NUTRITION PART 5: VITAMINS AND MINERALS

Apart from carbohydrates, proteins, fats, roughage and water, vitamins and minerals must also be included in your diet. There are quite a number of vitamins and minerals but according to your syllabus, you only have to know 2 vitamins (vitamins C and D) and 2 minerals (Iron and Calcium).

MINERALS
A. IRON

• The red blood cells contain the pigment haemoglobin which contains iron. This iron plays and important role in transporting oxygen around the body. Millions of red blood cells are broken down each day and their iron is stored by the liver and used to make more haemoglobin. However some iron is lost and adults have to take in about 15mg each day.
• Source of iron: Red meat, liver, kidneys, eggs, groundnuts, bread, spinach and other green vegetables.
• Diet deficient in iron: Anaemia - insufficient haemoglobin resulting in the reduction of the blood's oxygen carrying capacity.

B. CALCIUM

• Calcium (in the form of calcium phosphate) is deposited in the bones and the teeth (hence making them hard). In another way to say, calcium is very important for bones and teeth formation and development.
  
• Calcium is also present in blood plasma and plays and important role in blood clotting (without calcium, blood clotting becomes less efficient).
• Caclium is also needed for chemical changes which bring about muscle contraction and transmission of nerve impulses.
• Source of Calcium: Any diary products, especially milk.
• Note: Many calcium salts are insoluble in water and may pass through the alimentary canal without being absorbed. For calcium to be absorbed, vitamin D must also be included in your diet. So no point taking in tons and tons of calcium (literally speaking) without taking in vitamin D.
• Diet deficient in calcium may results in rickets (in children) and osteomalacia (in adults).

VITAMINS
A. VITAMIN D

• Vitamin D is a fat-soluble vitamin.
• Vitamin D is relatively resistant to heat and oxidation.
  
• Source of vitamin D: Fish liver oils, egg yolks, milk and margarine
• Morning Ultraviolet rays in sunlight helps your skin to make vitamin D. So if get enough morning sunlight, you may not need vitamin D in your diet.
• Main functions of vitamin D: Helps in the absorption of calcium (and phosphorus), hence promoting formation and proper development of bones and teeth.
• Deficient: Rickets in children (poor bones and teeth development). In severe cases, the bones may become soft and pliable and are readily bent under the weight. Hence bow legs. In adults, insufficient vitamin D in the diet may results in Osteomalacia (bones become soft and may break easily).
• Excess: Deposition of excess calcium may result in organs like the kidneys and the lungs (calcification).
  

B. VITAMIN C (ASCORBIC ACID)

• Vitamin C is a water soluble vitamin.
• Source of vitamin C: Citrus fruits and other fruits like papaya, guava, tomatoes and bananas. Fresh green vegetables are also very rich in vitamin C.
• Vitamin C is easily destroyed by heat. So, be very careful not to destroy your source of vitamin C when cooking.
• Functions: Very important for the formation of intercellular substances which are normally found in between the cells (that hold the cells together). Vitamin C is also important for maintaining healthy epithelial tissues.
• Deficient in vitamin C may lead to SCURVY (swollen bleeding gums, loosening of teeth, haemorrhages in the muscles and skin, poor healing of wounds and painful swollen joints)
• Excess: Excreted out from the body. It cannot be stored. So daily intake is necessary.
  

NUTRITION PART 4: ROUGHAGE AND WATER

ROUGHAGE

• When we eat vegetables and other plant materials, we are actually taking in a large quantity of plant cells (Remember the cell walls? They are made of inert carbohydrate called CELLULOSE)
• Humans cannot digest plant materials because humans cannot produce CELLULASE, an enzyme which can digest cellulose. Because of this, the plant cell walls reach the large intestine without being digested. This undigested part of the diet is called fibre or roughage.
• SO, WHAT THEN IS THE ROLE OF ROUGHAGE IN YOU DIET? The fibre add bulk to the contents of the colon and help it to retain water. This softens the faeces and reduces the time needed for the undigested materials to pass out of the body. This helps to prevent CONSTIPATION and keeps the colon in a healthy condition.
• Good sources of dietary fibres: wholemeal bread and bran.
  

WATER

NUTRITION PART 3: LIPIDS

LIPIDS

• Fats (solid), oils (liquid) and waxes.
• Lipids are compounds that consist of carbon, hydrogen and oxygen.
• A molecule of fat consists of 2 parts. The main part is called GLYCEROL and attached to it are three molecules of FATTY ACIDS. Different kinds of fats contain different fatty acids.
  

FUNCTIONS OF LIPIDS

• Reserve supply of energy when food is insufficient.
• Fats provide twice the amount of energy as carbohydrates.
• Stored beneath the skin (prevents heat loss) and around delicate organs (provides protection).
• Transport fat-soluble vitamins: Vitamins A, D, E and K.
• A constituent of the cell membrane.

EXTRA INFORMATION

• Unsaturated fats are 'good' fats. Found in Fish oils and vegetables.
• Saturated fats are ‘bad’ fats. Saturated fats increase the level of cholesterol in the body. Found in animal fats e.g. butter, burger, meat etc.
• Studies have shown that a diet rich in cholesterol and saturated fats increases the risk of heart disease.
  

NUTRITION PART 2: PROTEIN

• Proteins are very complex organic substances containing carbon, hydrogen, oxygen and nitrogen (sometimes sulphur and phosphorus).
• The basic units of proteins are amino acids.
• There are 20 essential amino acids.
• Proteins obtained from animal sources are called COMPLETE PROTEINS because they contain all the 20 essential amino acids.
• Proteins obtained from plant sources are called INCOMPLETE PROTEINS because not all the essential amino acids are present.

QUESTION?
HOW CAN VEGETARIANS GET ALL THE 20 ESSENTIAL AMINO ACIDS IN THEIR DIET (CONSIDERING THEY DO NOT TAKE ANIMAL PROTEINS WHICH CAN ACTUALLY PROVIDE THEM WITH THESE 20 ESSENTIAL AMINO ACIDS?

EFFECTS OF PROTEIN DEFICIENCY
The average human adults needs 50 to 100g of proteins a day. The deficiency of proteins in the diet of children may lead to a protein deficiency disease called KWASHIORKOR. Such children usually have swollen abdomens. Their skin cracks and becomes scaly.

FUNCTIONS OF PROTEINS

• Essential for synthesis of protoplasm (hence for growth and repairing worn out tissues).
• Essential for synthesis of enzymes and some hormones.
• Essential for the formation of antibodies to combat diseases.
• A source of energy only after all the fat reserve is used up (but mind you, fat reserve in the body will first be used if the body has insufficient glucose to be used as a source of energy).
  

NUTRITION PART 1: FOOD AND CARBOHYDRATE

This chapter discusses one of the characteristics of living things, feeding. All living things need food but the difference between plants and animals is that the green plants can make food by photosynthesis but animals have to to rely on other organisms (plants and other animals) as their source of food. Why do living organisms need food?

THE NEED FOR FOOD

• It provides the building materials for making new cells and tissues which are later used for growth.
• It provides energy for the chemical reactions (such as building complex molecules like proteins) which take place in living organisms to keep them alive. Apart from this, the energy is also used for activities such as movement, heart beat and transmission of nerve impulses. Animals also use energy for maintaining their body temperature.
• It provides substances for replacing worn out and damaged or wounded tissues.
  

CLASSES OF FOOD
Food can be divided into two main classes: Macro-nutrients (carbohydrates, proteins and fats) and Micro-nutrients (minerals, vitamins, dietary fibre and water). Macro-nutrients are those needed in large quantities whereas Micro-nutrients are those needed in minutes quantities.

CARBOHYDRATES
Carbohydrates are energy giving food. In fact, they are the most readily available source of energy. They contain the elements carbon, hydrogen and oxygen. When they are oxidized during respiration to provide energy, they are broken down into carbon dioxide and water. One gram of carbohydrate can provide an average of 16kJ of energy. If we eat more carbohydrates more than we need to, the excess is converted in the liver to glycogen for storage in the muscles and the liver itself. If the glycogen is not used for a very long time, it will eventually converted into fats and stored in the fat depots in the abdomen, round the kidneys or in the adipose tissues under your skin. SO BEWARE!!!


Carbohydrates can be further divided into three groups:

A. Polysaccharides
Made up of a large number of glucose molecules joined together. Examples: Starch, Glycogen and Cellulose.

• STARCH can be found in vegetable foods such as cereals, rice, potatoes and tapioca. It is not formed or stored by animals. In digestion, starch is broken down into maltose by enzyme, amylase.
• GLYCOGEN is a storage form of carbohydrate in animals (and also in fungi). For this reason, glycogen is also referred to as an "animal starch". In mammals, glycogen is commonly stored in the liver and muscles. Like starch, glycogen is suitable as storage materials because they are insoluble in water (so they do not change the osmotic pressure of the cells), they are large molecules (so unable to diffuse through cell membrane), they can be converted easily into glucose when needed, and they have compact shape (hence they can occupy less space in the cytoplasm).
• CELLULOSE is one of the component of the cell walls of plant cells. Unlike starch and glycogen, it is inert and very few organisms (those that can produce the enzyme, cellulase) can digest it. Even though, human cannot digest cellulose, plant materials must be included in the diet because it forms the bulk of undigested matter. Hence it prevents constipation.
  

B. Disaccharides (Complex sugars)
Each molecule of disaccharide is made up of two molecules of monosaccharides (simple sugars) condensed together. The general formula for all disaccharides is C12H22O11 (Remember that one molecule of water is removed when two molecules of monosaccharides (formula = C6H12O6) condensed.

• SUCROSE or cane sugar occurs in sugarcane stems, sweet fruits and certain roots like sugar beet and carrots. It consists of a glucose molecule and a fructose molecule combined together by condensation. It is not found in mammals. It can be digested by an enzyme called sucrase.

GLUCOSE + FRUCTOSE --> SUCROSE + WATER

• LACTOSE or milk sugar is found in the milk of all mammals. It is formed from a condensation process between a molecule of glucose and a molecule of galactose. Lactose can be broken down into glucose and galactose by an enzyme called Lactase.
  

GLUCOSE + GALACTOSE --> LACTOSE + WATER

• MALTOSE or malt sugar occurs in malted cereals and sprouting grains. It is formed from a condensation process between two molecules of glucose. Maltose can be broken down into glucose by an enzyme called maltase
  

GLUCOSE + GLUCOSE --> MALTOSE + WATER

C. Monosaccharides
Monosaccharides are also known as simple sugars. Examples: GLUCOSE, FRUCTOSE and GALACTOSE. They all have the same general formula - C6H12O6.

REDUCING AND NON REDUCING SUGARS

• Reducing sugars are glucose, fructose, galactose, maltose and lactose.
• Non-reducing sugar is sucrose.
• The presence of reducing sugar in food can be detected by means of Benedict's solution.
• When the blue Benedict's solution changed to brick red (or brown or yellow or orange), it indicates the presence of reducing sugar in the food.