This document discusses nutrition and energy balance. It states that energy intake and output must be balanced for stable body weight over time. When energy intake exceeds output, weight increases, and when intake is less than output, weight decreases. It also covers body energetics, listing the average calories provided by carbohydrates, fats, and proteins. Additional topics include daily nutrient requirements, protein deficiency diseases like kwashiorkor and marasmus, and factors that regulate food intake such as hormones and the hypothalamus.
2. Energy intake & output are balanced
Intake of different food provide energy that can be used to perform body
function or stored for later use.
Stability of body weight over a period of time requires that the person’s
energy intake be balanced with the energy consumed.
Example:
• When energy intake is more than the energy consumed that will result in
weight increase.
• When energy intake is less than the energy consumed that will result in weight
loss.
BODY ENERGETICS
3. Energy liberated from each gram of Carbohydrates is 4.1 calories, energy
liberated from each gram of Fat is 9.3 calories and energy liberated from each
gram of Protein is 4.3 calories.
All these substances vary in the average percentage that are absorbed in the
Gastrointestinal tract about 98% of Carbohydrates, 95% of Fat and 92% of
Protein are absorbed. Therefore the average energy in each gram of these
substances in diet is as follows:
Carbohydrates 4 calorie
Fat 9 calorie
Protein 4 calorie
ENERGY AVAILBALE IN FOOD
4. In this table we can see that
the composition of selected
food specially with high
proportions of fat and protein
in animal products. And the
food with high proportion of
carbohydrates is in vegetables
and grain products.
5. Daily requirements of protein is from 30 to 50 grams, person usually use from 20
to 30 grams of the body protein to produce body chemicals on daily basis. So the
cells will be able to form new protein to compensate those who were destroyed
depending on the person’s protein diet ( some proteins don’t have good
quantities of some essential amino acids and therefor cannot be used to replace
the destroyed protein, these proteins are called partial proteins).
In general proteins derived from animal product are better than proteins that
are derived from vegetables and grains and this is the reason why some
individuals in poor countries who depend on their protein intake from
vegetable and grain products develop a protein deficiency syndrome called
“Kwashiorkor”
AVERAGE DAILY REQUIRMENTS OF PROTEIN
6. KWASHIORKOR
Characteristics:
• Retarded growth
• Fatty liver
• Severe Edema
• Anemia
• Malabsorbtion due to atrophy of the
small intestinal villi.
• Depigmented bands in the hair or
skin.
• Loss of muscle with preservation of
subcutaneous fat
7. MARASMUS SYNDROME
Is caused by wide spread deficiency of almost all nutrients, notably
proteins.
Characteristics:
• Retarded growth
• Loss of muscle with loss of subcutaneous fat
• Prominent bones
• Loose skin
8. • Sensation of hunger associated with several objective sensations such as
contraction of stomach and restlessness and that’s cause the person to search
for food.
• The person’s appetite is the desire for certain type of food, if the food selection
was successfully done, the feeling of satisfaction occurs.
• Each of there feelings( Hunger, appetite and satisfaction) influenced by
environmental and cultural factors as well as specific centers in the brain
(Hypothalamus).
• Stimulation of the lateral nuclei of Hypothalamus (act as a feeding center) will
result in hyperphagia, conversely destruction on lateral nuclei of Hypothalamus
will result in lack of desire of food, muscle weakness, weight loss and decrease
in metabolism
REGULATION OF FOOD INTAKE
9. • Stimulation of the ventro medial nuclei of Hypothalamus (act as a satisfaction
center) will give complete feeling od satisfaction even in the presence of food
and the person refuses to eat (Aphagia)
• Conversely destruction of this region will result in too much and continuous
eating.
• The Paraventricular and dorsomedial nuclei of Hypothalamus also involved in
regulation of food intake. Example: lesions of paraventricular nuclei cause
excessive eating and lesion of the dorsomedial nuclei depress eating.
• Also these nuclei of Hypothalamus affect the secretion of several hormones
which is important in regulation energy balance and metabolism including
those from Thyroid and Adrenal glad and pancreatic cells.
REGULATION OF FOOD INTAKE
10. • Also Hypothalamus receives neural signals from gastro intestinal tract about
stomach filling and chemical signals from nutrients in blood (glucose, amino
acids and fatty acids) and other signals from the gastro intestinal tract
hormones and cerebral cortex (sight, smell and taste) that influence feeding
behavior.
• Hypothalamic feeding and satisfaction centers have high density of receptors
for neurotransmitters and hormones that control feeding behavior.
Decreases Feeding Increase Feeding
Serotonin,
Norepinephrine
Leptin
Insulin
Corticotropin- releasing hormone
Neuropeptide Y
Melanin concentrating hormone
Galanin
Cortisol
REGULATION OF FOOD INTAKE
11. • Other aspects of feeding is the mechanical action of the feeding process(
salivation, licking the lip, chewing and swallowing) so if we sectioned the brain
below Hypothalamus and above mesencephalon the person can still do the
mechanical features of feeding, therefore the actual mechanics of feeding
controlled by centers in the brain stems.
• We have centrals higher than Hypothalamus which is important in controlling
feeding specially appetite. These centers are Amygdala and Prefrontal Cortex.
• Destruction of Amygdala on both sides of the brain will lead to psychic
blindness in choice of food, in other words the human loses the appetite and
loses control of type and quality of food.
REGULATION OF FOOD INTAKE
12. • Factors regulating quantity of food intake are divided into :
a. Short Term Regulations
b. Intermediate and Long Term Regulations
FACTORS REGULATING QUANTITY OF FOOD INTAKE
13. Short Term Regulations:
Which concerns with preventing over eating at the time of each meal. We have several of
feedback signals as:
1. Gastro intestinal filling inhibition factor
When the gastro intestinal tract become full specially stomach and duodenum, stretching inhibition
signals is transmitted to suppress feeding centers .
2. Hormonal factors
Cholecystokinin a gastro intestinal hormone released when fat inters the duodenum has an effect on
suppressing feeding centers. Also presence of food in stomach and duodenum cause the pancreas to
secrete glucagon and insulin which have effect on suppressing feeding centers .
3. Oral receptors meters food intake
Oral factors related to feeding (salivation, chewing, tasting and swallowing) meters the food as it pass
through the mouth and after certain amount it suppresses the feeding centers
FACTORS REGULATING QUANTITY OF FOOD INTAKE
14. Intermediate and Long Term Regulations
Which concerns with maintaining normal quantities of energy stored in the body.
1. Glucostatic, aminostatic and lipostatic theories
Decrease in the blood contents of glucose or amino acids or lipids(Fatty acids) will cause hunger (
stimulating of feeding centers).
2. Relation between body temperature and food intake.
When a person is exposed to cold, he over eats and when a person is exposed to heat he under eat.
This is due to the interaction in the hypothalamus between temperature regulating system and food
regulating system. Example: increase food intake in the cold person leads to an increase in the
metabolic rate and an increase in the fat insulation. Both tend to correct the cold state
FACTORS REGULATING QUANTITY OF FOOD INTAKE
15. Intermediate and Long Term Regulations
3. Feedback signals from adipose tissue regulate food intake
Most of stored energy consist of fat, so the relation between the fat and the energy storing (food
intake) is as follows: recent studies suggest that hypothalamus senses the energy stored by peptide
hormones called leptin.
When adipose tissue increase there will be an increase in the production of leptin in the blood to reach
the leptin receptors in the hypothalamus, stimulating of these receptors will cause:
a. Decrease production of appetite stimulators
b. Increase production of hormones which decreases food intake as Corticotropin- releasing hormone
c. Increase in metabolic rate.
d. Decrease in insulin secretion which decrease the energy storage.
FACTORS REGULATING QUANTITY OF FOOD INTAKE
16. VITAMINS
Its an organic compound needed in small amount for normal body metabolism.
Vitamins are divided into Water soluble and Fat soluble.
Water Soluble Fat Soluble
Vitamin B1
Vitamin B2
Vitamin B3
Vitamin B6
Vitamin B12
Vitamin C
Folic Acid
Vitamin A
Vitamin D
Vitamin E
Vitamin K
17. Water soluble vitamins are not stored in the body, so regular intake of these vitamins
is important except for Vitamin B12 because it is stored in the liver in large quantities
which can last for months or even a year.
Toxicity from excessive intake is rare because excess amount will go out with the
urine
VITAMINS- Water Soluble Vitamins
18. The co-enzyme Thiamine pyrophosphate plays an important role in carbohydrates and
amino acids metabolism
Deficiency in this vitamin will cause:
Wet Beriberi
Dry Beriberi
Infantile Beriberi
Wernicke-korsakoff Syndrome.
VITAMINS- Water Soluble Vitamins
Vitamin B1 (Thiamine)
19. Wet Beriberi
Wet beriberi affects the heart and circulatory system. It is sometimes fatal, as it causes a
combination of heart failure and weakening of the capillary walls, which causes the peripheral
tissues to become edematous. Wet beriberi is characterized by:
• Increased heart rate
• Vasodilation leading to decreased systemic vascular resistance, and high output cardiac failure
• Elevated jugular venous pressure
• Dyspnea (shortness of breath) on exercise.
• Peripheral oedema (swelling of lower legs)
VITAMINS- Water Soluble Vitamins
Vitamin B1 (Thiamine)
20. Dry Beriberi
Dry beriberi causes wasting and partial paralysis resulting from damaged peripheral nerves. It is
characterized by:
• Difficulty in walking
• Tingling or loss of sensation (numbness) in hands and feet
• Loss of tendon reflexes
• Loss of muscle function or paralysis of the lower legs
• Mental confusion/speech difficulties
• Pain
• Involuntary eye movements
• Vomiting.
VITAMINS- Water Soluble Vitamins
Vitamin B1 (Thiamine)
21. Infantile Beriberi
Infantile beriberi usually occurs between two and six months of age in children whose
mothers have inadequate thiamine intake. In the acute form, the baby develops dyspnea
and cyanosis and soon dies of heart failure. Infantile Beriberi is characterized by: :
• Hoarseness, where the child makes moves to moan with no sound
• Weight loss, Vomiting, Diarrhea
• Pale skin
• Edema
• Ill temper
• Alterations of the cardiovascular system, especially tachycardia (rapid heart rate)
VITAMINS- Water Soluble Vitamins
Vitamin B1 (Thiamine)
22. Wernicke-korsakoff Syndrome.
also called wet brain or Korsakoff's psychosis, is the combined presence of Wernicke's
encephalopathy and Korsakoff's syndrome due to the close relationship between these
two disorders. WKS is usually secondary to alcohol abuse. It is characterized by:
• Ocular disturbances
• Changes in mental state
• Unsteady walking and stand (ataxia)
VITAMINS- Water Soluble Vitamins
Vitamin B1 (Thiamine)
23. Vitamin B2 is a component of two important coenzymes ( Flavin mononucletoide FMN
and Flavin adenine dinucleotide FAD) which are hydrogen carrier of the oxidative system
of mitocondria.
The deficiency in vitamin B2 causes:
• Cheilosis
• Corneal Vascularization
• Glossitis
• Dermaitis
VITAMINS- Water Soluble Vitamins
Vitamin B2 (Riboflavin)
24. Vitamin B3 act as a coenzymes in the form of Nicotinamide Adenine Dinucleotide (NAD) or Nicotinamide
Adenine Dinucleotide Phosphate NADP which are essential to glycolysis and they are hydrogen acceptors
they combine with hydrogen atoms .
The deficiency in vitamin B3 causes Pellagra :
Pellagra: A disease due to deficiency of niacin,
a B-complex vitamin.
Pellagra is the "disease of the four D's" --
Diarrhea;
Dermatitis: A scaly rash on skin exposed to light or trauma;
Dementia: Mental disorientation, delusions and depression; and
Death.
VITAMINS- Water Soluble Vitamins
Vitamin B3 (Niacin, Nicotinic Acid)
25. Vitamin B6 is necessary in synthesis of Niacin from Tryptophan.
The deficiency in vitamin B6 causes:
• Cheilosis
• Glossitis
• Anemia
• Nuerologic dysfunction
VITAMINS- Water Soluble Vitamins
Vitamin B6 (Pyridoxine)
26. Vitamin B12 is necessary in folate synthesis and in DNA synthesis and the major fuction
of B12 is the promotion of growth and promotion of red blood cells formation and
maturation .
The deficiency in vitamin B12 causes:
• Pernicious Anemia
• Megablastic Anemia
• Neurologic Dysfunction (Demyelination of the large nerve fibers of the spinal
cord)
VITAMINS- Water Soluble Vitamins
Vitamin B12 (Cobalamin)
27. Folic Acid
Act as hydroxymythyl and formyl groups.
The most important use in the body is in the syntheses of
purines, and thymine, which are required for formation of
DNA, therefore, Folic acid like Vitamin B12 is required for
replication of the cellular genes, thus its essential to promote
growth.
Folic acid is more potent growth promoter than vitamin B12,
and like vitamin B12 in the importance of RBC maturation.
Deficiency of Folic acid result in megaloblastic anemia, and it
does not cause neurologic changes as in Vitamin B12
deficiency.
28. Vitamin C is essential in collagen synthesis and hydroxylation of dopeamin in synthesis
of norepinephrine.
VITAMINS- Water Soluble Vitamins
Vitamin C (Ascorbic Acid)
The deficiency in vitamin C causes:
• Weakness in collagen fibers
• Defective wound healing
• Scurvy: is a disease resulting from a deficiency
of vitamin C. Scurvy often presents initially with
fatigue, followed by formation of spots on the
skin, spongy gums, and bleeding from the
mucous membranes.
Scurvy
29. Fat soluble vitamins are stored in the body, either in the cells or in the liver so
regular intake is not that important ( Person can stay from 5-10 months without
Vitamin A intake and from 2-4 months without Vitamin D intake.
VITAMINS- Fat Soluble Vitamins
30. Vitamin A is a term for a group of compounds (Retinoids) . Vitamin A is important in the
maintenance of mucus secretion epithelium. Also Retanol is a Vitamin A derivative and
its component of visual pigment Rhodopsin.
The deficiency in vitamin A causes:
• Night blidness due to insufficiant retinal rhodopsin
• Squmous metaplasia of tracia, bronchi and renal pelvis
Hypervitaminosis can cause alopecia, hepatoceluar damage and bone changes.
VITAMINS- Fat Soluble Vitamins
Vitamin A
31. Synthesized in the skin by ultra violate light.
It is important in Calcium and Phosphorus intestinal absorption.
The deficiency in vitamin D causes:
• Rickets in children
• Osteomalasia in adults due to improper calcium absorption.
Hypervitaminosis can cause growth retardation in children and hyper calciurea and
renal calculi in adults.
VITAMINS- Fat Soluble Vitamins
Vitamin D
32. Its an antioxidant.
The deficiency in vitamin E is rare but if it happens it can cause neurologic dysfunction
VITAMINS- Fat Soluble Vitamins
Vitamin E
33. It is essential in the formation of clotting factor ( II, VII, IX and X).
The deficiency in vitamin K will cause a bleeding problem marked by prolonged
prothrombin and activated partial thrombopastin time
VITAMINS- Fat Soluble Vitamins
Vitamin K
35. Magnesium act as a catalyst for many reactions specially those related to
carbohydrates metabolism.
The extracellular fluid magnesium concentration is slight only 1.8 to 2.5 mEq/l
Increased extracellular of magnesium depressed activity in the nervous system as
well as skeletal muscle contraction.
Low magnesium concentration causes irritability of the nervous system, peripheral
vasodilation and arrhythmias.
MINERALS
Magnesium (Mg)
36. Present in the body in the form of Calcium Phosphate in the bone.
Excess Calcium concentration in the extracellular fluid can cause the heart to stop in
systole and it can act as a mental depressant.
Low level of Calcium concentration can cause spontaneous discharge of nerve fibers
resulting in Tetany.
MINERALS
Calcium (Ca)
37. Phosphorus have the ability to combine reversibly with many coenzymes systems
with multiple other compound that are necessary in metabolic process
MINERALS
Phosphorus (P)
38. Trace elements are few elements present in the body in small quantities, yet without
any one of them deficiency syndromes will develop.
TRACE ELEMENTS
39. Iodine is very important in the formation and function of thyroid hormones which
are essential for maintaining normal metabolic rate in all the cells
TRACE ELEMENTS
Iodine (I)
Fluorine (F)
Presence of Fluorine in small amount during a certain
period of time when the teeth are being developed is
important for protecting against caries.
Excess intake of fluorine causes Fluorosis which affect
teeth and they become mottled and in sever cases it
causes bone enlargement.
Fluorosis
40. Is an integral part of many enzymes specially carbonic anhydrase which present in
high concentration in the red blood cells.
This enzyme is responsible for rapid combination of CO2 with water in the red blood
cells of the peripheral capillary and rapid release of CO2 from the pulmonary
capillaries into the alveoli.
This enzyme is also found in the gastrointestinal mucosa, in the tubules of the kidney
and in the epithelial cells of many glands. Therefore Zinc in small amount is
important for many reactions related to CO2 metabolism.
Zinc is also a component of lactic dehydrogenase and therefore it is important for the
interconversion between Pyruvic acid and lactic acid.
Finally zinc is a component of peptidases, therefore it is important in protein
digestion
TRACE ELEMENTS
Zinc (Zn)
41. The main function of iron is formation of Hemoglobin.
Two thirds of Iron in the body is in the form of Hemoglobin, and the rest is found in
other forms in the liver and bone marrow.
Electron carriers containing Iron ( specially in the cytochromes) are present in the
mitochondria and there fore iron is essential for transport of oxygen and for
operation oxidative system within the tissue.
Without Iron life can come to an end in seconds.
MINERALS
Iron (Fe)
42. Dietary Sources
B Complex Vitamins, except Vitamin
B12
Wholegrain cereal
Green leafy vegetables
Fish
Meat
Dairy Products
Vitamin B12
Food of animal origins only
Vitamin C
Fruits, Specially Citrus fruits and Tomatoes
Vegetables
Meat
Millk
43. Dietary Sources
Folic Acid
Green Leafy Vegetables
Citrus Fruits
Dried Beans and Peas
Vitamin A
Sweet Potato
Carrot
Butter
Liver of Turkey, Beef, Fish, and Chicken
Vitamin D
Sunlight
Vitamin E
Sunflower Oil
Almond Oil
Nuts Oil
Butter and Egg yolk
Vitamin K
Green Leafy Vegetables
Tomatoes
Olive Oil
Green Apples