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Community and Public Health Nutrition lec 7-Nutrition for Health Promotion and Disease

Prevention 1

Diet, Nutrition and the Infectious Diseases1-immune system

2-HIV/AIDS

Dr. Siham Gritly

Dr. Siham Gritly

Dr. Siham Gritly 2

Ref Ellie Whitney and Sharon Rady Rolfes; Under standing Nutrition, Twelfth Edition. 2011, 2008 Wadsworth, Cengage Learning

• Diet cannot directly prevent or cure infectious diseases, but good nutrition can strengthen, and malnutrition can weaken, the body’s defenses mechanisms against them

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glossary

• infectious diseases: diseases caused by bacteria, viruses, parasites, or other microorganisms that can be transmitted from one person to another through air, water, or food; by contact; or through vector organisms such as mosquitoes.

• antibodies: large proteins of the blood and body fluids, produced by the immune system in response to the invasion of the body by foreign molecules (usually proteins called antigens). Antibodies combine with and inactivate the foreign invaders, thus protecting the body.

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• antigens: substances that elicit the formation of antibodies or an inflammation reaction from the immune system.

• phagocytes: white blood cells (neutrophils and macrophages) that have the ability to ingest and destroy foreign substances.

• Phagocytosis: the process by which phagocytes engulf and destroy foreign materials.

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• Lymphocytes; white blood cells that participate in acquired immunity; B-cells and T-cells.

• B-cells: lymphocytes that produce antibodies. B stands for bone marrow, where the B-cells develop and mature.

• T-cells: lymphocytes that attack antigens. T stands for the thymus gland, where the T-cells mature.

• Cytokines; special proteins that direct immune and inflammatory responses

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Diet and Disease Prevention

• Concept of diseases• Many scientists defined diseases in different ways;• *Webster defined it as "a condition which body

health is impaired, a departure from state of health, an alteration of the human body interrupting the performance of vital function".

• *Oxford defined disease as "a condition of the body of some part of organ of the body in which its functions are disrupted deranged"

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• *Ecologist defined disease as "a mal-adjustment of the human organism to the environment'

• *pathologist defined disease as "abnormal variation in the structure of function of any part of the body“

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Diet and Health Promotion

• Diet and nutrition are important factors in the promotion and maintenance of good health and reducing risk of chronic and infectious diseases throughout the life

• Diet have strong effects, both positive and negative, on health throughout life

• physical activity also play important role in health promotion and disease prevention

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Nutrition and the Infectious Diseases

• infectious diseases: diseases caused by bacteria, viruses, parasites, or other microorganisms that can be transmitted from one person to another through air, water, or food; by contact; or through vector organisms such as mosquitoes.

• Example AIDS

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ref. Ellie Whitney and Sharon Rady Rolfes; Under standing Nutrition, Twelfth Edition. 2011, 2008 Wadsworth, Cengage Learning

• “Nutrition cannot prevent or cure infectious diseases, but adequate intakes of all the nutrients can help support the immune system as the body defends against disease-causing agents. If the immune system is impaired because of malnutrition or diseases such as AIDS, a person becomes vulnerable to infectious disease”.

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The Immune SystemThree types of human body;1-Natural or innate,2-Adaptive immunity,3-Passive immunity

Adaptive immunity involves the lymphocytes produced antibodies in response to the invasion of the body by foreign molecules (usually proteins called antigens) or people exposed that to immunization against diseases through vaccination Passive immunity is come from another source and it lasts for a short time. For example, antibodies in a mother's breast milk provide a baby with temporary immunity to diseases the mother has been exposed to.

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The Immune SystemThe body’s first lines of defense—the skin, mucous membranes, and GI tract normally prevent foreign substances (natural or innate). If these barriers fail, then the organs and cells of the immune system race into action. Foreign substances that gain entry into the body and elicit such a response are called antigens. Examples include bacteria, viruses, toxins, and food proteins that cause allergies.

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Organs of The Immune System

Organs of the immune system:• Spleen• Lymph nodes• Thymus

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Cells of the immune system:

• Cells of the immune system:• • Phagocytes• • Neutrophils• • Macrophages• • Lymphocytes• 1-B-cells• 2-T-cells

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Lymph tissues include the thymus, lymph nodes, and spleen.

The immune system is made up of a network of cells, tissues, and organs that work together to protect the body. The cells involved are white blood cells, Leukocytes are produced or stored in many locations in the body, including the thymus, spleen, and bone marrow. For this reason, they're called the lymphoid organs. There are also clumps of lymphoid tissue throughout the body, primarily as lymph nodes, that house the leukocytes.

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Cells of the immune system Two types of white blood cells, defend the body against infectious diseases phagocytes lymphocytes

• the phagocyte engulfs and digests foreign body's, in a process called phagocytosis.

• Phagocytes also secrete special proteins called cytokines that activate the metabolic and immune responses to infection

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White blood cell engulfing yeastthe phagocyte cell engulfs and digests foreign body's, in a

process called phagocytosis.

White blood cell (phagocyte) engulfing yeast cell. (Phagocytosis. Colored Scanning Electron Micrograph (SEM) of a cultured lymphocyte phagocytosing (engulfing) a yeast cell. At right, the lymphocyte white blood cell (blue) is using

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White blood cell Lymphocytes: There are two distinct types of lymphocytes:

B-cells and T-cells.

B-cells respond to infection by rapidly dividing and producing large proteins known as antibodies (immunoglobulins). Antibodies travel in the bloodstream to the site of the infection. There they stick to the surfaces of antigens and kill or otherwise inactivate them, making it easy for the phagocytes to ingest

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• Lymphocytes: The T-cells travel directly to the invasion site to fight the invaders.

• T-cells recognize the antigens displayed on the surfaces of phagocyte cells and multiply in response.

• Then they release powerful chemicals to destroy all the foreign particles that have this antigen on their surfaces.

• As the T-cells begin to win the battle against infection, they release signals to slow down the immune response.

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A number of different cells are considered phagocytes. Two types of immune system cells ingest and destroy foreign antigens by phagocytosis: neutrophils and macrophages.The most common type is the neutrophil, which primarily fights bacteria

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Nutrition and Immunity

• the immune system responds to change in nutrition status. Malnutrition has great effect on immunity system .

• Impaired immunity opens the way for infectious diseases, which typically raise nutrient needs and lower food intake.

• Impaired immunity is a characteristic of protein-energy malnutrition (PEM).

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Nutrients known to affect immunity

• • Fatty acids• • Folate• • Iron• • Protein• • Selenium• • Vitamin A• • Vitamin B6• • Vitamin C• • Vitamin E• • Zinc helps with the development of white bloods

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• Selenium (Se) constituent of glutathione peroxidase which has antioxidant function

• antioxidant protects the cell membrane against oxidative damage by H2O2

• This function is important in preventing lipid oxidation and protect cell against superoxide free radicals

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• Zinc also promotes wound healing, regulates immune function, serves as a co-factor for numerous antioxidant enzymes, and is necessary for protein synthesis and the processing of collagen

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ref. Ellie Whitney and Sharon Rady Rolfes; Under standing Nutrition, Twelfth Edition. 2011, 2008 Wadsworth, Cengage Learning

• without sufficient protein to make antibodies, the immune system loses its ability to fight infections.

• Deficiencies of vitamins and minerals also diminish the immune response,

• interactions between nutrients may enhance or impair immunity.

• optimal immunity depends on optimal nutrition—enough, but not too much, of each of the nutrients.

• People with weakened immune systems, such as the elderly, may benefit from a nutritious diet and supplements of selected nutrients

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AIDS (Acquired Immune Deficiency Syndrome)

• HIV (human immunodeficiency virus): the virus that causes AIDS. The infection progresses to become an immune system disorder that leaves its victims defenseless against numerous infections.

• AIDS (acquired immune deficiency syndrome): the late stage of HIV infection, in which severe complications develop.

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Viruses are parasite consists of nucleic acids (DNA or RNA. Only one of the nucleic acid should be present at a time in the virus. Viruses are dependent entirely on the host cell for their replication. The cell of the virus encode with the proteins that coat virus nucleic acid molecules to form virus particles or Virion (or protein complex).

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Virion functions are;

• 1-protects the nucleic acid of the virus from environmental factors during its transmission from host to another and from cell to cell, environmental factors as; enzymes, ultraviolet irradiation.

• 2-virion initiate the infection by binding to specific surface of the cell and thus enable viruses to induce infection (indicate the presence of pathogens).

• 3-virion act as structural and functional support for delivering the virus into host cell.

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The human immune system is the site of the attack by the virus

Acquired immune deficiency syndrome (AIDS) is a set of symptoms and infection resulting from the damage to the human immune system. This condition progressively reduces the effectiveness of the immune system and leaves individuals susceptible to infection and tumors.

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Pathogenesis of the disease

• HIV is transmitted through direct contact of a mucous membrane or the bloodstream with a bodily fluid containing HIV, such as

• Blood• Semen• Vaginal fluid• Breast milk

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monocytes and macrophages act as viral receptor

• On entering the virus invade the immune system cells monocytes and macrophages.

• Those cells act as viral receptor.• The virion binds with the cell and allows the

virus to enter the cells.

• Incubation period is long, usually infected person develop AIDs in 5-7 years.

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Monocytes and macrophages act as reservoir of the virus.

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Transmission of the disease

• HIV transmission involve• Anal intercourse which is the main route of

transmission in male homosexual, bisexual and heterosexual.

• Vaginal• Oral sex• Blood transfusion• contaminated needles • exchange between mother and baby during pregnancy,

childbirth or breastfeeding

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• Sexual transmission• Sexual transmission occurs with the contact

between sexual secretions of one person with the rectal, genital or oral mucous membranes of another oral sex.

• Infected male transmit the virus in his semen to recipients' body through rectal mucosa.

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• During vaginal intercourse, the virus penetrates the vaginal mucosa and inter to blood stream. During female to male transmission the virus being present in infected female in the vagina and cervical secretion

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• Transmission through blood transfusion and intravenous drugs

• Transmission may occur by intravenous drugs and through blood transfusion, usually virus present in blood plasma of infected person, which is the major risk for infection the risk also extended to people who give and receive tattoos.

• Blood transfusion infection had been reduced by screening all blood donation and heat treating

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• Mother-to-child transmission • The transmission of the virus from the mother to the

child can occur during the last weeks of pregnancy and at childbirth.

• In the absence of treatment, the transmission rate between a mother and her child during pregnancy, labor and delivery is 25%.

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• Breastfeeding also increases the risk of transmission by about 4 %.

• HIV-infected mothers should avoid breast-feeding their infant.

• It is difficult to diagnose infected child with HIV in the first few month of gestation

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Main features of the disease are persistent fever for more than 3 month, weight loss, diarrhea, anemia, infection such as pneumonia and other bacterial infection. Central nervous system is a major target for the infection and dementia may develop (mental illness), the virus inter the brain and damage of the brain cells occur.

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Health and sexual education is the key for prevention and limiting the disease

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Nutrition and AIDs http://www.webmd.com/hiv-aids/guide/nutrition-hiv-aids-enhancing-quality-life

• Medication along with proper nutrition is a major component of maintaining good health and quality of life for people living with HIV/AIDS.

• People living with AIDS have impaired immune systems and therefore are more susceptible to infections and diseases due to foodborne pathogens

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• For people with HIV/AIDS, energy requirements often increase in order to maintain their regular body weight

• The  (WHO) recommends vitamin A supplements for all young children 6 to 59 months old that are at high risk of vitamin A deficiency every 4 to 6 months

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The Basic Principles of Nutrition and HIVref http://www.webmd.com/hiv-aids/guide/nutrition-hiv-aids-enhancing-quality-life

• The principles include:• Eating a diet high in vegetables, fruits, whole

grains, and legumes• Choosing lean, low-fat sources of protein• Limiting sweets, soft drinks, and foods with

added sugar• Including proteins, carbohydrates, and a little

good fat in all meals and snacks

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ref http://www.webmd.com/hiv-aids/guide/nutrition-hiv-aids-enhancing-quality-life

• Recommendation for Calories are the energy in foods that provide body with fuel. To maintain your lean body mass, you may need to increase calories. To get enough calories:

• Consume 17 calories per pound of your body weight if you've been maintaining your weight.

• Consume 20 calories per pound if you have an opportunistic infection.

• Consume 25 calories per pound if you are losing weight.

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• Recommendation for Protein helps build muscles, organs, and a strong immune system. To get enough of the right types of protein

• Aim for 100-150 grams a day, if you are an HIV-positive man.

• Aim for 80-100 grams a day, if you are an HIV-positive woman.

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• If you have kidney disease, don't get more than 15%-20% of your calories from protein;

• Choose extra-lean beef, skinless chicken breast, fish, and low-fat dairy products.

• To get extra protein, spread nut butter on fruit, vegetables, or toast; add cheese to sauces, soups, potatoes, or steamed vegetables; add canned tuna to salads or casseroles

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• Recommendation for Carbohydrates • To get enough of the right types of carbohydrates:• Eat five to six servings (about 3 cups) of fruits and

vegetables each day.• Choose legumes and whole grains, such as brown rice and

whole-wheat flour, oats, and barley and potato as your starch sources.

• If you are diabetic or pre-diabetic or have insulin resistance, then most of your carbohydrates should come from vegetables.

• Limit simple sugars, such as candy, cake, cookies, or ice cream.

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Effects of Protein-Energy Malnutrition (PEM)on the Body’s Defense Systems

Body’s Defense System

Effects of PEM

Skin Thinned, with less connective tissue to serve as a barrier to protect underlying tissues; delayed skin sensitivity reaction to antigens

Digestive tract and other body linings

Antibody secretions and immune cell number reduced

Lymph tissues Immune system organs reduced in size; cells of immune defense depleted

General response

Invader kill time prolonged; circulating immune cells reduced; antibody response impaired

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• http://www.webmd.com/hiv-aids/guide/nutrition-hiv-aids-enhancing-quality-life• Ellie Whitney and Sharon Rady Rolfes; Under standing Nutrition, Twelfth Edition.

2011, 2008 Wadsworth, Cengage Learning• http://www.livestrong.com/article/354549-the-effect-of-exercise-on-the-cardiores

piratory-system/#ixzz2UUaL51TH• http://www.mayoclinic.com/health/medical/IM00642

• Scott K. Powers & Edward T. Howley; Theory and Application to Fitness and Performance, 6th edition. EXERCISE PHYSIOLOGY

• Sports Fitness Advisor: The Cardiovascular System and Exercise

• Read more: http://www.livestrong.com/article/192489-immediate-effects-of-exercise-on-the-cardiovascular-system/#ixzz1miWxuYrs

• Diastolic Blood Pressure During Exercise | eHow.com• Lactate Theshold Training. Len Kravitz, and Lance Dallec

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• Diet, nutrition, and the prevention of chronic diseases. Report of a WHO Study Group. Geneva, World Health Organization, 1990(WHO Technical Report Series, No. 797).

• Diet, physical activity and health. Geneva, World Health Organization, 2002 (documents A55/16 and A55/16 Corr.1).

• http://www.webmd.com/hiv-aids/guide/nutrition-hiv-aids-enhancing-quality-life

• Sareen Gropper, Jack Smith and James Groff, Advanced Nutrition and Human Metabolism, fifth ed. WADSWORTH

• Melvin H Williams 2010; Nutrition for Health, Fitness and Sport. 9th ed, McGraw Hill

• Heymsfield, SB.; Baumgartner N.; Richard and Sheau-Fang P. 1999. Modern Nutrition in Health and Disease; Shils E Maurice, Olson A. James, Shike Moshe and Ross A. Catharine eds. 9th edition

• Guyton, C. Arthur. 1985. Textbook of Medical Physiology. 6th edition, W.B. Company