Question for discussion:

4. Explain how the following dietary factors play a role in immune system response:

a. Omega 6 fatty acids
b. Carotenoids
c. Vitamin C
d. Zinc

A. Omega-6 Fatty Acids

Omega-6 fatty acids are considered essential fatty acid as they are necessary for human health but the body cannot make them. Omega-6 fatty acids play a crucial role in brain function as well as normal growth and development. Also known as polyunsaturated fatty acids (PUFAs).

Linoleic Acid is the primary Omega-6 fatty acid. A healthy human with good nutrition will convert linoleic acid into gamma linolenic acid (GLA), which will later by synthesized, with EPA from the Omega-3 group, into eicosanoids.
Some Omega-6s improve diabetic neuropathy, rheumatoid arthritis, PMS, skin disorders (e.g. psoriasis and eczema), and aid in cancer treatment. Although most Americans obtain an excess of linoleic acid, often it is not converted to GLA because of metabolic problems caused by diets rich in sugar, alcohol, or trans fats from processed foods, as well as smoking, pollution, stress, aging, viral infections, and other illnesses such as diabetes. It is best to eliminate these factors when possible, but some prefer to supplement with GLA-rich foods such as borage oil, black currant seed oil, or evening primrose oil.

Essential Fatty Acids (EFAs) supports the cardiovascular, reproductive, immune, and nervous systems. The human body needs EFAs to manufacture and repair cell membranes, so that the cells are able to obtain optimum nutrition and get rid of harmful waste products. One of the primary functions of EFAs is the production of prostaglandins, which helps to regulate body functions such as heart rate, blood pressure, blood clotting, fertility, conception, and playing a role in immune function by regulating inflammation and encouraging the body to fight infections. Essential Fatty Acids are also needed for proper growth in children, particularly for neural development and maturation of sensory system, male children have higher needs when compared to those of the females. Fetuses and breast-fed infants also require adequate supply of EFAs through the mother's dietary intake.

The video below shows the right amounts of Omega fatty acid intake for a healthy lifestyle/diet:



Citations:
http://goodfats.pamrotella.com/
http://www.umm.edu/altmed/articles/omega-6-000317.htm
http://www.youtube.com/watch?v=Gv1OPyRjBYk&feature=related
www.google.com

B. Carotenoids

Carotenoids, What are They? (in a glance, above)

Beta carotene is the most familiar carotenoid, but it is only one member of a large family. Researchers believe that it is not just beta carotene that but all the carotenoids working together.

The body converts beta carotene to vitamin A, which itself has anticancer properties and immune-boosting functions. But too much vitamin A can be toxic to the body, so it's better to get extra beta carotene from foods and let the body naturally regulate how much of this precursor is converted to the immune-fighting vitamin A. It's highly unlikely that a person could take in enough beta carotene to produce a toxic amount of vitamin A, because when the body has enough vitamin A, it stops making it.

Combating Various Viruses

A weakened immune system can wreak havoc on your health. Research shows that infections may contribute to heart disease, especially in people with weakened immune systems. Beta-carotene stimulates the immune system once it has undergone conversion to vitamin A.

Antioxidant actions of beta-carotene protect cells of the immune system from damage by reducing the toxic effects of reactive oxygen species Carotenoids are also shown to provide strong anti-inflammatory benefits (inflammation is a characteristic of autoimmune disorders) in addition to acting as powerful antioxidants, which can strengthen the immune system.

Beta carotene increases the number of infection-fighting cells, natural killer cells, and helper T-cells, as well as being a powerful antioxidant that mops up excess free radicals that accelerate aging.

Studies have shown that beta carotene can lower the risk of cardiovascular disease, especially strokes and heart attacks, giving scientific credence to the belief that a carrot a day can keep the heart surgeon away. Beta carotene also protects against cancer by stimulating the immune cells called macrophages to produce tumor necrosis factor, which kills cancer cells. It has also been shown that beta carotene supplements can increase the production of T-cell lymphocytes and natural killer cells and can enhance the ability of the natural killer cells to attack cancer cells.

Citations:

http://www.carotenoidcomplex.com/science/science4.html

http://www.stopgettingsick.com/template.cfm-1689

http://www.youtube.com/watch?v=lezuEDuQzJU

http://www.vitamin-basics.com/index.php?id=35

C. Vitamin C

Vitamin C is ranked one as of the top immune boosters for many reasons. It is widely known by many that it boosts the function of the immune system, and protect our bodies against viral infections and perhaps other diseases.

Vitamin C stimulates increased production white blood cells, especially specific types known as neutrophils, phagocytes, and lymphocytes.

Neutrophils would help attack foreign bacteria and viruses that are invading our body’s health. Additionally, vitamin C also help increase serum levels of antibodies that help fight infection and increases levels of interferon, an antibody that coats cell surfaces, preventing the entry of viruses. Vitamin C also helps to protect immune cells integrity. The Neutrophils help accumulate vitamin C to high concentrations, thus protecting these cell types from oxidative damage.

Below is a interesting video that shows a Neutrophil chasing a bacteria.
These white blood cellt help eliminate bacteria would increase with increased vitamin C in the body.


The phagocytic type of white blood cells naturally destroy waste material, harmful microorganisms, or other foreign bodies in the body by engulfing and absorbing (phagocytosing) them. In response to invading microorganisms, these cells release non-specific toxins, such as superoxide radicals and hypochlorous acid (bleach). These reactive substances kill pathogens, bacteria and viruses, but which in turn, would damage the cells themselves. However, having sufficient vitamin C, that has antioxidant functions, in the body, it helps to protect the phagocytic white blood cells from such effects which are actually known as ‘Auto oxidation’.

Vitamin C also raises HDL (good) cholesterol levels and reduces the risk of cardiovascular disease. It helps to lower blood pressure and interferes with the processes by which cholesterol is converted to plaque in the arteries.

Vitamin C plays a part in lowering rates of colon, prostate, and breast cancer. Studies have shown that cancer patients have increased requirements for vitamin C, and rapid metabolic depleted vitamin C stores. It is suggested, among other reasons, that cancer tumors tend to accumulate vitamin C needed for the creation of protoglycan, glycosaminoglicans, glucosamine, and collagen fibers, which might help encapsulate or restrain the growth of these tumors. Thus, improving then patient's immune system and prevent the cells from spreading and worsening.

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Citations:
http://www.stopgettingsick.com/template.cfm-1689
http://lpi.oregonstate.edu/infocenter/vitamins/vitaminC/
http://www.orthomolecular.org/library/jom/1992/pdf/1992-v07n04-p203.pdf
http://www.shands.org/health/HIE%20Multimedia/2/18107.htm
http://www.youtube.com/watch?v=I_xh-bkiv_c

D. Zinc

Zinc (Introduction):
Zinc is a trace element which has preventive and curative properties that is essential for good health.
Although zinc is only required in trace amounts in our body, it plays a vital role in many bodily functions. It is present in the tissues, bones, cells, organs and physiological fluids. The highest amounts are found in the muscles, teeth, bones, prostrate gland & pancreas.

Role of Zinc and Immunity Functions:
Zinc is known to play an important role in the immune system and zinc deficient subjects may experience increased susceptibility to a variety of pathogens. It is shown that T cell functions were affected adversely even when the deficiency of zinc was mild in humans. The immunological consequences of zinc deficiency may be responsible for decreased cell mediated immune functions in zinc deficient subjects.

Zinc is an essential trace element, influencing growth and affecting the development and integrity of the immune system. Zinc deficiency 'at risk' groups could lead to public health interventions with nutritional doses of zinc supplements to prevent alteration of the immune system and improve resistance to infections.

Here are abstracts of medical articles obtained from PubMed.gov ( U.S. National Library of Medicine, National Institutes of Health):

Immunological effects of zinc deficiency in sickle cell anemia (SCA):
(Department of Medicine, Harper Grace Hospital, Detroit, Michigan)

Zinc deficiency occurs frequently in SCA subjects. Studies have shown that several parameters of cellular immune functions may be altered in SCA subjects and related to a deficiency of zinc. The changes in SCA were due to zinc deficiency. Although it is well known that susceptibility to infections is a common problem in SCA subjects, whether or not supplementation with zinc will alter the pattern of infection and decrease morbidity in SCA on a long-term basis remains to be determined.

Some information regarding the sickle cell disease:


(Sickle Cell Anaemia at Molecular Level)


(Sickle Cell Anaemia Discussion)

Zinc and immune function: the biological basis of altered resistance to infection
[AM J Clin Nutr, 1998]
Department of International Health, The Johns Hopkins University School of Public Health, Baltimore, MD 21205, USA.

It is clear that zinc affects multiple aspects of the immune system, from the barrier of the skin to gene regulation within lymphocytes (white blood cells).
Zinc is crucial for normal development and function of cells mediating nonspecific immunity such as neutrophils and natural killer cells.
The effects of zinc on these key immunologic mediators is rooted in the myriad roles for zinc in basic cellular functions such as DNA replication, RNA transcription, cell division, and cell activation. Zinc also functions as an antioxidant and can stabilize membranes.


Other Immunity Functions of Zinc:
Zinc performs a major role in the metabolism and healthy functioning of the senses.
Zinc is needed for cell reproduction, tissue growth and repair.
It increases the production of white blood cells that fight infection. It also increases killer cells that fight against cancer and helps white cells release more antibodies. Zinc supplements have been shown to impede the growth of cancer.
* Zinc has antioxidant properties and is essential for our immune system. As such, it guards against diseases and infection, and hastens the healing of wounds.
* Zinc is linked to DNA and RNA synthesis as it facilitates cell division.
* It also heals the nervous system.
* Moreover, zinc has anti-inflammatory properties and is used to soothe rashes and heal wounds and cuts.
*Zinc increases the number of infection-fighting T-cells, especially in elderly people who are often deficient in zinc, and whose immune system often weakens with age. For infants and children, there is some evidence that dietary zinc supplements may reduce the incidence of acute respiratory infections.

Dietary Sources of Zinc:
Zinc cannot be synthesized in the body, so our only dietary sources of zinc are from our diet. Rich sources are oysters, nuts (like almonds), oil seeds, pulses, red meat, cereals, beans and dairy products. Small amounts of zinc are found in fruits and vegetables, including peas, potatoes and legumes. Absorption of zinc is aided by amino acids and peptides. The best source of zinc for infants and young children is zinc-fortified cereals.


Symptoms & Conseqeunces of Zinc Deficiency:
Maternal deficiency could influence critical events during pregnancy and fetal development, which may have teratogenic effect.
Lack of zinc has serious consequences; it can lead to neuro psychiatric disorders like dementia, depression, schizophrenia and Alzheimer's. Fatigue, tiredness, loss of appetite and even anorexia are symptoms of zinc deficiency, as it is responsible for appetite and taste. Other common symptoms are retarded growth and hormonal disorders. Lowered immunity leads to infections like colds and diarrhoea.

Zinc is essential for preventing and healing infections, maintaining a healthy brain, skin and reproductive system and boosting immunity. It has therapeutic uses in the treatment of prostrate disorders and skin problems like eczema and acne.

Note: Zinc is only required by the body in trace amounts so excess intake could lead to depletion of other minerals and toxicity. Hence, zinc suplementation should be taken only under medical supervision.

Citations:

Functions and Sources of Zinc
Deficiency Symptoms and Importance of an Essential Nutrient(Nita Mukherjee, 2010)
http://vitamins-minerals.suite101.com/article.cfm/functions-and-sources-of-zinc
Sources:
Abcvitaminslife.com, “The role of zinc in the human body”, (accessed February 24, 2010).
Stanford.wellsphere.com, “The importance of zinc to your body”, (accessed February 24, 2010).
Dietary-supplements.info.nih.gov, “Health professional fact sheet”, (accessed February 24, 2010).
Vitamins that heal-- Natural Immunity for better Health: H.K.Bakhru, Orient paperbacks, 1990.

Zinc and immunity, [Mol Cell Biochem, 1998]
Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan, USA.
Zinc and immune function, [Eur J Clin Nutr. 2002]
Immunological effects of zinc deficiency in sickle cell anemia (SCA), [Prog Clin Biol Res. 1989]
Zinc and immune function: the biological basis of altered resistance to infection, [Am J Clin Nutr. 1998]

http://www.ncbi.nlm.nih.gov/pubmed/9701160
www.stopgettingsick.com/template.cfm-1689
http://www.youtube.com/watch?v=9UpwV1tdxcs
http://www.youtube.com/watch?v=d5ZqHbuyABI

Instructions

Blogs on Immunology

Questions for Discussion:

Task 1: Post answers to the question allocated, in your respective group blogs by:
29/07/2010, Thursday, 12.00 pm

Questions for discussion

4. Explain how the following dietary factors play a role in immune system response:
a. Omega 6 fatty acids
b. Carotenoids
c. Vitamin C
d. Zinc

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Your blogs will be judged on the following criteria:

- Creativity
- Originality
- credibility of information
- presentation of information in a simple reader-friendly language.
- Citation of appropriate references
- Adherence to copyright matters(proper acknowledgement of the source of information)

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Task 2: You need to comment on any ONE of the groups posting.

-Group doing Q4- comment on the answers posted for Q5

You are welcome to post comments for other questions as well.
Blog addresses of other groups will be released on OLIVE on
30/07/10, Friday 12pm.

Remember to be objective while posting comments and your comments can be supported by any links you find informative/interesting. Post your comments to the respective questions by 04/08/10, Wednesday, 12.00pm.

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Task 3: You are required to rate the blogs created by other groups from your tutorial class. The group which gets the maximum points will be rewarded.

The assessment details for grading will be posted on
30/07/10 Friday 12pm
and all assessment should be completed by
04/08/10, Wednesday, 12pm.