The influence of Fat on the immune function

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Post subject: The influence of Fat on the immune function

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The influence of fat on the immune function has only recently come

under serious study.

 

High level of fat have a negative impact on the immune system and

decrease its ability to cope with cancer tumours, allergies,

infections by microbial organisms and both thymic-dependent and

thymic-independent antigens.

 

Immune responses can thus be enhanced or depressed,depending on the

 

*concentration* of dietary 'lipids'.

 

It has been found that high-fat diets consistently depress

'resistance'to malaria and tuberculosis in rats, and respiratory

infections in chickens and the same seems to be true for humans.

 

Lower respiratory tract infections in infants, for example, are

significantly more common in obese infants than in non-obese

infants, and in one third of obese infants, adolescents and adults

studied there was impairment of 'cell-mediated'immune responses

'

 

The mechanism whereby fats interfere with the

body's ability to combat the growth of cancerous tumours has also

been investigated.

 

A subpopulation of T-lymphocytes, known as natural killer cells,

specifically react to destroy tumour cells before they can

'proliferate'.

 

Recently it has been found that diets high in polyunsaturates,

particularly those rich in n-6 fatty acids

(e.g. linolenic acid),

impact negatively the ability of these killer cells to seek out

and 'destroy' cancer cells.

 

Three types of blood cells are associated with the

immune response and secrete substances that effect B- and T-cell

activity in many ways.

 

 

Examples of lymphokines are interferon and interluekon 1, of which

 

interferon stimulates T-cell proliferation and interleukon 1

stimulates

 

a broad range of cells, including the

natural killer cells, neutrophils, and B- and T-lymphocytes.

 

 

T-cells produce antibodies which combine with antigens,

rendering them inactive and enabling phagocytes to engulf the

invadersThese substances, including prostaglandin, are produced from

the

essential fatty acids, linolenic and linoleic acid.

 

 

Those prostaglandins that have a relaxing, anti-flammatory

and anti-clotting effect are generally formed from alpha-linolenic

acid whilst those with the opposite effect are manufactured from

linoleic acid and

arachidonic acid (AA, found mainly in

animal proteins, i.e. dairy and meat).

 

 

More than one hundred different 'prostaglandins' have been

identified,

and they promote or inhibit basic bodily functions such as fever,

blood

 

clotting, vasodilation

and constriction, stress, allergy responses, membrane permeability,

eye pressure, inflammation, steroid production, appetite, fat

metabolism and the functioning of the immune system.[iv]

 

When prostaglandins occur in a balanced relationship they tend to

relax

arteries and reduce blood pressure as well as slow down tumour

formation and decrease platelet aggregation, thus lowering the risk

of thrombus formation.

 

If the balance of prostaglandins is,however, disturbed then the

opposite effects are achieved.

 

It is interesting to note that tumour cells produce large amounts of

the

prostaglandin PGE2 and cancer patients can produce four times the

normal amount of this prostaglandin.

 

It has an immunorepressive effect and leucotriene B4 is a potent

chemotactic and chemokinetic agent.[v]

 

A reduction in the amounts of polyunsaturated fats (omega-6) in the

diet, can provide a

substantial anticarcinogenic effect.[vi]

 

A whole-food diet, which includies organic grains, legumes, seeds

and nuts will provide the ideal

blend of fatty acids and total fat composition to ensure the optimal

fuctioning of the immune system.

 

 

Fatty Acid Profiles of Foods High

in Beneficial 'Monounsaturated' Fats

 

Hazelnuts-highest in monounsaturated fats at 82%

Avocadoes- monounsaturated fat content at 80%

Sunflower,mono-75%

Sunflower,mono-75%

Olive Oil-73%

Almonds- 72%

Sesame-60%

Peanuts-56%

 

Source: Resnicow, K., Barone, J., Engle, A., Mliler, S., Haley,

N.C., Fleming, D., Wynder, E. 1991. Diet and serum lipids in vegan

vegetarians: A model for risk reduction. J. Am. Diet. Assoc. 91:447-

453

 

 

 

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www.amazingdiet.org

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References:

 

Maki, P.A., Newberne, P.M. 1992. Dietary lipids and immune

function. J.Nutr. 122:610-614.

[ii] Chandra, R.K. 1981. Immune response in overnutrition. Cancer

Res. 41:3795-3796.

[iii] Byman, L.D. 1991. Dietary fat and natural killer cell

function. Nutrition Today. Jan/Feb 1991, pp.31-36.

[iv] Lee, L.B. 1976. " Prostaglandins and blood pressure control "

(Combined clinical and basic science seminars) Am. J. of medicine

61:681.

[v] Jonnalagagadda, S.S., Mustad, V.A., Yu, S., Etherton, T.D., Kris-

Etherton, P.M. 1996. Effects of individual fatty acids on chronic

diseases. Nutrition Today. 31 (3) May/June 1996.

[vi] Barone, J., Hebert, J.R., Reddy, M.M. 1989. Dietary fat and

natural killer cell activity. Am.J.Clin.Nutri. 50:103-106.

Hebert, J.R., Barone, J., Reddy, M.M., Backlund, J.Y. 1990.

Natural killer cell activity in a longitudinal dietary fat

intervention trial. Clin.Immunol.Immunopathol. 54:103-1

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