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關節健康
Joint Health

EPA is a long-chain polyunsaturated fatty acid which has many joint-healing properties. Modern eating habits, however, promote an imbalance of dietary fatty acids with significant repercussions for health. Too many short-chain omega-6 fatty acids in the diet (in the form of vegetable oils) relative to omega-3s, result in the excessive production of pro-inflammatory eicosanoids and cytokines - substances which cause inflammation. [i]

Left untreated, inflammation - characterised symptomatically by pain, redness and swelling - may result in loss of function. In research studies, decreased synthesis of the inflammatory substances has been observed following supplementation with omega-3 polyunsaturated fatty acids, [ii] indicating that these good fats have a protective effect. EPA actively inhibits the production of these inflammatory substances by competing with the omega-6s for the enzymes responsible for the production of anti-inflammatory prostaglandins and leukotrienes - substances which relieve the inflammation and pain associated with rheumatoid arthritis.[iii]

EPA also has properties which aid the healing of ligament injuries by promoting cell migration, metabolism, growth and repair of the wounded area. It may also increase the rate at which collagen (a protein that is the main support of skin, tendon, bone, cartilage and connective tissue) is synthesised. [iv]

Through promoting the absorption of calcium in the body, EPA may also encourage increased bone density and strength.

Evening primrose oil (EPO) has many significant health-giving properties, owing to its high content of the long-chain omega-6 fatty acid GLA. Cold-pressed, organic and virgin, the oil retains all its natural goodness, including a source of botanical triterpenes - hormone-like substances which aid inflammation relief. Triterpenes mop up free radicals and reduce the pain of arthritis.

Research suggests that intake of GLA reduces the joint pain and swelling associated with arthritis. In a randomised, placebo-controlled trial by Zurier and colleagues, treatment with GLA for six months resulted in "statistically significant and clinically relevant reductions in the signs and symptoms of disease activity in patients with RA [rheumatoid arthritis]." [v] Other studies on GLA report a significant improvement in the following parameters: swollen joint count, tender joint count, tender joint score and pain.[vi] [vii] A further rheumatoid arthritis trial using GLA reported a considerable reduction in morning stiffness.[viii]

In vitro studies on the omega-6 fatty acid CLA suggest that it provides a multitude of benefits to the joints, including reducing the symptoms of rheumatoid arthritis.[ix] CLA is also thought to aid bone health by decreasing weight gain and concurrently increasing bone mass. Studies have shown that this omega-6 fatty acid reduces the breakdown of bone tissue and increases the rate of bone formation.[x]

By influencing body composition CLA may also lessen the pressure on the joints by reducing body fat while maintaining and increasing lean body mass. In a study by Gaullier and colleagues, involving supplementation with CLA, participants showed a 9% reduction in body fat and a 2% increase in lean body mass, with no change in diet or exercise. Specifically, CLA ensures that glucose is directed straight to muscle cells, preventing the nourishment of unwanted fat cells and concurrently encouraging muscle development.[xi]

Extra-virgin olive oil is a rich source of the omega-9 oleic acid. Its role in promoting cellular growth and healing makes it invaluable for helping with joint problems. In its most natural extra-virgin form, olive oil is high in antioxidants and polyphenols[xii] that bestow it with anti-arthritic and anti-inflammatory properties.[xiii] [xiv] [xv] [xvi][xvii] It also contains oleocanthol - a compound that may inhibit two key inflammation triggers. Regular intake of extra-virgin olive oil reduces joint pain and stiffness. Studies also suggest that it may be beneficial to sufferers of rheumatoid arthritis because of its localised anti-inflammatory actions which reduce joint swelling and pain.[vxiii] [xix] [xx]. Oleic acid may also help to maintain bone health and prevent calcium loss by promoting the absorption of nutrients in the body.

[i] James, M.J., Gibson, R.A., Cleland, L.G. Dietary polyunsaturated fatty acids and inflammatory mediator production. American Journal of Clinical Nutrition, 2000; Vol. 71, No. 1, 343S-348s.

[ii] Meydani S., Endres S., Woods M.M. et al. Oral (n-3) fatty acid supplementation suppresses cytokine production and lymphocyte proliferation: comparison between younger and older women. J Nutr 1991;121:547?55.

[iii] Lee T.H., Hoover R.L., Williams J.D., et. al. Effect of dietary enrichment with eicosapentaenoic and docosahexaenoic acids on in vitro neutrophil and monocyte leukotriene generation and neutrophil function. N Engl J Med 1985;312:1217-1224. See also: Calder P.C. Immunomodulatory and anti-inflammatory effects of n-3 polyunsaturated fatty acids. Proc Nutr Soc 1996;55:737-774.

[iv] Hankenson, K.D. et al. Omega-4 fatty acids enhance ligament fibroblast collagen formation in association with changes in interleukin-6 production. Proceedings of the Society for Experiemental Biology and Medicine, 2000, Vol. 223, pp88-95.

[v] Zurier R.B. et al. Gamma-Linolenic acid treatment of rheumatoid arthritis. A randomized, placebo-controlled trial. Arthritis Rheum. 1996 Nov ;39(11):1808-17.

[vi] Lee T.H., Hoover, R.L., Wiilliams, J.D. et al. Effect of dietary enrichment with eicosapentaenoic and docosahexaenoic acids on in vitro neutrophil and monocyte leukotriene generation and neutrophil function. N. Engl J Med 1985;312;1217-1224.

[vii] Calder P.C. Immunomodulatory and anti-inflammatory effects of n-3 polyunsaturated fatty acids. Proc Nutr Soc 1996;55:737-774.

[viii] Brzeski M, Madhok R, Capell HA. Evening primrose oil in patients with rheumatoid arthritis and side-effects of non-steroidal anti-inflammatory drugs. Br J Rheumatol 1991;30:370-372.

[ix] Watkins, B.A., Seifert, M.F. Conjugated Linoleic Acid and Bone Biology, Journal of the American College of Nutrition.

[x] Banu, J. Bhattacharya, A. Rahman, M. O"Shea, M. and Fernandes, G. Effects of conjugated linoleic acid and exercise on bone mass in young male Balb/C mice, Lipids in Health and Disease 2006, 5:7 doi:10.1186/1476-511X-5-7
[xi] Gaullier J.M., Halse J., Hoye K., Kristiansen K., Fagertun H., Vik H., Gudmundsen O. Conjugated linoleic acid supplementation for 1 y reduces body fat mass in healthy overweight humans. Am J Clin Nutr. 2004 Jun;79(6):1118-25.

[xii] Alarcon de la Lastra C., M.D. Barranco, V. Motilva and J.M. Herrerias. 2001. Mediterranean diet and health: biological importance of olive oil. Curr. Pharm. Des. 7:933.

[xiii] Martinez-Dominuez E., R. de la Puerta and V. Ruiz-Gutierrez. Protective effects upon experimental inflammation models of a polyphenol-supplemented virgin olive oil diet. Inflamm. Res. 2001; 50:102.

[xiv] Linos A., V.G. Kaklamani, E. Kaklamani, Y. Koumantaki, E. Giziaki, S. Papazoglou and C.S. Mantzoros. Dietary factors in relation to rheumatoid arthritis: a role for olive oil and cooked vegetables? Am. J. Clin. Nutr. 1999. 70:1077.
[x] Linos A., E. Kaklamanis, A. Kontomerkos, Y. Koumantaki, S. Gazi, G. Vaiopoulos, G.C. Tsokos and P. Kaklamanis. The effect of olive oil and fish consumption on rheumatoid arthritis - a case control study. Scand. J. Rheumatol. 1991. 20:419.

[xvi] Kremer J.M., D.A. Lawrence, W. Jubiz, R. DiGiacomo, R. Rynes, L.E. Bartholomew and M. Sherman. Dietary fish oil and olive oil supplementation in patients with rheumatoid arthritis. Clinical and immunologic effects. Arthritis Rheum. 1990. 33:810.

[xvii] Kjeldsen-Kragh J. Mediterranean diet intervention in rheumatoid arthritis. Ann. Rheum. Dis. 2003. 62:193.

[xviii] Skoldstam L., L. Hagfors and G. Johansson. An experimental study of a Mediterranean diet intervention for patients with rheumatoid arthritis. Ann. Rheum. Dis. 2003.62:208.

[xix] Darlington L.G., Ramsey N.W. Olive oil for rheumatoid patients? Br J Rheumatol 1987;26:129.