Perilla Seed May Help Asthma

Summary
White blood cells (leucocytes) produce something called leukotrienes during an asthmatic attack. Diets containing alpha-linolenic acid, like perilla seed oil, inhibit leukotriene production. After a perilla diet, leukotriene-C4 was suppressed in some, but not all asthma patients. Clinical readings of these two populations were compared to understand factors affecting leukotriene suppression. The two differed in quality of breathing (speed and volume of respiration) and the amounts of fatty acids, like cholesterol. The group sensitive to the perilla diet showed improved clinical symptoms associated with asthma by suppressing leukotriene-C4 production.

Introduction
Recurrent inflammation of lungs and airways results in asthma, causing shortness of breath, tightness in the chest, coughing, and wheezing. The airways become inflamed, blocking narrower branches. Inflammatory cells secrete substances like leukotrienes in airways, increasing mucus secretion and windpipe contraction. This impedes the flow of air to the lungs. Cell membranes of activated leucocytes produce leukotrienes that enhance asthma symptoms. However, fatty acids like omega-3 and -6, also present in cell membranes, suppress leukotriene generation. This study examines how a perilla seed oil diet in asthma patients affects leukotriene-C4 generation by leucocytes. Perilla seeds are rich in alpha-linolenic acid.

Methods
* A total of 26 mild asthmatic patients were tested for lipid profiles and respiratory function. Then, they were given 10 to 20 g/day of perilla seed oil for four weeks.
* After four weeks, leukotriene-C4 production was suppressed in 15 patients (Group A). The rest formed group B.
* Lipid profiles and ventilatory parameter tests were performed again for each.
* Leukotriene-C4 from blood was estimated using previously described biochemical techniques. The data was analyzed statistically.

Results
* Leukotriene-C4 production in group A significantly reduced after four weeks, while it increased significantly in group B.
* At the start of the study, respiratory speed and breathing volume for group A were significantly lower than group B.
* After four weeks of perilla diet, speed of expiration increased for both groups. Maximum lung capacity increased for group A, but not for group B. Even after this increase, group A values remained lower than those of group B.
* Before the perilla diet, total cholesterol, good and bad cholesterol, and phospholipids readings were much higher in group A than in B, while triglyceride levels were much lower. After the diet, all the values for both groups went down considerably.

Shortcomings/Next steps
The patients continued taking their own medication for asthma during the study, which may have caused certain changes in lipid values. Also, regular diets of some may have been higher in certain fatty acids, affecting the data. Further studies should try to minimize the differences in therapy and dietary habits of the volunteers.

Conclusions
Cells causing inflammation during asthma attack produce leukotrienes. Series 4 leukotrienes, like leukotriene-C4, are known to amplify the obstructive effects of asthma by increasing airway contraction and blockage. Alpha-linolenic acid helps with the production of series 5 leukotrienes, suppressing series 4 production. Perilla seed oil contains alpha-linolenic acid, and including it in one’s diet markedly suppresses leukotriene-C4 in some asthmatics. Group A patients had asthma that was clinically more severe. Leukotriene-C4 may have worsened their respiratory function. The changes in lipid profiles show that the diet containing alpha-linolenic acid affects lipid metabolism as well. The study shows that diet can help overcome asthmatic symptoms in a portion of asthmatic patients.

For More Information:
Effects of Perilla Seed Oil in Diet of Asthma Patients
Publication Journal: International Archives of Allergy and Immunology; 2000
By Makoto Okamoto; Fumihiro Mitsunobu; Okayama University Medical School, Tottori, Japan

*FYI Living Lab Reports Are Summaries of the Original Research.
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