Effect Of Diet On Platelet Activation - Brief Article

Nutrition Research Newsletter, July, 2001

Along with diet, platelets have an important role in atherosclerosis, thrombosis, and cardiovascular disease (CVD). Epidemiologic data indicate that both polyunsaturated fatty acids (PUFA) and vegetables can protect from CVD, but concern has arisen that the imbalance between PUFAs and bioactive vegetable compounds may lead to oxidative stress. There is also research that connects diet to platelets causing platelet hyperactivity, which is considered to be a risk factor for thrombosis.

Some Finnish researchers examined the effects of dietary unsaturated fatty acids and vegetable compounds on platelet activation. A group of 25 healthy Finnish volunteers were divided into two groups and consumed one of the experimental diets for six weeks. A high linoleic acid diet (10% of calories) with small amounts of vegetables (no berries or apples) was consumed by nine women and tour men, while the second group (eight women and four men) consumed a high oleic acid diet (12% of energy) with considerable amounts of vegetables, berries, and apples. Because PUFAs may be potential sources of oxidative stress to the body, a large difference in PUFA intake was used in this study to change the oxidative status of the two groups. Another strategy to modify the oxidative status was the use of vegetables, berries and apples, which contain antioxidants and other bioactive molecules that may prevent oxidative stress. The diets were isocaloric. Blood samples were taken at baseline and at the end of the dietary intervention.

Compliance with the experimental protocol was good, as indicated by changes in plasma fatty acids and concentrations of vitamin C, [Beta]-carotene, and tocopherol. Platelet activation was not affected by treatments as indicated by no differences in platelet aggregation, protein kinase C (PKC) total activity, and the levels of PKC isoenzymes. In addition, biomarkers of oxidative status did not differ between groups. These oxidative markers, plasma fatty acids, antioxidants, flavonoids, and lipoprotein fractions did not correlate with platelet PKC activity.

Earlier studies have shown that a four-week period is long enough to induce differences in fatty acid profiles and physiologic responses during different dietary interventions. The results from this six-week study show that it was enough to induce changes in dietary compliance markers. However, in the healthy subjects with adequate vitamin intakes, modification of dietary unsaturated fatty acids and vegetable compounds did not change platelet activation. The authors acknowledge that the use of PKC in dietary interventions has been quite rare and it would be beneficial to use a larger population in future research studies.

M. Misikangas, R. Freese, A. M. Turpeinen, and M. Mutanen. High Linoleic Acid, Low Vegetable, and High Oleic Acid, High Vegetable Diets Affect Platelet Activation Similarly in Healthy Women and Men, Journal of Nutrition 131:1700-1705 (June 2001) [Address correspondence to: M. Misikangas. E-mail: marjo.misikangas@helsinki.fi.].