Reducing saturated fat in boys' diets improves heart health later

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(Free-Press-Release.com) December 15, 2005 -- �Early nutrition may play an important role in the later vascular health of males,� said Olli T. Raitakari, M.D., Ph.D., lead author of the study. �It may be associated with less atherosclerosis and a lower future risk of cardiovascular diseases.�

The reduced fat diet didn�t significantly affect cholesterol levels or the artery health of girls who participated in the intervention trial called STRIP (Special Turku Coronary Risk Factor Intervention Project).

The reason for this finding remains unknown, �but may be related to the differences in sex hormone levels,� said Raitakari, assistant professor and head of clinical physiology at the University of Turku in Finland. The finding was consistent with studies that show that after reducing saturated fat in the diet, men�s �bad� cholesterol levels drop more than women�s do.

In this study, researchers recruited 1,062 infants from 1,054 volunteer families during the children�s five-month visit to a health center.

At seven months of age, 540 infants (284 boys, 256 girls) and their families were randomized to a low-saturated-fat diet (intervention group). The remainder � 522 infants (266 boys, 256 girls) and their families (control group) � ate an unrestricted diet. The intervention groups began a lower-fat diet immediately after weaning.

Physicians and dietitians provided dietary and lifestyle counseling to the intervention group families twice a year. The control children received neither from the research team. Parents recorded the family�s food intake over four days, twice a year.

These records showed that children in the intervention group consistently consumed 2 percent to 3 percent fewer calories than those in the control group. The intervention children received 2 percent to 3 percent fewer calories from saturated fats than the control group, and 0.5 percent to 1.0 percent more calories from polyunsaturated fats, which are more heart-healthy than saturated fats. Throughout the 11 years, boys in the diet group consistently had a cholesterol level 5 percent to 8 percent lower than boys in the control group.

Researchers gauged the functioning at age 11 of the children�s endothelium, the inner lining of blood vessels.

�Normal endothelium is essential to vascular health because it maintains a balance that favors vasodilation and inhibits inflammation, the development of blood clots, and the formation of atherosclerosis,� Raitakari said. �If the endothelium is not working properly, it predisposes a person to vasoconstriction and the development of atherosclerosis.�

Of the 1,062 children initially enrolled in STRIP, 614 attended their 11-year follow-up visit. Researchers got ultrasound images of arteries from 369 of them, and used the images to assess the endothelium�s functioning.

When blood flow increases, vessels respond by releasing nitric oxide, a major factor in the dilation of arteries. By inflating and deflating a normal blood pressure cuff placed around the upper arm, the researchers increased blood flow in the arm and recorded the dilation response of vessels with ultrasound.

The average maximum dilation fell within normal range for all the study participants. Still, the difference between boys in the intervention group and those in the control group � though relatively small � was statistically significant, 9.62 percent versus 8.36 percent, Raitakari said.

This finding indicated better endothelial health in the intervention group compared to the boys eating a typical Finnish diet.

Comparable figures among the girls were statistically insignificant.

An analysis indicated that the intervention group�s superior endothelial function stemmed from eating the lower-fat diet early in life rather than later.

�This means that the higher endothelial function seen in boys in the intervention group is not merely a reflection of recent cholesterol control, but suggests the importance of early and long-term cholesterol control in influencing vascular function,� Raitakari said.

The findings are the latest to emerge from STRIP. Previous reports showed that beginning a low saturated-fat diet in infancy with individualized diet and lifestyle counseling could lower cholesterol in children without harming their growth or neurological development.

Co-authors are Tapani R�nnemaa, M.D., Ph.D.; Mikko J. J�rvisalo, M.D., Ph.D.; Tuuli Kaitosaari, M.D.; Iina Volanen, M.D.; Katariina Kallio, M.D.; Hanna Lagstr�m, Ph.D.; Eero Jokinen, M.D., Ph.D.; Harri Niinikoski, M.D., Ph.D.; Jorma S. A. Viikari, M.D., Ph.D.; and Olli Simell, M.D., Ph.D.

Statements and conclusions of study authors that are published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.

More information can be found online at http://www.americanheart.org/

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