It is a well known fact that whole-grain foods keep triglycerides in their limits and keep a check on them. Advancing a step further, a study by Agricultural Research Service scientists in California provides the know-how as to how whole grains do that.
According to ARS chemist Nancy L. Keim, "Lipoproteins are the body's means of moving lipids to muscles, where they're used for energy, or to fatty tissue, where they're stored as reserves."
AdvertisementIt is known in health sectors that High density lipoproteins are good, while low-density lipoproteins are bad.
An investigation into the effect that whole-grain foods and refined grains have on lipoproteins was conducted by Keim and colleagues.
Participants were 10 women, age 20 to 45; who volunteered for the study each completed a whole-grain regimen and a refined-grain stint. The first 3 days of the whole-grain phase, the volunteers ate six to eight servings of whole-grain foods a day, on average.
Next came the refined-grain regimen, when the women ate foods such as a refined-grain cereal at breakfast, white rice with their evening meal, and graham crackers for the after-supper snack.
On the fourth and final day of both stints, the women came to the nutrition centre to eat breakfast. Blood samples before their meal and at three intervals afterwards were collected by the investigators.
Lipoproteins were separated out using an ultracentrifuge. The finding was that very low-density lipoproteins (VLDL) contained significantly more triglycerides following the refined-grain test breakfast than after the whole-grain test breakfast. Additionally, after the refined-grain test meal their VLDLs had significantly higher levels of a worrisome protein called "apolipoprotein CIII" (apoCIII).
"In medical studies, apoCIII has been associated with high levels of triglycerides and increased risk of heart disease. It's also been shown to interfere with the work of an enzyme called "lipoprotein lipase." VLDLs are naturally rich in triglycerides, so you want the lipoprotein lipase-your triglyceride-removing mechanism-to be very efficient. If the apoCIII protein on your VLDLs slows down the lipoprotein lipase, triglycerides may spend more time in your VLDLs instead of where they belong-in your muscles or fat tissue. The longer the triglycerides remain in your VLDLs, the more likely they are to be oxidized or to infiltrate your arteries. Neither outcome is good," says Keim
William F. Horn and Manuel C. Tengonciang, Jr., of the Davis center, and Tara A. Hembrooke, formerly at the centre collaborated with Keim in the study and reported preliminary findings at the 2005 meeting of the Federation of American Societies for Experimental Biology.
Therefore even under the microscope whole grains come as a winner.