SAN FRANCISCO, Jan. 17 (Xinhua) -- A new study indicates that people with metabolic syndrome need significantly more vitamin E, an antioxidant important for cell protection.
Defined by diagnosis of three or more of several conditions, including abdominal obesity, elevated lipids, high blood pressure, pro-inflammatory state, a pro-thrombotic state and insulin resistance or impaired glucose tolerance, metabolic syndrome affects millions of people in the United States.
About the new study, published in the American Journal of Clinical Nutrition, Maret Traber, a professor in the Oregon State University (OSU) College of Public Health and Human Sciences and Ava Helen Pauling Professor in the Linus Pauling Institute, said "the research showed that people with metabolic syndrome need about 30-50 percent more vitamin E than those who are generally healthy."
Done by researchers in the Linus Pauling Institute at OSU and the Human Nutrition Program at the Ohio State University, the study was a double-blind, crossover clinical trial focusing on vitamin E levels in people with metabolic syndrome, which is often related to obesity.
More than 30 percent of the American public are obese, and more than 25 percent of the adults in the United States meet the criteria for metabolic syndrome, putting them at significantly increased risk for cardiovascular disease and type-2 diabetes, which are primary causes of death in the developed world.
Nutrition surveys have estimated that 92 percent of men and 96 percent of women in the United States fail to get an adequate daily intake of vitamin E in their diet. The micronutrient is found at high levels in almonds, wheat germ, various seeds and oils, and at much lower levels in some vegetables and salad greens, such as spinach and kale.
In addition to protecting cells, Vitamin E affects gene expression, immune function, aids in repair of wounds and the damage of atherosclerosis, prevents fat from going rancid and is important for vision and neurologic function.
"In previous work we showed that people with metabolic syndrome had lower bioavailability of vitamin E," Traber said. "Our current work uses a novel approach to measure how much vitamin E the body needs."
By "labeling" vitamin E with deuterium, a stable isotope of hydrogen, the researchers were able to measure the amount of the micronutrient that was eliminated by the body, compared to the intake. The advanced research laboratory tests showed that people with metabolic syndrome retained 30-50 percent more vitamin E than healthy people - showing that they needed it.
However, with metabolic syndrome, likely resulting in higher levels of oxidative and inflammatory stress, even as those people's tissues were taking up and retaining the needed vitamin E, their blood levels by conventional measurement appeared about the same as those of a normal, healthy person.
"We've discovered that vitamin E levels often look normal in the blood, because this micronutrient is attracted to high cholesterol and fat," Traber was quoted as saying in a news release. "So vitamin E can stay at higher levels in the circulatory system and give the illusion of adequate levels, even as tissues are deficient."
"This basically means that conventional vitamin E blood tests as they are now being done are useless."