Doctors from the Free Radical Research Group, National Research Institute for Food and Nutrition in Rome, Italy, reported that eight healthy men and six healthy women aged 25 to 40 ate a special high-fat meal before and after taking 110 mcg of selenium yeast per day for 10 days. There was no placebo group in the study. The meals contained an especially toxic, but common, fat by-product called a lipid hydroperoxide (LH), which forms when natural polyunsaturated fatty acids overheat during manufacture, cooking or frying. LH can attach to low-density lipoprotein (LDL, the “bad” cholesterol) in the blood, damage (oxidize) cells on arterial walls and form the plaque that doctors believe leads to hardening of the arteries, a type of atherosclerosis.
Immediately before and three hours after each meal, researchers measured blood-fluid (plasma) levels of selenium, antioxidants, LH-LDL and an unstable compound that results from oxidized fat called malondialdehyde (MDA). After the first meal, LH-LDL levels increased 2% and MDA levels increased 10%. After taking selenium yeast for 10 days and eating the second high-fat meal, levels of LH-LDL and MDA did not increase significantly. Researchers noted that throughout the study, plasma levels of selenium were adequate and did not change significantly, and concluded that supplementing with selenium to adequate levels reduces risk for chronic and degenerative diseases such as atherosclerosis.