Barley

Dutch researchers used a crossover study with 10 healthy men to compare the effects of cooked barley kernels and refined wheat bread on blood sugar control. The men ate one or the other of these grains at dinner, then were given a high glycemic index breakfast (50g of glucose) the next morning for breakfast. When they had eaten the barley dinner, the men had 30% better insulin sensitivity the next morning after breakfast.
American Journal of Clinical Nutrition, January 2010; 91(1):90-7. Epub 2009 Nov 4.

White rice, the staple food in Japan, is a high glycemic index food. Researchers at the University of Tokushima found that glucose levels were lower after meals when subjects switched from white rice to barley.
Rinsho Byori. August 2009; 57(8):797-805

Scientists at the Functional Food Centre at Oxford Brookes University in England fed 8 healthy human subjects chapatis (unleavened Indian flatbreads) made with either 0g, 2g, 4g, 6g or 8g of barley beta-glucan fiber. They found that all amounts of barley beta-glucan lowered the glycemic index of the breads, with 4g or more making a significant difference.
Nutrition Research, July 2009; 29(7):4806

In a crossover study involving 17 obese women at increased risk for insulin resistance, USDA scientists studied the effects of 5 different breakfast cereal test meals on subjects’ insulin response. They found that consumption of 10g of barley beta-glucan significantly reduced insulin response.
European Journal of Nutrition, April 2009; 48(3):170-5. Epub 2009 Feb 5.

University of Connecticut researchers reviewed 8 studies evaluating the lipid-reducing effects of barley. They found that eating barley significantly lowered total cholesterol, LDL (“bad”) cholesterol, and triglycerides, but did not appear to significantly alter HDL (“good”) cholesterol.
Annals of Family Medicine, March-April 2009; 7(2):157-63

Swedish researchers at Lund University have determined that certain whole grain products can help control blood sugar for up to ten hours. A team led by Anne Nilsson fed twelve healthy subjects test meals including different whole and refined grains, and found that barley and rye kernels at one meal had a long-lasting effect on controlling blood sugar extending to most of the day after the whole grain breakfast, or overnight with whole grains at dinner.
European Journal of Clinical Nutrition, March 2008; 87(3):645-54

A randomized double-blind study in Japan followed 44 men with high cholesterol for twelve weeks, as the men ate either a standard white-rice diet or one with a mixture of rice and high-beta-glucan pearl barley. Barley intake significantly reduced serum cholesterol and visceral fat, both accepted markers of cardiovascular risk.
Plant Foods and Human Nutrition, March 2008; 63(1):21-5. Epub 2007 Dec 12.