Ethnic differences in levels of HDL, the "good"
cholesterol, may be due, at least in part, to diet, a new
study from Canada suggests.
South Asians ate the most carbohydrate and had the lowest HDL
cholesterol levels, while Chinese individuals ate the least
carbohydrate and had the highest levels of the beneficial blood
fat, Dr. Anwar T. Merchant of the Population Health Research
Institute in Hamilton, Ontario and colleagues found.
Previous research has identified ethnic differences in cholesterol
and other blood fat levels that couldn't be explained by genes,
obesity, lifestyle factors or diet, Merchant and his team
note, but these analyses usually looked at dietary fat, not
carbohydrate consumption. When calories from carbohydrates
replace energy from fat in a person's diet, both LDL and HDL
cholesterol levels fall while triacylglycerol levels rise,
the researchers explain.
To investigate the role of carbohydrate and HDL levels in
a population containing a variety of ethnic groups, Merchant
and his colleagues analyzed the diet and blood fats of 619
Canadians of Native American, South Asian, Chinese and European
descent. The researchers report their findings in the American
Journal of Clinical Nutrition.
As mentioned, South Asians ate the most carbohydrates, followed
by Europeans, Native Americans, and Chinese. After adjustment
for several factors including age, ethnicity, body mass index
and alcohol intake, the association between carbohydrates
and lower HDL cholesterol remained, with people consuming
the most carbs having an average level of 1.08 mmol/L, compared
to 1.21 mmol/L for those who ate the fewest carbohydrates.
Each additional 100 gram per day of carbohydrates was tied
to a 0.15 mmol/L drop in HDL cholesterol. Triacylglycerol
levels also rose in tandem with carbohydrate intake.
The researchers also found that consuming more sugar-sweetened
soft drinks, juices and snacks was tied to a lower HDL level.
"Differences in HDL and triacylglycerols observed in different
ethnic groups may be due in part to carbohydrate intake,"
the researchers write. "Reducing the frequency of intake of
sugar-containing soft drinks, juices and snacks may be beneficial."
SOURCE: American Journal of Clinical Nutrition, January 2007.