Soy Protein May Reduce Cholesterol Levels in Diabetics
In 1999, the Food and Drug Administration (FDA) officially
recognized the cholesterol-lowering effects of soy protein, but allowing a new health
claim which stated that 25 grams of soy protein per day may reduce the risk of
heart disease. Now, in a new study published in the Journal of Nutrition, researchers
have found that in increased intakes of soy protein may reduce cholesterol
levels in people with type-2 diabetes. This study emphasized prevention by
studying adults with type-2 diabetes who are free of diabetic complications and
not taking glycemic or lipid-lowering mediations.
In a double -blind, randomized, crossover,
placebo-controlled intervention study (Pipe et al 2009), 29 type-2 diabetics were
assigned to consume a daily dose of 40 grams of soy protein isolate (SPI),
which also contained 80 mg of aglycone isoflavones, or milk protein isolate for
57 days. At the end of the intervention they underwent a 28 day washout period,
and then were assigned to receive the other protein. The results of the study
showed that when using the soy protein, subjects experienced a significant
reduction in LDL cholesterol levels of 0.17
mmol/l, and a reduction in the ratio of LDL
to HDL cholesterol of 0.03 points.
Another result from soy protein consumption was a drop in
the ratio of apolipoprotein B:apolipoprotein A-I, compared to the milk protein
intervention. Apolipoprotein B is the main apolipoprotein of LDL cholesterol
and is responsible for the transport of cholesterol to tissues. In high
concentrations it has been linked to plaque formation in the blood vessels.
The researchers concluded, "These data demonstrate that
consumption of soy protein can modulate some serum lipids in a direction
beneficial for CVD risk in adults with type
2 diabetes,"
Reference
Pipe EA, Gobert CP, Capes SE, Darlington GA, Lampe JW, Duncan AM. Soy Protein Reduces Serum LDL
Cholesterol and the LDL Cholesterol:HDL
Cholesterol and Apolipoprotein B:Apolipoprotein A-I Ratios in Adults with Type
2 Diabetes. Journal of Nutrition 2009;139: 1700-1706.