At least a handful of small studies have suggested that consuming cranberry juice can increase HDL levels by up to 10%.
Most recently, a study published in the British Journal of Nutrition described the effect of cranberry juice consumption on 30 overweight men with modestly elevated LDL cholesterol levels. For 16 weeks, the men drank increasing amounts of a low-calorie cranberry juice cocktail(up to about 2 cups per day). At the end of this period, these individuals were found to have significantly increased their HDL levels by about 8%.
Researchers attributed the elevation in HDL levels to the flavenoids found in cranberry juice.
Since cranberry juice is harmless, drinking the stuff seems like a reasonable idea for anyone looking to raise their HDL levels. If so, the peak effect on HDL in most of these studies has been seen with about 1 cup of cranberry juice per day - the low calorie stuff, DrRich reminds you.
So, go ahead and drink cranberry juice, but the mainstay of raising HDL levels is still weight loss and exercise.
Ruel G, Pomerleau S, Lemieux S, Lamarche B, Couillard C. Favourable impact of low-calorie cranberry juice consumption on plasma HDL-cholesterol concentrations in men. Br J Nutr. 2006 Aug;96(2):357-64.