My balanced carb and protein diet is stabilized at 25gm fat, 100gm carbs, and 100gm protein, plus 10gm omega 3's in flax and fish oil. And I eat 5 times per day, and measure my blood sugar 5 times per day. Therefore, I know immediately how any supplement effects my blood sugar.
Ginger tea has been a real winner for me. This morning, I woke up with fasting blood glucose of 93, something that is in the normal range. My ginger tea last night made the difference, because I had my usual meal of 25gm protein, 25gm carbs for dinner.
You can purchase ginger tea at many places on the web. Try to get 100 percent ginger tea, as it will effect blood glucose the best.
Other blood sugar lowering natural substances include alpha lipoic acid (plus biotin) available from http://www.vitacost.com
While you are there, buy some reishi capsules! I just love seeing that glucose meter dip when I take ordinary food supplements. But your food must be stabilized, so you can see the effect of the supplements. Food first, supplements second.