What would cause low blood sugar in a non diabetic? mine was 69 mg/dl today. i have had issues in the past with it being even lower.

Non clinical : Although there is a rare tumor called Insulinoma which causes low blood sugar in people not taking any diabetes medicines, most of the time, low blood sugars in the range you mention are of no clinical significance. They don't reflect a disease. Any symptoms you experience may be incorrectly attributed to "low glucose". Glucose in 30s and 40s are definitely worrisome and should be investigated.

Hypoglycemia: Blood sugar 69 is still normal but lower end of normal, some people are more sensitive to insulin, rare cause is over production of insulin from tumors but that is very very rare. People tend to have these problem are adviced to take small frequent meals.

Normal: A blood sugar of 69 is normal for someone who does NOT have diabetes.