Quantities of lactose, lactic acid, and other metabolites in yogurt

Question

It's common to see vague statements about how people with limited lactose tolerance may be able to eat yogurt, because the bacterial fermentation eliminates some of the lactose. However, I haven't been able to find any quantitative information on how much lactose remains. I'm sure it varies widely with different cultures and methods, but I'd love to have even a few specific examples where someone fermented some yogurt and assayed it for lactose.

Similarly, I'd like to know how much of the lactose ends up in the form of lactic acid vs. glucose and galactose monosaccharides vs. other metabolites. This seems potentially important in terms of predicting the caloric content and metabolic effects of yogurt (e.g., blood glucose response).

I've done some searches on the web and in the scientific literature, but I haven't been able to find information on the carbohydrate composition of yogurt or other fermented foods. Can anyone point me to a source?

Answer 1

The following is quoted from this site:

If you're lactose intolerant and looking for yogurt, go Greek. Greek yogurt, which is thicker because much of the whey, the watery part of milk, has been strained out in processing. This also removes much of the lactose. Greek yogurt supplies less than 6.8 grams of lactose per 6-ounce serving, compared to less than 8.5 grams in whole-fat yogurt or 14 grams in non-fat yogurt. Hard cheeses such as cheddar have even less lactose, between 0 to 2 grams per ounce. Milk, in comparison, has approximately 11 grams in one cup.

(Emphasis added.)

Also note that probiotic yogurt (ie: with the cultures still living intact) has the additional benefit of breaking down lactose in the gut where there is a lactase deficiency. See here.

Sorry I don't have more specific info on other metabolites at this stage.