Fermented dairy products, such as yogurt and kefir are fine because they are predigested and, therefore, more easily metabolized. It's pasteurized dairy that's the problem.
Remember that there's a difference between "living" and "dead" foods. The microbes in most fermented foods are destroyed by pasteurization or processing.
Fermentation increases the medicinal value and nutrition of foods, helping to maintain a healthy population of micro-flora in the gut, which is important because there are so many external pollutants, allopathic medicines, and low nutrient foods that destroy life support gut bacteria.
The flora in living cultured foods form a "living shield" that covers the small intestine's inner lining and helps inhibit pathogenic organisms including unhealthy overgrowth of candida.
I eat mainly sardines and sockeye salmon. Stay away from tuna, sea bass, grouper, mackeral etc because they are high in mercury.