Two common emulsifiers (found in foodstuffs such as mayo and mustard) kill off important gut biome bacteria.
http://www.zmescience.com/medicine/nutrition-medicine/emulsifiers-fat-processed-food-0302015/
The original Nature paper:
http://www.nature.com/articles/nature14232.epdf?referrer_access_token=YQxFH-8czRaaLavfmHqlstRgN0jAjWel9jnR3ZoTv0OKski5KELCofuYPkpLIczYHL5YrRNNH6rcX-FgmRFkTKbgMwVfpUxDulWBJNyQD4M2r2kXoS_BSbXQNGItvC7QpAbwdYjLuUL_WKSRSL8yJrpifCsgfvFNxQSQxNWXPuLI3YjvO5dGKM8743iO7VuoCXZl8nq-gm0bBk-t1Q1IVHgN5Ht7WDQQ_Cz5lmMY1KoKry0Ab6pydQpY_z9QCszU&tracking_referrer=http%3A%2F%2Fwww.nature.com%2Fnews%2Ffood-preservatives-linked-to-obesity-and-gut-disease-1.16984%3FWT.mc_id%3DTWT_NatureNews
http://www.zmescience.com/medicine/nutrition-medicine/emulsifiers-fat-processed-food-0302015/
The original Nature paper:
http://www.nature.com/articles/nature14232.epdf?referrer_access_token=YQxFH-8czRaaLavfmHqlstRgN0jAjWel9jnR3ZoTv0OKski5KELCofuYPkpLIczYHL5YrRNNH6rcX-FgmRFkTKbgMwVfpUxDulWBJNyQD4M2r2kXoS_BSbXQNGItvC7QpAbwdYjLuUL_WKSRSL8yJrpifCsgfvFNxQSQxNWXPuLI3YjvO5dGKM8743iO7VuoCXZl8nq-gm0bBk-t1Q1IVHgN5Ht7WDQQ_Cz5lmMY1KoKry0Ab6pydQpY_z9QCszU&tracking_referrer=http%3A%2F%2Fwww.nature.com%2Fnews%2Ffood-preservatives-linked-to-obesity-and-gut-disease-1.16984%3FWT.mc_id%3DTWT_NatureNews