Yeah, I wouldn't overestimate how good our immune systems is at protecting us from contaminated water.[1] Where I grew up, at the start of the 20th century man

Yeah, I wouldn't overestimate how good our immune systems is at protecting us from contaminated water.[1] Where I grew up, at the start of the 20th century many children died in infancy from contaminated water and milk. Also the gut is an 'immune privileged' part of the body, meaning that the immune system does not attempt to keep it sterile like the rest of the body.[2] We need a healthy micro-biome for digestion and to synthesize vitamins etc, but this means that it's also relatively easy to get sick from contaminated water and food. [1] The World Health Organization says that every year more than 3.4 million people die as a result of water related diseases, making it the leading cause of disease and death around the world. [2] https://www.ncbi.nlm.nih.gov/pubmed/16972898 https://www.ncbi.nlm.nih.gov/pubmed/16972898