Monday, July 15, 2013
Being anaemic can be good for you sometimes!
John Murray, a physician and his wife were working in Somali refugee camps. Here they noticed that despite severe anaemia and repeated exposure to pathogens, like that causing TB, malaria and brucellosis, these refugees were free from these infections. So while treating anaemia, he decided to use caution and treated only part of the population with iron supplements. Suddenly the refugees being treated for anaemia started showing increased rate of infection. Though the anaemia was gone, infections had skyrocketed- What happened? Iron is one of the most important elements in every life form on earth (except for a few microbes). We need iron; to transport our oxygen in blood, to build enzymes that convert sugar into energy and for the proper functioning of our immune system. In nature, life thrives where iron is in abundance and the iron rich winds from Sahara keep the North Atlantic's marine life thriving. So when bacteria and other microbes invade our body, the first thing they seek is the life giving iron. Our body knows this and has devised mechanism to protect this all important liability. Our body has a protein called chelator on continuous patrol. Chelators lock up iron molecules and prevent them from being used by others. The natural openings in our body (eyes, noses, ears, mouth, genitals) are all rich with chelators. When we fall sick, our immune system prepares for a fight back with what is called 'acute phase response' a part of this response is to lock away the iron in the body, so that it is unavailable to anyone. Mother's milk contains lactoferrin - a chelator like protein that binds with iron, making it unavailable to bacteria and prevents infections in newborns. So when we give iron supplements to a person who is ill, it acts against all the hard-work the body is putting in to fight the infection. About forty years ago, doctors in New Zealand routinely injected Maori babies with iron supplements. They believed that Maori diet was lacking Iron and the babies would be anaemic. Maori babies who received these iron supplements were seven times more susceptible to deadly infections, including meningitis and septicaemia. Like all of us, babies have isolated strains of harmful bacteria in their system, but this is normally kept under control by their bodies. When doctors gave the iron supplements, they basically laid a buffet table for these pathogens. Iron supplements in food too can be bacterial banquet. Many infants have botulism spores in their gut (these are found in honey too- hence the warning not to feed honey to infants under the age of one). If these spores germinate, the results can be fatal. A study of infant botulism showed that babies who were fed with iron-supplemented formula instead of breast-fed, had 100% fatality. Today with this new understanding of iron- pathogen relationship, iron supplements are being reconsidered in medical treatments.