Nicole's Bio in Fiji

Lactase Evolution


Lactose intolerance is a very common condition. It is the inability to digest lactose, a sugar found in milk and dairy products. Humans are born with the ability to produce an enzyme called lactase. Lactase is needed to digest lactose, as it cannot be absorbed directly into the bloodstream along the gastro- intestinal tract. As humans mature, their production of lactase is dramatically decreased by about 90%in non dairy consuming populations. This is because all mammals except humans do not drink milk in adulthood.

The way lactose intolerance has come to be is through natural selection. Natural selection is the process by which a species adapts to their environment. It is based on three main principles. In this case, the principle is, “individuals who survive can go onto produce offspring”. As lactose and dairy became available and needed for survival, the gene that regulates the shutting off of lactase production mutated so that humans were able to continue to digest lactose. In some populations this can happen depending on the presence of cows. If an area has absolutely no dairy producing animal, the people will not have been exposed to lactose and therefore will have not developed the mutated gene. It works the other way as well; if cows are present, it is very likely that natural selection will have worked to pass down the adaptation onto the offspring.

In India, cows have been present for a long time. Historically and currently cattle is considered sacred. As a result of this fact, the Indian people have been consuming the milk from cows for a very long time. This is opposite to the Fijian population, where cows are relatively new. This means that the Fjian people have not been exposed to drinking milk in adulthood and haven’t yet developed the ability to produce lactase in adulthood.

These pictures show a cow in India and a graph of the percentages of lactose intolerance globally.….0…1c.1.21.img.BHUdK1ijWzs#biv=i%7C7%3Bd%7CeMqtDMReED8ApM%3A….0…1c.1.21.img.qSPuNr6EhkI&q=lactose%20intolerance#biv=i%7C3%3Bd%7ChJHynObfu6EqcM%3A



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