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Lactose intolerance: Adding a section to this article about lactose intolerance by region and it's related history.

Add to causes section:

Lactose intolerance could also be created by damage to the small intestine where lactase is produced. Damage could be cause by:
 * Celiac Disease
 * Crohn’s disease
 * Infection
 * Surgery
 * Injury

Lactose Intolerance Background
The ability to digest lactose after infancy changed throughout history to become a far less prominent symptom of aging. This was due to the incorporation of dairy products into the daily lives of certain regions. It is now apparent that particular ethnicities have a higher, or lower, production of lactase as the aging process continues. The culture of an area is able to change the digestive process of it's descendants over time in a form of rapid evolution that has brought about changes visible through a timeline of genetic history. Among the most intolerant to lactose are Native Americans, and the most tolerant are the Northern Europeans.

Basic Trends:
About 65% of people experience some form of lactase deficiency as they age past infancy. Sometimes premature babies are lactose intolerant for a period after birth. Typically, in the first four years a person is alive lactase production decreases by 90%, but this varies. Some cultures have developed a tolerance later in life due to a need for unfermented milk products, this is especially true in Northern Europe lineages where it is so rare only 5% of people are unable to digest dairy. Lactose intolerance can start as a child, teen, or even adult and possibly babies, though this is very uncommon. Lactase continues to be produced in the digestive system in Northern Europe, Arabia, and some regions of Africa, but the rest of the world consists of much higher rates of deficiency. . Northern Europeans are least likely to be lactose intolerant However, some regions produce people with great numbers of intolerance, such as Eastern Asia (where about more than 90% are intolerant)  .Native Americans are a group that are entirely lactose intolerant; the Navajo Indians even used their federal supply of powdered milk to paint their adobe homes, because they could not drink it.

Statistics:
Ethnicities with high rates of lactose intolerance include:
 * Asian american
 * African american
 * Native american
 * Hispanics/latinos
 * Southern Europeans

Chart of groups and intolerance

Lactose Consumption and Intolerance in Contemporary American Culture
Due to the railroad expansion in the late 1880s milk consumption grew due to the new system that allowed daily pick ups of fresh milk to be brought to the people. Whole milk made in America became increasingly popular with the two billion pounds produced in 1870 increasing to eight-teen billion pounds by 1900. In the middle of the 20th century advertisers began to spread the idea that milk was very important to one’s health. They promoted a rhetoric that children especially needed to continue to drink milk past infancy. This perpetuated the idea that drinking milk was normal. Still later an increase in intolerance was seen between 2002 and the 1990s. Now, greater than 30 million Americans (typically of African and Asian decent) are unable to digest lactose after childhood is over.

Hunter-gatherers and Lactose Intolerance
Back when food was obtained through a hunter-gatherer culture people did not keep livestock. The children were weened off of their mothers' breast milk earlier, so as to not take unnecessary nutrients from the mother. This resulted in a shorter lactation period which allowed mothers to decrease the time between pregnancies, since their fertility would be able to rise up again once the breast-feeding had ceased. Ultimately, more sequential births resulted in a higher rate of infant mortality for hunter-gatherer families.

The cultures that had introduced livestock as a means of living were able to feed their children milk in order to keep more of them alive. This is how the period of lactose tolerance began to extend. For some people, the further back their ancestors introduced dairy the more they can tolerate it later in life.

Food culture has a unique relationship with biology where the culture can actually change the ability of the body to digest certain items overtime through exposure, therefore actually changing the digestive chemistry in a certain group.

European Origins
Back in the 1970s a clay pot was found in Central Poland, the pot was in a location of an old farm and contained an unusual feature; it was covered in tiny holes. This pot dated back 7,000 years to a time when Central Europe was just beginning to farm. Archeologist, Peter Bogucki, who found the pot speculated that it could have been made used for making cheese since it appeared similar to the modern day tool used to separate the milk fat solids from the liquid whey to prepare the cheese. This was confirmed when in 2011 Mélanie Roffet-Salque analyzed the fat debris located on the pot. She found enough evidence of milk fat to conclude that this pot was a tool for cheese making. This pot became the first evidence of cheesemaking in Europe. Around the time this pot was made there was a spread of a genetic mutation throughout Europe that allowed people to digest lactose. It is now believed that many of the current Europeans are descendants from the first dairy farmers in the area.

Today, dairy is a prominent part of Polish food culture, especially fermented milk products like sour cream, cheese, and yogurt. Dairy in Poland does not just come from cows now, but is also often from sheep or goats as well. A popular form of dairy in Poland is sour cream. It is used in a variety of dishes including salad dressings, cakes, soups, and roast meat dishes just to name a few. Polish yogurt, known as kefir, is likewise a popular form of dairy consumed in the country. Cheeses in the country are made with sour milk and cheese curds, and varies by region. The Polish enjoy using their cheeses to make cheese fillings, cheesecake, and cheese soup all of which are typically made with the cheese that comes from he curds or sour milk.

Middle Eastern Origins
Middle Eastern farmers from 11,000 years ago started to learn to heard cattle as the transition from hunter-gathering to farming began. They learned that by fermenting milk into cheese or yogurt they could reduced the amount of lactose to a bearable level. This along with the European mutation are referred to as the Milk Revolution.

Genetics
Genetically, the LCT gene encodes the steps to making the lactase enzyme. It is natural for this gene to reduce activity with age, and is controlled by regulatory element. Weaning babies off breastmilk could have originated due to the body’s natural decrease in production of lactase. Without lactase dairy will remain in the gut stealing water from the body until it swells and forms a gas producing microbes substrate. Women are more likely to be lactose intolerant than men.

Mutations
Certain traits spread due to migration. Some groups over time developed a mutation on chromosome 2 that allows them to continually produce lactase. This means people can keep drinking milk which is important for certain milk reliant communities. Those who do not have the mutation become intolerant. It is unknown when this mutation began. Some estimate that in 4000 B.C. mutations in Sweden and the Arabian Peninsula started the mutation and spread to Europe. Others say one case in the middle east triggered this in 4500 B.C. and it then spread from there. A few believe that there was a more contemporary shift mutation originating in the East African Tutsi.

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