What causes the symptoms of lactose intolerance?

Answer 1

Lactose intolerance is the inability to digest lactose. Lactose intolerance happens when the small intestine does not make enough of the enzyme lactase. Enzymes help the body absorb foods. Not having enough lactase is called lactase deficiency.

Answer 2

The bacteria in your digestive tract can't destroy the lactose in milk. It's genetic and most people in the world are lactose intolerant!

More specifically, all ADULT humans were originally lactose intolerant. Genetically, there seems to be an "off" switch that occurs in early childhood, somewhere between 4 and 6 years old. Before then, humans (like other mammals) can easily digest milk products, as made obvious by breastfeeding. The change is in the ability of the body to produce the proper enzymes which can breakdown lactose into usable parts. For those without the proper enzymes, lactose is nutritionally useless; while not poisonous, it is about as useful as eating grass, and can cause an allergic reaction.

However, sometime between 10,000 and 20,000 B.C.E., there appears to have been a genetic mutation in certain populations of humans, which either (a) prevented this genetic switch from being thrown, or (b) activated a whole different gene. This allowed those populations of humans to continue to digest lactose their entire life. The genetic mutation seems to have occurred somewhere in the Mediterranean region, as lactose-tolerant humans are those of a European or North African or Mesopotamian genetic descent, and was likely a result of the very high association with milk-producing livestock that those populations had. Historically, this meant people native to Europe, the Russian Steppes, North Africa, the Middle East, Persia, and part of India seem to have acquired the gene through inbreeding. Native Australians, all native Americans (north, south, and central), and those of Chinese descent did NOT get the mutation. Most Asians are lactose intolerant, due to a massive wave of native Chinese migrations that occurred in the 15-10,000 B.C.E. timeframe, which replaced any local population with one of Chinese stock.

Additionally, the mutation does not seem to follow a classic Mendellian dominant/recessive pattern. Thus, should a lactose-tolerant person have a child with a lactose-intolerant person, the child will likely (though not certain) be lactose tolerant. Statistics vary, but the odds are somewhere in the 5:1 range in favor of being lactose tolerant. Thus, as global populations slowly intermarry, it is highly likely that all populations will convert to being mainly lactose-tolerant, but a substantial minority (10-20%) will continue to be lactose-intolerant.

Answer 3

Lactose is a sugar molecule that's composed of glucose and galactose. In order for lactose to be absorbed in the body, the glucose and galactose must be split. A lactase enzyme performs this action.

In an individual's body who is lactose intolerant, they are missing the lactase enzyme. The lack of the lactase enzyme is caused by one of three reasons: hereditary, secondary, or developmental.

Answer 4

Lactose intolerance is a condition that results from loss of production of lactase, the enzyme that breaks down lactose, or "milk sugar." Most of us have adequate lactase enzyme in infancy, but as we age, it is commonly lost. This is why lactose intolerance can occur at any time in life. Everyone is affected differently. Those who continually consume milk products from their early years onward have a higher incidence of retaining production of this enzyme than individuals who abstain from or inconsistently consume milk products post-infancy. Loss of production of lactase enzyme causes the body to be unable to digest (break down; metabolize) milk sugar. Side effects of varying severity may result in excess gas, bloating, acid stomach/indigestion, cramps and diarrhea. Symptoms are typically proportional to the amount of lactose ingested -- the more you eat, the harder time your body has of eliminating it. Thankfully, lactase enzyme is readily available over-the-counter in generic form; the most common brand name is Lactaid. Lactase enzyme can be purchased in pill form, or added to milk and milk products before sale, as in Lactaid and other brands of lactose-free milk. Different people need different amounts of lactase enzyme, and more may be necessary when ingesting larger amounts of lactose-containing foods. If taking lactase enzyme in pill form, it is most effective at preventing uncomfortable symptoms of lactose intolerance when taken with the very first bite (or sip) of a lactose-containg food, such as milk, yogurt or ice cream.

Answer 5

chemical in balance

Answer 6

Lactose intolerance.