Lactose is what type of molecule

The lactose disaccharide molecule is naturally broken into their simple sugar parts by an enzyme called lactase, present in the digestive system of people who are tolerant to lactose. Once the enzyme breaks the bond of the double-sugar lactose molecule, glucose and galactose are easily absorbed. When lactase is not sufficiently present in the gut, it remains undigested as it enters the large intestine. Here it interacts with natural bacteria and ferments, creating the uncomfortable symptoms of lactose intolerance.

This is not an allergy, as it does not involve our immune system. It is very important that this intolerance should not be confused with milk allergy, a reaction to certain proteins in milk, which can lead to potentially life-threatening conditions. In a way, lactose intolerance is a simple chemical problem in almost all cases, the lack of the enzyme lactase. Despite the similar name, lactase is not a carbohydrate, but a more than times larger protein molecule, that will catalyse the hydrolysis of lactose in the stomach.

Often the production of lactase diminishes in adulthood, but in regions of the world with a continuous high intake of dairy products, notably Europe, many grown-ups retain their production of this enzyme and can still digest milk. Lactose is a small and polar molecule and is therefore water soluble but less soluble in fats.

This means that dairy products such as butter and cheese, where fat gets concentrated, contain less lactose than milk. The same goes for fermented products where the bacteria eat some of the lactose and produce lactic acid , C 3 H 6 O 3. This also means that whey, the liquid residue from cheese manufacturing , is a good source of lactose, and this is how this chemical is produced on an industrial scale, usually in countries with a highly centralized cheese production. The pure lactose can then be used in other foodstuffs such as coffee creamers, confectionery, baked goods, meat products, and even in canned fruit and vegetables.

So if you have a problem with this molecule you may want to read the label of ingredients carefully when you go shopping. This also goes for some pharmaceutical products, as lactose is used for making tablets and filling capsules. Lactose is also the raw material for the similar molecule lactulose, an effective laxative. So, how do you cope with being lactose intolerant when living among milk-lovers?

There are two solutions if you want to keep eating and drinking these products. Either you buy the enzyme, lactase, in small capsules and let them work on the food before or while you eat it, or you buy the increasingly common low-lactose or lactose-free dairy products. The former are made in dairies by adding lactase enzymes to the milk and letting it hydrolyse the lactose before packaging.

The hydrolysis, as you now know, produces two sugar molecules from one, a possible taste problem. A remedy to this problem is to pass the milk through a column of a porous material with a high affinity for lactose molecules, to get the lactose level low enough not to cause taste problems after subsequent hydrolysis with lactase.

However, in some humans mostly those with ancestry in the approximate geographic region of Europe, the Middle East and India , the enzyme is retained in adulthood, and dairy products form a substantial part of the adult diet. It would appear that millennia of animal husbandry in those regions, with the milking of sheep, cattle, goats and water buffalo, has caused an evolutionary adaptation to an adult diet containing milk.

This process of retaining infant characteristics into adulthood is one of the simplest routes of evolutionary adaptation, and is known as neoteny The fact that at least some humans have made adaptations to lactose in the adult diet would, incidentally, appear to cast doubt on some arguments by proponents of the so-called 'Stone-age diet', who argue that human metabolic needs have not changed since the last ice age. Explain it with Molecules.

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