Absorbtion

Description

The efficient absorption of nutrients is vital. Someone could eat as many fruits and vegetables, or take as many supplements and health foods as they could manage, but if they weren't absorbing the nutrients contained in them, there would be no point. One particular area of interest is the absorption of minerals especially when consumed in supplemental form.

In nature minerals have either a positive or negative charge, and therefore they are usually bound to another chemical to make them neutral. For example calcium can be found in many forms such as calcium carbonate, calcium chloride and calcium oxide. These forms of calcium are usually described as calcium salts (in the same way that sodium becomes a 'salt' when bound to chloride which forms common table salt). Many other minerals can exist as salt forms and it is this type of mineral that is found in many nutritional supplements.

However, supplements of a high quality will not contain minerals in their salt forms, but will contain minerals in what is known as Amino Acid Chelated (AAC) forms. This type of mineral is superior to the salt form as it is more easily absorbed into the bloodstream through the intestinal wall.

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Nutritional Supplements

Amino Acid Chelation (The Science Bit!)

Amino acids are the building blocks of every protein molecule and protein structure, such as muscle. If a protein molecule were a house, then the amino acids would be the bricks! The combining of minerals to amino acids not only improves the absorption of minerals but also reduces the irritation which some nutrients, such as iron, can cause to the intestinal tract.

When minerals enter the small intestine as a salt form, such as magnesium carbonate, the molecule will split into two smaller molecules of magnesium and carbon. These two molecules are then electrically charged, either positively or negatively, which renders them difficult to absorb as the charged molecule will stick to what ever it can find to become neutral again. If it is allowed to stick to the wall of the small intestine, it not only will be difficult to absorb, but it will also cause irritation. Also, once absorbed into the bloodstream the magnesium needs to be bound to a specific protein because it can't just float around in the blood by itself! Therefore, the body has to work before the mineral can be used.

By consuming a mineral which is amino acid chelated, it would mean that the mineral is connected to specific amino acids, so it will not split as easily in the stomach, as do the salt forms, which reduces the risk of gastrointestinal upset. The mineral/amino acid complex would also be electrically neutral (neither positive nor negative), which means easy absorption, and is already bound to protein so the body can use it instantly.

Many minerals compete for absorption. For example, high levels of zinc can reduce the amount of iron that is absorbed and vice versa. This is because all minerals are absorbed through the same pores, or gates, in the small intestine which are called channel ions. As there are a limited number of these pores in the intestinal cell wall, you can imagine that the queue to get through could be quite long and if you were an iron mineral trying to compete against ten zinc minerals, your chances of absorption are reduced.

Minerals, which are chelated with amino acids, do not compete with each other which means that high consumption of one mineral, such as iron, will not cause low absorption of another mineral, such as zinc. This is because the body will recognise the amino acids and not the minerals, and these are usually absorbed by a different mechanism. Therefore, the body is absorbing minerals in a supplement in the same way that they would absorb minerals present in foods, which are usually bound to protein molecules such as the minerals found in meat. It's rather like putting an iron molecule into a balloon made from amino acids, which then bursts once inside the body and releases the mineral for the body to use.

Chelating minerals to amino acids is a relatively simple and natural process. Digestive enzymes are used to break down large protein molecules, derived from rice, into the individual amino acids which forms an amino acid 'soup'. The minerals are then added to this soup and the natural reaction of chelation occurs with no other chemicals needing to be added. The minerals will move around in the soup until they have found the correct types and amounts of amino acids to bind to.

Consuming minerals in this form will also protect them from other compounds that can prevent their absorption. Such compounds are called phytates, which are found in fibre, tannins, which are found in tea, and oxalates, which are found in foods such as spinach. These molecules would usually be able to bind to minerals and force them to be excreted. However, the bond between minerals and amino acids is so strong that AAC minerals would not be affected by these molecules and therefore would be free to pass into the blood stream.

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Related Links

European Journal of Clinical Nutrition. The site is an electronic version of the journal, which provides rapid publication of high quality papers in the field of nutritional science.

Food Sources

References