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Monday, June 21, 2010

Mighty Minerals - The Majors Part 2

Today we are learning about the other 3 "major" minerals - phosphorus,. potassium and sodium. Let's begin!

Phosphorus is the second largest mineral in your body (after calcium) and is required by every cell in your body. You'll find it in bones (85% of phosphorus is found here) and teeth, as well as acting as a pH buffer in your blood. Phosphorus is also a part of phospholipids which transport cholesterol through the circulatory system; and many of the vitamins which act as coenzymes also contain some phosphorus in the form of phosphate. It is part of adenosine triphosphate (the "P" in ATP) which is important for metabolism. The best sources are dairy products, meat, legumes and fish. The daily recommended values is 700 mg per day.

Potassium is one of the metallic minerals which plays a role in muscle contraction - which is why low potassium levels lead to cramping during exercise. It also plays a role in nerve impulses and the conversion of food into energy (glucose into glycogen). Potassium helps to regulate blood pressure and is therefore linked to the prevention of hypertension; the sodium / potassium balance is critical (they are balanced by chloride). Luckily, potassium is easy to find - bananas, watermelon, strawberries, apricots, legumes and milk are all good sources. The daily recommended intake is 3500 mg per day.

Sodium is the most abundant cation in our bodies where it helps to maintain the osmotic pressure between our blood and our cells. It is often referred to as an electrolyte because of its role in balancing the anion/cation makeup (calcium, potassium and chloride also fit in this category). Sodium is primarily extracellular, whereas potassium is intracellular. It is this balancing act, the transfer of sodium and potassium in and out of cells that accounts for the majority of the energy expenditure of your whole body. People generally excrete 90% of their ingested sodium; your kidneys pull excess sodium out of your body and you lose some by sweating. Even the most athletic amongst us probably do not need to increase our sodium intake (marathon runners are an exception, as is anyone who has lost ~3 quarts of fluid), as the US diet is rather high in this particular mineral. (Note: not everyone is affected in the same way by sodium, so while it is generally recommended that everyone reduce their daily intake, there is no one correct amount for everyone.) There is a daily intake we should try to meet, but unlike the other minerals, this is a "less than", not an "at least" value of 2400 mg per day.

Well, we've covered all of the major minerals, and next we will move on to the trace minerals. Although they may not be needed in the same quantities, they are none the less important to your body's overall health and its functions!

Monday, June 7, 2010

Mighty Minerals - The Majors

As I stated in my last post, minerals are divided into major and trace. The major minerals are also the best known and include: calcium, chloride, magnesium, phosphorus, potassium and sodium. Since these are needed in larger quantities than the trace minerals, I thought it best to start here with the first three.

Calcium is the most abundant mineral in the body - around 2% of your body weight. Even small children are taught that calcium is important for teeth and bones, but calcium's role in nerve transmission, muscle contraction (especially your heart), hormone production and blood coagulation is less well known, but not less important. There is also some research emerging that links calcium to the prevention of colon, breast and prostate cancers (although it is too early to know conclusively). The best sources include dairy products, dark leafy green vegetables, seeds and soybeans. The daily recommended amount varies for sex and age but is typically between 1000 - 1200 mg per day.

Chloride is best known as the other half of the compound sodium chloride (aka salt). It is an anion (has a negative charge) and it is the dominant anion in your blood where it balances the cations (positively charged): sodium and potassium. Chloride helps regulate the pH of your blood, is found in your cerebrospinal fluid, helps with the conservation of potassium, and is involved in the production of stomach acid (hydrochloric acid). The most obvious source of this mineral is salt, but it can also be found in vegetables like tomatoes and asparagus. The daily recommended value for this mineral is 750 mg per day (not hard to get with the amount of salt in the typical diet).

Magnesium is othe fourth most abundant mineral in your body and is of the major essential minerals found in your bones, teeth and muscles. In the body it is usually combined with phosphate. It is a cation like calcium and potassium. Magnesium is required for the ATP cycle (metabolism), as it activates the enzymes involved in the process. It also has a role in the nervous system, muscle contraction (keeps your heart beat regular), repair of DNA, and blood vessels. The best sources of magnesium are meat, poultry, fish, dark green leafy vegetables, soybeans, nuts and seeds. The recommended daily value for magnesium is 400 mg per day.

We will complete the major minerals phosphorus, potassium and sodium on the next post - so check back soon!