God's Chemistry Set: Phosphorus and the Cola Controversy

As with my last blog, (M for Magnesium), this entry is expanding on one of the elements discussed previously in a frequently visited story, this time Phosphorus. The blog "Fire and Brimstone" is currently number three on the list, battling it out for second place with "Salt of the Earth." There must be schools out there somewhere that are looking at the third period of the Periodic Table regularly. All of the elements discussed in my top three blogs - Sodium, Magnesium, Aluminum, Phosphorus, Sulfur and Chlorine - are in the third period.

Phosphorus is the chemical element with symbol P and atomic number 15. A multivalent nonmetal of the Nitrogen group, Phosphorus as a mineral is almost always present in its maximally oxidized state, inorganic phosphate. Elemental phosphorus exists in two major forms — white phosphorus and red phosphorus — but due to its high reactivity, it is never found as a free element. Phosphorus was the 13th element to be discovered and the first element discovered in modern times.

White Phosphorus is the least stable, the most reactive and the most toxic of the allotropes. It consists of tetrahedral P₄ molecules, in which each atom is bound to the other three atoms by a single bond. White Phosphorus gradually changes to red Phosphorus. Red Phosphorus is polymeric in structure. It can be viewed as a derivative of P₄ wherein one P-P bond is broken, and one additional bond is formed between the neighboring tetrahedron resulting in a chain-like structure. Red Phosphorus may be formed by heating white phosphorus to 250 °C (482 °F) or by exposing white Phosphorus to sunlight.

Phosphorus is highly flammable and pyrophoric (self-igniting) upon contact with air. White Phosphorus is used as an additive in napalm. The odor produced on combustion has a characteristic garlic smell. Elemental Phosphorus glows in the dark (when exposed to Oxygen) with a very faint tinge of green and blue. The term phosphorescence (re-emitting light that previously fell onto a substance and excited it) is derived from Phosphorus but the reaction that gives Phosphorus its glow is properly called chemiluminescence (glowing due to a cold chemical reaction).

Due to its flammability, Phosphorus was used in "strike anywhere" matches, first produced in the 1830s. They were sensitive to storage conditions, toxic and unsafe, as they could be lit by striking on any rough surface. Their production was gradually banned in different countries starting in 1872 up until 1925. As a consequence, the "strike-anywhere" matches were gradually replaced by the "safety matches" we know today. White Phosphorus was replaced with Phosphorus Sesquisulfide (P₄S₃), Sulfur or Antimony Sulfide. Such matches are hard to ignite on an arbitrary surface and require a special strip containing red Phosphorus. The Phosphorus heats up upon striking, reacts with the Oxygen-releasing compound in the head and ignites the flammable material.

Phosphoric Acid binds Calcium
And may decrease Bone Density
So drink Cola in Moderation

Inorganic Phosphorus in the form of the Phosphate ((PO₄)⁻³) is essential for most life, playing a major role in biological molecules. Phosphate is a key component of DNA, RNA, and Adenosine Triphosphate (ATP). Nearly every cellular process that uses energy obtains it in the form of ATP. It is also found in the phospholipids that form all cell membranes. Elemental Phosphorus was first isolated from human urine, and bone ash was an important early Phosphate source. The chief commercial use of Phosphorus compounds is for the production of fertilizers to meet the need for Phosphorus that plants require to grow. Elemental Phosphorus is highly toxic, causing severe liver damage. Ingestion of white Phosphorus can also cause a medical condition known as "Smoking Stool Syndrome" where the stool will emit white smoke when exposed to air.

One area of debate involving Phosphorus is around the use of Phosphoric acid (H₃PO₄) in carbonated soft drinks, primarily colas. Phosphoric acid is added to give colas their tangy flavor. It also slows the growth of molds and bacteria, which otherwise would multiply rapidly in the sugary solution.

Phosphoric acid has been linked to lower bone density in some epidemiological studies. One such study showed that women who consume colas daily have a lower bone density than those who don't. Total phosphorus intake was not significantly higher in daily cola consumers than in non-consumers; however, the Calcium-to-Phosphorus ratios were lower. Consuming highly acidic substances can promote a deterioration of the teeth, jawbone, pelvis and femur. From this study and others like it, drinking Phosphoric acid appears to dissolve away your skeletal system.

Phosphate binds Calcium and can lead to increased elimination of Calcium from your system. Another study suggests that the decreased systemic Calcium is due to the fact that if someone has a high soda intake, they have a low milk intake - substituting soda for milk as their source of liquids. This study concluded that the net effect of carbonated beverages — including those with caffeine and Phosphoric acid — is negligible, and that the skeletal effects of carbonated soft drink consumption are likely due primarily to milk displacement.

Phosphorus itself is an important bone mineral. But if you're getting a disproportionate amount of Phosphorus compared to the amount of Calcium in your diet, that could lead to bone loss. Aside from this risk of osteoporosis, Cola consumption has also been linked to chronic kidney disease and kidney stones.

American consumption of carbonated soft drinks fell to 491 twelve ounce servings in 2009, down from 507 servings in 2008. (Per capita consumption peaked in 1998 at 576 twelve ounce servings.) Only a small fraction of the Phosphate in the American diet comes from additives in soft drinks. One twelve ounce can of cola contains approximately 37 mg of Phosphorus. The recommended daily intake is about 1000mg so drinking six sodas a day would constitute only about 22% of the daily allowance. Most Phosphorus comes from meat and dairy products. The amount of Phosphoric acid in soda is minimal compared to that found in chicken or cheese and no one's telling us to stop eating chicken. So your reason for not drinking cola should be its sugar content and artificial food colorings, not the Phosphoric acid.

There are a few things you can do to boost your bone health:

Cut down your cola intake by one or two cans a day or switch to a non-cola soda if you can not stop entirely.
For every soda you skip, reach for a glass of milk instead.
Add milk instead of water when you prepare pancakes, waffles, and cocoa.
Add nonfat powdered dry milk along with liquid milk to recipes using milk - puddings, cookies, breads, soups, gravy, and casseroles.
Take a Calcium and Vitamin D supplement if you still aren't getting enough Calcium.
Get plenty of weight-bearing and resistance exercise. Walk, walk, walk everywhere!