Monday Dec 29, 2008 (foodconsumer.org) -- A new study suggests that high intake of inorganic phosphates found in a variety of processed foods including meats, cheeses, beverages and bakery products may promote growth of lung cancer and even increase the risk of developing the disease in individuals predisposed to the disease.

The animal study led by Myung-Haing Cho, D.V.M., Ph.D., and his colleagues at Seoul National University showed using a diet with the levels of inorganic phosphates commonly found in human diets lung cancer-model mice developed tumors with a larger size and had faster growth of the tumors.

In the study, the researchers fed mice for as short as four weeks a diet with 0.5 to 1.0 percent of inorganic phosphates, the levels similarly found in common human diets and found that the animals grew lung cancer faster than controls.

The study appears in the first issue for January of the American Journal of Respiratory and Critical Care Medicine.

Phosphates are commonly used in processed foods and beverages including bakes goods, soft drinks, cereals, cheese, imitation dairy products, frozen desserts, egg products, ice cream, meat products, dairy products and seafood among others.

"In the 1990s, phosphorous-containing food additives contributed an estimated 470 mg per day to the average daily adult diet," Dr Cho said. "Phosphorous intake (now) could be increased by as much as 1000 mg per day."

"Although the 0.5 percent was defined as close to 'normal,' the average diet today is actually closer to the one percent diet and may actually exceed it," Dr. Cho noted. "Therefore, the 0.5 percent intake level is actually a reduced phosphate diet by today's scale."

John Heffner, M.D., past president of the American Thoracic Society said "We know that only some patients who smoke develop lung cancer but the reasons for this varying risk are unknown. This study now provides a rationale for funding case-control studies in humans to determine the potential role of dietary phosphates in promoting cancer."

Lung cancer is the number one cause of cancer death and is also the most frequently diagnosed solid cancer.  In the United States, 215,020 men and women are expected to be diagnosed with the disease and 161,840 are expected to die from the disease in 2008, according to the National Cancer institute.

Some other side effects of phosphates have been reported.   Higher levels of phosphorus in the blood may increase calcification of the major arteries and heart valves and raise the risk of cardiovascular disease in patients with moderate chronic kidney disease (CKD), a study in the Journal of the American Society of Nephrology (JASN) suggests.

Another study also published in the JASN showed that high-normal phosphorus levels are linked to increased coronary artery calcium even in healthy adults without kidney disease.