A food additive that is becoming more common in a variety of products has been linked to an increased risk of lung cancer as well as a more vigorous spread of the disease.

A study, published in the January issue of the American Journal of Respiratory and Critical Care Medicine, was performed in laboratory mice but, according to the authors, should serve as a warning to people with a high risk of lung cancer or who have the disease to avoid the additive -- inorganic phosphates -- as much as possible.

Inorganic phosphates are found in many processed foods, such as meats, cheeses, beverages and bakery products. The substances are used to increase water content and improve food texture. In the 1990s, the average adult daily diet contained about 470 milligrams of inorganic phosphates, said the lead author of the study, Myung-Haing Cho of Seoul National University. But today's intake could be more than 1,000 milligrams a day depending on one's diet.

In the study, Cho fed mice with lung cancer a diet containing .5% to 1% of inorganic phosphate, which is comparable to the average amount in a human adult's diet. At the end of the four-week study, analysis of the lung tissue showed an increase in the size and growth of the tumors.

Inorganic phosphates stimulate certain cell signaling pathways that have been linked to the development of non-small cell lung cancer. Cho says future studies should try to determine what is a safe level of inorganic phosphates in the diet.

"The results of this study suggest that dietary regulation of inorganic phosphates has a place in lung cancer treatment," he said in a news release. "Our eventual goal is to collect sufficient information to accurately assess the risk of these phosphates."

Lung cancer is the leading cause of cancer deaths in the world.

-- Shari Roan

Photo credit: Advanced Cell Technology Inc.