The senator says industry has made progress in removing phos and more regulation could have consequences.

WASHINGTON — Senator Rand Paul of Kentucky in a March 9 letter to the Food and Drug Administration expressed ”significant concerns” about the F.D.A.’s preliminary determination that partially hydrogenated oils (phos) are no longer Generally Recognized As Safe because they cause industrial trans fat.

The F.D.A. in the Federal Register of Nov. 8, 2013, said it had tentatively determined phos are not GRAS for any use in food based on current scientific evidence establishing health risks associated with trans fats. If the F.D.A.’s proposed rule is finalized, food manufacturers no longer would be permitted to sell phos, either directly or as ingredients in food products, without prior F.D.A. approval.

While recognizing scientific studies have shown trans fats contribute to cardiovascular disease, Dr. Rand said industry has made progress in eliminating phos from products. From 2003-12, the average daily per capita intake of trans fat from products containing phos decreased by 78% to 1 gram, he said in the letter sent to Margaret Hamburg, F.D.A. commissioner.

“The preliminary determinations that phos are no longer GRAS at any level causes practical and process concerns,” said Dr. Paul, who is a graduate of the Duke University School of Medicine and previously was a practicing ophthalmologist. “Many foods contain very small pho amounts left over from processing, and phos are used to help with shelf life or texture. Additional reformulation of products will likely remove many food choices from grocery store shelves and/or raise food prices.”

He said the likely product substitutes might have nutritional, palatability and environmental concerns.

“Considering these implications, it is reasonable to suggest that your agency’s policy would require drastic dietary changes of the average American who eats processed or animal-based foods, thus I am unsure of the efficacy of this burdensome, maybe even impossible, requirement when the market and individual decision-making has already led to healthier choices.”

He added the Office of Management and Budget (OMB) should examine the cost of reformulating or eliminating some foods. A cost-benefit analysis from the F.D.A. estimated it would cost between $12 billion and $14 billion over 20 years.