Dimethylpolysiloxane vs Partially Hydrogenated Oils: which is worse?

What is Dimethylpolysiloxane?

Dimethylpolysiloxane (PDMS, polydimethylsiloxane) is a silicone-based polymer used as an antifoaming agent in food and beverages. It prevents the formation of foam during food manufacturing and cooking. It is the same base material used in silicone cookware, medical devices, and contact lenses.

What is Partially Hydrogenated Oils?

Partially hydrogenated oils (PHOs) are vegetable oils that have been treated with hydrogen gas in the presence of a catalyst to make them semi-solid at room temperature. This process creates artificial trans fatty acids (trans fats) as a byproduct. They were developed in the early 20th century as a cheaper, longer-lasting alternative to lard and butter.

Documented risks

Dimethylpolysiloxane: Dimethylpolysiloxane is generally considered non-toxic. It is not absorbed by the gut and passes through the digestive system unchanged. The FDA permits it at up to 10 ppm in cooking oils. EFSA's evaluation found no evidence of toxicity at permitted food use levels. There are no established cancer or reproductive toxicity concerns with PDMS at food use concentrations. The compound is the same base polymer used in many safe medical applications including contact lenses and breast implants (though the medical grade is different purity). The main environmental concern is PDMS persistence in the environment, as it is not readily biodegradable. Primary consumer concern is psychological rather than toxicological: the fact that it is used in both McDonald's frying oil and Silly Putty (which also contains PDMS) generates public attention, but the chemistries are actually different grades of the same polymer family.

Partially Hydrogenated Oils: Artificial trans fats (from PHOs) have the most well-established cardiovascular harm of any food ingredient ever banned. Multiple large meta-analyses have confirmed that trans fat consumption increases LDL ('bad') cholesterol, decreases HDL ('good') cholesterol, increases inflammatory markers, and significantly raises cardiovascular disease risk. The Harvard Nurses' Health Study and other landmark prospective studies in the 1990s identified trans fat as uniquely harmful — worse than saturated fat in its cardiovascular effects. A 2006 NEJM meta-analysis by Mozaffarian et al. estimated that eliminating artificial trans fats from the US diet could prevent 72,000 to 228,000 heart attacks per year and 30,000 to 100,000 coronary heart disease deaths annually. The WHO estimates that industrially produced trans fats cause over 500,000 cardiovascular deaths per year globally. The FDA revoked PHOs' GRAS status in 2015 based on this evidence, with compliance by 2018. Denmark banned artificial trans fats in 2003, the first country to do so, and observed a dramatic reduction in cardiovascular mortality in subsequent years.