Saturday, March 18, 2017
Once again, an article about fast food has been posted on several “healthy living” websites and reposted on FaceBook. On this occasion, HealthZone.Tips writes about McDonald’s french fries under the title:
When You Find Out What is in McDonald’s French Fries, You Will Be Disgusted!
Whatever you think about fast foods, you would expect the article to be accurate and not merely sensational. The article claims that McDonald’s puts more than ten ingredients into its fries, and quotes Grant Imahara (Myth Busters), suggesting that the fries are not really potatoes! This article is just plain scaremongering, and I wonder what is the author’s motivation.
The post lists the main ingredients, noting that there are other components:
Hydrogenated soybean oil
Natural beef flavour
Tertiary butylhydroquinone (TBHQ)
and states that “The three offenders on the list are TBHQ, dimethylpolysiloxane and hydrogenated soybean oil”.
Notice that there is no mention of the amounts of these “offenders” in the fries, as you would find on a food label - usually as grams per 100 grams and grams per serving.
So let’s look at these three components.
Tertiary butylhydroquinone E319, an anti-oxidant, is used as a preservative for unsaturated vegetable oils and also for many edible animal fats. Both the FDA and the Scientific Panel on Food Additives, Flavourings, ProcessingAids and Materials in Contact with Food of EFSA regard TBHQ as safe when used at the permitted levels. The Panel stated that, “Based on the data reviewed, the Panel concluded that TBHQ is not carcinogenic and that further genotoxicity studies were unnecessary. TBHQ is used in many foods and also in perfumery. In a medium serving of french fries (133 g) there is about 22 g fat and thus about 4.4 mg TBHQ. Using the EFSA acceptable daily intake (ADI) of 0.7 mg/kg body weight for a 70 kg human, this equates to about 9% of the ADI, which itself has a 100x safety factor built in.
Dimethylpolysiloxane E900 is a polymeric organosilicon compound, used as an antifoamer in cooking oils to prevent foaming and splatter. FSANZ permits a maximum of 10 mg/kg of the final food. The WHO summarised a number of studies of the effect of DMPS on humans and animals with “None of these studies has revealed any significant toxicity. The metabolic studies, including those in man, indicate that the orally administered dimethylsiloxanes are mainly excreted unchanged in the faeces.” It is difficult to obtain data on levels of DMPS in final foods, but using data from Five Guys, I estimate that the level in the frying oil could be around 0.004% and in the fries, the final level could be around 0.9 mg in a medium serving of fries, or 6.8 mg/kg fries.
Hydrogenated soybean oil is used in the production of margarine, shortening, and salad and cooking oils. The US FDA Committee on GRAS substances concluded that “There is no evidence in the available information on hydrogenated soybean oil that demonstrates, or suggests reasonable grounds to suspect, a hazard to the public when it is used as a direct or indirect food ingredient at levels that are now current or that might reasonably be expected in the future”.
For those readers who live in New Zealand: I consulted a fats and oils chemist. He told me that
They don’t use hydrogenated soy in Nz and never have done; the oil is now monounsaturated canola/sunflower oil. TBHQ is no longer used. As far as he is aware, the oil blend no longer contains DMPS, and even when it was used, the level was around 1ppm.