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New Yorkers fond of eating out in the last decade weren't just saved from doing the dishes. Residents' blood levels of artificial trans fats, which increase the risk of heart disease, dropped following a 2006 citywide policy that banned restaurants from using the fats.
For people who dined out frequently, the decrease was even greater: Levels of the fats declined by about 62 percent for New Yorkers who ate out four or more times per week, the team reports online February 21 in the American Journal of Public Health.
An estimated 1 in 5 city residents eats out that frequently, says study coauthor Sonia Angell, deputy commissioner of the New York City Department of Health and Mental Hygiene in Queens. "We think [the ban] has just been a win overall for New Yorkers ... in particular for those who dine out more frequently."
Researchers analyzed blood samples of adult city residents from before and after the ban, taken as part of a health and nutrition survey that queried participants on their dining habits. The samples, 212 from 2004 and 247 from 2013–2014, revealed a drop from 49.2 to 21.3 micromoles per liter, suggesting that trans fat levels plunged by about 57 percent overall among New Yorkers.
Artificial trans fats, also called trans fatty acids, end up in foods like fried chicken and doughnuts, anything that is fried, baked or cooked in partially hydrogenated vegetable oils. The fats increase the amount of low-density lipoprotein, commonly known as "bad" cholesterol, in the body while lowering high-density lipoprotein, the "good" cholesterol.
Source: https://www.sciencenews.org/article/ban-artificial-trans-fats-nyc-restaurants-appears-be-working
(Score: 2, Informative) by Anonymous Coward on Saturday March 02 2019, @09:27PM
Just because there is a difference doesn't mean it is for the reason you like. Here is what they did:
https://ajph.aphapublications.org/doi/abs/10.2105/AJPH.2018.304930 [aphapublications.org]
If you test samples from 2004 and 2014 at the same time, the older samples will have "degraded" so there will be a different proportion of trans-fats.
A quick search as to whether fatty acids degrade when frozen (I assume these samples were frozen but they dont supply those details) I found this about fish fillets:
https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1439-0426.2008.01176.x [wiley.com]
Table 1 shows linolelaidic acid decreases to about a third of the initial value after 6 months, and palmitelaidic acid triples in the same time. I don't see the other two that they mention (trans-vaccenic and elaidic acid). Either way, a 50% change in fatty acid composition after 10 years of storage is not unsurprising.