Trans fats are uncommon in nature but commonly produced industrially. They are made by exposing polyunsaturated vegetable oils to a chemical process that involves high heat, hydrogen gas and a metal catalyst. Industrial trans fats often exist in partially hydrogenated vegetable oils, margarine, and fried food and are added to packaged prepared foods to increase shelf life and reduce costs. Only small amounts of trans fats occur naturally in food.
In the recent decades, trans-fats have been put in the spotlight for its harmful effects on human health. Lots of researches have been carried out to explore this topic. Studies widely confirmed that trans fats intake increases the risk of some chronic diseases such as cardiovascular disease and type 2 diabetes and also associates with pro-inflammatory states in the human body.
Trans fats negatively associate with human reproductive health
Human reproductive health largely relies on fats. Appropriate fat supply (balanced healthy fats) could boost both female and male fertility. On the opposite, bad fats (e.g. trans fats) could result in reproductive system disorder.
Female fertility issues have been linked to trans-fat intake. Scientific studies have found consuming more trans fats is associated with higher rate of fetal loss, failure of implantation and ovulatory dysfunction. A 2018 published paper further confirmed trans fats intake decrease women pregnancy rates, and more omega-3 unsaturated fats intake results higher fecundity.
Limiting trans fats intake
The dietary guidelines for Americans 2015-2020 suggest to limit trans fats intake, but there is not a limit value. Currently, no known requirement of trans fats for body functions is discovered. Therefore, we recommend doing your best to avoid trans fats consumption.
Reading food labels
Reading food labels could help eliminate most trans-fats from our diet. Trans-fats is listed in bold print on food labels.
Since trans-fats is now visible on packaging labels, manufacturers are trying their best to remove trans-fats from their ingredients. Now, most foods sold in grocery stores with nutrition labels are containing 0 trans fats. Keep in mind, though, a product contains up to 0.5-gram trans fats can claim to have 0 (according to FDA).
Ingredients list could provide more information about hidden trans fats. According to USDA Food Composition Databases, oils and solid fats containing most added industrial trans fats including
- industrial partially hydrogenated oils ( “partially” may be removed to hide trans fats)
- vegetable oil spreads
- cream substitute
When above ingredients appear in the list, it is better to look for an alternative, especially if it’s something you eat regularly.
Bakery and restaurant foods are major hidden sources of trans fats in the modern diet, as most of them are not required to create a nutrition label. Limiting dining out and bakeries without nutrition labels are recommended to minimize trans fat intake.