DEAR DR. BLONZ: I keep seeing the word "hydrolyzed" on ingredient labels, but I am not sure what it means. Is it anything like "partially hydrogenated"? -- H.S., Anderson, South Carolina
DEAR H.S.: "Hydrolyzed" refers to a chemical process in which a large compound is broken down after reacting with water (hence the "hydro").
An example of its use in the world of food is the splitting apart of proteins, which are composed of long chains of amino acid building blocks. Proteins are large, complex molecules, and get broken into their individual building blocks before absorption by our bodies. Our digestive system is designed to perform this action.
The "hydrolyzed" you spotted on a label was likely associated with an ingredient called "hydrolyzed vegetable protein" (HVP). But if digestion will accomplish the goal, why break apart a protein before it enters the body? Food scientists discovered that certain individual amino acids could enhance flavor. Small amounts of hydrolyzed proteins began being used as additives in processed foods after tests revealed it helped bring out the natural flavor of some foods.
A related issue deserves mention here. There has been, in the past, some concern about HVP due to its association with monosodium glutamate (MSG), which tends to form in hydrolyzed proteins. Some people claimed an extreme sensitivity to MSG, including symptoms like headaches and discomfort. The resulting polarizing uproar led to the phrase "No MSG" appearing on countless menus and labels. Blinded studies, however, in which individuals did not know whether they were consuming MSG or a placebo, failed to support the effect -- even with many who claimed sensitivity. The discussion was further complicated given that MSG is naturally present in the body, it forms naturally in foods, and it has been in use as an additive for over 100 years.
The conclusion reached by researchers was that MSG is generally regarded as safe at the levels found in foods. It is used as an additive in snacks, fast foods, soups, seasonings and dressings. A small number of people can react to MSG in certain circumstances, especially with elevated levels of intake. (Read about the sensitivity angle at b.link/ywsqat, and more big-picture stuff at b.link/2jdyrc.)
Back to your ingredient label question: The phrase "partially hydrogenated" refers to a different process altogether. Hydrogenation refers to adding hydrogen; in this case, it can be used to modify a liquid vegetable oil into a solid block of fat. Partial hydrogenation takes this process part of the way and creates a semisolid fat, the characteristics of which depend on its intended use.
Partial hydrogenation has been widely used in food processing because it allows inexpensive vegetable oils to be used in many different food applications -- from margarine and shortening to cookies, crackers, fries and pastries.
However, further research revealed a significant downside to partially hydrogenated fats: Hydrogenation produced the trans fatty acids associated with an increased risk of health issues, including heart disease and certain cancers. The consistent refrain, as research progressed, was that trans fats must be avoided. In 2003, the FDA began requiring manufacturers to declare the level of trans fats present in a serving of their products.
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