When “0 grams trans fat” is unhealthy

Whole grains and trans fat free
What could be wrong? Rancidity

“0 grams trans fat” = healthy, right?  Maybe not.  I found a half-used box of graham crackers in my pantry, and opened the package.  Phew!  Something was not right.  But what was it?  These are graham crackers after all, invented as a whole grain food.  While they’re mostly made with refined flour now, they retain a major Health Halo.  And now they’re made without dreaded trans fats, which are linked to heart disease.  What could be wrong?  They were rancid.

What are trans fats and why are we afraid of them?  Trans fats are a specific form of fat produced when liquid vegetable fats are hydrogenated.  Hydrogenated fats are more solid at room temperature, and are ideal for making stick margarine, shortenings and deep fry oils.  But it turns out trans fats are unique in another way: in the human body they raise the risk for heart disease.  And once that link was discovered, food manufacturers have been scrambling to reduce use of hydrogenated fats, so they can label the packages “trans fat free”.

But it turns out trans fat had one benefit when used in foods: it prevents oxidation that causes rancidity.  Unhydrogenated fats, such as vegetable oils, are especially vulnerable to attack by oxygen.  When oils are exposed to air, when a package is opened, those fats start oxidizing.  It’s a slow process, and depends on how the food is stored.  Warm temperatures and light exposure can accelerate the process.  The result of all that fat oxidation: rancidity.  The fats, and the food, have an off odor and taste.  These graham crackers reeked of rancidity.

They don’t look rancid.

Rancid fats are sneaky.  They don’t look different.  The foods don’t necessarily get moldy or brown at the edges.  They don’t turn a different color or lose texture.  They look absolutely the same.  Yet they’re rancid, inedible and unhealthy.

The campaign against trans fats in food has some unexpected consequences.  Bakery products made with oils are more more prone to rancidity if they’re stored too long.  You can protect your crackers, cookies, snack foods, chips and other items by:

  1. buying small packages and using them up quickly
  2. storing foods in tightly closed packages out of light and away from heat
  3. looking for “best if used by” dates on the package

If you’ve got an open box of crackers that smells ‘off’, throw it away.  The small of rancid fat is unmistakeable and off-putting.  It doesn’t smell like something you want to eat.  Other foods prone to rancidity are:

  • vegetable oils
  • nuts
  • whole grain flours
  • other whole grain foods like flax seed and wheat germ
  • nut butters
  • salad dressings
  • snack foods

Rancid graham crackers, who knew?  I admit, the package was sitting around for a very long time.  And now it’s headed for the trash.

Copyright: All content © 2010-2018 Nutrition Strategy Advisors LLC. Photographs © Donna P Feldman, unless otherwise attributed. Reproduction or use without permission is prohibited.