November 11, 2019
People who have high levels of trans fats in their blood are more likely to develop Alzheimer’s disease years later, according to a new report. Trans fats, once commonly added to baked goods and other processed foods, are known to be bad for heart health. The findings show they may also be bad for the brain.
Trans fats, also known as trans fatty acids, can be found naturally in meat, milk and other animal products in small amounts. But they are also produced in various steps of the food industry, particularly as partially hydrogenated vegetable oils, chemically modified fats that were once commonly added to processed foods to lengthen shelf life and to keep flavors stable. Until a few years ago, many cookies, chips, crackers, cakes and other “junk” food were high in trans fats. But trans fats were found to raise cholesterol levels and increase the risk of heart disease and diabetes, so in the U.S., high levels trans fats were banned in 2018 from many foods and are no longer used widely.
But trans fats are common in many of the snack foods in foreign countries, and are still found in low amounts in many snack foods in the United States. The Food and Drug Administration allows foods that contain less than 0.5 grams of trans fats per serving to be labeled as containing no trans fats. Trans fats also are found naturally in small amounts in beef, milk and certain other meats and dairy products, so most of us have some levels of trans fats in our blood.
For the study, researchers looked at 1,628 men and women living in a single town in Japan. Their average age was around 70. At the start of the study, the researchers took blood levels of elaidic acid, one of the most common trans fats in processed foods. Importantly, elaidic acid is also impacting on your cholesterol level by lowering your good cholesterol (HDL).
They followed them for around 10 years. During that time, 377 developed Alzheimer’s disease or another form of dementia.
The researchers found that those with the highest levels of elaidic acid in their blood were 50 to 75 percent more likely to develop Alzheimer’s disease or another form of dementia than those with low levels of the trans fat in their blood.
“These results give us even more reason to avoid trans fats,” said study author Dr. Toshiharu Ninomiya of Kyushu University in Fukuoka, Japan. “In the United States, the small amounts still allowed in foods can really add up if people eat multiple servings of these foods, and trans fats are still allowed in many other countries.”
The researchers considered a variety of factors that can raise the risk of dementia, including high blood pressure, diabetes and smoking. Those with the highest trans fat blood levels still were at higher risk of developing dementia.
Certain foods high in trans fats were also associated with a higher dementia risk. Sweet pastries were particularly likely to increase dementia risk, followed by trans-fat containing margarine, candies, croissants, non-dairy creamers, ice cream and crackers. The findings appeared in Neurology, the medical journal of the American Academy of Neurology.
The World Health Organization is seeking a global ban on trans fats by 2023. “These public health efforts have the potential to help prevent dementia cases around the world, not to mention the decrease in heart disease and other conditions related to trans fats,” Dr. Ninomiya said.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Takanori Honda, PhD, Tomoyuki Ohara, MD, PhD, Masakazu Shinohara, MD, PhD, et al: “Serum elaidic acid concentration and risk of dementia: The Hisayama study.” Neurology, October 23, 2019.