For years it has been known that eating foods with artificial trans fats has serious health effects. It has been linked to increased risk of coronary heart disease, atherosclerosis, inflammation, and risk of early death, diabetes, and poorer memory in middle-aged men. Now the results of a study, which followed 1628 older residents of a Japanese community for a decade, found that we can add dementia and Alzheimer's disease to this list.
The researchers measured blood levels of elaidic acid, which is a biomarker for artificial (industrial) trans fats. Those persons in the groups with the highest levels of elaidic acid had higher levels of dementia and Alzheimer's disease after a decade (a linear association - the higher the levels, the higher the incidence), but there was no association with vascular dementia.
The researchers found that eating sweet pastries, margarine, sugar confections (e.g. candy, caramels, chewing gum), croissants, nondairy creamers, ice cream, and rice crackers were all the strongest predictors of having higher serum elaidic levels in this study. [Notice that margarine, which for years was considered "healthy", is now considered "unhealthy" because of its trans fats.]
The FDA banned the use of trans fats in foods starting June 2018, but there is a big loophole, a really big loophole. Foods containing less than 0.5 grams of trans fats are allowed to be labeled as ZERO grams of trans fats, because they are allowing the companies to round downward. So if a person eats a number of foods per day containing these "minimal" amounts, they add up. And in this way one can wind up with pretty high levels in the blood. [By the way, some countries still allow trans fats. Also, read the interesting story of the man behind the U.S. ban.]
Where are trans fats still found? Trans fats are found in partially hydrogenated oils, as well as in other types of refined oils, monoglycerides, diglycerides and other emulsifiers, and even in flavors and colors. They are found in a lot of processed food (e.g. baked goods, vegetable shortening, vegetable oils, whipped toppings), so read ingredient labels carefully and avoid them. As usual, best are real whole foods . If you see something that you don't routinely have and cook with in your kitchen, then avoid that ingredient. For example, do you have monoglycerides in your kitchen? NO? Then it's an ingredient to avoid.
From Medscape: Trans Fats Tied to Increased Dementia Risk
Higher serum trans-fat levels have been associated with a significantly elevated risk of dementia, including Alzheimer's disease (AD), results of a large, longitudinal study show.
Participants with the highest concentrations of serum elaidic acid, a major trans-fatty acid formed in the partial hydrogenation of vegetable oils, had a 53% increased risk of dementia. This group also had a 43% higher likelihood for developing AD compared with those with the lowest levels.
"We found that higher serum elaidic acid levels were associated with greater risk of developing all-cause dementia and Alzheimer's disease, after adjustment for traditional risk factors as well as dietary saturated and polyunsaturated fatty acids intake," principal investigator Toshiharu Ninomiya, MD, PhD, told Medscape Medical News.
"In addition, the self-reported intake of breads, margarine and confectioneries were correlated with serum elaidic acid levels, although the magnitude of the correlation was not strong," added Ninomiya, a professor in the Departments of Epidemiology and Public Health and the Center for Cohort Studies, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Previous research has linked excessive consumption of trans fats to the development of coronary artery disease, diabetes, and other conditions. Given these health concerns, the FDA banned artificial trans fats from grocery store and restaurant foods in June 2018. The agency permits foods with less than 0.5 grams of trans fats to be labeled as containing zero grams of trans fats, so some foods still contain partially hydrogenated oils.
"These results give us even more reason to avoid trans fats," Ninomiya said in a news release. "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."
However, less is known about any potential association between trans fat and dementia. The few studies in the literature have yielded inconsistent results, the researchers note. In search of a more definitive answer, the investigators assessed data from 1628 participants in the ongoing, prospective Hisayama Study. The 925 women and 703 men completed questionnaires and provided blood samples in 2002 to 2003. All were 60 years or older at baseline.
The researchers also classified serum levels of elaidic acid into quartiles, and then followed participants prospectively for a median of 10.3 years. Over more than a decade of follow-up, 377 participants developed all-cause dementia, including 247 who developed AD and 102 who developed vascular dementia.
Using the lowest quartile of serum elaidic age concentration group as a reference, the likelihood for developing all-cause dementia significantly increased with higher serum trans-fat groups. ... "Although significant linear trends were observed, the risk of developing dementia and AD appeared to increase at the level of the third quartile," the researchers note.
Again, using the lowest serum trans-fat cohort as reference, the risk for developing AD increased with increasing concentrations of elaidic acid. Investigators found no significant association between higher elaidic acid levels and risk of vascular dementia.