As noted by neurologist Dr. David Perlmutter, author of “Grain Brain” and “Brain Maker,” your diet and other lifestyle factors have major implications for your Alzheimer’s risk.
Indeed, according to research1,2 published in the journal Lancet Neurology in 2011, up to half of all Alzheimer’s cases could be prevented by addressing modifiable lifestyle contributors such as physical inactivity, depression, smoking, high blood pressure, midlife obesity and diabetes.
Three dietary components shown to promote this neurological degeneration are sugar (especially processed fructose), grains and trans fats. Research3,4from the Mayo Clinic, published in the Journal of Alzheimer’s Disease in 2012, found diets rich in carbohydrates are associated with an 89% increased risk for dementia while diets high in healthy fats are associated with a 44% reduced risk.
As noted by the authors,5 “A dietary pattern with relatively high caloric intake from carbohydrates and low caloric intake from fat and proteins may increase the risk of MCI [mild cognitive impairment] or dementia in elderly persons.” Similarly, a 2013 study6 in the journal BioMed Research International reported that:
“Increasing epidemiological studies suggest that diet and nutrition might be important modifiable risk factors for AD [Alzheimer’s disease].
Dietary supplementation of antioxidants, B vitamins, polyphenols, and polyunsaturated fatty acids are beneficial to AD, and consumptions of fish, fruits, vegetables, coffee, and light-to-moderate alcohol reduce the risk of AD … Adherence to a healthy diet, the Japanese diet, and the Mediterranean diet is associated with a lower risk of AD.”
Trans Fat Consumption Increases Your Dementia Risk
Most recently, research7 published in the October 2019 issue of Neurology found a strong link between trans fat consumption and incidence of dementia and its various subtypes, which includes Alzheimer’s disease (AD).
The study included 1,628 Japanese seniors aged 60 and older. None had dementia at the outset of the study, which went on for 10 years. Levels of elaidic acid — a biomarker for industrial trans fat — in the participants’ blood were measured using gas chromatography/mass spectrometry.
Based on those levels, the hazard ratios for all-cause dementia, AD and vascular dementia were calculated using the Cox proportional hazards model. As reported by the authors:8
“Higher serum elaidic acid levels were significantly associated with greater risk of developing all-cause dementia and AD after adjustment for traditional risk factors. These associations remained significant after adjustment for dietary factors, including total energy intake and intakes of saturated and polyunsaturated fatty acids.”
This increase in risk was not slight. As reported by CNN,9 people in the highest quartile of elaidic acid levels were 74% more likely to develop dementia. Those in the second-highest quartile had a 52% higher risk. No association between trans fat and vascular dementia was found.
Of the various processed foods found to contribute to elevated elaidic acid levels, pastries were the biggest contributors, followed by margarine, candy, caramels, croissants, nondairy creamers, ice cream and rice cakes.10
Dr. Richard Isaacson, a neurologist and director of the Alzheimer's Prevention Clinic at Weill Cornell Medicine in New York, who was not involved in the study, commented on the findings to CNN:11
"The study used blood marker levels of trans fats, rather than more traditionally used dietary questionnaires, which increases the scientific validity of the results. This study is important as it builds upon prior evidence that dietary intake of trans fats can increase risk of Alzheimer's dementia."
What Is Trans Fat?
As explained by CNN:12
“… artificial trans fats are created by an industrialized process that adds hydrogen to liquid vegetable oils to make them more solid (think of semi-soft margarine and shortening).
The food industry loves trans fats because they are cheap to produce, last a long time and give foods a great taste and texture. Besides fried foods, trans fats are found in coffee creamer, cakes, pie crusts, frozen pizza, cookies, crackers, biscuits and dozens of other processed foods.”
Trans fats are different from an unsaturated fat by a single hydrogen molecule on the opposite side of a carbon bond.13 This one positional change is responsible for the difference in characteristics of the fat, and the increased danger to your health.
Aside from dementia, strong evidence also links trans fats with inflammation and the development of insulin resistance and heart disease (all of which also happen to be risk factors for Alzheimer’s).
Faced with overwhelming evidence of harm, the U.S. Food and Drug Administration removed partially hydrogenated oils (a primary source of trans fat) from the list of “generally recognized as safe” (GRAS) list of food ingredients in 2015, and as of June 18, 2019, food manufacturers are no longer allowed to use partially hydrogenated oils in foods14 due to their health risks.
Processed foods manufactured before this date, however, are allowed to remain on the market until January 1, 2021.15 (Compliance dates vary depending on whether manufacturers had “limited use” permissions for partially hydrogenated oils, but these are the final dates where all use must cease.)
However, that doesn’t mean that trans fats have been entirely eliminated and are of no further concern. What’s more, as long as a food contains less than 0.5 grams of trans fat per serving, food manufacturers are allowed to label it as trans fat free.
The problem with this is that many experts agree there is no safe threshold below which trans fats are safe.16 To determine whether a product might still contain trans fats, carefully read the ingredients list.
Any item containing partially hydrogenated vegetable oil is bound to contain trans fat, even if the label says “0 Trans Fat.” Fried food and baked goods in general are also suspect.17,18 As lead study author Dr. Toshiharu Ninomiya, a professor at Kyushu University in Fukuoka, Japan, noted in a press release:19
"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."