Alzheimer’s disease is a leading cause of dementia, affecting millions of people worldwide, accounting for up to 70 percent of all the dementia cases. It is deadly, too, typically claiming the lives of patients within three to six years after diagnosis.

As research on Alzheimer’s advances, scientists are increasingly looking at lifestyle factors like diet. If the researcher can uncover the dietary influence on the risk of developing dementia, we would get the possibility to reduce the risk by changing lifestyle well, or just the menu.

A recent study sheds light on how dietary fats, specifically saturated fats, might contribute to Alzheimer’s risk and emphasizes the role of genetics in understanding this connection.

The study
The study used a method called Mendelian randomization, which uses genetic data to help identify cause-and-effect relationships.

The research drew from two large genetic databases. The UK Biobank and the Finnish FinnGen consortium which provided data from hundreds of thousands of participants of European ancestry.

Genetic variants associated with high-fat consumption, including total fat and saturated fat, were analyzed in connection with Alzheimer’s risk. The findings revealed that a higher intake of total fat and saturated fat was associated with an increased risk of late-onset Alzheimer’s disease.

Interestingly, polyunsaturated fats, often considered "healthy fats," showed no significant relationship with Alzheimer’s risk. This suggests that while certain fats may be detrimental to brain health, others might be neutral or even beneficial. The analysis also confirmed that these relationships held even when accounting for other dietary factors like protein and carbohydrate intake.

The science behind these results highlights the complex interaction between diet and brain health. High intake of saturated fats may lead to increased inflammation, insulin resistance, and oxidative stress in the brain, all of which are known to play roles in Alzheimer’s progression. By triggering inflammation and stress in brain cells, these fats could create conditions that accelerate cognitive decline.

Conclusion
While this study provides important insights, it’s not the final word. Mendelian randomization studies, though robust, rely on genetic approximations of lifestyle factors and may not capture the full scope of dietary impacts.

Future research could dive deeper, particularly into how different types of fats influence Alzheimer’s over time and across diverse populations. However, for those interested in minimizing Alzheimer’s risk, this study supports the idea that limiting saturated fats may be a wise choice for long-term brain health.

About the scientific paper:

First Author: Yunqing Zhu, China
Published: The British Journal of Psychiatry. October 2024.
Link to paper: https://www.cambridge.org/core/journals/the-british-journal-of-psychiatry/article/association-between-dietary-fat-intake-and-the-risk-of-alzheimers-disease-mendelian-randomisation-study/8728F5AE1B957ECAD17D4475D5383C40