Effects of saturated and monounsaturated fatty acids on cognitive impairment: evidence from Mendelian randomization study

Eur J Clin Nutr. 2024 Jul;78(7):585-590. doi: 10.1038/s41430-024-01437-5. Epub 2024 Apr 17.

Abstract

Background: Prior observational studies have suggested correlations between saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) with cognitive function. However, causal relationships remains unclear.

Methods: We assessed the causal impact of two SFAs (palmitic acid [PA] and stearic acid [SA]) and two MUFAs (oleic acid [OA] and palmitoleic acid [POA]) on cognitive function-related traits, and dementia-related traits by univariable Mendelian randomization (UVMR) and multivariable Mendelian randomization (MVMR) analyses.

Results: UVMR indicated β of 0.060 (P = 4.05E-06) for cognitive performance score and 0.066 (P = 4.21E-04) for fluid intelligence per standard deviation (SD) increase in OA level. MVMR indicated: (i) β of -0.608 (P = 8.37E-05) for fluid intelligence score per SD increase in POA; (ii) β of 0.074 (P = 0.018) for fluid intelligence score per SD increase in OA; (iii) β of 0.029 (P = 0.033) for number of incorrect matches in round per SD increase in PA; and (iv) β of 0.039 (P = 0.032) for number of incorrect matches in round per SD increase in SA. In addition, a secondary MVMR analysis after excluding the effect of polyunsaturated fatty acids suggested that: (i) β of -0.043 (P = 1.97E-02) for cognitive performance score per SD increase in PA and (ii) β of -0.079 (P = 1.79E-03) for cognitive performance score per SD increase in SA.

Conclusions: Overall, UVMR and MVMR suggest that OA may be beneficial for cognitive function, while POA, PA, and SA may have detrimental effects on cognitive function.

MeSH terms

  • Cognition / drug effects
  • Cognitive Dysfunction*
  • Dementia
  • Fatty Acid Desaturases
  • Fatty Acids*
  • Fatty Acids, Monounsaturated*
  • Humans
  • Intelligence / drug effects
  • Mendelian Randomization Analysis*
  • Oleic Acid
  • Palmitic Acid
  • Polymorphism, Single Nucleotide
  • Stearic Acids

Substances

  • Fatty Acids, Monounsaturated
  • Fatty Acids
  • palmitoleic acid
  • Stearic Acids
  • stearic acid
  • Oleic Acid
  • Palmitic Acid
  • FADS2 protein, human
  • Fatty Acid Desaturases