A new study published in the journal Aging And Disease suggests that low blood levels of the nutrient choline may represent a key biological connection between obesity and increased risk of neurodegeneration, including Alzheimer's disease.
The research, conducted by a team at Arizona State University, involved 30 young adult participants in their 20s and 30s — half with obesity and half with healthy weight — who underwent fasting blood tests. The scientists measured circulating choline, markers of inflammation, insulin and glucose levels, liver-related enzymes, and a protein named Neurofilament light chain (NfL), which is released into the blood when nerve cells are damaged.
Participants with obesity demonstrated significantly lower circulating choline compared with their healthy-weight peers. This low choline strongly correlated with higher percentage of body fat, evidence of liver dysfunction (via elevated liver-related enzymes), insulin resistance, and elevated inflammatory cytokines. In addition, obese individuals had higher levels of NfL, and those NfL levels were inversely correlated with choline — meaning as choline dropped, NfL rose. This pattern echoes that observed in older individuals with mild cognitive impairment or Alzheimer’s disease.
Because elevated NfL is considered a biomarker of neuronal injury and neurodegeneration, the researchers interpret these findings as early, subclinical signs of brain stress and damage — even in young adults who have not shown cognitive symptoms. This raises the possibility that metabolic dysfunction linked to obesity might trigger a cascade — from low choline to inflammation, liver stress, insulin resistance, and neuronal stress — that over decades could raise Alzheimer’s risk.
The study stops short of proving causation — it didn’t include cognitive testing, and the sample size was small and limited in diversity. The researchers acknowledge that these are early findings and that larger, more varied studies are needed to confirm whether low choline in young obese adults indeed predicts long-term cognitive decline.
The researchers also highlight the role of choline as a nutrient essential not only for liver and metabolic health, but also for brain health — including the maintenance of cell membranes, control of inflammation and making neurotransmitters.
