Nearly half of all dementia cases may be preventable, and most of those risk factors respond to what your patients eat
STUDY: Lugavere M, Missouri Medicine 2026;123(3)
STUDY TYPE: Narrative review
FUNDING: Independent
Background
The 2024 Lancet Commission identified 14 modifiable dementia risk factors that together account for 45% of cases, including obesity, hypertension, diabetes, depression, and high LDL cholesterol. Most of these respond directly to diet, and this narrative review gives a taste of that data
Ultra-processed Foods
These industrial foods have the strongest link to dementia. In a large prospective cohort, each 10% increase in ultra-processed food intake predicted a 25% higher dementia risk. A 2024 meta-analysis of more than 860,000 adults found a 44% greater risk among the heaviest consumers.
Omega-3 Fatty Acids
There are two types of omega-3: EPA is important in mood, and DHA in cognition. DHA is the structural omega-3 fat in neuronal membranes, and most Americans fall well short of adequate intake. In the Framingham Offspring Study, people in the highest fifth of red blood cell DHA had a 49% lower risk of Alzheimer’s disease compared to those in the lowest fifth.
Leafy Greens and Carotenoids
Daily leafy-green consumption was associated with the cognitive equivalent of being 11 years younger. These vegetables are rich in folate, vitamins E/K, carotenoids, and nitrates (which convert to nitric oxide, enhancing cerebral blood flow).
Carotenoids are plant pigments responsible for the vibrant red, orange, and yellow colors in many fruits and vegetables. Brain concentrations of carotenoids (lutein, zeaxanthin, and lycopene) were roughly half in people with Alzheimer’s compared to cognitively normal controls. Tomatoes are rich in a cartenoid (lycopene) and improved cognition in a recent controlled trial.
Olive Oil
Olive oil improves cognition and prevents dementia in controlled trialsy. Consuming about half a tablespoon daily was associated with a 28% lower risk of dementia-related death in a large US cohort, independent of overall diet quality and ApoE4 status.
Protein, Creatine, and Eggs
Protein and creatine support the aging brain. Intakes of 1.2–1.6 g/kg/day, spread across meals, preserve lean mass and insulin sensitivity. Creatine, concentrated in beef, pork, salmon, and cod, supports neuronal energy; meta-analyses show consistent improvements in short-term memory and reasoning.
Red meat may impair vascular health while improving brain health in other ways. In the UK Biobank cohort of nearly 500,000 adults followed for 8 years, each 50 grams per day of unprocessed red meat was linked to a 19% lower risk of all-cause dementia and a 30% lower risk of Alzheimer’s disease. Red meat is rich in minerals like iron; B-vitamins, and creatine. Eggs, which are rich in brain-healthy choline, are also linked to a lower dementia risk.
The Depression Link
Diet also treats depression, which is itself a dementia risk factor. The SMILES trial found a Mediterranean whole-food diet produced clinical remission in one-third of depressed patients, four times the rate of the control group.
Childhood Diet
A separate review, published on the same day, finds strong evidence for food and cognition from early life. In a Kenyan trial, school children who received a meat supplement outperformed all other groups in non-verbal reasoning and arithmetic. An egg intervention in Burkina Faso reduced developmental delays in communication, motor skills, and social functioning. Maternal nut intake in pregnancy predicted better cognitive scores in offspring up to age 8.
Practice Implications
- For most patients, the Mediterranean style diet is a good place to start.
- For patients with elevated LDL, cut ultra-processed foods, sweets, and isolated fats before restricting lean meats or dairy. Add fiber from vegetables, legumes, and nuts. Screen for hypothyroidism as a reversible cause of elevated LDL.
—Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
