Overstates scientific confidence: While a few small studies reported cognitive improvements in people with dementia who followed a ketogenic diet, the results are preliminary. More research is needed to draw definite conclusions.
FULL CLAIM: “Coconut oil in your diet is a remedy for Alzheimer’s”
REVIEW
A Facebook reel posted on 17 April 2024 claimed that “coconut oil in your diet is a remedy for Alzheimer’s”. The person speaking in the reel is John Gray, relationship counselor and author of the 1990s best-seller Men Are from Mars, Women Are from Venus.
In the reel, Gray argued that neurons die because “the brain cells just aren’t getting fuel” and that consuming medium-chain triglyceride (MCT) oil—a type of fatty acid distilled from coconut oil—provides the brain with the energy it needs.
As of this review’s publication, the reel accumulated over 750,000 views.
Alzheimer’s disease is the leading cause of dementia, a term that groups a range of symptoms affecting cognitive ability. Alzheimer’s progressively destroys nerve cells and connections within specific brain regions. Over time, this damage causes a decline in the person’s ability to think, remember, and reason up to a point that interferes with the most basic daily activities. While some medicines can help temporarily manage symptoms and slow down the progression of the disease, there is currently no cure for Alzheimer’s.
Alzheimer’s non-profits and support groups such as Alzheimer’s Research UK and Alzheimer’s societies in the U.K. and Canada explain that current evidence doesn’t support the claim that coconut oil prevents or treats Alzheimer’s.
Like many other health-related myths, the notion that coconut oil improves brain function is based on a grain of truth. But as this review will show, this notion relies on unvalidated hypotheses, making the claim unsupported.
What is the scientific basis behind the claim?
While researchers don’t know yet what exactly causes neurons to die in people with Alzheimer’s, several hypotheses are currently under investigation[1]. One hypothesis involves the dysregulation of glucose metabolism in the brain.
Glucose is the primary energy source for the brain, and as such, it plays a critical role in brain function[2]. With aging, the brain becomes less efficient in using glucose. This effect is even more pronounced in people with Alzheimer’s, who often show reduced glucose metabolism and insulin resistance in brain regions affected by the disease[3,4].
Evidence from epidemiological studies also shows that having type 2 diabetes is associated with a higher risk of developing dementia later in life[5,6]. This further suggests that Alzheimer’s and diabetes share some common molecular mechanisms.
While brain cells preferentially obtain their energy from glucose, they can also use alternative sources when glucose isn’t available in sufficient amounts. One of these sources is ketone bodies, acids that result from burning fat instead of glucose for energy.
Coconut oil is rich in MCTs, a type of fatty acid that can quickly enter the bloodstream and be broken down into ketone bodies[7]. Both MCTs and ketone bodies can cross the blood-brain barrier, constituting a readily available energy source for the brain.
Proponents of coconut oil claim that it can restore brain function by providing the brain with the energy that people with Alzheimer’s can’t obtain from glucose. However, this theory has important caveats.
First, researchers still don’t know whether the observed changes in glucose metabolism are a cause or a consequence of Alzheimer’s. Therefore, as Science Feedback explained in an earlier review, it is unclear whether these changes play any role in the development and progression of the disease.
Second, even if altered glucose metabolism contributes to the disease, it is also unknown whether increasing the levels of ketone bodies as an alternative energy source could effectively counter the damage that Alzheimer’s causes in the brain.
Evidence supporting the use of coconut oil to improve brain function in people with dementia is preliminary
Although the hypothesis that glucose metabolism dysregulation in the brain contributes to developing Alzheimer’s is still unvalidated, researchers are already exploring whether targeting glucose metabolism can improve brain function in these patients.
A search# on PubMed, a repository of scientific publications in biology and medicine maintained by the U.S. National Library of Medicine, returned only a couple of pilot studies evaluating the specific effect of coconut oil on dementia. One clinical trial published in the Journal of Alzheimer’s Disease in 2018 found that consuming a Mediterranean diet enriched with coconut oil improved orientation, memory, and language in 44 people with Alzheimer’s[8].
In 2023, a larger trial also published in the Journal of Alzheimer’s Disease evaluated the effect of virgin coconut oil on cognitive function in 120 people from Sri Lanka with mild-to-moderate Alzheimer’s[9]. During the 24-week follow-up, the study found no benefit of coconut oil in cognition in people with Alzheimer’s, except in a small subset of patients carrying a genetic variant that increases the risk of developing the disease.
These results don’t provide sufficient evidence to back up the claim that coconut oil is a “remedy” for Alzheimer’s, as the Facebook reel claimed.
Research on the potential benefit of increasing ketones in people with Alzheimer’s is also inconclusive
The ketogenic or “keto” diet has also been proposed as a strategy to increase the ketone levels in the brain and improve cognitive function in people with Alzheimer’s and other types of dementia. This dietary pattern strictly limits carbohydrates and replaces them with fats, forcing the body to use fat instead of glucose for energy.
Since the 1920s, the keto diet has been successfully used to reduce seizures in people with epilepsy[10] and is currently a treatment option in patients who don’t respond to antiepileptic drugs. However, its potential benefit in people with dementia isn’t so evident.
A few studies suggest that a keto diet might improve memory, daily function, and quality of life in people with mild dementia[11-13]. However, all are pilot studies with few participants (14 to 26 individuals) and a short-term follow-up. Furthermore, these studies only evaluated the keto diet in Alzheimer’s patients with mild dementia, which makes the results nongeneralizable to more advanced stages of the disease. Finally, the cognitive improvements observed in these trials disappeared once the patients returned to their usual diet.
In other words, while these preliminary results warrant further research on the potential benefits of the keto diet in people with Alzheimer’s, they don’t demonstrate that this diet—let alone coconut oil supplements—prevent or treat Alzheimer’s.
As a final note, it is important to remember that simply because coconut oil is natural doesn’t necessarily mean it is safe.
Coconut oil and MCT supplements are rich in saturated fats. When consumed in large amounts, these products can cause side effects, including diarrhea, abdominal pain, and cramping. In the long term, they can also lead to weight gain and increase the risk of developing high cholesterol and fatty liver disease. For all these reasons, coconut oil and MCT supplements aren’t recommended for people with conditions such as diabetes, heart disease, and liver dysfunction.
NOTE
# Pubmed search query (Coconut AND Oil) AND (dementia OR Alzheimer’s)
REFERENCES
- 1 – Liu et al. (2019) History and progress of hypotheses and clinical trials for Alzheimer’s disease. Signal Transduction and Targeted Therapy.
- 2 – Daniel (2018) Brain Glucose Metabolism: Integration of Energetics with Function. Physiological Reviews.
- 3 – Chen and Zhong (2013) Decoding Alzheimer’s disease from perturbed cerebral glucose metabolism: Implications for diagnostic and therapeutic strategies. Progress in Neurobiology.
- 4 – Kellar and Craft (2020) Brain insulin resistance in Alzheimer’s disease and related disorders: mechanisms and therapeutic approaches. Lancet Neurology.
- 5 – Xue et al. (2019) Diabetes mellitus and risks of cognitive impairment and dementia: A systematic review and meta-analysis of 144 prospective studies. Ageing Research Reviews.
- 6 – Amidei et al. (2021) Association Between Age at Diabetes Onset and Subsequent Risk of Dementia. JAMA.
- 7 – Schönfeld and Wojtczak (2016) Short- and medium-chain fatty acids in energy metabolism: the cellular perspective. Journal of Lipid Research.
- 8 – De la Rubio Orti et al. (2018) Improvement of Main Cognitive Functions in Patients with Alzheimer’s Disease after Treatment with Coconut Oil Enriched Mediterranean Diet: A Pilot Study. Journal of Alzheimer’s Disease.
- 9 – Malika et al. (2023) Effect of Virgin Coconut Oil Supplementation on Cognition of Individuals with Mild-to-Moderate Alzheimer’s Disease in Sri Lanka (VCO-AD Study): A Randomized Placebo-Controlled Trial. Journal of Alzheimer’s Disease.
- 10 – Wheless (2008) History of the ketogenic diet. Epilepsia.
- 11 – Taylor et al. (2017) Feasibility and efficacy data from a ketogenic diet intervention in Alzheimer’s disease. Alzheimer’s and Dementia.
- 12 – Brandt et al. (2019) Preliminary Report on the Feasibility and Efficacy of the Modified Atkins Diet for Treatment of Mild Cognitive Impairment and Early Alzheimer’s Disease. Journal of Alzheimer’s Disease.
- 13 – Phillips et al. (2021) Randomized crossover trial of a modified ketogenic diet in Alzheimer’s disease. Alzheimer’s Research and Therapy.
