A new systematic review published in BMC Geriatrics suggests that supplementing with medium-chain triglycerides (MCTs) may provide cognitive benefits for older adults without dementia.
MCTs are a type of fatty acid found in foods like coconut oil and palm kernel oil that may help provide the brain with an alternative energy source.
Key Facts:
- MCT supplementation was associated with improved memory, particularly working memory, in 4 out of 6 studies included in the systematic review.
- Benefits were seen with both short-term ketogenic meals containing MCTs as well as longer-term daily MCT supplementation lasting up to 3 months.
- Improvements appeared more robust in those with lower baseline memory scores.
- Exact optimal dosage and composition of MCT oils is still unknown.
- More research is still needed to confirm effects and determine ideal supplementation strategies.
Source: BMC Geriatrics
The Quest to Preserve Cognitive Health in Aging Brains
Age-related cognitive decline is a pressing public health concern as global populations continue to age.
Dementia currently affects over 55 million people worldwide, with numbers expected to triple by 2050.
Even in the absence of dementia, normal aging is associated with deterioration of certain cognitive skills like processing speed, executive function, and memory.
With no definitive pharmaceutical treatments available to prevent cognitive decline, attention has turned to modifiable lifestyle factors like diet and exercise that may help maintain brain health into old age.
One dietary strategy garnering particular interest lately is supplementation with medium-chain triglycerides (MCTs).
MCTs: A Ketogenic Approach to Feeding the Aging Brain
MCTs are a form of fatty acid with chains of 6-12 carbon atoms.
Compared to longer chain fatty acids, MCTs are absorbed more rapidly and metabolized more efficiently into ketones.
Ketones are able to cross the blood-brain barrier and act as an alternative fuel source for the brain.
This mechanism of “nutritional ketosis” induced by MCTs is thought to support cognitive function in two key ways:
- Providing extra energy to compensate for age-related declines in glucose metabolism in the brain
- Stimulating growth of new mitochondria and enhancing mitochondrial function to create more cellular energy
Because the MCTs are absorbed through the portal vein and liver, they are able to induce mild ketosis without needing to follow an extremely low-carb ketogenic diet.
This makes MCT supplementation an appealing potential intervention for older adults at risk of malnutrition.
Review Assesses Impact of MCTs on Memory in Older Adults
A systematic review recently published in BMC Geriatrics aimed to evaluate the existing evidence around whether MCT supplementation can benefit memory in individuals aged 60+.
The authors performed a comprehensive literature search, identifying 6 relevant randomized controlled trials with a total of 228 older adult participants.
Interventions included both short-term ketogenic meals containing MCTs as well as longer-term daily oral MCT supplements lasting up to 3 months.
Memory outcomes included tests of working memory, verbal memory, visual memory, and logical memory conducted before and after MCT interventions.
The key findings were:
- 4 out of 6 studies showed significant improvements in certain aspects of memory associated with MCT supplementation.
- Benefits were most consistently seen for working memory, the ability to temporarily hold and manipulate information in the mind.
- Improvements appeared more robust in those with lower baseline scores on memory testing.
- Exact optimal dosage and composition of MCT supplements is still unknown.
While promising, the authors caution more research is still needed to confirm effects and flesh out details of ideal supplementation strategies.
Only a small number of studies met the eligibility criteria for inclusion in the review.
Clinical trials often differed in dosing protocols and composition of MCT supplements.
And meta-analysis was deemed inappropriate due to heterogeneity between studies.
Nonetheless, these preliminary findings provide hope that MCTs may provide cognitive benefits for aging brains.
Details of The Research
Single Ketogenic Meals
Two studies explored cognitive impacts of a single MCT-containing ketogenic meal.
In a randomized crossover trial, 19 healthy older adults consumed a 502-calorie breakfast meal containing either 20g of MCTs or 20g of long-chain triglycerides (LCTs).
Testing 90 and 180 minutes later found no significant differences in working memory between conditions.
However, those with lower baseline cognitive function showed improved performance after the MCT meal [Ota 2016].
Similarly, a ketogenic meal with 19.9g of MCTs led to significantly better working memory performance 90 minutes later compared to an LCT meal in a study of 20 older adults.
Those with higher baseline cognitive function saw the greatest gains [Yomogida 2021].
In both studies, the immediate cognitive boost from MCTs was not robust enough to reach statistical significance for the entire sample.
But the subgroup findings suggest MCTs may provide acute benefits for those experiencing mild age-related cognitive difficulties.
Daily MCT Supplements
Four other studies trialed the effects of daily MCT oil supplements over 2 weeks to 3 months.
Several found improvements in certain memory domains associated with MCT use:
- In 31 older nursing home residents, 3 months of 6g/day of MCTs increased memory recall versus control as measured by the MMSE cognitive screening test [Abe 2020].
- Similarly, MCTs improved scores on memory tests like the Nishimura Mental State Exam over 3 months in another trial of 25 older nursing home residents [Abe 2017].
- No significant differences were seen in immediate or delayed logical memory after 3 months of 18g/day of MCTs in 63 healthy older adults. But those in the MCT group did improve their test scores over time, unlike controls [Mutoh 2022].
However, a 2-week trial of different doses of MCTs in 80 healthy older adults found no impacts on immediate or delayed verbal memory compared to placebo [O’Neill 2019].
Overall the daily supplementation studies indicate potential for modest memory benefits emerging after longer-term MCT use, though findings are mixed.
Nursing home samples with some pre-existing cognitive decline saw the strongest effects.
MCT supplementation & neuroprotective effects
This systematic review provides preliminary evidence that MCT supplementation may enhance certain aspects of memory function in older populations without dementia.
Impacts appear more robust in those with lower baseline cognitive scores.
While promising, there are several caveats:
- Small sample sizes and heterogeneity between studies limits conclusions. More large rigorous RCTs are needed.
- Optimal dosage and composition of MCT supplements is still unclear.
- Longer follow-up is needed to determine if benefits are sustained over time.
- Effects may depend on baseline cognitive status, genetics, and other individual factors.
Nonetheless, this adds to the growing body of research suggesting MCTs and nutritional ketosis could be a fruitful target for cognitive enhancement in aging.
MCT supplements or coconut oil may provide a safe, accessible way to promote brain health later in life.
As the global population ages, preserving cognitive abilities into old age is an increasingly pressing public health challenge.
MCTs likely will not reverse existing dementia.
However, emerging data indicates they may help maintain cognitive faculties with aging.
MCTs show particular promise as a strategy for those experiencing mild age-related cognitive changes.
More studies are needed to replicate and extend these findings.
But in the meantime, adding a bit more coconut oil into your diet certainly seems unlikely to hurt.
References
- Study: Medium chain triglycerides may improve memory in non-demented older adults
- Authors: Panagiotis Giannos et al. (2022)
