The Ketogenic Diet: A Game Changer in Alzheimer’s Disease?
The ketogenic diet (KD) may have more to offer than weight-loss. Preliminary studies on the popular diet show promise in improving cognitive performance in the early stages of Alzheimer’s disease (AD). Sounds simple, right? Let’s take a closer look!
What is Alzheimer’s disease?
AD is a neurodegenerative disease that is predominantly manifested by dementia. Close to 750,000 Canadians and at least 44 million people worldwide are living with AD or other types of dementia1, struggling through routine intellectual tasks as simple as thinking and problem solving, while fighting against progressive memory loss.
“The number of individuals affected by Alzheimer’s disease and related dementia, in Canada, will increase by 200,000 in the next 10 years. ”
What is the underlying pathology of AD?
The underlying mechanisms of neurodegeneration in AD are not fully understood. Table 1 lists a summary of the proposed mechanisms.
How is AD treated?
At the moment, there is no effective pharmaceutical treatment to prevent the development or modify the progress of AD. There are only a handful of approved drugs, which either:
a) regulate neurotransmitter activity, improving symptoms related to memory, thinking, language, judgment and other thought processes (cholinesterase inhibitors); or
b) work to improve attention, awareness, and the ability to perform simple tasks (memantine).[3]
The history of the Ketogenic Diet (KD)
Considering the link between AD and impaired glucose metabolism in the brain, as well as emerging clinical and pre-clinical trial results, it’s reasonable to deduce that a low carbohydrate diet may halt the hallmarks of AD, namely neurodegeneration and dementia.
In fact, a study by Krikorian et al. showed that even a short-term (6-week) use of such a diet could improve memory function in aging adults at high risk of AD.[5]
The KD itself is not a new discovery – first introduced in the 1920s to treat drug-resistant epilepsy. But, current studies show that it may also have neuroprotective effects in other neurodegenerative conditions, like Parkinson’s and Alzheimer’s disease.
What does the KD look like?
The KD consists of a very high-fat (long and medium chain fatty acids), very low-carbohydrate, Atkins-style diet. It aims to provide total body caloric requirements as follows:[3]
- 90% fat
- 7% protein
- 3% carbohydrate
Given the generally low adherence to the KD due to its nature, and in an attempt to make it more palatable, several versions of it have been proposed (Table 2). However, no particular version of the KD diet has proven superior.
How does the KD work?
The KD works essentially by altering metabolism. Table 3 highlights its therapeutic actions:
Are there any downsides to the KD?
· Will aging adults adhere to a restricted diet that deprives them from some of the foods they love?
· What about the weight loss that may follow?
· Is the KD going to complicate the existing sensory and motor challenges in people with AD?
· Does it interact with concomitant medications and health conditions?
These are just some of the questions that remain unanswered due to the lack of sufficient data. Meanwhile, the most common side effects have been identified (Table 4), and should be monitored on an individual basis.
So, what’s the bottom line?
Are the benefits of the KD tangible enough to warrant the dietary sacrifices it demands? Can the side effects be managed safely in people with AD?
The available data are promising at best. But, for now, the decision to adopt the KD as a therapeutic approach will have to be reached by individuals and their physicians. At least until more solid data from longer-term human studies can shed better light on the benefits and caveats of the KD.[3,5]
References
1. Alzheimer’s & Dementia Help | Alzheimer’s Association of Canada. Alzheimer’s Association. //www.alz.org/ca/dementia- alzheimers-canada.asp
2. Alzheimer Society of Canada. https://alzheimer.ca/en/Home/Get-involved/Advocacy/Latest-info-stats
3. Rusek M, Pluta R, Ułamek-Kozioł M, Czuczwar SJ. Ketogenic Diet in Alzheimer’s Disease. Int J Mol Sci. 2019;20(16). doi:10.3390/ijms20163892
4. Newcombe EA, Camats-Perna J, Silva ML, Valmas N, Huat TJ, Medeiros R. Inflammation: the link between comorbidities, genetics, and Alzheimer’s disease. J Neuroinflammation. 2018;15. doi:10.1186/s12974-018-1313-3
5. Włodarek D. Role of Ketogenic Diets in Neurodegenerative Diseases (Alzheimer’s Disease and Parkinson’s Disease). Nutrients. 2019;11(1). doi:10.3390/nu11010169
6. Kossoff EH, Hartman AL. Ketogenic Diets: New Advances for Metabolism-Based Therapies. Curr Opin Neurol. 2012;25(2):173-178. doi:10.1097/WCO.0b013e3283515e4a
