by Bianca Garilli, ND
Every 65 seconds someone in the US develops Alzheimer’s disease (AD), resulting in approximately 5.7 million Americans currently living with this condition. These numbers are expected to rise dramatically over the next several decades with projections of nearly 14 million people living with AD by the year 2050 and an associated $1.1 trillion in healthcare costs.1
AD is the most common form of dementia, characterized by impaired cognitive capacity beyond what is considered part of “normal aging”; it includes symptoms such as memory loss and inability to create new memories, difficulty in solving problems, and disorientation in time and space.2 AD is caused by beta-amyloid (Aβ) peptide plaques forming in synapses, along with neurofibrillary tangles (NFTs) consisting of twisted strands of tau proteins developing in the hippocampal neurons of the brain.2 Over time these deposits interfere with normal neuron transmission and may lead to neuronal death.3 Several other well-studied hypotheses believed to play a role in the development of AD include decreased cholinergic transmission in the brain and extensive oxidative stress resulting in metabolic abnormalities in neuronal mitochondria as well as neuronal apoptosis.2
These chronic and progressive brain changes are most likely related to long-term exposure to dysfunctional brain insulin signaling and brain glucose metabolism fueled in some cases by an underlying genetic susceptibility in those individuals with an ApoE4 allele.2-3
A recent review article explored leveraging lifestyle modalities to reduce factors associated with brain insulin and glucose dysfunction.3 The dietary component of the approach promotes a combination of ketogenic and Mediterranean food patterns, which replaces saturated fats from animal sources with coconut products, and encourages a high diversity of plant foods rich in phytonutrients and vitamins.3 A more in-depth look at these recommendations and their potential benefits for reducing risks associated with onset of AD is described below.
Mediterranean diet (Mediet) – the Mediet has been studied extensively for its anti-inflammatory and nutrient density and has been found to effectively support a reduction in chronic disease risks and mortality.3-4 This dietary and lifestyle approach:
- Emphasizes a high fruit and vegetable intake
- Focuses on whole grains and legumes over refined grains
- Maintains a focus on nuts, fish and olive oil as sources of unsaturated fats
- Recommends moderation in the consumption of red wine, red meat and poultry
- Encourages regular physical activity as part of the overall lifestyle
Ketogenic diet (keto diet) – the keto diet has garnered considerable attention recently. Following the keto diet results in the production of ketone bodies, which can be utilized by the brain for energy, in place of glucose. By substituting ketone bodies for glucose, several of the main potential drivers of AD (excess insulin in the brain, dysregulation of insulin receptor activity and production of advanced glycation end products or AGEs) is limited.3 The macronutrient distribution of the keto diet typically involves the following ranges:3
- 60-80% of calories from fats
- 5-15% of calories from carbohydrates
- 15-30% of calories from protein
Animal model evidence for high-fat/low-carb diet in reducing AD
Levels of Aβ-42, the toxic isoform of Aβ peptide, were reduced in AD mice models following a diet high in saturated fatty acid (SFAs) at 79% of total calories; and low in carbohydrates at 0.76% of total calories. This may potentially indicate not only the benefits of a low carbohydrate diet but also the beneficial impact of adhering to a diet high in SFAs.3
A case for a Keto-Mediet with coconut
Coconut oil, Cocos nucifera, is a mostly saturated, medium-chain fatty acid (MCFA). MCFAs are an important SFA source of energy in the body as they bypass the carnitine shuttle pathway and enter the mitochondria directly. MCFAs from coconut may play a significant role in the aging adult population’s diet, particularly for those who have difficulty breaking down and utilizing dietary fats. Coconut MCFAs can also be used in place of long-chain SFA, such as those found in red meat, dairy and various types of processed foods, as needed when adhering to a keto diet approach.3
Following a Keto-Mediet with coconut encourages a combination of components from both the Mediterranean and ketogenic diets, including a high-phytonutrient, anti-inflammatory, high-fiber, low-carbohydrate, high medium chain SFA approach which focuses on 7 key food categories including: fruits, vegetables, proteins, fats and nuts, dairy, grains, and beverages. Coconut is recommended to replace some or all sources of saturated animal fats, and the limited carbohydrates are mainly sourced from whole grains. Additional details of this modified Keto-Mediet with coconut adult food pyramid include:3
- Pyramid base consists of fruits (2-3 serving per day), vegetables (2-3 cups per day) and beverages such as water, broth soup, green tea, other forms of teas (ashwagandha and almond), black coffee, juice with pulp, and coconut water
- Second level of pyramid consists of fats (from plants and fish including olive oil, fatty fish, coconut oil, avocados, walnut oil, camellia oil, and vegetable oil) and nuts, protein (lean meats, tofu, fish, poultry, eggs) and dairy (1-2 cups of low-fat milk or yogurt per day) with coconut and soy milk substituting for butter and milk from animals as desired
- Third level of pyramid consists of grains (bread, cereal, rice, pasta, etc.) at < 50 grams per day or 1-2 cups per day with at least half of the total coming from whole grains
- Top of pyramid consists of “snack” or “junk” food and should be avoided all together or consumed infrequently
In summary, this review article recommends following a Keto-Mediet with coconut substitution along with regular physical exercise to support delay in AD onset in those with risk factors, to improve weight management, and to prevent cardiovascular disease.
Why is this Clinically Relevant?
- A combination of Mediterranean and ketogenic diet approaches help combat dysfunctional brain insulin signaling and brain glucose metabolism, processes that underlie AD
- The Keto-Mediet is also supportive of weight management and cardiovascular health
- Replacing long-chain SFA with coconut products, which mainly consists medium chain SFA may be beneficial in individuals requiring greater energy sources or those who have difficulty metabolizing and utilizing long-chain SFAs
- Alzheimer’s Association. 2018 Facts and Figures. https://www.alz.org/facts/overview.asp. Accessed May 7, 2018.
- Sanabria-Castro A, Alvarado-Echeverria I, Monge-Bonilla C. Molecular pathogenesis of Alzheimer’s disease. Ann Neurosci. 2017;24(1):46–54.
- Perng BC, Chen M, Perng JC, Jambazian P. A Keto-mediet approach with coconut substitution and exercise may delay the onset of Alzheimer’s disease among middle aged. J Prev Alzheimers Dis. 2017;4(1):51-57.