Short, medium and long chain fatty acids

Each fat consists of a glycerol molecule and three fatty acids. Together, these two components form the so-called triglycerides. The fatty acids can be saturated or unsaturated. The saturated fatty acids are divided into short-chain, medium-chain and long-chain fatty acids on the basis of their molecular size, i.e. the length of their carbon chains or the number of their carbon atoms. Short-chain fatty acids are those with up to 6 carbon atoms, medium-chain fatty acids are those with 8 to 12 carbon atoms, and long-chain fatty acids are those with more than 12 carbon atoms.

Short- and medium-chain fatty acids are easier to digest than long-chain ones. The short-chain fatty acids are largely utilized directly by the intestinal cells. The medium-chain fatty acids, on the other hand, reach the liver directly via portal vein (vein that collects blood from the abdominal organs) after being absorbed in the intestinal cells, independently of bile acids and fat-splitting enzymes. The direct route without further circulation in the bloodstream means that medium-chain fatty acids contribute little to fat stores.

Once in the liver, medium-chain fatty acids are converted to ketone bodies (or ketones for short) via the process of beta-oxidation, largely to acetone, acetoacetate, and beta-hydroxybutyrate. The latter are further metabolized in the mitochondria to water, carbon dioxide and energy (see Figure 1).

Metabolism of medium-chain and long-chain fatty acids in comparison

Figure 1: Metabolism of medium-chain and long-chain fatty acids in comparison. LCT: Long-chain triglycerides; LCFA: Long-chain fatty acids; MCT: Medium-chain triglycerides; MCFA: Medium-chain fatty acids; TG: Triglycerides (Modified according to [7]).

In comparison, the long-chain fatty acids have a much longer digestion path, which only takes place with the help of bile acids and fat-splitting enzymes. They are packaged together with cholesterol and proteins in so-called lipoproteins and enter the bloodstream via a long detour through the lymph. During this circulation of lipoproteins, their fatty components can distribute and accumulate in the body tissues. On this journey through the vascular system, some of these fats can be deposited on the arterial walls, contributing to atherosclerosis.

MCT oils

Medium-Chain Triglycerides or MCT oils are mostly produced from coconut and palm kernel fat. As the name suggests, they contain medium-chain fatty acids with 8 carbon atoms (caprylic acid) and 10 carbon atoms (capric acid). These, after being absorbed in the intestine, travel with the blood of the portal vein directly to the liver, where they are rapidly converted into ketones and metabolized for energetic purposes (see Figure 1).

Thus, due to their content of medium-chain fatty acids, MCT oils are fast energy carriers that boost the metabolism and are either burned directly to meet energy requirements – for example in the skeletal muscles – or used to produce ketone bodies. Caprylic acid (8 carbon atoms) has a particularly ketogenic effect, and it can also enter the brain directly and be used by astrocytes for energy production and ketone formation. By now, some MCT oils are available, which exclusively contain this medium-chain fatty acid.

Coconut oil

Coconut oil, on the other hand, contains only about 14% of the medium-chain fatty acids with 6 to 10 carbon atoms, and about half of it consists of lauric acid (12 carbon atoms). For a long time, there was disagreement as to whether the latter fatty acid, lauric acid, which has twelve carbons, should be counted among the medium-chain fatty acids at all.

The crucial question, however, is whether lauric acid can also stimulate ketone formation. A scientific review [1]), for which only studies with coconut oil or lauric acid were evaluated, has answered this question: Since the early 1980s, it has been proven in animal experiments as well as in humans that a part (about 28 %) of lauric acid, like long-chain fatty acids, first reaches the lymph before it reaches the liver. Some lauric acid is also found in depot fat. However, most of the lauric acid consumed (72%) follows the same pathways as the other medium-chain fatty acids. It is therefore also more easily digested and absorbed directly by the liver, where it is also used for energy production and ketone formation.

In addition to fats, coconut oil also contains other valuable substances: depending on the production method, it has a decent amount of antioxidant phenolic acids, such as p-coumaric acid, ferulic acid, caffeic acid and catechic acids, but also to a small extent vitamin E as a tocopherol-tocotrienol mixture.

However, coconut oil can also contain undesirable substances. Therefore, special attention should be paid to the quality of the coconut oil. In 2021, for example, a chemical test by the German consumer magazine Öko-Test revealed that many oils were contaminated with extremely high levels of harmful substances such as mineral oils [2]. In some cases, the orientation values for saturated hydrocarbons were clearly exceeded, and carcinogenic aromatic hydrocarbons were also detected, which should not be used in food. Therefore, please inform yourself about the purity of your coconut oil before buying it.

Preventive and therapeutic effects in Alzheimer’s disease

In other sections, we have already described in detail the energetic undersupply of the brain and cerebral insulin resistance as a driving factor in Alzheimer’s disease. The fact that the medium-chain fatty acids in MCT or coconut oil are also capable of forming ketones and counteracting this energy crisis in Alzheimer’s disease has already been confirmed by several studies. This was demonstrated particularly impressively in the case of Steve Newport: His wife, the American physician Dr. Mary Newport, had shown for the first time a therapeutic effect of coconut oil on Alzheimer’s disease [3], by “treating” her husband, who was suffering from an early form of Alzheimer’s disease, with coconut oil. And with success: after only a few weeks, there was a tremendous improvement in his cognitive abilities. In addition, Steve Newport gradually improved his memory, word-finding ability, social participation and gait. Magnetic resonance imaging also showed no further brain atrophy over a long period of time [3].

This is not an isolated case, as shown by several other studies on Alzheimer’s patients in early and advanced stages: In almost all of them, an increase in cognitive functions, processing speed and/or memory performance of dementia patients was observed shortly after the administration of ketogenic oils or ketone preparations [4], [5].

Medium-chain fatty acids, such as those found in coconut oil and MCT oil, can also counteract the development of Alzheimer’s disease through other mechanisms: Intervention studies, for example, have shown that a diet containing a controlled amount of medium-chain fatty acids compared with the same amount of long-chain fatty acids resulted in a significant decrease in body fat. The reason for this is that medium-chain fats do not deposit in the bloodstream due to the lack of circulation, but the energy derived from their metabolism is efficiently converted into fuel for organ and muscle use [6]. Thus, these fats tend not to contribute to fat depots, but are used for energy production.

Furthermore, lauric acid, the major fatty acid in coconut oil, supports the formation of beneficial high-density lipoprotein (HDL) cholesterol, which is of health benefit because the HDL fraction may reduce the risk of hyperlipidemia and thus counteract the development of cardiovascular disease and also Alzheimer’s disease [7]. Furthermore, lauric acid also has the potential to delay the rate-determining step in cholesterol biosynthesis, the conversion of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) protein to mevalonate, by inhibiting the enzyme HMG-CoA reductase in the body – thus it also has a cholesterol-lowering effect [7].

The latter mechanisms could thus be responsible for the fact that medium-chain fatty acids, in the right nutritional context, could also be helpful in the treatment of dyslipidemia, elevated LDL, insulin resistance, type 2 diabetes, obesity, and hypertension, all of which are risk factors for cardiovascular complications but also for Alzheimer’s dementia. These findings should thus also invalidate concerns that coconut oil consumption is a risk factor for cardiovascular disease due to its saturated fatty acids – an assumption that is still held by the German Nutrition Society (DGE) and the German Federal Center for Nutrition (BZfE) and, as shown, is misleading.

It is also now known that medium-chain fatty acids, in particular caprylic acid (8 carbon atoms), possess antibacterial effects on a variety of pathogenic Gram-positive and Gram-negative microbes, including Campylobacter jejuni, Listeria monocytogenes, and Clostridium perfringens[8]. Thus, this fatty acid has been successfully used as an alternative to antibiotics in animal studies. In addition, it has shown great potential to counteract dysbiosis (poor colonization) of the human gut by specifically keeping pathogenic germs in check. A lack of intestinal integrity in particular, which is strongly promoted by dysbiosis, is considered a risk factor in the development of Alzheimer’s disease (see also the fact sheet “Dementia and intestinal health” which is available to you free of charge in the download area of “Knowledge stops dementia”).

Furthermore, the antioxidant substances in coconut oil, such as the phenolic acids and vitamin E mixture, could also support the therapeutic effect of coconut oil against AD by inhibiting oxidative damage, a key factor in the pathology of AD [7]. In animal studies, for example, they have shown a beta-amyloid-reducing effect and reduced cognitive deficits in Alzheimer’s mice [9].

The following figure illustrates all the effects of coconut oil and its ingredients in the context of Alzheimer’s prevention and therapy:

Therapeutic effects of coconut oil for the treatment of Alzheimer's disease

Figure 2: Therapeutic effects of coconut oil for the treatment of Alzheimer’s disease. Ac: acetone; AcAc: acetoacetate; ßHB: beta-hydroxybutyrate (Modified from [7])


Although long-term clinical data from large cohorts are not yet available, experts now agree that medium-chain fatty acids, such as those found in coconut oil but also in MCT oils, should be recommended as a treatment or preventive measure for Alzheimer’s disease and its comorbidities, such as cardiovascular disease and type 2 diabetes, because they have extremely promising functional properties.

We can say confidently, given current knowledge, that minor brain “energy gaps” that are common in aging, can be “closed” with coconut oil and/or MCT oils. Also, for Alzheimer’s prevention, these slightly increased blood levels of ketones, as they can already be achieved with a few teaspoons of coconut oil or MCT oil (corresponding to about 20 to 30 grams of medium-chain fatty acids), would be sufficient. However, be sure to pay attention to the quality of the coconut oil and consume only pollutant-tested and high-quality products.

However, coconut oil should never be the only fat in the diet, as it contains hardly any unsaturated fatty acids. Other fatty foods must also be consumed to meet the need for the remaining essential fatty acids. Ideal for this purpose are fish consumption, fish or algae oils, as well as flax, hemp or walnut oil, flaxseed or walnuts. These foods primarily supply fatty acids of the omega-3 family. Olive oil, with its valuable oleic acid fraction, antioxidant polyphenols, vitamins, and anti-inflammatory oleocanthal, should also be an integral part of a diet that protects and maintains your brain health.


  1. Dayrit FM (2015) The properties of lauric acid and their significance in coconut oil. J Am Oil Chem Soc 92:1–15. DOI 10.1007/s11746-014-2562-7
  2. ÖkoTest Einkaufsratgeber, Jahrbuch für 2021 Sonderheft J2010: 18-23
  3. ↑1 ↑2 Newport, M et al.: A new way to produce hyperketonemia: Use of ketone ester in a case of Alzheimer’s disease. Alzheimers & Dementia 2015;11:99-103
  4. SV Ramesh, V Krishnan, S Praveen et al (2021) Dietary prospects of coconut oil for the prevention and treatment of Alzheimer’s disease (AD): A review of recent evidences. Trends in Food Science & Technology 112: 201-211
  5. Matthew C. L. Phillips, Laura M. Deprez, et al. (2021) Randomized crossover trial of a modified ketogenic diet in Alzheimer’s disease. Alzheimer’s Research & Therapy 13: 51. doi: 1186/s13195-021-00783-x
  6. Fernando WMADB, Martins IJ, Goozee KG, et al., (2015) The role of dietary coconut for the prevention and treatment of Alzheimer’s disease: potential mechanisms of action, Br. J. Nutr. 114(1): 1-14.
  7. ↑1 ↑2 ↑3 ↑4 Sandupama P, Munasinghe D, Jayasinghe M (2022) Coconut oil as a therapeutic treatment for alzheimer’s disease: a review. Journal of Future Foods 2/1: 41-52.
  8. Roopashreea PG, Shilpa S.Shettya SS, Kumarib NS (2021) Effect of medium chain fatty acid in human health and disease. Journal of Functional Foods. Volume 87, 104724
  9. F. Mirzaei, M. Khazaei, A. Komaki, et al., Virgin coconut oil (VCO) by normalizing NLRP3 inflammasome showed potential neuroprotective effects in Amyloid-β induced toxicity and high-fat diet fed rat, Food Chem. Toxicol. 118 (2018) 68-83.