Medium chain fatty acids & COCONUT OIL – A REVIEW OF POTENTIAL APPLICATIONS

 Medium chain fatty acids (MCFA) that contain 8–12 carbons and are saturated are constituents of milk and have been associated with beneficial effects linked with metabolic activities. It has been postulated that MCFA may help to reduce the risk of developing features of metabolic syndrome , a cluster of metabolic disorders including dyslipidaemia, hypertension, obesity and glucose intolerance, where insulin resistance is the core phenomenon and co-occurrence is associated with increased CVD risk.

1.Earlier studies have shown that dietary substitution of medium chain triglycerides (MCT) for long chain triglycerides (LCT) can influence energy balance and thus it was postulated that they may promote weight reduction .

MCFAs are hydrolysed more rapidly and metabolized more completely after absorption across the epithelial barrier . They are transported directly to the liver via the portal circulation unlike the LCFA that are preferentially incorporated into chylomicrons as LCT and transported via lymph.

Once transported to the liver, the MCFA can follow various catabolic pathways including beta-oxidation, omega-oxidation, and peroxisomal oxidation .

Medium-chain triglycerides, constituents of coconut and palm kernel oils, are medium-chain fatty acid esters of glycerol.. The fatty acid groups of MCTs include dodecanoic [12:0], octanoic [8:0], hexanoic [6:0] and decanoic [10:0] acids (Figure 1), so these oils are a simple, economical and well-accepted way to consume MCFA .

2.Lauric acid (C:12) is a saturated medium chain fatty acid, from 6 to 12 carbon atoms and is present high quantity in coconut oil and palm kernel oil, approximately 45g/100 g edible portion. It has been associated with certain health benefits of coconut oil intake .

 Lauric acid is also contained in plant oils, fruits, seeds and in breast milk .(Caprylic acid is also called as octanoic acid, is a saturated fatty acid and carboxylic acid. They are found naturally in the milk of various mammals and as a minor constituent of coconut oil and palm kernel oil. Two other acids are named after caprylic acid: caproic acid (C6) and capric acid (C10). Together, these three fatty acids comprise 15% of the fatty acids in goat milk fat .

A number of health benefits have been attributed to this oil. These include benefits in skin care, hair care, stress relief, weight loss and cholesterol level maintenance, immuno-modulatory effects, cardiovascular uses, and more recently in Alzheimer’s disease .However for several years, coconut oil was demonized and consumers were made to believe that coconut oil is deleterious to health as it would block the arteries and cause heart disease. The tide has turned and in recent times recognition of the positive health effects of coconut oils have emerged stronger. The use of coconut oil, especially virgin coconut oil is in vogue, though some people still remain skeptical. This article attempts to scientifically review the therapeutic benefits of this oil.

MCFA are more rapidly absorbed from the gut directly to the liver via the portal vein compared to long chain fatty acids which are absorbed primarily via the lymphatic duct and into the peripheral circulation .

Medium chain fatty acid do not rely on membrane transporters for uptake into cells and it can be directly transported to the mitochondrial inter-membrane space without the carnitine shuttle.

Metabolism of medium-chain fatty acids promotes the generation of ketones. Both the rapid absorption and β-oxidation of MCFA suggest these fatty acids have a physiologically important function .

Furthermore, animal data suggest that medium-chain fatty acids can readily cross the blood-brain barrier (BBB) and be oxidized by the brain .

 a daily intake of 10 g of MCT for a 12-week period significantly reduced body weight, body fat, abdominal subcutaneous fat and waist and hip sizes in subjects with a body mass index (BMI) of ≥23 kg m−2, suggesting that intake of MCT could be effective for preventing obesity in subjects with a high BMI.

Interestingly, the use of a mixture of both medium- and long-chain triacylglycerols as substitutes for common edible vegetable oils has resulted in the FOSHU (Food for Specified Health Use) product with the trade name ‘Healthy Resseta’ which has been shown to have a suppressing effect on body fat accumulation and to increase diet induced thermogenesis and is now widely sold in Japan (Aoyama, Nosaka, & Kasai, 2007; Ogawa et al., 2007).

Medium-chain fatty acids (MCFAs) are saturated or unsaturated fatty acids found at high concentrations in food such as coconut oil, with lauric acid (C12:0) representing ∼50% of its fat content. MCFAs are quickly oxidized by the liver and thus less obesogenic than LCFAs. Due to this, medium-chain triglycerides are commonly used in parenteral nutrition, providing a rapidly accessible source of energy for the body . MCFAs can also interact with both immune and non-immune cells through the G-protein-coupled receptor .

Medium-chain fatty acids (MCFAs) have emerged as potential therapeutic agents for various health conditions. MCFAs, found in coconut oil and palm kernel oil, are rapidly metabolized and can improve metabolic features and cognition in humans .

They have been shown to suppress fat deposition through enhanced thermogenesis and fat oxidation, potentially aiding in the prevention and treatment of metabolic syndrome 

Recent studies using Dictyostelium discoideum as a model have proposed direct molecular mechanisms for decanoic acid, independent of ketone generation, which could impact the treatment of epilepsy, cancer, and bipolar disorder .

In chronic kidney disease, MCFAs may play a protective role by providing an efficient energy source and potentially modulating disease progression . However, caution is advised when using MCFAs as the main dietary energy source, as some adverse effects have been reported .

3. COCONUT OIL:

 3.1 Antioxidant and Anti-stress Activity :

  A study carried out by Yeap SK et al evaluated the antistress and antioxidant effects of virgin coconut oil in  vivo. VCO  reduced lipid  peroxidation and  increase the  activity  of SOD  in the  serum of  mice undergoing the forced swim test and the brains of mice subjected to chronic cold restraint.

VCO has been reported to be rich in polyphenols and these contribute to the increased antioxidant enzyme levels, which in turn reduces inflammation and  lipid peroxidation in VCO-treated  mice. Restoration of brain antioxidant  levels  hinders  further  neuronal  damage  thereby  preventing  subsequent  monoamine depletion.

The potential of VCO to prevent exercise- and chronic cold restraint stress-induced damage and to restore the antioxidant balance was demonstrated and this was attributed to the polyphenols and medium-chain fatty acids present in VCO. In another study on the comparative effect of VCO with copra oil,  olive  oil  and  sunflower  oil  on  endogenous  antioxidant  status  and  paraoxonase-1  activity  in ameliorating the  oxidative stress in rats, findings revealed that dietary  VCO improved the antioxidant status as compared to the other three oil- fed groups, as was evident from increased catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase activities in tissues.  

3.2. Hepatoprotective activity

   Several  studies  have reported  the antioxidant activity of  VCO. Oxidative stress  induced by the generated free radicals plays a lead role in the development of hepatic toxicity. A study was conducted on hepatoprotective activity of VCO on 2, 4-Dichlorophenoxyacetic acid (2, 4-D) induced liver damage in rats. Rats treated with 2, 4-D showed a significant liver damage with increased serum transaminases and alkaline phosphatase enzymes activities, hepatic lipid peroxidation and liver free fatty acids. Serum total protein,  albumin,  hepatic  superoxide  dismutase  and  glutathione  peroxidase  enzymes  activities  were significantly reduced. Inflammation and necrosis were observed in liver sections of treated rats. VCO oil treated animals showed an improvement in hepatic antioxidant enzymes, serum transaminases activities and  liver  free  fatty  acids  levels  which  was  confirmed  by  histopathological  examination,  thereby establishing the hepato protective activity of VCO. 

 

3.3. Anti-inflammatory, analgesic, and antipyretic activities of VCO

   A  study conducted  by Intahphuak  et al,  evaluated the  anti-inflammatory,  analgesic, and  antipyretic effects of VCO in rats using ethyl phenyl propiolate-induced ear edema and carrageenan and arachidonic acid-induced paw edema. VCO was found to possess moderate anti-inflammatory effects. 

Through  reduction  of the  transudative  weight,  granuloma  formation, and  serum  alkaline  phosphatase activity, VCO exhibited an inhibitory effect on chronic inflammation. In acetic acid-induced writhing, the model for analgesic activity and for yeast-induced hyperthermia for antipyretic activity, VCO showed a moderate analgesic and antipyretic effect. 

 

3.4. Wound Healing Effect

  Wound healing is a complex process where the skin or other body tissue repairs itself after injury. The oil of Cocos nucifera has been reported to be an effective wound healing agent. Nevin et al studied the effect  of topical  application of  virgin coconut  oil on  skin components  and antioxidant  status during dermal wound healing in young rats. In their study, animals were treated for 10 days with VCO, 24 hours after  creation  of the  wound.  VCO’s  healing  activity  was evaluated by  monitoring time for  complete epithelization in addition to  various parameters of the  wound's granulation tissue. Solubility  pattern of collagen, glycohydrolase activity and granulation tissue histopathology were also studied. Animals treated with  VCO  showed  much  faster  wound  healing  activity,  indicated  by  a  decreased  time  in  complete epithelization and higher levels of various skin components. The significant increase of Pepsin-soluble collagen and glycohydrolase activities observed indicated higher collagen cross- linking and its turnover. They concluded that the  wound healing activity of  VCO may be a cumulative effect of various minor biologically active components present within .

3.5. Effect on Dermatitis

  Atopic dermatitis (AD) is a chronic skin disease characterized by features of defective epidermal barrier function and inflamed cutaneous layer. In this condition trans epidermal water loss (TEWL) is increased and the ability of the stratum corneum to hold water is impaired. This leads to decreased skin capacitance and hydration. A study by Evangelista et al investigated the topical effect of VCO on SCORAD index, trans epidermal water loss, and skin capacitance in mild to moderate pediatric atopic dermatitis using a randomized controlled trial design. A total of 117 patients included were evaluated at baseline, and then at 2, 4,  and 8 weeks respectively. The  results concluded the superiority of VCO over mineral oil among pediatric patients with mild to moderate AD 19.

3.6. Use as an Ocular Rewetting Agent :

  Dry eye is a symptom caused by the lack of quality /quantity of tears or defect on the ocular surface area. That leads a condition of discomfort, visual disturbance; tear film instability, increased osmolality of the tear film and inflammation of the ocular surface, which ameliorate the damage to the ocular surface.

Among all the therapeutic option for dry eyes, artificial tears is the mainstay for the initial management of dry eye patient. Due to the complexity of tear film, it is difficult to manufacture tears  that would  be similar to that of the human eye. Several brands of artificial tears are commercially available, that would consist of Hydroxypropyl methyl cellulose, Poly vinyl alcohol, sodium hyaluronate and oil based tears. A previous study showed that liposomal spray applied on closed eye lid had increased the thickness of lipid layer and also significantly increased the tear film stability. On account of this study Dept. of Optometry and vision science at Malaysian University evaluated the usage of VCO as a supplement for tear film. 

Coconut oil – a review of potential applications :

A pilot study was carried out on the efficacy of VCO as an ocular rewetting agent on Rabbit eyes. VCO was found to be safe in the dry eye and its anti-inflammatory property was attributed to be responsible for its significant beneficial effect in the management of dry eyes20. 

3.7. Effect on Alzheimer’s disease

  In  the  neurological  disorder  Alzheimer's  disease  (AD),  memory  loss  and  cognitive  decline  occurs because  of  death  of  brain  cells.  The  neurodegenerative  disease  starts  as  mild  dementia  getting progressively worse. In the brain, the lipid macromolecule, cholesterol is utilized as an antioxidant, for structural scaffolding of the neural network, as an electrical insulator (to prevent ion leakage), and as a functional membrane component. Cholesterol is  utilized in  the wrapping  and synaptic  delivery of the neurotransmitters and also plays an important role in the formation and functioning of synapses in the brain. Several studies21 have proven the lack of cholesterol in the brains of AD patients.  In contrast, a positive  correlation  (better  memory  function  and  reduced  dementia)  was  observed  between  high cholesterol levels and longevity in a population above 85 years old .

A study appearing in the American     Journal of Cardiology in February 2011 suggested that a diet with adequate amounts of saturated fat is essential  to  maintain  HDL  high  cholesterol  levels.  Those  with  deficiencies  and  suffering  from neurological disorders needed to consider a diet that is high in saturated fat.

The saturated fat of coconut oil provides the brain with an alternate source of energy in ketones. Ketones are high energy fuels that nourish the brain.

 Fasting /starvation can trigger the production of   ketones.  Ketones are also formed by the conversion of medium chain fatty acids in certain foods. Coconut oil is nature’s richest source of these medium chain triglycerides (MCTs) .

 A study done in 2004 took MCTs from coconut oil and put them into a drink that was given to Alzheimer’s patients while a control group took a placebo. They observed significant  increases  in levels of  the ketone  body beta-hydroxybutyrate (beta-OHB)  90 minutes  after treatment. When cognitive  tests were  administered, higher  ketone values  were associated with greater improvement in paragraph recall with MCT treatment relative to placebo across all subjects23.  

3.8. Effect on blood pressure elevation  :

  Hypertension or elevated blood pressure is the main risk factor for cardiovascular complications such as coronary  heart  disease,  atherosclerosis,  and  stroke.  Many  studies  to  prevent  the  elevation  of  blood pressure have been carried out. 

 

  Badlishah Sham Nurul-Iman et al carried out a study on Effect of VCO on prevention of blood pressure elevation and Improves Endothelial Functions in rats fed with repeatedly heated  palm oil.  This study explored the effects of virgin coconut oil (VCO) in male rats fed repeatedly with heated palm oil on blood pressure, plasma nitric oxide level, and vascular reactivity. In their study elevation of blood pressure was created by the repeated feeding of heated palm oil. On overheating, the free radicals that were generated induced oxidative stress within the blood vessel, affecting the NO level in the endothelial cells. In male rats, supplementation with repeatedly heated palm oil VCO was found to prevent blood pressure elevation and to also decrease nitric oxide deactivation. In addition, VCO did not influence relaxation but decreased vasoconstriction of the endothelium.

3.9. Immunomodulatory effect :

  In  1966,  Jon  Kabara  discovered  that  Medium Chain  Fatty  Acids  (MCFA’s)  of  virgin coconut  oil  are incredible for  antimicrobial properties that  kill harmful  viruses, bacteria,  fungi, and parasites.   When MCFA’s are digested, they break down into free fatty acids and monoglycerides 25  .Lauric Acid, Capric acid, and Caprylic acid are the important medium chain fatty acids present in coconut oil that possess antimicrobial  activity.  Their monoglyceride  form,  monolaurin, monocaprylin, and  monocaprin  hinder microbes from terrorizing the immune system. Individually, these fatty acids act on microbes in different ways. Some may kill a particular organism that causes fungal infections but may not be as useful on other microbes.  Unitedly,  however  they  act  as  a  highly  powerful  defence  against  diseases.  Monolaurin (monoglyceride form of lauric acid) is considered to have the best antiviral, antifungal, and antibacterial effect.  

 

3.10. Effect on blood sugar control

  A study on  Insulinotropic potency of lauric  acid: a metabolic rationale for  medium chain  fatty acids (MCFA) in TPN formulation by Garfinkel M et al proved that the effect of MCFA on insulin secretion depends upon its  chain length. Among all MCFA capric  acid (C10) and  lauric acid were  observed to display the most potent effects on insulin secretion27. Another study proved that, as compared to other oils, coconut oil in the diet enhanced insulin action and improved binding affinity

 3.11. Effect on weight loss  :   A  study  conducted  on  the  effect  of  dietary  medium-  and  long-chain  triacylglycerols  (MLCT)  on accumulation of body fat in healthy humans by Kasai M et al proved that a daily intake of MLCT diet could cause a reduction in body weight and body fat accumulation. Volunteers in a double-blind study for 12  weeks,  consumed  daily  at breakfast,  test  bread, with  1.7  g MCFA,  bread  made  with  long-chain triacylglycerols (LCT) was consumed by the control group. A significant decrease of body weight and amount of fat, with a significant decrease in serum total cholesterol was observed in the test group29. In another  study  on  the  effect  of  dietary  supplementation  with  coconut  oil  on  the  biochemical  and anthropometric  profiles  of women  with abdominal  obesity  (waist circumferences  (WC)  >88 cm)  the intake of dietary supplement with VCO was observed to decrease the amount of abdominal fat30.

4. CONCLUSION

   People of traditional cultures of the South Pacific Islands, Asia, Africa and the Central America have used coconut oil for generations in traditional coconut-based diets. These people suffer very much lower rates of obesity, heart disease, cancer, diabetes, arthritis and other health problems than those in North America  and  Europe  who  don't  eat  coconut-based  food  at  all.  Till  very  recently,  coconut  oil  was demonized and consumers were made to believe that coconut oil is deleterious to health as it would clog arteries and cause heart disease. The tide has turned and in recent times recognition of the positive health effects  of coconut  oils has  emerged stronger  and coconut  oil, especially  virgin coconut  oil is  being extolled for its beneficial properties.