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Sexy Fats – Part II: A Research Review of Coconut Oil and Medium Chain Triglycerides

Two schools of thought tend to exist about coconut oil:

  1. The Uninformed: It’s a saturated fat and it’s horrible for you. Don’t smell it, don’t look at it, and don’t let your kids play at friends houses whose parents use it.
  2. The Overzealous: It’s the most amazing thing on the planet; it will cure AIDS, give you the energy of Robert Downey Jr. on a coke binge, make your skin softer than 10,000 thread count sheets, give you the body composition of an Olympic sprinter, and possibly give you X-ray vision.

Both of those are obviously poor positions to take on the subject, so let’s take a look at the research in hopes of gaining an objective understanding. But before we do that, here’s a quick coconut oil lesson to get everyone up to speed: Coconut oil is either refined or unrefined, the latter being the preferable form for ingestion from a health standpoint. Unrefined coconut oil is derived from coconuts either by quick drying the coconut meat and then machine pressing the oil out, or by wet-milling, which skips the drying process and separates the oil from the coconut water after its pressed out of the meat. The oil is about 90% saturated, comprised mostly of lauric acid, and to a much lesser degree myristic and palmitic acids. Due to the high saturation, it does not degrade under heat and is highly resistant to oxidation and rancidity. This makes it a good choice for higher heat cooking compared to unsaturated fats. It has a mild coconut taste that doesn’t come through strongly when used for cooking, unless you use quite a bit. It remains a solid up to about 76 degrees Fahrenheit, so it can be used as either a solid or a liquid depending on preparation temperature. We’re going to take a look at some studies on coconut oil itself, as well as some studies looking directly at MCT’s. First the coconut oil studies:

Study #1

In vitro antimicrobial properties of coconut oil on Candida species in Ibadan, Nigeria.
The emergence of antimicrobial resistance, coupled with the availability of fewer antifungal agents with fungicidal actions, prompted this present study to characterize Candida species in our environment and determine the effectiveness of virgin coconut oil as an antifungal agent on these species. In 2004, 52 recent isolates of Candida species were obtained from clinical specimens sent to the Medical Microbiology Laboratory, University College Hospital, Ibadan, Nigeria. Their susceptibilities to virgin coconut oil and fluconazole were studied by using the agar-well diffusion technique. Candida albicans was the most common isolate from clinical specimens (17); others were Candida glabrata (nine), Candida tropicalis (seven), Candida parapsilosis (seven), Candida stellatoidea (six), and Candida krusei (six). C. albicans had the highest susceptibility to coconut oil (100%), with a minimum inhibitory concentration (MIC) of 25% (1:4 dilution), while fluconazole had 100% susceptibility at an MIC of 64 microg/mL (1:2 dilution). C. krusei showed the highest resistance to coconut oil with an MIC of 100% (undiluted), while fluconazole had an MIC of > 128 microg/mL. It is noteworthy that coconut oil was active against species of Candida at 100% concentration compared to fluconazole. Coconut oil should be used in the treatment of fungal infections in view of emerging drug-resistant Candida species.
PMID: 17651080 [PubMed – in process]

My Comments: Overdependence on anti-biotics and anti-bacterial cleaning agents has caused mutated resistant species of bacteria to develop. This can potentially become a serious health concern. Big thumbs up for coconut oil being used successfully here to treat resistant fungal infections.

Study #2.

Effects of coconut oil on testosterone-induced prostatic hyperplasia in Sprague-Dawley rats.
Benign prostatic hyperplasia (BPH) is the benign uncontrolled growth of the prostate gland, leading to difficulty with urination. Saw palmetto lipid extracts (SPLE), used to treat BPH, have been shown to inhibit prostate 5a-reductase, and some major components, such as lauric, myristic and oleic acids also inhibit this enzyme. Coconut oil (CO) is also rich in fatty acids, mainly lauric and myristic acids. We investigated whether CO prevents testosterone-induced prostate hyperplasia (PH) in Sprague-Dawley rats. Animals were distributed into seven groups (10 rats each). A negative control group were injected with soya oil; six groups were injected with testosterone (3 mg kg(-1)) to induce PH: a positive control group, and five groups treated orally with SPLE (400 mg kg(-1)), CO or sunflower oil (SO) (400 and 800 mg kg(-1)). Treatments were given for 14 days. Rats were weighed before treatment and weekly thereafter. Rats were then killed and the prostates were removed and weighed. CO (400 and 800 mg kg(-1)), SPLE (400 mg kg(-1)) and SO at 800 mg kg(-1), but not at 400 mg kg(-1), significantly reduced the increase in prostate weight (PW) and PW:body weight (BW) ratio induced by testosterone (% inhibition 61.5%, 82.0%, 43.8% and 28.2%, respectively). Since CO and SPLE, but not SO, contain appreciable concentrations of lauric and myristic acids, these results could be attributed to this fact. In conclusion, this study shows that CO reduced the increase of both PW and PW:BW ratio, markers of testosterone-induced PH in rats.
PMID: 17637195 [PubMed – indexed for MEDLINE]

My Comments: Another thumbs up for coconut oil having medicinal properties. BPH is an extremely common problem for aging men, and this seems to be a viable treatment option (if it is repeatable in humans).

Study #3

Energy restriction with high-fat diet enriched with coconut oil gives higher UCP1 and lower white fat in rats.

OBJECTIVE: To investigate the effects of overfeeding on a high fat diet, enriched in coconut oil, and the influence of food restriction on the uncoupling protein (UCP1) expression and on body fat content. DESIGN AND SUBJECTS: In experiment I, female Wistar rats were fed ad libitum either a normal-fat diet (control group, C) or a high-fat diet (HF), enriched in coconut oil, for 7 weeks. In experiment II, HF rats after finishing experiment I were fed (for 3 weeks) either the normal-fat diet (group CAHF, Control After High Fat) or food restricted diets which provided 60% of the energy intake of group CAHF: a group fed a low-energy, normal-fat diet (LENF) and another fed a low-energy, high-fat diet (LEHF). MEASUREMENTS: Body and fatty depot weights. Food intake. Protein and UCP1 levels of interscapular brown adipose tissue. RESULTS: High-fat diet feeding promoted an increase in body fat content, body weight and UCP1 levels. Energy restriction induced similar body weight reduction in groups LENF and LEHF. However, some adipose depots were more strongly reduced in the rats fed the high-fat diet enriched in coconut oil (group LEHF) than in the rats fed the normal-fat diet (Group LENF). Specific UCP1 was 2.0 (group LENF) and 3.4 (group LEHF) times higher than in controls (group CAHF). CONCLUSION: The coconut-oil enriched diet is effective in stimulating UCP1 expression during ad libitum feeding and in preventing its down regulation during food restriction, and this goes hand in hand with a decrease of the white fat stores.

PMID: 9806312 [PubMed – indexed for MEDLINE]

My Comments: Finally some body composition research! This demonstrates the possibility of coconut oil being useful for both hypercaloric and hypocaloric states of body composition manipulation. Unfortunately, good research on coconut oil is slim, especially with regards to body composition. We’ll take a look at the MCT research next, as coconut oil is comprised mostly of this type of fat.

Study #1

Greater rise in fat oxidation with medium-chain triglyceride consumption relative to long-chain triglyceride is associated with lower initial body weight and greater loss of subcutaneous adipose tissue.
OBJECTIVE: Medium-chain triglyceride (MCT) consumption has been shown to increase energy expenditure (EE) and lead to greater losses of the adipose tissue in animals and humans. The objective of this research was to examine the relationship between body composition and thermogenic responsiveness to MCT treatment. DESIGN: Randomized, crossover, controlled feeding trial, with diets rich in either MCT or long-chain triglyceride (LCT) (as olive oil) for periods of 4 weeks each. SUBJECTS: A total of 19 healthy overweight men aged (x+/-s.e.m.) 44.5+/-2.5 y with a body mass index of 27.8+/-0.5 kg/m(2). MEASUREMENTS: EE and body composition were measured using indirect calorimetry and magnetic resonance imaging, respectively, at the baseline and end point of each feeding period. EE was measured for 30 min before consumption of a standard meal and for 5.5 h following the meal. RESULTS: Body weight (BW) decreased (P<0.05) by 1.03+/-0.25 kg with MCT consumption compared to 0.62+/-0.29 kg with LCT consumption. The difference in average EE between MCT and LCT consumptions was related to initial BW, such that men with lower initial BW had a greater rise in EE with MCT consumption relative to LCT on day 28 (r=-0.472, P=0.04) but not day 2 (r=-0.368, P=0.12). Similar results were obtained with fat oxidation on day 28 (r=-0.553, P=0.01). The greater rise in fat oxidation with MCT compared to LCT consumption on day 2 tended to be related to greater loss of BW after MCT vs LCT consumption (r=-0.4075, P=0.08). CONCLUSION: These data suggest that shunting of dietary fat towards oxidation results in diminished fat storage, as reflected by the loss of BW and subcutaneous adipose tissue. Furthermore, MCT consumption may stimulate EE and fat oxidation to a lower extent in men of greater BW compared to men of lower BW, indicative of the lower responsiveness to a rapidly oxidized fat by overweight men.
PMID: 12975635 [PubMed – indexed for MEDLINE]

My Comments: An interesting study showing enhanced weight loss with MCT’s over olive oil. The overall weight loss in both groups was low for a 4 week trial period, which makes one wonder how this would have turned out with a more weight loss specific protocol. This study also suggests that the men of lower body weight responded better to MCT’s than the most overweight men, although they were all considered overweight.

Study #2

Medium- versus long-chain triglycerides for 27 days increases fat oxidation and energy expenditure without resulting in changes in body composition in overweight women.
OBJECTIVE: To determine the effects of long-term consumption of medium chain (MCT) versus long chain triglycerides (LCT) on energy expenditure (EE), substrate oxidation and body composition. HYPOTHESIS: MCT consumption will not result in greater EE, substrate oxidation, and body weight loss compared with LCT consumption. RESEARCH METHODS AND PROCEDURES: Seventeen healthy obese women participated in this randomized, crossover inpatient trial. Meals were prepared and consumed on site for two periods of 27 days. Diets containing 40% of energy as fat, with treatment fat comprising 75% of the total fat, were designed to supply each subject with their individual weight-maintaining energy needs. The MCT diet contained 67% of treatment fat as MCT oil (49% octanoate, 50% decanoate) whereas the LCT diet contained exclusively beef tallow as treatment fat. Body composition was assessed by magnetic resonance imaging (MRI) on day 1 and 28 of each phase while energy expenditure was measured on day 2 and 27. RESULTS: Changes in total and subcutaneous adipose tissue volumes following consumption of MCT and LCT were not different (-0.61+/-0.38 l vs -0.54+/-0.48 l and -0.58+/-0.35 l vs -0.48+/-0.40 l, respectively). Average EE and fat oxidation were greater (P<0.05) during MCT than LCT consumption (0.95+/-0.019 vs 0.90+/-0.024 kcal/min, respectively, for EE and 0.080+/-0.0026 vs 0.075+/-0.0022 g/min, respectively for fat oxidation). DISCUSSION: These results show that long-term consumption of MCT enhances EE and fat oxidation in obese women, when compared to LCT consumption. The difference in body composition change between MCT and LCT consumption, although not statistically different, was consistent with differences predicted by the shifts in EE. It can be concluded that substitution of MCT for LCT in a targeted energy balance diet may prevent long-term weight gain via increased EE.
PMID: 12532160 [PubMed – indexed for MEDLINE]

My Comments: One thing I like about this study is that it was fairly well controlled. Since it was an “inpatient” study, meals were prepared for the participants to help minimize the study being adulterated by external factors. Although MCT’s outperformed LCT’s, it wasn’t really by enough to care about. It would have been interesting to see a lower fat diet (instead of 40% fat), and a more reasonable amount of MCT substitution (instead of 67% of fat intake). I can’t imagine realistically going over 15-20% of total fat with MCTs, and even that would be high.

Study #3

Medium-chain triglycerides increase energy expenditure and decrease adiposity in overweight men.
OBJECTIVE: The objectives of this study were to compare the effects of diets rich in medium-chain triglycerides (MCTs) or long-chain triglycerides (LCTs) on body composition, energy expenditure, substrate oxidation, subjective appetite, and ad libitum energy intake in overweight men. RESEARCH METHODS AND PROCEDURES: Twenty-four healthy, overweight men with body mass indexes between 25 and 31 kg/m(2) consumed diets rich in MCT or LCT for 28 days each in a crossover randomized controlled trial. At baseline and after 4 weeks of each dietary intervention, energy expenditure was measured using indirect calorimetry, and body composition was analyzed using magnetic resonance imaging. RESULTS: Upper body adipose tissue (AT) decreased to a greater extent (p < 0.05) with functional oil (FctO) compared with olive oil (OL) consumption (-0.67 +/- 0.26 kg and -0.02 +/- 0.19 kg, respectively). There was a trend toward greater loss of whole-body subcutaneous AT volume (p = 0.087) with FctO compared with OL consumption. Average energy expenditure was 0.04 +/- 0.02 kcal/min greater (p < 0.05) on day 2 and 0.03 +/- 0.02 kcal/min (not significant) on day 28 with FctO compared with OL consumption. Similarly, average fat oxidation was greater (p = 0.052) with FctO compared with OL intake on day 2 but not day 28. DISCUSSION: Consumption of a diet rich in MCTs results in greater loss of AT compared with LCTs, perhaps due to increased energy expenditure and fat oxidation observed with MCT intake. Thus, MCTs may be considered as agents that aid in the prevention of obesity or potentially stimulate weight loss.
PMID: 12634436 [PubMed – indexed for MEDLINE]

My Comments: Again, this study showed MCT’s outperforming LCT’s (olive oil), but not by enough to get excited about. Although, like previous studies, neither group showed major changes, so this could still carry more significance in an environment more conducive to body composition change.

Study #4

Endogenous fat oxidation during medium chain versus long chain triglyceride feeding in healthy women.
OBJECTIVE: To compare the effect of medium chain triglycerides (MCT) vs long chain triglycerides (LCT) feeding on exogenous and endogenous oxidation of long chain saturated fatty acids (LCSFA) in women. SUBJECTS: Twelve healthy female subjects (age 19-26 y, body mass index (BMI) 17.5-28.6 kg/m2) DESIGN AND MEASUREMENTS: In a randomized cross-over design, subjects were fed weight maintenance diets providing 15%, 45% and 40% of energy as protein, carbohydrate and fat, respectively, with 80% of this fat comprising either a combination of butter and coconut oil (MCT) or beef tallow (LCT). Following 6 days of feeding, subjects were given daily oral doses of 1-(13)C labelled-myristic, -palmitic and -stearic acids for 8 days. Expired 13CO2 was used as an index of LCSFA oxidation with CO2 production assessed by respiratory gas exchange. RESULTS: No difference in exogenous LCSFA oxidation was observed as a function of diet on day 7. On day 14, greater combined cumulative fractional LCSFA oxidation (16.9 +/- 2.5%/5.5 h vs 9.1 +/- 1.2%/5.5 h, P < 0.007), net LCSFA oxidation (2956 +/- 413 mg/5.5 h vs 1669 +/- 224 mg/5.5 h, P < 0.01), and percentage dietary LCSFA contribution to total fat oxidation (16.3 +/- 2.3%/5.5 h vs 9.5 +/- 1.5%/5.5 h; P < 0.01) were observed in women fed the MCT vs LCT diet. With the MCT diet, but not the LCT diet, combined cumulative fractional LCSFA oxidation (P < 0.03), net LCSFA oxidation (P < 0.03), and percentage dietary LCSFA contribution to total fat oxidation (P < 0.02) were increased at day 14 as compared to day 7. Day 14 results indicated increased endogenous LCSFA oxidation during MCT feeding. CONCLUSION: The capacity of MCT to increase endogenous oxidation of LCSFA suggests a role for MCT in body weight control over the long term.
PMID: 11033985 [PubMed – indexed for MEDLINE]

My Comments: The group fed MCT’s + butter showed a much higher rate of Long Chain Saturated Fatty Acid oxidation than the group fed Long Chain Triglycerides in the form of beef tallow. Quite large differences between groups in this one. As the conclusion states, this shows a potential for helping with fat loss.

Study #5

Dietary medium-chain triacylglycerols suppress accumulation of body fat in a double-blind, controlled trial in healthy men and women.
We investigated the effect of long-term ingestion of dietary medium-chain triacylglycerols (MCT) on body weight and fat in humans. Using a double-blind, controlled protocol, we assessed the potential health benefits of MCT compared with long-chain triacylglycerols (LCT) in 78 healthy men and women [body mass index (BMI) > or = 23 kg/m(2): n = 26 (MCT), n = 30 (LCT); BMI < 23 kg/m(2): n = 15 (MCT), n = 7 (LCT)]. Changes in anthropometric variables, body weight and body fat during the 12-wk MCT treatment period were compared with those in subjects consuming the LCT diet. The subjects were asked to consume 9218 kJ/d and 60 g/d of total fat. The energy, fat, protein and carbohydrate intakes did not differ significantly between the groups. Body weight and body fat in both groups had decreased by wk 4, 8 and 12 of the study. However, in the subjects with BMI > or = 23 kg/m(2), the extent of the decrease in body weight was significantly greater in the MCT group than in the LCT group. In subjects with BMI > or = 23 kg/m(2), the loss of body fat in the MCT group (-3.86 +/- 0.3 kg) was significantly greater than that in the LCT group (-2.75 +/- 0.2 kg) at 8 wk. In addition, in subjects with BMI > or = 23 kg/m(2), the decrease in the area of subcutaneous fat in the MCT group was significantly greater than that in the LCT group at wk 4, 8 and 12. These results suggest that the MCT diet may reduce body weight and fat in individuals (BMI > or = 23 kg/m(2)) more than the LCT diet.
PMID: 11694608 [PubMed – indexed for MEDLINE]

My Comments: Another comparison study using an MCT group and an LCT group. At week 8, the MCT group had lost 8.5 pounds of body fat, and the LCT group had lost 6 pounds of body fat. The total calorie and macronutrient intake between groups was the same. An extra 2.5 pounds of fat (not just body weight) without any extra energy expenditure or additional caloric restriction, not bad. 

Study #6

Value of VLCD supplementation with medium chain triglycerides.
BACKGROUND: Medium chain triglycerides (MCT) are energetically less dense, highly ketogenic, and more easily oxidised than long chain triglycerides (LCT). MCT also differ from LCT in their digestive and metabolic pathways. OBJECTIVE: To test the effects of MCT supplementation during a very low calorie diet (VLCD). SUBJECTS AND METHODS: Three groups of tightly matched obese women with body mass index (BMI)>30 kg/m(2) received an isoenergetic (578.5 kcal) VLCD (Adinax, Novo Vital, Sweden) enriched with MCT or LCT (8.0 and 9.9 g/100 g Adinax respectively) or a low-fat (3 g/100 g) and high-carbohydrate regimen. The diets were administered over 4 weeks. Body composition was measured with DEXA and appetite/satiety-according to Blundell. Beta hydroxybutyric acid concentration in plasma and nitrogen excretion in urine was measured during consecutive days of VLCD. The study was performed in a randomised double-blind manner. RESULTS: The MCT group showed a significantly greater decrease in body weight during the first 2 weeks. The contribution of body fat to the total weight loss was higher while the contribution of fat-free mass (FFM) was lower. The MCT group had a higher concentration of ketone bodies in plasma and a lower nitrogen excretion in urine. Hunger feelings were less intense while satiety was higher. These differences were observed during the first 2 weeks of treatment and gradually declined during the third and fourth weeks. CONCLUSIONS: Replacement of LCT by MCT in the VLCD increased the rate of decrease of body fat and body weight and has a sparing effect on FFM. The intensity of hunger feelings was lower and paralleled the higher increase of ketone bodies. These effects gradually declined, indicating subsequent metabolic adaptation. Further studies are required to confirm the protein-sparing and appetite-suppressing effects of MCT supplementation during the first 2 weeks of VLCD treatment.
PMID: 11571605 [PubMed – indexed for MEDLINE]

My Comments: In this study using a Very Low Calorie Diet (VLCD), the MCT diet outperformed the LCT diet by increasing the amount of fat lost, preserving a higher amount of muscle, and decreasing hunger sensations. For some reason in this study the effects seemed to taper after the first 2 weeks, which could be due to any number of variables.

Study #7

Lower weight gain and higher expression and blood levels of adiponectin in rats fed medium-chain TAG compared with long-chain TAG.
Previous studies demonstrated that, compared with long-chain TAG (LCT), dietary medium-chain TAG (MCT) could improve glucose tolerance in rats and humans. It has been well established that adiponectin acts to increase insulin sensitivity. The effects of dietary MCT on adiponectin serum concentration and mRNA levels in adipose tissue were studied in rats. Male Sprague-Dawley rats were fed a diet containing 20% MCT or LCT for 8 wk. After 6 wk of dietary treatment, an oral glucose tolerance test was performed. Rats fed the MCT diet had less body fat accumulation than those fed the LCT diet (P < 0.01). The cell diameter of the perirenal adipose tissue, one of the abdominal adipose tissues, was smaller (P < 0.01) in the MCT diet group. The serum adiponectin concentration was higher (P < 0.01) in the MCT diet group than in the LCT diet group. The adiponectin content in the perirenal adipose tissue was higher (P < 0.01) in the MCT diet group. The MCT-fed group had a higher adiponectin mRNA level in their perirenal adipose tissue (P < 0.05). The increase of the plasma glucose concentration after glucose administration (area under the curve) was smaller (P < 0.01) in the MCT diet group than in the LCT diet group. These findings suggest that dietary MCT, compared with LCT, results in a higher serum adiponectin level with transcriptional activation of the adiponectin gene in rats. We speculate that improved glucose tolerance in rats fed an MCT diet may be, at least in part, ascribed to this higher serum adiponectin level.
PMID: 17707987 [PubMed – indexed for MEDLINE]

My Comments: Probably due to the adiponectin elevation, the rats fed MCTs demonstrated better glucose tolerance and insulin sensitivity, and positive body composition changes compared to the LCT group. This is a profound benefit if repeatable in humans.

Summary

Although the American Heart Association and the World Health Organization would like to see Americans avoid saturated fats at all costs, this is truly outdated and misinformed thinking. Due to a greater understanding of nutrition and related biochemistry, the more up to date recommendations point towards saturated fats making up around 1/3 of our total fat intake. Aside from this point, it should be noted that coconut oil and MCT’s are metabolized entirely differently by the body than animal based saturated fats. Taken from an article written by Conrado S. Dayrit in the Philippine Journal Of Cardiology entitled “Coconut Oil: Atherogenic or Not?”:

According to the universally accepted Lipid-Heart Theory, high saturated fats causehypercholesterolemia and coronary heart disease. Coronary morbidity and mortality are said to be highest in the countries and peoples consuming the highest amounts of saturated fats. Coconut oil, with its saturated medium chain fats, has been especially condemned for this reason. The true facts are just the opposite. The countries consuming the highest amounts of coconut oil – the Polynesians, Indonesians, Sri Lankans, Indians, Filipinos have not only low serum cholesterol but also low coronary heart disease rates.
The reason why coconut oil cannot be atherogenic is basic. Coco oil consistspredominantly of 65% medium chain fatty acids (MCFA) and MCFAs are metabolized rapidly in the liver to energy and do not participate in the biosynthesis and transport of cholesterol. Coconut oil, in fact, tends to raise the HDL and lower the LDL:HDL ratio. Coco oil is not deposited in adipose tissues and therefore does not lead to obesity. It is primarily an energy supplier and as fast a supplier of energy as sugar. MCFAs therefore differ in their metabolism from all the long chain fatty acids, whether saturated or unsaturated.
The pathogenesis of atherosclerosis has recently taken a complete paradigm shift – from a simple deposition of cholesterol and cholesterol esters to an inflammatory condition where numerous genetically dependent factors – dyslipoproteinemias, dysfunctions of endothelial and other cells leading to invasions of the subendothelial region by macrophages, smoothmuscle cells, leukocytes and T cells – all interplay in a scenario still not fully understood.

If you decide to incorporate coconut oil into your diet, be sure to use unrefined (as opposed to the “refined for cooking”) coconut oil, it can be found at any health food store. As previously mentioned, degradation under heat is not an issue, so it is more versatile for cooking than unsaturated fats. I use it frequently for cooking eggs, grilling meat, salad dressings, or drizzling over steamed veggies. In looking at a small sample of the research, it appears that coconut oil could have a potential positive effect on numerous parameters of health and body composition. Much like DAG oil from Sexy Fats Part I, it’s certainly no miracle that will melt fat of at light speed and increase your lifespan by decades, but it just may be worth including as a portion of your daily saturated fat intake.

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