Sexy Fats – Part I: A Research Review of 1,3-Diacylglycerol
In 1999, Arthur Daniels Midland/Kao released a cooking oil by the name of Enova. Theoretically, due to different methods of metabolism less of the oil would be stored as fat compared to traditional cooking oils. Popularity was established immediately in Japan, but the U.S. hasn’t caught on to nearly the same extent. The question is, does it work? Do any legitimate benefits exist with regards to body composition, blood lipids, and the anti-obesity hormonal framework? Can it help us to lose body fat and improve overall health at the same time?
We’re going to look at the research and find out. First off, this basic overview of dietary fat metabolism will allow for a greater understanding of what the research is looking at. Taken from Kao Corp’s R&D page:
Fats ingested from food undergo digestive decomposition in the small intestine by fat-decomposing enzymes known as lipases. Fats are converted principally to 2-monoacylglycerol (2-MAG) and fatty acids and are absorbed into the surface of the small intestines. After absorption, those materials are resynthesized to triacylglycerol (TAG) in small intestinal epithelial cells and form lipoprotein particles termed chylomicron. When chylomicron passes through the lymph ducts and enters the blood, it is decomposed by lipoprotein lipases (LPL) present in capillary vessels of adipose tissue and other tissues. Fatty acids thus generated are incorporated in muscle and adipose tissue. Partially decomposed lipoprotein particles that remain are termed remnants. These remnants are absorbed primarily by the liver and metabolized.
When foods containing fat are ingested, the level of serum triacylglycerol rises temporarily. Recently, a symptom of sustained elevation of postprandial serum triacylglycerol has been reported and is termed “postprandial hyperlipidemia”. An emerging relationship has also been shown between the onset and progression of arteriosclerotic lesions and the elevation of remnant lipoproteins levels in the blood. Those remnant lipoproteins are intermediate metabolites created by metabolization of lipoproteins abundant in triacylglycerol.
Let’s take a look at some of the more recent studies; each one will be followed by my comments.
Suppressive effects of diacylglycerol oil on postprandial hyperlipidemia in insulin resistance and glucose intolerance.
The diacylglycerol (DAG), a commonly used as a cooking oil in Japan, results in a lower elevation of serum triglyceride (TG) after ingestion compared to triacylglycerol (TAG). Postprandial hyperlipidemia (PPHL) and an increase in remnant lipoproteins (RLP) levels are risk factors for CAD, and a close relationship between PPHL and type 2 diabetes and/or insulin resistance has been reported. To evaluate the effect of DAG on PPHL in insulin resistance and glucose intolerance, 11 subjects with a normal glucose tolerance (NGT) and 14 subjects with IGT received oral fat tolerance test (OFTT) twice. They ingested emulsified test oils prepared with either DAG or TAG. In the IGT subjects, after the DAG and TAG load, the serum concentrations of TG, RLP-TG, and RLP-cholesterol increased throughout the 4-h study. The responses of these variables above baseline after the DAG load were significantly smaller than those after the TAG load (p<0.05). In contrast, in the NGT subjects, changes in these parameters were much smaller than those observed for IGT subjects. The difference in the integrated responses for serum RLP-cholesterol concentration during OFTT between DAG and TAG in all subjects can be easily explained by the integrated response of insulin rather than glucose during oral glucose tolerance test (r=0.7, p<0.01). DAG was more effective in insulin resistant and hyperinsulinemic participants regardless of glucose intolerance, and may be beneficial in reducing the extent of CAD risk in such individuals. PMID: 17125771 [PubMed – as supplied by publisher]
My comments: Controlling postprandial hyperlipidemia is a very good thing for diabetics and those trying to lose body fat. Thumbs up on that.
Metabolism of diacylglycerol in humans.
Obesity resides upstream of the constituents of metabolic syndromes such as diabetes, hypertension, hyperlipidemia, and arteriosclerosis. Postprandial hyperlipidemia is also implicated in atherogenesis. Therefore, factors that influence the body adiposity and the magnitude of postprandial hyperlipidemia have been intensively investigated. Diacylglycerol (DAG) oil, which is defined to contain DAG 80% (w/w) or greater in the present presentation, is an edible oil with similar taste and usability compared with conventional edible oil rich in TAG. Safety of DAG has been widely evaluated and listed as a GRAS (Generally Recognized as Safe) substance by US FDA. The aim of this review was to summarize the metabolism and nutritional functions of DAG based on the data from scientific journals and conference publications. Effect of DAG ingestion on postprandial elevations of serum lipids was investigated in several dosages, food formula, and in subjects in various conditions. Postprandial triglyceride in serum and the chylomicron fraction are significantly smaller after DAG consumption compared with TAG with a similar fatty acid composition in healthy subjects, and was remarkably reduced in subjects with insulin resistance. Long-term DAG ingestion in controlled diet or free-living condition significantly decreased body adiposity and improved type II diabetic complications. A single dose DAG consumption significantly increased fat oxidation as compared to eucaloric TAG ingestion. DAG oil consumption might be beneficial in reducing the risk factors for lifestyle-related diseases such as obesity, visceral obesity, postprandial hyperlipidemia, insulin resistance, and atherosclerosis. PMID: 17392138 [PubMed – in process]
My Comments: Like the previous study, this one notes an enhanced effect for those with pre-existing insulin resistance symptoms. This study also demonstrates significantly increased fat oxidation compared to the same amount of a traditional oil (canola). Definitely a good thing.
Effects of dietary diacylglycerol on energy metabolism.
In the present study, we characterized diacylglycerol (DAG) oil in terms of energy metabolism by comparing oxygen consumption and respiratory quotient (RQ), as well as blood parameters, in rats after administration of emulsions containing either DAG or triacylglycerol (TAG) with similar fatty acid composition. Twelve male Wistar rats (250-280 g) were acclimatized, and then catheterized into the stomach, and held individually in Bollman restraining cages. After 24 hours fasting, each emulsion containing either DAG or TAG (10 g/kg body weight) was infused. Oxygen consumption and fat oxidation in the DAG group gradually increased after administration of the DAG emulsion and became significantly higher than those of the TAG group. RQ in both groups dropped after administration of emulsion, but the values of the DAG group were significantly lower than that of the TAG group. The postprandial serum triglyceride level was significantly increased from 60 minutes after administration in the TAG group, and 240 minutes in the DAG group, compared to the preprandial level. The serum triglyceride level tended to be lower in the DAG group than in the TAG group at 60 minutes and thereafter, and the statistical difference between the TAG and DAG groups was significant at 300 minutes after administration. These results suggest that DAG oil infusion might lead to higher energy expenditure and lipids oxidation compared to TAG oil with a similar fatty acid composition. PMID: 16941418 [PubMed – indexed for MEDLINE]
My Comments: This study shows not only higher lipid oxidation rates, but higher oxygen consumption in the DAG group. Higher energy expenditure without moving your lazy ass…definitely a bonus.
Effects of diacylglycerol oil on adiposity in obese children: initial communication.
Several studies have shown that diacylglycerol (DAG) oil may suppress accumulation of body fat in adults compared to triacylglycerol (TAG) oil. In this study, we investigated the effect of DAG oil as part of dietetic therapy in obese children. The participants were 11 male and female obese children who were under treatment at the outpatient clinic (four boys, seven girls, age: 7-17 years old). Daily-use cooking oil was changed to DAG oil, and the effects on abdominal fat areas, adipocytokines, and serum lipids were investigated. The total and subcutaneous fat areas significantly decreased in the 5th month after ingestion of DAG oil. Leptin was significantly lower than the initial level after ingestion of DAG oil. The ingestion of DAG oil decreased both the abdominal fat area and leptin in obese children, suggesting that DAG oil prevents obesity in children as well as in adults. PMID: 16886587 [PubMed – indexed for MEDLINE]
My Comments: This study was interesting as it looked at longer term effects of DAG oil, as the previous studies were looking solely at an acute response. The decrease in leptin is beneficial; as it suggests an increase in leptin sensitivity (typically obese people will have higher than optimal leptin levels due to impaired leptin signaling). This also showed an increase in abdominal fat loss, and it’s good for the kids!
Dietary diacylglycerol in a typical meal suppresses postprandial increases in serum lipid levels compared with dietary triacylglycerol.
OBJECTIVE: The objective of the present study was to verify the effect of a dietary oil, consisting mainly of diacylglycerol (DAG) oil, in a typical meal on postprandial changes in serum triacylglycerol (TAG) and remnant-like particle cholesterol (RLP-C) compared with dietary triacylglycerol (TAG) oil. METHODS: In a double-blind, randomized, crossover design, 43 healthy Japanese men and women ingested test meals (2093 kJ of energy, 30 g of protein, 19 g of lipids, and 51 g of carbohydrates) containing 10 g of DAG oil (DAG meal) or TAG oil (TAG meal). Blood samples were collected in a fasting state (0 h) and at 2, 3, 4, and 6 h after ingestion of the meal. RESULTS: Postprandial TAG, RLP-C, and chylomicron TAG concentrations were significantly lower after the DAG meal compared with the TAG meal. In 29 subjects with fasting serum TAG levels of at least 1.13 mmol/L (100 mg/dL), differences in postprandial serum changes between meal types were even more remarkable and the incremental areas under the response curve (0 to 6 h) for serum TAG and RLP-C concentrations after the DAG meal were significantly smaller than those after the TAG meal. CONCLUSIONS: These results suggest that DAG oil in the daily diet is useful for the prevention of postprandial hyperlipidemia and related disorders. PMID: 16459225 [PubMed – indexed for MEDLINE]
My Comments: A nice human study with realistic dosages, combined with realistic meals (about 2tsp of DAG oil with a meal). Again, demonstrating the beneficial effect on PPHL.
Diacylglycerol: efficacy and mechanism of action of an anti-obesity agent.
Obesity is at the forefront of global health issues and directly contributes to many chronic illnesses. Several dietary components show promise in the treatment of obesity, one of which is oil rich in diacylglycerols (DAGs). Present objectives are to examine scientific knowledge concerning DAG to assess evidence supporting the effects on substrate oxidation rates, body weight and fat mass, and blood lipids, and to assess safety, as well as elucidate potential mechanisms of action. DAG can be synthesized by an enzymatic process to produce mainly 1,3-isoform DAG. This 1,3-DAG oil is believed to have the ability to increase beta-oxidation, to enhance body weight loss, to suppress body fat accumulation, and to lower serum triacylglycerol levels postprandially. While certain animal and human studies indicate that consumption of 1,3-DAG has positive physiological effects, others report no effect. The mechanisms of action of DAG are suggested to decrease the resynthesis of chylomicrons as well as shunting them directly to the liver through the portal vein, where they are oxidized. This increased fat oxidation may influence control of food intake by increasing satiety.Further study into the precise mechanism is required to understand its effects. Safety studies show no risks in consuming a diet rich in DAG oil. Overall, consumption of oils with higher amounts of DAG, specifically 1,3-DAG, may be useful in the battle against obesity. PMID: 16339116 [PubMed – indexed for MEDLINE]
My Comments: This abstract doesn’t give us any results, but points towards the mechanism of action. This brings up a very interesting point by suggesting a possible increase in satiety, which we all know can make or break compliance to a diet. The ability to feel an increased sense of fullness after a meal without increasing calories? Sounds pretty good to me.
Consumption of diacylglycerol oil as part of a reduced-energy diet enhances loss of body weight and fat in comparison with consumption of a triacylglycerol control oil.
BACKGROUND: Diacylglycerol is a natural component of edible oils that has metabolic characteristics that are distinct from those of triacylglycerol. OBJECTIVE: We assessed the efficacy of an oil containing mainly 1,3-diacylglycerol in reducing body weight and fat mass when incorporated into a reduced-energy diet. DESIGN: The study was a randomized, double-blind, parallel intervention trial that was conducted at an outpatient clinical research center. The subjects (n = 131) were overweight or obese men (waist circumference > or = 90 cm) and women (waist circumference > or = 87 cm). Food products (muffins, crackers, soup, cookies, and granola bars) containing diacylglycerol or triacylglycerol oil and having the same fatty acid composition were incorporated into a reduced-energy diet (2100-3350-kJ/d deficit) for 24 wk. Percentages of change in body weight, fat mass, and intraabdominal fat area were assessed. RESULTS: In an intention-to-treat analysis, body weight and fat mass decreased significantly more in the diacylglycerol group than in the triacylglycerol group (P = 0.025 and 0.037, respectively). By the end of the trial, mean body weight had decreased 3.6% and 2.5% in the diacylglycerol and triacylglycerol groups, respectively. Fat mass decreased 8.3% and 5.6% in the diacylglycerol and triacylglycerol groups, respectively. CONCLUSION: Foods containing diacylglycerol oil promoted weight loss and body fat reduction and may be useful as an adjunct to diet therapy in the management of obesity.
My Comments: This is an older study (2002), but an important one. The DAG group showed a much higher rate of body fat loss than the TAG group.
Finally, a brand new study ahead of publication
Dietary 1,3-diacylglycerol protects against diet-induced obesity and insulin resistance. To investigate the effect of dietary 1,3-diacylglycerol (DAG) on the development of insulin resistance (IR) and obesity, brown adipose tissue-deficient mice, a model of high-fat diet-induced IR and obesity, were fed Western-type diets (WTD) containing either DAG oil (n = 8) or standard triacylglycerol (TAG) oil (n = 9) for 15 weeks, beginning at 8 weeks of age. Although brown adipose tissue-deficient mice became obese on both TAG- and DAG-enriched WTD (TAG-WTD and DAG-WTD), the mice eating DAG-WTD gained less weight and had less body fat accumulation. The results of glucose tolerance tests conducted after 5 weeks of each WTD were not different. However, after 10 weeks of each WTD, impaired glucose tolerance developed in the TAG-WTD group but was prevented by DAG-WTD.Exploratory analyses of gene expression suggested that consumption of DAG-WTD was associated with reduced phosphoenolpyruvate carboxykinase gene expression in liver and increased expression of the genes for peroxisome proliferator-activated receptor alpha, lipoprotein lipase, and uncoupling proteins 2 and 3 in skeletal muscle. There were no effects of the DAG-WTD on fasting and postprandial plasma triglyceride (TG) levels, hepatic TG content, or the rate of secretion of TG from the liver. These findings suggest that diets enriched in 1,3-DAG oil may reduce WTD-induced IR and body fat accumulation by suppressing gluconeogenesis in liver and stimulating fat oxidation in skeletal muscle. PMID: 17950109 [PubMed – in process]
My Comments: Mice in this study were all brown adipose tissue (BAT) deficient, which significantly effects metabolism of dietary fats. They were able to show an increased expression of PPAR-a, LPL, and UCP 2 and UCP3, all very good things with regards to improving body composition. This also showed a suppression of hepatic gluconeogenesis and increased fat oxidation in skeletal muscle. All very good things.
Summary and Application
Research demonstrates many beneficial attributes to consumption of diacylglycerol. Is it an effortless ticket to super health and 4% body fat? Of course not, but it can certainly help the process when combined with a good nutrition plan and well designed workout. If you decide to incorporate DAG oil in your diet, your best bet is using it to replace an equal amount of less functional fats as opposed to just adding extra DAG oil on top of your current fat intake. Use the oil for consumption at room temp, or low to medium heat cooking. Avoid high heat cooking, as it can denature the oil. It has a very neutral taste that allows for high versatility. You can dress salads or steamed veggies with it, add it to shakes, or just take it right off the spoon. It may be a perfect fat to include in a pre-workout meal as well (especially when using low-carb or CKD diets), for various reasons that I will avoid getting into just yet. Stay tuned for Sexy Fats, Part II…