Most conventional cooking oil is in the form of TAG, although DAG is a natural component found in edible oils and is currently used in small quantities in foods as an emulsifier.
Typically, TAG is broken down in the gut and then resynthesised by enzymes to be used as energy, while the excess is accumulated and stored in the body, causing increased body fat, fatty liver, and atherosclerosis, and leading to coronary heart disease, hypertension, and other chronic diseases.
People with abnormal glucose and lipid metabolism are often accompanied by long-term overweight or obesity. Being overweight for an extended period makes it more difficult and takes longer to lose weight.
“In the context of the current pandemic-level global rates of obesity, glucose and lipid metabolic diseases, it is highly desirable to develop effective and inexpensive complementary dietary nutraceuticals to manage obesity, blood sugar, and lipids,” researchers from Southeast University in China said.
Unlike TAG, DAG is not incorporated into chylomicrons and are released into the portal circulation.
“If DAG oil controls weight and improves lipid metabolism, then DAG oil can be used as daily cooking oil to combat obesity-related chronic diseases. We hope to provide new methods and ideas for controlling and preventing metabolic-related diseases when possible,” they published in Journal of Functional Foods.
So far, evidence on DAG oil in reducing body weight and abdominal fat is unclear, some studies have found that DAG oil effectively reduces body weight in healthy and diabetic individuals compared with TAG oil, while some did not find any beneficial impact of DAG oil on body weight.
In total, 11 randomised controlled trials were selected for this study. Researchers assessed the effects of DAG oil on body weight, body mass index, waist circumference, serum TAG, and blood glucose in both healthy subjects as well as those with glucose and lipid metabolism-related diseases.
The intervention group consumed DAG oils, while the control group used TAG oils.
The studies were published between 2000 to 2017, across Japan, China and America.
The duration of the studies was between two weeks to one year.
DAG oil supplementation
The findings revealed that DAG oil resulted in a significant reduction of body weight, body mass index, waist circumference, as well as serum TAG in people with glucose and lipid metabolism diseases.
However in the healthy group, only a significant effect was seen in body weight and body mass index.
People with glucose and lipid metabolism diseases are often associated with high visceral fat, large waist circumference and high serum TAG levels.
“DAG oil can reduce visceral fat content significantly, which may explain why DAG oil plays a more significant role in reducing waist circumference and serum TAG in people with diseases related to glucose and lipid metabolism (instead of healthy people),” researchers said.
They suggested that more weight reduction could be achieved when TAG oil is replaced with DAG oil for this group of people, adding the longer the DAG oil intake, the better the weight loss effect.
“As part of a healthy diet, the consumption of DAG oil should be encouraged to help maintain normal blood lipid levels and reduce the risk of heart disease. Healthy dietary patterns containing DAG oil will be a new choice for consumers in the future.”
In terms of blood glucose, there are no significant effect in both groups.
One of the limitations of this meta-analysis was not assessing the dose–response relationship, since different studies had different doses of DAG oil.
In the US, the Food and Drug Administration (FDA) has designated DAG oil as a “generally regarded as safe” (GRAS) substance, while the European Food Safety Authority (EFSA) and the People's Republic of China's National Health Commission have approved a decision on DAG oil, recognising it as a novel food and allowing it to be put on the market.
Source: Journal of Functional Foods
“The effect of DAG oil replacing TAG oil on weight control and glycolipid metabolism: A meta-analysis of randomized controlled trials”
Authors: Wenqing Ma, et al.