METHODS: We systemically searched PubMed, CENTRAL and Scopus up to June 2018. We searched for published interventional studies on biomarkers of glucose metabolism (defined as fasting glucose, fasting insulin, HOMA, 2-hour post prandial glucose and HbA1C) that compared palm oil- or palm olein-rich diets with other edible vegetable oils (such as olive oil, canola oil and soybean oil). Two reviewers independently extracted data and assessed study risks of bias. Mean differences of outcomes were pooled for the meta-analysis.
RESULTS: We identified 1921 potentially eligible articles with only eight included studies. Seven randomised cross-over trials and one parallel trial were included. Study population were among young to middle-aged, healthy, non-diabetic, and normal weight participants. Intervention duration ranged from three to seven weeks, and fat substitution ranged from 15% to 20% energy. There were insignificant differences in fasting glucose when compared to partially hydrogenated soybean oil [-0.15mmol/L (-0.46,0.16) P = 0.33, I2 = 48%], soybean oil [0.05mmol/L (-0.09,0.18) P = 0.49, I2 = 0%] and olive oil [0.04mmol/L (-0.09,0.17) P = 0.76, I2 = 0%]. Insignificant effects were also seen on fasting insulin when compared to partially hydrogenated soybean oil [1.72pmol/L (-11.39,14.84) P = 0.80, I2 = 12%] and olive oil diet [-0.14pmol/L (-4.87,4.59) P = 0.95, I2 = 0%].
CONCLUSION: Current evidence on the effects of palm oil consumption on biomarkers of glucose metabolism is poor and limited to only healthy participants. We conclude that little or no additional benefit will be obtained by replacing palm oil with other oils rich in mono or polyunsaturated fatty acids for changes in glucose metabolism.
RESULTS: Increases in homogenization pressure and emulsifier concentration were observed to have significant (P soybean oil LNDCs prepared using 15 g kg-1 and 10 g kg-1 DATEM emulsifier, respectively, were determined to be the most stable (as observed throughout a 15-day storage period at ambient temperature of 28 ± 2 °C), with properties closest to those of a commercial LNDC. When added to black coffee, both LNDCs displayed a good whitening effect by increasing the L* value from 26.73 ± 0.16 (black coffee) to ≥40.82 ± 0.56 (black coffee + LNDCs). Sensory evaluation showed that there were no significant (P > 0.05) differences between the prepared and commercial LNDCs in terms of their color, appearance, and overall acceptability.
CONCLUSION: Shelf-stable LNDCs with qualities comparable to commercial LNDC were successfully fabricated. Valuable insights into the effects of homogenization pressure, oil type, and emulsifier concentration, as well as functionality and consumer acceptance of the LNDCs when added into black coffee, were obtained. © 2020 Society of Chemical Industry.