Health effects of various edible vegetable oil: An umbrella review

Vegetable oils, derived from diverse sources such as seeds, nuts and some fruits play a significant role in dietary health. However, the current evidence on the health effects of different types of vegetable oil consumption remains controversial. This umbrella review aims to synthesize evidence from systematic reviews and meta-analyses to assess the health outcomes associated with various vegetable oils. A comprehensive literature search was performed up to July 31 2023 on twelve databases for studies examining association of different vegetable oils with health outcomes in adults. Data was extracted independently by two authors, with evidence strength assessed using the GRADE criteria. A total of 48 studies including 206 meta-analyses were included. Moderate to very low certainty evidence showed that monounsaturated and polyunsaturated fatty acids such as canola oil, virgin olive oil and rice bran oil are beneficial in reducing serum total cholesterol and low-density lipoprotein levels. Conversely, low to very low certainty evidence suggest that oils high in saturated fats such as coconut oil and palm oil increase total cholesterol and low-density lipoprotein levels but also raised high-density lipoprotein levels. Very low certainty evidence showed the consumption of olive oil, sesame oil and coconut oil could improve blood sugar control. Low certainty evidence showed olive oil consumption reduced the risk of breast, digestive and other cancers. Moderate to very low certainty evidence suggested that canola oil and sesame oil consumption reduced body weight. The consumption of vegetable oil appears to offer different health benefits, with summary estimates indicating beneficial effects on reducing lipid levels especially with monounsaturated and polyunsaturated rich oils when consumed in recommended amounts. Future research should focus on long-term studies and comprehensive dietary assessments to better understand the health impacts of vegetable oils, providing a basis for informed dietary recommendations. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021239210.