Health effects. No qSRs are available on the role of fats and oils as a food group and health outcomes (Høyer et al., 2021; Rosqvist & Niinistö, 2023).
As discussed in the background review by Rosqvist and Niinistö, the degree of saturation is the primary mediator in terms of the health effects of dietary fats and oils together with different contents of bioactive components and degree of processing (Rosqvist & Niinistö, 2023). Replacing animal-based saturated fats (mainly butter) with plant-based fats (unsaturated oils) may reduce the risk of cardiovascular diseases and mortality. Regarding specific oils, the evidence mostly concerns olive oil, which has been favourably associated with cardiovascular disease, type 2 diabetes, certain types of cancer as well as all-cause mortality. Rapeseed oil is also associated with lower LDL-cholesterol compared with sources of saturated fatty acids and other types of oil in RCTs, while palm oil and coconut oil increase LDL-cholesterol compared with oils rich in MUFA and PUFA (Rosqvist & Niinistö). The average daily intake of 25 g/10MJ of rapeseed oil and some other oils would secure the recommended intake of essential fatty acids (Retterstøl & Rosqvist, 2023; Rosqvist & Niinistö, 2023). Rapeseed oil is a preferable source of added fat due to its nutritional profile.
For cardioprotective effects, vegetable oils rich in unsaturated fatty acids and margarines produced therefrom should be preferred over butter and butter-mixes, hard margarines, and tropical oils (palm, palm kernel, shea, and coconut oil) (Rosqvist & Niinistö, 2023).
Environmental impacts. The high production and consumption of animal-based fats contribute to GHGE, reduced biodiversity, and loss of nature (Harwatt et al., 2023; Meltzer et al., 2023; Trolle et al., 2023). Palm oil is a major driver of deforestation and has the highest carbon and biodiversity impacts of all vegetable oils, followed by soybean oil (Bajzelj et al., 2021). Among the main fat sources, sunflower and rapeseed oil have the lowest GHGE. Land and water use are highest for olive oil and sunflower oil (Harwatt et al., 2023). When oil crops are grown in intensive large-scale cropping systems with low diversity, they have a negative impact on biodiversity. Rapeseed and sunflower can contribute with variety to cereal dominated crop rotations and thereby reduce the need for chemical plant protection, making them beneficial in Nordic agricultural landscapes. In addition, flowering crops support pollinators (Harwatt et al., 2023; Meltzer et al., 2023; Trolle et al., 2023).