An assessment of the economic and heart health benefits of replacing saturated fat in the diet with monounsaturates in the form of rapeseed (canola) oil

Abstract

Summary There is a well-established requirement for the UK population to reduce the saturates content of its diet from around 13.3% energy (E) intake to 10% E intake (including alcohol) and to improve fat quality by increasing monounsaturated fatty acid (MUFA) intake. Canola (rapeseed) oil is one of the richest sources of dietary MUFAs and is a good source of the omega-3 polyunsaturated fatty acid (PUFA) alpha-linolenic acid. Recent advances using conventional plant breeding have led to the development of high-oleic canola, which has an increased level of MUFA and greater oxidative stability, making it suitable for a wide range of culinary purposes including frying. Around 7% of dietary saturated fatty acid (SFA) intake in adults derives from potatoes (fried potatoes and chips) and savoury snacks, with the value increasing to 13%–15% SFA in 4–18-year-olds. Traditionally, frying oils have been high in saturates content and their replacement with lower SFA alternatives provides the opportunity for food manufactures to lower SFA content of food with minimal consumer intervention. It has been estimated that at least half of the SFA in this category of foods can be replaced. In this review of literature, ten intervention studies were identified, where SFAs and/or carbohydrates were replaced by rapeseed oil, and the effect on blood lipids were reported. Results from these studies were pooled using standard meta-analysis methods. The standard mean differences in total cholesterol (Total-C) and low-density lipoprotein cholesterol (LDL-C) were 0.86 mmol/l [95% confidence interval (CI): −1.05 to −0.66] (ten studies) and 0.87 mmol/l (95% CI: −1.07 to −0.66) (nine studies), respectively, both significant (P 0.1). Using the pooled data, it can be calculated that each gram of SFA intake reduction was associated with reductions in both Total-C and LDL-C of 0.03 mmol/l, while each gram increase in either MUFA or PUFA reduced Total-C by 0.05 and 0.09, respectively, and LDL-C by 0.04 mmol/l and 0.08 mmol/l, respectively. It was also calculated that each 10 g increase in MUFA or rapeseed oil intake was associated with a reduction in Total-C of 9.8% and 5.8%, respectively. In 2006, annual direct healthcare costs associated with coronary heart disease were estimated at £3.2 billion and the overall cost to the UK economy was nearly £9.0 billion. Assuming 3.5 g total fat (typically 30% E SFA) is replaced by 3.5 g rapeseed oil, then it can be predicted that Total-C will be reduced by 1.9%, equivalent to an annual reduction of £61 million direct health costs and £171 million total costs.