Blackmores Institute

Examining forty healthy, mildly hypercholesterolemic volunteers, researchers randomised them into two groups to receive daily, either two whole apples or a sugar-matched apple control beverage. 
 
 They found that consuming two whole apples daily decreased serum total cholesterol (TC), low density lipoprotein cholesterol (LDL), triacylglycerols and plasma intercellular cell adhesion molecule-1 (ICAM-1) with no detrimental effect on high density lipoprotein (HDL) cholesterol concentrations compared to the control.
 
 “The potential ability of apples to reduce serum TC has been attributed mainly to the fibre fraction, pectin in particular; however, polyphenols may also play an important role. Pure apple polyphenols at daily doses between 600 and 1500 mg decreased TC and LDL cholesterol. In contrast, a cloudy apple juice (803 mg polyphenols) had no effects on blood lipids. A total of 990 mg polyphenols (854 mg oligomeric proanthocyanidins [PAs]) per day was provided by two Renetta Canada apples in our study, which supports the hypothesis that polyphenols play a role in cholesterol lowering,” the authors explained.
 
 According to the study, apples are an excellent source of polyphenols (typically 110mg/100g) and fibre (2-3G/100g) which may be responsible for the potential health effects attributed to apples.
 
 “Apple polyphenols include flavanols [catechin and proanthocyanidins] as the major class (71–90%), followed by hydroxycinnamates (4–18%), flavonols (1–11%), dihydrochalcones (2–6%), and anthocyanins (1–3%) which are found only in red apples.
 
 “PAs and flavanol monomers, as extracts or within a food, have been shown to lower serum cholesterol, raise HDL cholesterol, inhibit LDL oxidation, activate endothelial nitric oxide synthase, prevent platelet aggregation, and block inflammatory responses in atherosclerosis, although data from human intervention studies are limited and sometimes contradictory,” the authors said.
 
 “In this eight-week dietary intervention study, we examined the hypothesis that the supplementation of the habitual diet of 40 healthy mildly hypercholesterolemic subjects with two fresh whole apples (Renetta Canada) daily would result in TC reduction and beneficial effects on vascular function and other markers of CVD, compared with a sugar-matched apple control beverage. Renetta Canada is an apple variety rich in PAs and dihydrochalcones and was previously shown to possess beneficial effects on gut microbiota composition and activity in vitro.”
 
 “Our findings show clear cause and effect between the inclusion of two apples into normal diets and improved cardiovascular disease risk factors by reducing TC, LDL cholesterol and ICAM-1 and increasing microvascular vasodilation in healthy subjects with mildly raised serum cholesterol concentrations,” the authors concluded.
 
 Source:
 Am J Clin Nutri. 2019. DOI: 10.1093/ajcn/nqz282.

It may be time to update the old adage of ‘an apple a day’ with a new randomised controlled study finding that consuming two apples a day had beneficial hypocholesterolaemic and vascular effects in hypercholesterolaemic individuals.

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