Written by Joyce Smith, BS. Study evidence suggests that daily consumption of apples rich in fiber and proanthocyanidins provides beneficial hypocholesterolemic and vascular effects for mildly hypercholesterolemic individuals.
Plant foods, including fruits, when consumed regularly have been associated with reduced risk of cardiovascular disease (CVD) 1. The worldwide popularity of apples (12% of all consumed fruits) and their alleged health benefits have led to epidemiological studies suggesting that frequent apple consumption is inversely associated with acute coronary syndrome, total CVD mortality, and all-cause mortality 2,3. These potential health benefits may be attributed to apples’ rich source of polyphenols (typically 110 mg/100 gm) and fiber (233gm/100gm). Included are the flavonols catechin and proanthocyanidins (PAs), the most prevalent (71–90%) which have been shown in studies to lower serum cholesterol, raise HDL cholesterol, inhibit LDL oxidation, activate endothelial nitric oxide synthase, prevent platelet aggregation, and block inflammatory responses in atherosclerosis 4,5. While apple consumption has been associated with hypolipidemic effects, with reductions in total cholesterol (TC) and LDL cholesterol in animal models, these studies cannot be directly extrapolated to humans 6. Pectin, the main soluble fiber in apples, has been shown to promote a more rapid transit time and gastric emptying and provide a beneficial effect on lipid and glucose absorption. Apple polyphenols and fiber may also beneficially modulate the gut microbiota composition and activity. 6
The present study 7 examined whether eating two apples a day would improve cardiovascular health and reduce cholesterol. This was a randomized, controlled, crossover trial of 41 mildly cholesterolemic volunteers (17 men, 23 women), aged 29-69 years, with BMI (19-33 kg/m 2) and total cholesterol of less than 5.2 mmol/L. Researchers allocated volunteers into two groups to receive daily either two whole apples (green variety “Renetta Canada”) or an apple sugar-matched control beverage (CB) for 8 weeks. After a 4-week washout, the two groups switched interventions for an additional 8 weeks. Before and after each intervention period, fasting blood was collected to measure serum lipids, glucose, insulin, bile acids, anthropometrics (height, weight, body fat, and waist circumference), microvascular reactivity and arterial stiffness.
Compared to the CB, whole apple (WA) consumption improved cardiovascular health in the following ways:
- Decreased serum total cholesterol (WA: 5.89 mmol/L; CB: 6.11 mmol/L; P = 0.006),
- Decreased LDL cholesterol (WA: 3.72 mmol/L; CB: 3.86 mmol/L; P = 0.031),
- Decreased triglycerides (WA: 1.17 mmol/L; CB: 1.30 mmol/L; P = 0.021),
- Decreased intercellular cell adhesion molecule-1 (WA: 153.9 ng/mL; CB:159.4 ng/mL; P = 0.028),
- Increased serum uric acid (WA: 341.4 μmol/L; CB: 330 μmol/L; P = 0.020).
The response to endothelium-dependent microvascular vasodilation was greater following apple consumption [WA: 853 perfusion units (PU), CB: 760 PU; P = 0.037] than CB consumption. However, apple consumption had no effect on blood pressure or other CVD markers.
Study limitations included the fact that the study was small in size, of short duration, and was non-blinded. However, evidence suggests that eating two apples a day provides a slight reduction in cholesterol compared to the apple drink. While it’s not clear whether this small reduction would lead to a decrease in heart disease or stroke, even small benefits such as eating fruits every day would likely accumulate over a lifetime of healthy eating.
Source: Koutsos, Athanasios, Samantha Riccadonna, Maria M. Ulaszewska, Pietro Franceschi, Kajetan Trošt, Amanda Galvin, Tanya Braune et al. “Two apples a day lower serum cholesterol and improve cardiometabolic biomarkers in mildly hypercholesterolemic adults: a randomized, controlled, crossover trial.” The American journal of clinical nutrition 111, no. 2 (2020): 307-318.
©The Author(s) 2019. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/)
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Posted March 30, 2020
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
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- Hansen L, Dragsted LO, Olsen A, et al. Fruit and vegetable intake and risk of acute coronary syndrome. British journal of nutrition. 2010;104(2):248-255.
- Hodgson JM, Prince RL, Woodman RJ, et al. Apple intake is inversely associated with all-cause and disease-specific mortality in elderly women. British Journal of Nutrition. 2016;115(5):860-867.
- Rasmussen SE, Frederiksen H, Struntze Krogholm K, Poulsen L. Dietary proanthocyanidins: occurrence, dietary intake, bioavailability, and protection against cardiovascular disease. Molecular nutrition & food research. 2005;49(2):159-174.
- Hollands WJ, Tapp H, Defernez M, et al. Lack of acute or chronic effects of epicatechin-rich and procyanidin-rich apple extracts on blood pressure and cardiometabolic biomarkers in adults with moderately elevated blood pressure: a randomized, placebo-controlled crossover trial. The American journal of clinical nutrition. 2018;108(5):1006-1014.
- Koutsos A, Tuohy KM, Lovegrove JA. Apples and cardiovascular health—is the gut microbiota a core consideration? Nutrients. 2015;7(6):3959-3998.
- Koutsos A, Riccadonna S, Ulaszewska MM, et al. Two apples a day lower serum cholesterol and improve cardiometabolic biomarkers in mildly hypercholesterolemic adults: a randomized, controlled, crossover trial. The American journal of clinical nutrition. 2020;111(2):307-318.
