Heart failure is a form of cardiovascular disease that is characterised by an inability to efficiently pump blood around the body. Heart failure risk can be predicted by measuring the left ventricular systolic dysfunction (LVSD), which is asymptomless in most people. Evidence suggests that food and dietary patterns are both able to influence the dysfunction of the left ventricle which can lead to heart failure. This association is important to fully understand because it is estimated that in the US ≈300,000 deaths occur each year because of heart failure and currently the incidence and prevalence of heart failure is increasing. The link between diet and heart failure might involve the development of the metabolic syndrome or diabetes. Studies have shown that a 1% increase in haemoglobin A1c (HbA1C; glycated haemoglobin) increases heart failure risk by 15%.
Research published in the American Journal of Clinical Nutrition in 20091 used a cross-sectional design study of 4601 participants to investigate the association between left ventricular mass and function with dietary patterns. The study participants were between the ages of 45 to 84 years and were free of clinically diagnosed cardiovascular disease. The researchers used a reduced rank regression technique to identify dietary pattern in the subjects that were associated with metabolic syndrome. Metabolic syndrome is characterised by insulin resistance, weight gain and abdominal obesity, and is a risk factor for type 2 diabetes. There was a positive association between high glycaemic index foods, high-fat meals, cheeses and processed foods and risk factors for metabolic syndrome, and a negative association with low intakes of vegetables, soy, fruit, green tea, black tea, low-fat dairy desserts, seed, nuts and fish.
Analysis using a multivariate model showed that for every 1-unit increase in the reduced rank regression dietary pattern score, there was a 0.32-g.m2 increase in left ventricular mass/body surface area, a 0.43-mL/m2 decrease in stroke volume to body surface area and a 0.21% decrease in left ventricular ejection fraction. However, the associations between dietary patterns and left ventricular mass and stroke volume were attenuated and were not significant when statistical adjustments were made to account for metabolic syndrome components. These results would therefore tend to suggest that the dietary patterns mediate their affect on left ventricular function by altering risk for metabolic syndrome. This is in support of previous findings that showed that left ventricular mass increased in a step wise manner as metabolic syndrome components increased. This is more evidence for the link between diet and heart health that falls outside of the outdated realms of the cholesterol theory.
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