Eating a plant-based diet is a simple and easy way to look after your heart. Plant-based foods such as fruit, vegetables, legumes, whole grains, nuts and seeds are lower in saturated fat and many are a source of fibre. A diet low in saturated fat is important for maintaining a healthy cholesterol level as part of a healthy balanced diet and lifestyle.
Plant foods such as almonds, oats and soya have a specific cholesterol lowering effect.
In the US the FDA has approved a heart health claim for both soya protein and nuts (almonds, hazelnuts). Soya foods can lower cholesterol in a number of ways. Nuts mainly contain unsaturated fats and very little saturated fats.
In Europe the blood cholesterol lowering effect of beta-glucans from oat and barley has also been recognized.
The most important behavioral risk factors are an unhealthy diet, physical inactivity and tobacco use. Together these three risk factors are responsible for about 80% of CHD and stroke.
One of the most important modifiable risk factors is raised blood cholesterol. The World Health Organisation (WHO) estimates that over 60% of CHD and 40% of stroke in developed countries is due to total blood cholesterol levels in excess of the theoretical minimum, 3.8mmol/L. People with abnormal blood lipids have a three-fold greater risk of heart attack compared to those with normal levels. The WHO calculated that each 1% reduction in Low Density Lipoprotein-cholesterol (LDL-cholesterol) in the population, could lead to a 2%–4% reduction in CVD.
Plant-based eating patterns and plant-derived foods have a number of characteristics that may contribute to their role in heart health. Eating more fruit, vegetables, legumes, whole grains, nuts and seeds is a simple and easy way to support a healthy heart.
In real life, soya foods displace other foods in the diet: soya drink replaces dairy milk, soya dessert replaces dairy-based desserts, tofu mince replaces meat … . As such, swapping foods that are high in saturated fat, such as meat and dairy, with soya foods that contain polyunsaturated fats, reduces the amount of saturated fat and cholesterol in the diet. It’s been estimated that in a typical western diet, the displacement of meat and dairy foods by soya is likely to lower LDL-cholesterol by a further 3.6-6%.
Overall soya can therefore reduce LDL-cholesterol by between 4.3-10.3%. This has clinical significance, as it’s been suggested by the WHO that each 1% reduction in LDL-cholesterol in the population could lead to a 2 to 4% reduction in cardiovascular diseases.
Figure: effects of soya on LDL
Findings from clinical studies show that supplementing the diet with soya reduces systolic and diastolic blood pressure in hypertensive individuals. A meta-analyses of 11 studies found that soya isoflavones lowered blood pressure in hypertensive subjects, but not in normotensive subjects.
Soya isoflavones appear to have a beneficial effect on the endothelium (the inner lining of cells in blood vessels). Isoflavones may also increase the elasticity of the aorta and so can improve vascular function.
Jenkins DJ, Mirrahimi A, Srichaikul K et al. Soy Protein Reduces Serum Cholesterol by Both Intrinsic and Food Displacement Mechanisms. J Nutr 2010.
Anderson JW, Bush HM. Soy protein effects on serum lipoproteins: a quality assessment and meta-analysis of randomized, controlled studies. J Am Coll Nutr 2011;30:79-91.
Liu XX, Li SH, Chen JZ et al. Effect of soy isoflavones on blood pressure: A meta-analysis of randomized controlled trials. Nutr Metab Cardiovasc Dis 2011.
He J, Gu D, Wu X et al. Effect of soybean protein on blood pressure: a randomized, controlled trial. Ann Intern Med 2005;143:1-9.
Taku K, Lin N, Cai D et al. Effects of soy isoflavone extract supplements on blood pressure in adult humans: systematic review and meta-analysis of randomized placebo-controlled trials. J Hypertens 2010.