The circulatory system isn’t usually the first thing that comes to mind in the area of heart health. The hot topics are usually cholesterol and blood pressure; but, the circulatory system is an intricate and systemic system often overlooked. Wikipedia defines it as “an organ system that passes nutrients, such as amino acids and electrolytes; gases; hormones; blood cells, etc., to and from cells in the body to fight off disease, and stabilize the body temperate and pH to maintain homeostasis.” The circulatory system is composed of two systems transporting two types of fluids, i.e., blood and lymph: the cardiovascular system, which includes blood, the heart and blood vessels; and the lymphatic system—lymph, lymph nodes and lymph vessels. Together, they ensure blood flow throughout the body.
Its main components are the heart, arteries, capillaries and veins. Arteries are blood vessels carrying blood away from the heart, while veins carry blood to the heart. Capillaries are tiny vessels connecting arteries to veins. These passage ways are extremely small, and blockage or narrowing of these areas can cause serious problems.
Endothelial cells line the entire circulatory system. They are a key player in its performance, including vasoconstriction (constriction of blood vessels) and vasodilation (the widening of blood vessels), both involved in controlling blood pressure; blood clotting— thrombosis and fibrinolysis; and atherosclerosis, a condition in which the build-up of fatty materials cause the artery wall to thicken. Endothelial dysfunction is a precursor to atherosclerosis and vascular diseases such as coronary heart disease (CHD) or hypertension.
Dietary intervention, supplementation and numerous nutritional compounds can preclude the breakdown of the circulatory system by promoting vascular health, functional blood flow and more.
Back to Basics
As with most things, the beginning is usually a good place to start; in this case, the starting point—diet modification (augmenting or omitting)—has proven its worth. The U.S. Department of Agriculture (USDA) reported on several studies pointing to oat’s ability to promote healthy circulation. In 2006, researchers at Tufts University found one of the major polyphenols of oats—avenanthramide-c—inhibited vascular smooth muscle cells (SMC), an important process in the initiation and development of atherosclerosis.1 The inhibitory effect warranted oat’s potential health benefits in the prevention of CHD beyond its known effect of lowering blood cholesterol. Again in 2008, Tufts researchers discovered oat’s talent, via its avenanthramides, for decreasing the expression of endothelial proinflammatory cytokines, which is vital to circulatory health, as inflammation in the arterial walls is a precursor to atherosclerosis.2
Another dietary addition that keeps the blood moving is walnuts. Yale University researchers randomized 24 subjects with type 2 diabetes to a diet including 56 g/d of walnuts or a diet without walnuts for eight weeks.3 This was the only dietary intervention and then the two groups swapped diets. After the walnut-enriched diet phase, endothelial function was significantly better compared with function after the walnut-free diet. Fasting serum glucose increased, while serum total cholesterol and low-density lipoprotein (LDL) cholesterol were lower after eight weeks of the walnut diet versus baseline. There were no changes in anthropomorphic measures and insulin sensitivity. Similarly, soy nuts improved blood pressure and lowered LDL cholesterol when substituted for non-soy protein in a therapeutic lifestyle diet in hypertensive women.4
Along the same line, nattokinase, from fermented soy beans, also has cardiovascular benefits. An eight-week, double blind, placebo-controlled trial found increased intake of nattokinase may play an important role in preventing and treating hypertension.5 A total of 86 participants ranging from 20 to 80 years of age with an initial untreated systolic blood pressure (SBP) of 130 to 159 mmHg received nattokinase (2,000 FU/capsule; as NSK-SD®, from JBSL-USA ) or a placebo capsule. Compared with the control group, net changes in SBP and diastolic blood pressure (DBP) were -5.55 mmHg and -2.84 mmHg, respectively, after the eight-week intervention. The corresponding net change in renin activity was -1.17 ng/mL/h for the nattokinase group compared with the control group (P<0.05). In an unpublished study from Japan Bio Science Laboratory (JBSL), 11 health subjects (five male, six female, aged 21 to 65) who met eligibility criteria ingested of 2,000 FU/d of nattokinase (as 100-mg softgel capsules of NSK-SD). A pharmacokinetic pattern was observed for NSK-SO between baseline and 48 hours post-dose, peaking at approximately 13.3 hrs ± 2.5 hours post-dose. Statistically significant increases in detectable serum nattokinase from baseline were seen two hours and 24 hours. In conclusion, nattokinase was found to have significant profibrinolytic and antihypertensive effects.
A Japanese study confirmed natto’s role in heart health, noting, “Dietary natto-extracts supplementation suppressed intimal thickening produced by endothelial injury in rat femoral artery. [Natto] showed enhanced thrombolysis near the vessel wall.”6
