Into the Heart

Arterial Destiffening

Arterial stiffness is associated with increased risk of cardiovascular events.

A number of factors are thought to contribute to arterial stiffness include decreased elastin and increased collagen in the arterial wall, abnormal endothelial regulation of arterial smooth muscle tone, and the accumulation of advanced glycation end products, which lead to protein cross-linking (collagen becomes stiffer and less susceptible to hydrolytic turnover).

Stiffness of large arteries increases with age, even in healthy individuals without cardiovascular disease. However, arterial stiffness is less pronounced in those who engage in regular endurance exercise.

Even once established, large artery stiffness can be diminished by a program of physical exercise. For example, one study found, three months of aerobic training (walking or jogging, 40 minutes per day at 70% to 75%) of maximum heart rate enhanced carotid artery compliance to levels observed in endurance trained men of similar age.

The vascular benefits of exercise are indirectly related to a decline in the release of neurohumoral vasoconstrictors and reduced efferent sympathetic tone, and to endothelial mechanical signaling associated with increased pulsatile flow and stretch and consequent enhanced nitric oxide stimulation.

Noteworthy: diminished arterial stiffness is associated with aerobic training; not resistance training (weight lifting).

Source:
Mechanism, Pathophysiology and Therapy of Arterial Stiffness
Arteriosclerosis, Thrombosis & Vascular Biology 2005 25:932

Cardiovascular Benefits of Isoflavones

Nutrient gene interactions and the therapeutic potential of diet in the prevention and/or treatment of cardiovascular diseases is significant. Diets containing natural antioxidants appear to afford protection against coronary heart disease.

Soybean isoflavones genistein and daidzein have natural antioxidant properities.Epidemiological evidence indicates that an increased intake of soy isoflavones is associated with a lower incidence of coronary heart disease.

In clinical studies, isoflavones have been shown to acutely modulate vascular reactivity in healthy postmenopausal women and male subjects in vivo. Infusion of genistein or dihydroequol into the brachial artery, at concentrations achieved in populations consuming an isoflavone rich diet, evoked concentration and endothelium dependent increases in forearm blood flow. A high dietary intake of isoflavones is associated with a lower pulse wave velocity. This means less vascular stiffening.

Isoflavones also modulate vascular tone by inhibiting Ca2+ influx via L-type Ca2+ channels in vascular smooth muscle cells.

Longer-term supplementation with soy isoflavones improves arterial compliance in men and postmenopausal women, increases plasma nitrite/nitrate levels and decreases plasma endothelin-1 levels.

Chocolate chiffon pie made with polyphenol rich dark chocolate & silken tofu, nurtures the heart !

Source:
Activation of endothelial nitric oxide synthase by dietary isoflavones: Role of NO in Nrf2-mediated antioxidant gene expression
Giovanni E. Mann, David J. Rowlands MD's,
Cardiovascular Research (2007) 75(2):261-274

The phytoestrogen genistein produces acute nitric oxide dependent dilation of human forearm vasculature with similar potency to 17beta-estradiol.
Walker H.A., Dean T.S., Sanders T.A.
Circulation (2001) 103:258–262.

The Vascular Benefit of Weight Loss

During each heartbeat a pulse wave travels from the heart down the arterial wall; in advance of blood flow. The more rigid the wall of the artery, the faster the wave moves.

Arterial pulse wave velocity (PWV) reflects arterial stiffness and is related to the severity of atherosclerosis: a progressive thickening and hardening of the walls of medium and large arteries that result from inflammed fatty deposits on the inner arterial lining. An increase in PWV is known to predict future cardiovascular events.

There is a relationship between weight change and pulse wave velocity change. Specifically there is an association between weight gain and arterial stiffness progression. On a more healthful note, data also confirms an association between weight loss and arterial stiffness regression.

A two year study of healthy adults aged 20 to 40 years found a mean annual pulse wave velocity regression of 29.9 cm/s for those with a 4.5 kg annual weight loss and a 18.2 cm/s progression for those with a 4.5 kg annual weight gain. 4.5 kg equals ten pounds.

Arterial stiffening influences the load imposed on the ventricles, the efficiency of cardiac ejection and the perfusion of the heart. Stiff arteries diminish heart performance.

Source:
Weight Change is Associated with Change in Arterial Stiffness Among Healthy Young Adults.
Dr. Kim Sutton-Tyrell
Hypertension 2005; 45:187

More Isoflavones Please ...

Cellular damage resulting from oxidative stress is believed to be a major contributor of cardiovascular disease through LDL cholesterol oxidation and to cancer through DNA strand breaks that may lead to mutations. In humans, isoflavones have been found to prevent LDL oxidation in vivo and to inhibit DNA damage in vitro. Studies indicate the antioxidant and anti-proliferative properties of soy isoflavones afford protection against oxidative stress.

A 2006 study evaluated the effects of soy isoflavones in soymilk (71 mg day) and in a dietary supplement (70 mg day) on markers of immunity and oxidative stress in postmenopausal women. An additional group of women in the study (control group) received a milk like supplement or a placebo dietary supplement.

Plasma concentrations of 8-OHdg* reflect oxidative damage to DNA, and concentrations increase during repair of DNA. The postmenopausal women in the isoflavone treatment groups had significantly lower concentrations of 8-OHdg than did the control group. B cells are small white blood cells that stimulate immune defenses. Isoflavone intervention also resulted in higher B cell populations.
                  a bit more about soy isoflavones . . .
Isoprostanes are compounds produced by the peroxidation of phospholipids in tissues, and elevated concentrations have been found in plasma and urine during periods of oxidative stress. An additional study found dietary soy isoflavones (34 mg genistein & 21 mg daidzein/equol) decreased f2-isoprostane** concentrations and increased resistance of LDL cholesterol to oxidation.

Soy isoflavones seem to behave like antioxidants and afford a degree of protection against diseases resulting from oxidative damage. When enriching ones diet with soy isoflavones, it is important to find (organic) soymilk, tofu and supplements manufactured from Non-GMO Soy: natural soybeans with no genetic modification.

*8-hydroxy-2-deoxy-guanosine
**8-epi-prostaglandin F2a

Sources:
Soy isoflavones modulate immune function in healthy postmenopausal women
Tracy A Ryan-Borchers, Jean Soon Park, MD's
American Journal of Clinical Nutrition, Vol. 83, No. 5, 1118-1125, May 2006

Isoflavone Phytoestrogens consumed in Soy Decrease F2-isoprostane Concentrations and Increase Resistance of Low Density Lipoprotein to Oxidation in Humans.
Helen Wiseman, James D O'Reilly MD's
American Journal of Clinical Nutrition, Vol. 72, No. 2, 395-400, August 2000