Hypertension that does not respond to basic lifestyle modifications, including dietary improvements, weight loss, exercise, and stress management, can be rooted in various etiological dysfunctions. Genetics can certainly exert a strong influence on blood pressure, but so can disruptions in vascular, hormonal, renal and neurological regulatory functions. Heavy metal toxicities are another potential trigger. Oxidative stress is nearly always both a cause and effect of hypertension, making antioxidant support a necessary addition to any plan.
Identifying the cause of hypertension can be difficult. The variability in causes can also make specific nutraceutical recommendations difficult because a very individualistic approach is required. What may be effective for one patient, may not work for another. Understanding the mechanisms of action behind some of the most well-studied nutraceuticals for hypertension can be helpful in determining where to start and what to suggest for patients.
Aged Garlic Extract
Aged Garlic Extract (AGE) ranks high on the list for hypertension, due to its high efficacy and tolerability. A meta‐analysis of 9 RCTs, including 482 individuals treated with AGE for 8 to 26 weeks showed a weighted mean difference for systolic blood pressure of -9.1 mmHg and for diastolic blood pressure of -3.8 mmHg. Hypertension can indicate problems with the hydrogen sulfide (H2S) and nitric oxide (NO) signaling pathways, which are important for inducing smooth muscle relaxation, vasodilation, and blood pressure reduction. Garlic‐derived polysulfides stimulate the production of vascular H2S, enhancing the regulation of endothelial NO. Further, AGE “has ACE inhibitory and Ca++‐channel blocking activity, both of which reduce catecholamine sensitivity, increase bradykinin and NO, and improve arterial compliance.”
It is important to note that the H2S and NO pathways are influenced by vitamins B6, B12, and folate levels, so individuals with MTHFR polymorphisms may not respond as favorably to AGE until these nutrient levels are supported. Molybdenum levels should also be assessed because of their role in sulfur detoxification.
L-Arginine is a semi-essential amino acid that functions as a substrate of nitric oxide synthase and has been shown to significantly reduce blood pressure. A meta-analysis of 11 RCTs, including 387 subjects, showed a weighted mean difference for systolic blood pressure of -5.39mmHg and for diastolic blood pressure of -2.66mmHg. Another meta-analysis of placebo-controlled trials performed to determine the effects of L-arginine on blood pressure in pregnant women showed similar results and prolonged gestational age, giving an option for women at risk for preeclampsia. L-arginine not only supports NO production, but improves glucose metabolism and lowers blood sugar, and positively affects renal function which may make it a good option for “salt sensitive” individuals.
Increasing dietary sources of potassium is important, but attaining levels high enough to address some forms of hypertension can be difficult. Potassium is routinely deficient in most diets and yet, it is extremely important in maintaining the correct sodium/potassium balance required to manage blood pressure. A meta-analysis of 23 RCTs involving 1213 subjects concluded that potassium supplementation significantly improved both systolic and diastolic blood pressure in a dose-dependent relationship. Not only is potassium supplementation important to balance dietary sodium, but it also improves blood pressure by reducing vascular resistance.
Like potassium, magnesium is an important nutrient for inducing vascular resistance, and low serum concentrations are an independent risk factor for high blood pressure. Unfortunately, magnesium intake has been steadily declining among western countries and even the most health-conscious individuals are lacking. According to a meta-analysisof ten cohort studies, including 20,119 cases of hypertension and 180,566 participates, a 100mg/day increase of magnesium intake was associated with a 5 percent reduction in the risk of hypertension. Magnesium is the fourth most abundant mineral in the body and its effects on blood pressure have been noted for the past four decades. This mineral regulates cell membrane permeability for sodium and acts as a calcium antagonist to modulate vascular smooth muscle tone and contractibility.
More recent research is focusing on the role of oxidative stress and impaired antioxidant systems as one of the key etiologies of hypertension. Vascular damage from reactive oxygen species (ROS) and reactive nitrogen species (RNS) not only triggers hypertension, but is also exacerbated by high blood pressure, creating a vicious cycle of chronic inflammation which leads to hypertension-associated cardiac risk factors. In a previous blog, we discussed CoQ10 and homocysteine as good markers of oxidative stress, related to hypertension.
More recently, vitamin D has been identified as a promising anti-hypertensive through the activation of antioxidant mechanisms. Low serum vitamin D, a well-established global problem, has been associated with hypertension. Vitamin D decreases renin-angiotensin-aldosterone system (RAAS) activity, modulates endothelial function, and regulates vascular oxidative stress. Several clinical studies have shown vitamin D to improve blood pressure in a dose-dependent manner.
Hawthorn (Crataegus oxyacantha)
Hawthorn has a long history of use for cardiovascular health. Its high bioflavanoid content renders it a highly effective antioxidant that has been shown to reduce oxidative and inflammatory stress in models of deoxycorticosterone acetate (DOCA) salt-induced hypertension. Studies also show it can activate endothelial nitric oxide synthase (eNOS),causing vasodilation, and reducing blood pressure.
Pomegranate (Punica granatum)
Pomegranate is another antioxidant-rich botanical to consider, due to its high content of polyphenols. In a double-blind, placebo-controlled RCT of 55 subjects taking pomegranate extract or placebo for 8 weeks, a significant decrease in diastolic blood pressure was noted among the test group.
Hypertension doesn’t seem to be taking a vacation from our list of prominent (and growing) health problems any time soon. Correspondingly, more individuals are concerned about the lack of non-pharmaceutical options for managing this condition. And yet, numerous nutraceuticals have shown significant impact on blood pressure when used in combination with positive lifestyle changes. It may take a little effort to determine which nutraceutical will best address each individual case, but with effort, one (or two) is almost certain to bring optimistic results.
By Nicole Spear, MS, CNS