Pharmacists can safely recommend several nutrients that can be helpful in the prevention and treatment of hypertension. This article will discuss magnesium, coenzyme Q10 (CoQ10), fish oils, vitamin C, and garlic. Although potassium is another important blood pressure- regulating nutrient, physicians usually monitor potassium levels in hypertensive patients, however, so I have not included potassium in this article.
Magnesium is one of the most commonly deficient nutrients in American diets, and it is one of the most critical nutrients required for regulating and maintaining normal blood pressure. A meta-analysis of 34 clinical trials revealed a strong, consistent inverse relationship between magnesium levels and blood pressure.1 In the Honolulu Heart Study, which evaluated 61 nutritional variables, magnesium intake had the strongest association with blood pressure.2
Numerous studies report that magnesium supplementation effectively lowers blood pressure in patients with hypertension. For example, researchers found that all patients with elevated blood pressure taking 625 mg of magnesium daily for 4 weeks experienced significant reductions in blood pressure.3 A double-blind, placebo-controlled trial showed that magnesium supplementation produced significant reductions in both systolic and diastolic blood pressures.4 Results from a 6-week, double-blind, placebo-controlled trial showed that magnesium (600 mg/day) lowered intracellular sodium levels in addition to producing significant decreases in systolic and diastolic blood pressures.5
Because a large single dose of magnesium can cause diarrhea, I routinely suggest that people take 200 to 300 mg of magnesium 2 or 3 times daily. Also, patients who take drugs that can cause magnesium depletionsuch as estrogen-containing medications (oral contraceptives and hormone replacement therapy), loop and thiazide diuretics, and digoxinmay need additional magnesium supplementation.6
CoQ10 is another very effective nutritional antihypertensive agent. Peter Langsjoen, a cardiologist, conducted a remarkable study using CoQ10 in patients with hypertension. He initiated high-dose coenzyme Q10 therapy in 109 hypertensive patients. In 80% of these patients, the diagnosis of essential hypertension had been established for a year or more prior to starting CoQ10, with an average time of 9.2 years since diagnosis. Dosages were adjusted to meet a target blood level of 2 mcg/mL (the average oral dose used was 225 mg/day). Within 1 to 6 months (average 4.4 months), 51% of these patients were able to completely discontinue from 1 to 3 antihypertensive medications.7
Additional CoQ10 studies conducted in Japan have reported similar antihypertensive benefits.8,9 Dosages generally range from 100 to 200 mg/day. Because CoQ10 is a fat-soluble nutrient, it should be taken with a meal containing fat, which will enhance its absorption.
The long-chain omega-3 fatty acids EPA and DHA, known as fish oils, also lower blood pressure. In a meta-analysis of 31 placebo-controlled clinical trials, both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) provided blood pressure-lowering benefits in hypertensive individuals.10 In these studies, patients ingested from 3 to 15 g of fish oils daily. One study provided a mechanism of action for the blood pressure-lowering effects of EPA and DHA. Apparently these long-chain omega-3 fatty acids improve the elasticity of the arteries, which results in a reduction of blood pressure and vascular resistance.
In a 7-week, double-blind, placebo- controlled trial, 38 volunteers received 3 g of either EPA or DHA or a placebo. The EPA group registered a 36% improvement in arterial function, and the DHA group had a 27% improvement, but the placebo group experienced no improvement.11
It is important to recommend extra antioxidants (especially vitamin E) for people taking omega-3 supplements. A good level of natural vitamin E is 400 international units, and now studies indicate that taking mixed tocopherols is better than just taking vitamin E as dalpha tocopherol.
Several studies report an inverse relationship between plasma levels of vitamin C (ascorbic acid) and blood pressure.12,13 In one study, volunteers were fed a vitamin C-deficient diet for 30 days, followed for 30 days by a diet containing adequate vitamin C. Individuals who experienced the greatest reduction in plasma vitamin C levels had the largest increases in blood pressure 1 month later. People in the lowest 25th percentile of plasma vitamin C levels had blood pressure readings 7 mm Hg higher than people in the upper 25th percentile of plasma vitamin C levels.14
A mechanism of action for the blood pressure-lowering effects of vitamin C is now known. It has been shown that vitamin C improves endothelium-dependent vasodilation by restoring or improving the production of endothelial nitric oxide in patients with essential hypertension.15 Several studies report that a significant number of Americans (especially smokers, African Americans, Hispanics, and the elderly) have low dietary levels and low blood levels of ascorbic acid, which may be one of the causes of hypertension.
Garlic is a natural agent that has mild antihypertensive effects. In a meta-analysis of 10 randomized clinical trials lasting 4 weeks or longer, doses ranging from 600 to 900 mg of garlic extract per day provided a lowering of systolic and/or diastolic blood pressure.16
A Word of Caution
High-dose magnesium and/or coenzyme Q10 can be so effective in some hypertensive individuals that dosage levels of antihypertensive drugs may need to be reduced. For this reason, I suggest that patients who are taking blood pressure drugs contact their physicians before beginning these therapies.
Dr. Pelton is director of education at Integrative Health Resources Inc. continued from page 18 continued from page 34
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