Saturday, July 28, 2012

Dietary supplements and hypertension: potential benefits and precautions


Dietary supplements are used extensively in the general population and many are promoted for the natural treatment and management of hypertension.

Coenzyme Q10, Fish Oil, Garlic, and Vitamin C

In a review of the many dietary supplements promoted for the management of hypertension, pharmacists in Atlanta and Mississippi found coenzyme Q10, fish oil, garlic, and vitamin C with evidence of possible benefits.

They also identified 4 products that were consistently associated with increasing blood pressure (ephedra, Siberian ginseng, bitter orange, licorice).


CoQ10 has been shown in two studies to further reduce both systolic blood pressure (SBP) and diastolic blood pressure (DBP) after 8 weeks when added to conventional antihypertensive agents. SBP was reduced by 17.8 mm Hg in the treatment group and 1.7 mm Hg in the placebo group.

Another study showed when CoQ10 was administered to patients with essential hypertension for 10 weeks, a statistically significant decrease in both SBP and DBP was noted.

In the fourth study CoQ10 doses were adjusted to achieve a serum concentration of ≥2.0 μg/mL. Participants were followed for 1 year or longer, with dose adjustments made on a monthly basis if needed. Statistically significant decreases in both SBP and DBP were noted.

Fish Oil

In a parallel designed trial of normotensive and hypertensive men, participants were randomized to receive either fish oil (eicosapentaenoic acid, docosahexaenoic acid) or placebo for 4 months followed by a 2-month washout period and reassessment. No significant BP change was noted in either group of normotensive participants. In the fish oil hypertensive group, average SBP decreased by 6 mm Hg and DBP by 5 mm Hg during the treatment period and then returned to baseline after the 2-month washout.15

Another team of researchers examined the effects of fish oil in obese, hypertensive, and dyslipidemic participants with and without diabetes over 13 weeks. Participants also started the American Heart Association Step I diet. Both groups had statistically significant reductions in both SBP and DBP.16


In a 12-week trial, researchers demonstrated statistically significant reductions in both supine and standing SBP and DBP with garlic supplementation. However, despite a long history of use, the efficacy of garlic in hypertension is still debated.

Many of the concerns are the same as with other DSs: product inconsistencies, lack of standardization, variable formulations, and questionable study design and quality. Given the wide variation of products used and other limitations of the existing evidence, it is difficult to make a definitive recommendation for the use of garlic in the treatment of hypertension.

Vitamin C

A one-time loading dose of 2 g of ascorbic acid followed by 500 mg daily for 1 month achieved a significant 13-mm Hg reduction in SBP, but not DBP in participants.

After receiving 200 mg of ascorbic acid 3 times daily for 6 months, a statistically significant reduction (approx. 20mm Hg) in SBP was demonstrated in elderly patients (65 years and older) with drug refractory hypertension compared with younger adults (younger than 65 years) who failed to show a significant BP reduction.

These findings are of interest, although the limited data, product inconsistencies, lack of standardization, variable formulations prevent global recommendations on the efficacy of these DS in the treatment of hypertension.

Consumers must be reminded that they should not consume DS without the supervision of a medical doctor or pharmacist.



Rasmussen CB, Glisson JK, Minor DS. Dietary supplements and hypertension: potential benefits and precautions. J Clin Hypertens (Greenwich). 2012 Jul;14(7):467-71. 2012; 14:467-471.

You can read the full text HERE

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