Supplements of the soluble fibre-rich cocoa husk extract reduced systolic blood pressure in spontaneously hypertensive rats by 10 to 15 mmHg, according to findings published in the Journal of Agricultural and Food Chemistry.
The soluble cocoa fibre product (SCFP) is reportedly rich in soluble fibre, antioxidants and polyphenols. Using a patented enzymatic process the product is obtained from cocoa husks. “This new source of soluble fibre was shown to have potential application as a functional food ingredient,” said the researchers.
Researchers from Universidad Complutense in Madrid, Natraceutical Group, and the Instituto de Fermentaciones Industriales (CSIC) fed rats genetically predetermined to develop high blood pressure (hypertension) a daily supplement of the soluble fibre-rich cocoa husk extract for 17 weeks. Improvements in the animals’ blood pressure were reversed, however, when the SCFP was withdrawn after 20 weeks, said the researchers.
“We have shown that the antioxidant properties of SCFP and the polyphenol content of this fibre could be in part responsible for its antihypertensive effect,” wrote the researchers, led by Marta Miguel from the CSIC.
“The fibre may also benefit hypertension through the control of body weight, and it may also control increased angiotensin II in the hypertensive condition by inhibiting [angiotensin converting enzyme (ACE)],” they added.
ACE inhibitors work by inhibiting the conversion of angiotensin I to the potent vasoconstrictor, angiotensin II, thereby improving blood flow and blood pressure.
High blood pressure (hypertension),defined as having a systolic and diastolic blood pressure (BP) greater than 140 and 90 mmHg, is a major risk factor for cardiovascular disease (CVD) - a disease that causes almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169bn ($202bn) per year.
Miguel and her co-workers divided 20 male spontaneously hypertensive rats into two groups. The animals were randomly assigned to receive either tap water (control) or a solution of SCFP (0.75 grams per day) for 17 weeks. The animals received only tap water for four weeks after this.
Improvements in systolic and diastolic blood pressure were observed in the group receiving the cocoa extract, but not in the control group. Withdrawal of the cocoa extract led to blood pressure increases, said the researchers.
Levels of malondialdehyde (MDA - a reactive carbonyl compound and a well-established marker of oxidative stress) were lower in the SCFP group, while ACE activity was also “slightly decreased”, said the researchers.
“We have demonstrated the antihypertensive and antioxidant properties of SCFP,” wrote the researchers.
“The control of body weight and the control of increased angiotensin II may be involved in the antihypertensive effect of this product.”
The need for clinical trials
The researchers noted that the exact mechanisms involved in the antihypertensive effect of SCFP have not been fully elucidated, and that more studies are recommended. “Therefore, further clinical trials should also be carried out before suggesting SCFP as a functional ingredient to prevent and/or attenuate the development of hypertension,” they concluded.
Cocoa powder benefits
Natraceutical, recently acquired by French botanicals giant Naturex, has been investing in the science behind its cocoa-derived products. An earlier study from the company and using its CocoanOX powder found that rodents fed 300 milligrams of cocoa powder per kilogram of body weight experienced a reduction in blood pressure similar to a 50 mg/kg dose of Captopril, a well-known pharmaceutical anti-hypertensive (Journal of Agricultural and Food Chemistry, Vol. 57, pp. 6156-6162).
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, doi: 10.1021/jf902080b
“Changes in Arterial Blood Pressure of a Soluble Cocoa Fiber Product in Spontaneously Hypertensive Rats”
Authors: D. Sanchez, M. Quinones, L. Moulay, B. Muguerza, M. Miguel, and A. Aleixandre