Black Sesame Seeds

Eat Black Sesame Seeds to Lower Blood Pressure

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Black Sesame SeedsAccording to the latest statistics from the American Heart Association, more than 2,200 Americans die of cardiovascular disease (CVD) a day (based on 2007 mortality rate data). That averages out to one death every 39 seconds. Putting it another way, CVD accounted for 33.6 percent (813,804) of the roughly 2 million deaths in 2007 in the United States. And nearly 33 percent of those occurred before the age of 75, while more than 150,000 of those people were under the age of 65.[1]  

The stats are frightening, so how can you go about lowering your risk of cardiovascular disease? While a healthy diet and regular exercise are the biggies, there are some other lesser-known things you can do to help protect yourself. For example, a new study from Thailand looked at the antihypertensive and antioxidant effects of dietary black sesame meal.[2]

Hypertension, or high blood pressure, is a major risk factor for cardiovascular disease, which could lead to stroke, myocardial infarction, renal failure and death.

Past research has found that sesame seeds can improve oxidative stress because they contain antioxidants vitamin E and lignans, including sesamin, sesamolin and sesamol. In addition to impaired balance between relaxing and contracting factors in blood vessels, hypertension is also caused by increased pro-oxidant and decreased antioxidant activities. Thus, sesame could be helpful in decreasing the risk of CVD.

However, the authors of the study at hand claimed that the antihypertensive effect of black sesame meal, a product of sesame oil manufacturing, has not been previously investigated.

Black sesame seeds are similar to the more common white sesame seeds, but are not hulled. And black sesame seeds are thought to yield the best quality of oil and contain the most antioxidants like vitamin E.

Researchers acknowledged that past studies have shown conflicting results with regard to the effects of vitamin E on blood pressure. Unlike the study at hand, though, those ones investigated the effect of supplementation of either alpha-tocopherol (the predominant form of vitamin E) alone or mixed with gamma-tocopherol (another predominant form of vitamin E) supplementation on the blood pressure of diabetic or hypertensive patients who took antihypertensive drugs.

The current researchers felt that the interaction with the blood pressure meds may have diminished the effects or that the dose of vitamin E was too high. Additionally, black sesame meal contains gamma-tocopherol, which was reported to be lower in patients with coronary heart disease.

So on to black sesame seeds we go. And because they wanted to examine their preventive effects, they chose a study group of 30 prehypertensive (i.e., slightly elevated blood pressure) but otherwise healthy men and women (average age 50 years) who were not taking any medication or dietary supplements that affected their blood pressure. Prehypertension was classified either by systolic blood pressure (SBP) from 120 to 139 mmHg or diastolic blood pressure (DBP) from 80 to 89 mmHg.

The subjects were divided into two groups matched by age, body mass index (BMI) and blood pressure – 15 in the black sesame meal group and 15 in the placebo group. During the four-week study period, they were each asked to take six black sesame meal capsules (or identical looking placebos), three times a day, with water after a meal. They were asked to avoid any other vitamins or dietary supplements during this time, and also to maintain their current diet and exercise routines.

The researchers made their own supplements by roasting and pressing sesame seeds, grinding the remaining sesame meal into powder, and mixing it with an adsorbent. According to the authors, this process is the same as that used for commercial preparation. Each capsule contained 0.42 grams of black sesame meal. (This is a good time to mention that they are applying for a patent on black sesame meal, which they noted as a competing interest.)

Twelve-hour fasting blood samples were collected to measure levels of malondialdehyde (MDA), a marker for oxidative stress, and vitamin E levels. And, of course, blood pressure was also measured prior to the participants taking the supplements or placebo pills, and then at the end of the study period.

After four weeks, SBP was significantly decreased in the sesame group by an average of 8.2 mmHg, while it was only slightly decreased in the placebo group.

To put this in context, the author cited the INTERSALT study that showed a 2-3 mmHg reduction of SBP was associated with a 4 percent decrease in mortality from CVD in the United States and U.K.[3] and a 6.4 percent decrease in mortality from stroke in Japan.[4]

The authors said, “Based on these longer term studies, if the present reduction in [blood pressure] with sesame meal (8.2 mmHg) was sustained in the long term, this could reduce the risk of CVD and stroke by 16.4 percent and 26.2 percent respectively.”

As for DBP, it did decease in the sesame group and increased in the placebo group, but the changes between the two groups were not enough to be deemed statistically significant.

When it came to MDA concentrations (remember MDA is an indicator of oxidative stress), the levels significantly decreased in the sesame group, but not in the placebo group.

Finally, there were no apparent side effects induced by black sesame meal throughout the study.

When all was said and done, the researched concluded: “This study suggests a beneficial effect of dietary black sesame meal on a reduction in blood pressure in pre-hypertensive humans. It is likely that the antihypertensive effect is due to decreased oxidative stress. Taken together with the absence of side effects and inexpensive preparation, the regular ingestion of dietary black sesame meal may be beneficial for CVD prevention in individuals with prehypertension, or even those with hypertension.”

Where to Find Black Sesame Seeds

If you are a person with high blood pressure or prehypertension you may want to consider reaping the benefits of black sesame seeds. You can get them in a variety of forms — hulled or unhulled, in bulk or jars, as an oil or ground in a capsule.

The first place you could look is your local supermarket. They will most likely be in the spice section or with the nuts and dried fruits. You could also try an Asian specialty store if there is one nearby as black sesame seeds are a common ingredient in many Asian dishes. A health food store is also likely to carry them, or you can even get them online.

If you buy whole sesame seeds, which are easier to find than the pill form, you could eat them whole or grind them into a powder. Typical dosage ranges from 9-30 grams per day but, as always, be sure to speak with your doctor before beginning any supplement regimen. Also, they can promote bowel movements, so you may want to avoid them if you have trouble with loose stools.

Overall, though, there do not seem to be negative side effects with consuming black sesame seeds, and the blood pressure-lowering effect seems like a great reason to give them a shot.

[1] Roger, V, et al. Heart Disease and Stroke Statistics—2011 Update. Circulation. 2011; 123: e18-e209 [Epub ahead of print.]

[2] Wichitsranoi, J, et al. Antihypertensive and antioxidant effects of dietary black sesame meal in pre-hypertensive humans. Nutr J. 2011; 10: 82.

[3] Stamler J, Rose G, Stamler R, Elliott P, Dyer A, Marmot M. INTERSALT study finding: public health and medical care implications. Hypertension. 1989;14:570–577.

[4] Japanese Society of Hypertension. Japanese Society of Hypertension guidelines for the management of hypertension (JSH 2004) Hypertens Res. 2006;29(Suppl):S1–S105. doi: 10.1291/hypres.29.S1.

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