Study Roundup: Which Oil May Lower Blood Pressure?
If you are looking for more ways to control your blood pressure and cholesterol levels through food, it may be time to add one or two more varieties of cooking oil to the pantry. At a recent 2012 scientific meeting on high blood pressure held by the American Heart Association, researchers from the Department of Cardiovascular Disease at Fukuoka University Chikushi Hospital in Japan, presented encouraging findings on the impact of blended sesame and rice bran oil on cardiovascular health. Study participants who cooked with the blended oil saw a significant drop in blood pressure, as well as improved cholesterol levels. Most notably, the researchers found cooking with a combination of these oils was nearly as effective at reducing high blood pressure and cholesterol as a commonly prescribed high blood pressure medication. When the study participants used the oil blend along with the medication, the positive effects were even greater.
The Expert Take
“We often read about the many health benefits of mono- and polyunsaturated oils, but unsaturated fats only have a positive effect, if they replace saturated fats in the diet,” says Tina Ruggiero, MS, RD, LD, a nutrition expert and cookbook author. “If they're simply added to the diet, they won't work as intended; you're just adding more fat to your overall diet.”
Fortunately, when it comes to using both rice bran oil and sesame oil in cooking, they are versatile, tasty, and easy to integrate into different recipes. As Ruggiero points out, “Rice bran oil has a very mild flavor, and you can barely detect it. So, that makes it useful for all types of applications—from tempura to baking and grilling, and salad dressings. Most of all, rice bran oil has a high smoke point. This means that it can be heated to very high temperatures without altering its flavor.”
As for sesame oil, Ruggiero says it’s a very popular ingredient used in India, the Middle and Far East, and it has various uses. “Dark sesame oil is made from toasted sesame seeds and has a very profound flavor. Light sesame oil is processed from the raw seeds, so the taste is apparent yet more delicate. Sesame oil is great for seasoning sea vegetables or spinach; it's delicious when flavoring curry; it gives noodles a whole new flavor profile and sesame oil is wonderful in stir fries.”
Source and Method
During the 60-day study conducted in New Delhi, India, researchers recruited 300 men and women (average age 57) with mild to moderately high blood pressure, and divided them into three groups. One group was treated with a commonly used blood pressure-lowering medication called a calcium-channel blocker (nifedipine); the second group was given the oil blend and told to use about an ounce each day in their meals, and the final group received the medication and the oil blend. All three groups saw drops in their systolic blood pressure, which is the top number in a blood pressure reading, and measures the force of blood against your artery walls when the heart is pumping.
Participants using just the oil blend or the medication saw a significant drop (anywhere from 11-16 points) in both their systolic and diastolic blood pressure. However, those who used the oil blend in conjunction with medication saw the greatest improvements in their blood pressure readings: a drop of 36 points in systolic pressure, and a 24-point drop in diastolic pressure.
While there were no changes in recorded cholesterol levels for the study participants just using the blood pressure medication, those using the oils alone or along with the drug, saw a 26 to 27 percent drop in their LDL ("bad" cholesterol) and a 9.5 to 10.9 percent increase in their HDL ("good" cholesterol) levels.
The researchers theorize that the unsaturated fatty acids found in the oils, combined with their antioxidants, such as sesamin, sesamol, sesamolin and oryzanol, may be what’s responsible for the results. Other studies have shown, that monounsaturated and polyunsaturated oils, and antioxidants, which are compounds found in plants, have been linked to lower blood pressure and total cholesterol.
A study published in the Journal of Clinical Biochemistry and Nutrition in July 2012, found that rice bran oil significantly lowered total serum cholesterol and LDL cholesterol levels in a group of 35 people with type 2 diabetes, who were randomly assigned a placebo or 250 ml of rice bran oil every day for five weeks. In a study published this month in the Journal of Clinical Hypertension, 30 men were randomly assigned to take 35 grams of either sesame oil or a placebo daily for two months. Those assigned the oil showed lower readings of their systolic blood pressure after about two weeks on the regimen. Both studies suggest that there is a heart-protective effect with the use of sesame and rice bran oil in the diet.
The Bottom Line
While more research studies are needed to replicate these promising results on the cardiovascular benefits of sesame and rice bran oil, mixed together or not, adding them to your diet couldn’t hurt.