Saturday, October 23, 2010
About one in three US adults has high blood pressure; this is a big problem because blood pressure elevation is a leading contributor to heart attacks and stroke. Amrita Ahluwalia, a professor of vascular biology at Queen Mary’s William Harvey Research Institute in England, has found that blood pressure can be lowered effectively by natural means – drinking 8 ounces of beet juice daily. The nitrate (NO-3) found in beet juice is converted in saliva, by bacteria on the tongue, to nitrite (NO-2); in the acidic environment of the stomach. Nitrite is then converted by various enzymes to nitric oxide (NO). Nitric oxide is a gas that diffuses freely across cell membranes, and signals the smooth muscle surrounding blood vessels to relax, thus resulting in lower blood pressure and increased blood flow. NO also prevents blood platelets and white blood cells from sticking to blood vessel walls, thereby helping to lessen a buildup of plaque. Viagra and related drugs stimulate erections primarily by providing increased NO to blood vessels in the penis. Nitroglycerin, used to decrease the pain of angina, also works by releasing NO to dilate blood vessels in the heart muscle.
Professor Ahluwalia and her team found that in healthy volunteers, blood pressure was reduced within an hour of drinking about 8 ounces of beet juice, with a peak at 3-4 hours later, and some degree of reduction for 24 hours. Since nitric oxide is also formed after eating green leafy vegetables, the mechanism of action of the DASH diet may be similarly explained. The DASH diet – Dietary Approach to Stop Hypertension – emphasizes eating large amounts of vegetables and fruits, along with some low-fat dairy products and little added salt. Look at dashdiet.org for a good discussion of this effective plan.
A recent study of beet juice showed that athletes given beet juice could complete a cycling test for a significantly longer time than when given a placebo. They were able to use oxygen more efficiently during endurance exercise. This finding may also help people with poor fitness who need to increase their exercise tolerance.
Beet juice can have side effects, so it is important to discuss these with you doctor before starting to use it regularly. This is especially true for people taking medication to lower blood pressure. Drinking beet juice can cause dizziness, perhaps because of the drop in blood pressure. Beets can cause red urine and feces, which is a harmless side effect but could make the uninformed think they are bleeding internally. Occasionally people drinking beet juice have a temporary paralysis of the vocal cords, making it hard to talk for a period of time. This can be alarming – and should signal the user to stop the beet juice regimen. Some people are allergic to beets – there is a correlation here with allergy to latex. Beet juice should not be given to children.
If you don’t have your own juicer, it may be expensive to buy beet juice. Biotta sells organic beet juice (17 ounce bottle) on line for $5 plus shipping: With enough demand, your local natural foods store might stock the juice. If this is all too much, you may get the same good results in lowering blood pressure from the DASH diet.
Readers of this column may remember that chocolate contains compounds that activate the nitric oxide system in our bodies. The Kuna Indians who live off the coast of Panama drink lightly processed cocoa as their main beverage and do not show an increase in blood pressure with aging. It is hard to consume chocolate or cocoa regularly and not get an overdose of sugar and in some cases fats. However, by using plain unsweetened cocoa powder combined with xylitol, mashed banana or pomegranate juice, chocolate lovers can stay on a healthy diet!
Sadja Greenwood, MD, MPH back issues on this blog