A recent conference on Nutrition and Health, sponsored by the University of Arizona, contained many useful ideas for everyday life. The problems with sugar, in last week’s column, were on the menu. Here is another topic.
Beets and Greens: These foods contain nitrates, which used to be considered harmful because of serious health problems when infants drank contaminated well water. However, it was found that the main problem was fecal bacteria in the wells, rather than excess nitrates. In the 1970’s, researchers found that dietary nitrates (NO3) are converted into nitric oxide (NO), in the presence of L-arginine (an amino acid) and oxygen. NO is an important ‘signaling molecule’ in the body, diffusing rapidly – as it is a gas – across cell membranes. It causes relaxation of the smooth muscles that line blood vessels, resulting in lower blood pressure and increased blood flow. Nitroglycerine works to lessen the pain of angina (chest pain resulting from lack of oxygen for the heart muscle) by its conversion to NO. Viagra works to simulate penile erection by the release of NO. The production of NO is elevated in people living in high altitudes, which helps them get more oxygen by dilation of the blood vessels in their lungs. NO transmits messages between nerve cells and is associated with memory, learning, sleeping, feeling pain, and depression.
Researchers at Wake Forest University studied volunteers over age 70 given a diet containing beet juice and high nitrate vegetables. The subjects were found to have increased blood flow to their brains, potentially helping to avoid dementia. Studies on beet juice, at the University of Exeter, found it enables people to exercise up to 16% longer. The amount of nitrate in studies on athletes was the equivalent of what is found in 2-3 red beets or a plate of spinach. Other vegetables high in nitrates are kale, lettuce, parsley, cabbage, celery, radishes and turnips.
People with high blood pressure may be interested to know that the DASH Diet (Dietary Approach to Stop Hypertension) may owe at least some of its effectiveness to an emphasis on green leafy vegetables. For those who want quick results without cooking, beet juice is available on line. Mix it with soda water or plain water, and start with a little at a time. A few people don’t feel well after drinking beet juice.
The Dash Diet This diet, which has been shown to be effective in lowering blood pressure, can work surprisingly well within two weeks. DASH is described on line at the WebMD site and also in the book – The DASH Diet Action Plan – based on the National Institutes of Health Research. This book has great reviews, and should be read by anyone who is serious about reducing blood pressure and possibly getting off of blood pressure medications. Of course, it is important to talk to your doctor about changing your medicines. For those who want to start the eating plan right away, here it is. Eat more vegetables, fruits and low or non-fat dairy foods. Eat less red meat, processed meat, sweets and foods high in fat. Eat more whole grains, fish, and poultry. Read labels carefully, and avoid foods high in salt. For snacks, try unsalted popcorn (avoid the buckets in movies!), unsalted nuts of all kinds, raisins, and low or non-fat yogurt. Don’t forget that the nitric oxide (NO) in green vegetables and beets will rapidly go to work for you, by relaxing your arteries, increasing blood flow, and lowering your blood pressure. And, of course, there’s moving the body, which is also good for you, your arteries and your blood pressure. See you on the trails!
Sadja Greenwood, MD, MPH