Transcript: Fennel Seeds to Improve Athletic Performance
Dozens of studies now suggest that the nitrates in vegetables, such as beets and green leafy vegetables, may help both sick people, as a low-cost prevention and treatment intervention for patients suffering from blood flow disorders, such as high blood pressure and peripheral vascular disease, as well as healthy people, as an effective, natural performance-enhancing aid for athletes. Most of the studies were done with beet juice, which is why I was so delighted to see a study on whole beets, as I reported before, showing the same benefit, but what about studies on whole green leafy vegetables?
There was this study a while ago suggesting that one of the reasons that, at the age most Americans and Europeans are dying, the Okinawan Japanese are looking forward to many more years of good health is all the nitrate in their green leafy vegetables, which tends to bring down blood pressures when put to the test. The reason I didn’t report on it at the time is because I had never heard of these vegetables. I know what chrysanthemum flowers are, but I didn’t think most of my viewers would be able to find these at the local store.
What about good old American, red, white, and blue greens, like frozen spinach? It hadn’t been tested… until now. They wanted to test the immediate effects on our arteries of a single meal containing a cooked box of frozen spinach for both arterial stiffness and blood pressure. First, they needed a meal to increase artery stiffness and pressure; so, they gave people a chicken and cheese sandwich, which lowered the elasticity of their arteries within hours of eating, but add the spinach and the opposite happens. After chicken and cheese, the force the heart has to pump goes up within minutes, but the spinach keeps things level. So, a meal with lots of spinach can lower blood pressure and improve measures of arterial stiffness. That’s great for day-to-day cardiovascular health, but what if you want a whole food source that can improve your performance when you’re out hiking or something? Beets and spinach aren’t the most convenient of foods; is there anything we can just add to our trail mix?
If you look at the list of high nitrate vegetables, you’ll see there isn’t much that you can just stick in your pocket—unless, fennel seeds, which are actually not seeds, rather the whole little fruits of the fennel plant, have a lot. Let’s find out. Fennel seeds are often used as mouth fresheners after a meal in both the Indian sub-continent and around the world. You’ll typically see a bowl of candy coated fennel seeds as you walk out of Indian restaurants.
And when you chew them you can get a significant bump in nitric oxide production, which has the predictable vasodilatory effect of opening up blood vessels, making them a cheap, easy-to-find, light-weight, nonperishable source of nitrates. They single out mountaineers, thinking chewing fennel seeds could help maintain oxygen levels at high altitudes and help prevent H.A.P.E. (high altitude pulmonary edema), one of the leading killers of mountain climbers once you get more than like a mile and a half over sea level. Not to be confused with H.A.F.E caused by the expansion of gas at high altitudes, a condition known as High Altitude Flatus Expulsion, known to veteran back-packers as Rocky Mountain barking spiders.
But fennel seeds may help with that too, as traditionally, they’ve been used as a carminative, meaning a remedy for intestinal gas. Fennel has also shown antihirsutism activity, combatting excessive hair growth in women, the so-called bearded woman syndrome, but applying a little fennel seed cream can significantly reduce it. But if fennel seeds have such a strong hormonal effect, should we be worried about chewing them? Well, there have been cases reported of premature breast development among young girls drinking fennel seed tea a couple times a day for several months. Their estrogen levels were elevated, but after stopping the tea, their chests and hormone levels went back to normal.
Current guidelines recommend against prolonged use in vulnerable groups, children under 12, pregnant and breastfeeding women, and perhaps your pet rat, as rodents metabolize a compound in fennel called estragole into a carcinogen, but our cells appear able to detoxify it.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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