Tuesday, July 12, 2011
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Research Reveals New Secret Weapon for Tour De France, Beetroot Juice
ScienceDaily (July 1, 2011) —
Winning margins in the Tour de France can be tight -- last year just 39 seconds separated the top two riders after more than 90 hours in the saddle. When every second counts, riders do everything possible to gain a competitive advantage -- from using aerodynamic carbon fibre bikes to the very latest in sports nutrition.
Now there could be a new, completely legal and rather surprising weapon in the armoury for riders aiming to shave vital seconds off their time -- beetroot juice.
Research by the University of Exeter, published in the journal Medicine and Science in Sports and Exercise, has shown drinking the juice enables competitive-level cyclists to cut down the time it takes to ride a given distance. This is the first study which has shown that beetroot juice can be effective in a simulated competition environment.
For the study, nine club-level competitive male cyclists were asked to compete in time trials over 4km (2.5 mile) and 16.1km (10 mile). All the riders were asked to do each time trial twice. Each time they drank half a litre of beetroot juice beforehand. On one occasion they had normal beetroot juice, on the other occasion -- unbeknown to the triallists -- the beetroot juice had a key ingredient, nitrate, removed.
The researchers monitored athletes' VO2 levels (showing the amount of oxygen consumed) during exercise to ensure that the cyclists worked at maximum effort on each occasion.
Results showed that when the cyclists drank ordinary beetroot juice they had a higher power output (measured in watts) for the same level of effort -- suggesting their muscles and cardio-vascular system were being more efficient.
On average, riders were 11 seconds (2.8%) quicker over the 4km distance and 45 seconds (2.7%) faster over the 16.1km distance.
Professor Andrew Jones, from the University of Exeter, lead author on the research, said: "This is the first time we've studied the effects of beetroot juice, and the high nitrate levels found in it, on simulated competition.
"The findings show an improvement in performance that, at competition level, could make a real difference -- particularly in an event like the Tour de France where winning margins can be tight."
Beetroot juice is a natural source of nitrate, which is thought to be the active ingredient in affecting athlete's performance.
The nitrate has two physiological effects. Firstly, it widens blood vessels, reducing blood pressure and allowing more blood flow. Secondly, it affects muscle tissue, reducing the amount of oxygen needed by muscles during activity. The combined effects have a significant impact on performing physical tasks, whether it involves low-intensity or high-intensity effort.
Previous studies by the University of Exeter uncovered the impacts of beetroot juice and have begun to look in detail at its effects on different kinds of physical activity.
The beetroot juice used in this research was provided by James White Drinks.
Brief History of Beetroot
Modern varieties of beets are derived from the sea beet, an inedible plant that grows wild along the coasts of Europe, North Africa, and Asia. The garden beet has been cultivated for thousands of years. In ancient Greece, beets were so highly valued that, according to myth, a beet was offered on a silver platter to Apollo at Delphi. Today, beets are grown in many regions of the world. The leading beet-producing regions of the United States are California, Colorado, New Jersey, Ohio, and Texas. The beet is a cool-weather biennial that is cultivated as an annual. Beets are grown from seeds sown in early spring and are ready to harvest 60 to 80 days after planting. Beets are not harmed by frost, but hot weather can toughen the roots. Thus, in regions with hotter summers, they are planted in early fall for winter and spring harvest. Consequently, fresh beets are available all year.
Nutrients in Beetroot
Beet greens are a very good source of calcium, iron, Vitamins A and C. Beetroots are an excellent source of folic acid. They are a very good source of fiber, manganese and potassium. Beet greens and beetroot are a good source of phosphorus, magnesium, iron and vitamin B6. Betacyanin is the pigment that gives beetroot its color, and has powerful antioxidant properties.
Beets, raw Nutritional value per
100 g (3.5 oz)
Energy 180 kJ (43 kcal)
* Carbohydrates 9.56 g
Dietary fiber 2.8 g
* Fat 0.17 g
* Protein 1.61 g
Vitamin A equiv. 2 ?g
- beta-carotene 20 ?g
- lutein and zeaxanthin 0 ?g
Thiamine (Vit. B1) 0.031 mg
Riboflavin (Vit. B2) 0.040 mg
Niacin (Vit. B3) 0.334 mg
Pantothenic acid (B5) 0.155 mg
* Vitamin B6 0.067 mg
* Folate (Vit. B9) 109 ?g
* Vitamin C 4.9 mg
* Calcium 16 mg
* Iron 0.80 mg
* Magnesium 23 mg
Phosphorus 40 mg
Potassium 325 mg
Zinc 0.35 mg
A comprehensive breakdown of nutrients can be found in the Nutrition Database where this food can also be added to a meal planner.
Beetroot for Cholesterol Reduction
Beet fiber has been shown to have cholesterol lowering capabilities. In a study on rats with induced high blood cholesterol, a red beet fiber diet caused a reduction of serum cholesterol and triglyceride levels (by 30 and 40%, respectively) and a significant increase in HDL cholesterol (good cholesterol). This diet induced also a significant decrease (almost by 30%) of cholesterol content in the aorta.
Beetroot for Blood Pressure
Beetroot juice has been shown to lower blood pressure in subjects with normal blood pressure. In healthy volunteers, approximately 3 hours after ingestion of 500 ml of beetroot juice, blood pressure was substantially reduced, an effect that correlated with peak increases in plasma nitrite concentration, nitrite being the blood pressure reducing ingredient.
Beetroot and nitrate capsules are equally effective in lowering blood pressure indicating that it is the nitrate content of beetroot juice that underlies its potential to reduce blood pressure. It has also been found that only a small amount of juice is needed – just 250ml – to have this effect.
Beetroot for Cardiovascular Disease Prevention
Betaine, a nutrient found in beets and some other foods lowers plasma homocysteine, a possible risk factor for cardiovascular disease. Betaine supplements are manufactured as a byproduct of sugar beet processing. Betaine “supplementation” has however been found to increase blood LDL cholesterol and triglyceride concentrations in healthy humans, which may undo the potential benefits for cardiovascular health of betaine supplementation through homocysteine lowering.
Beetroot for Healthy Liver FunctionBeetroot contains the bioactive agent betaine, which supports healthy liver function. When the liver is functioning properly, fats are broken down efficiently, aiding weight loss, and preventing fatigue and nausea.
Beetroot for Cancer Prevention
The in vitro inhibitory effect of beet root extract on Epstein-Barr virus early antigen (EBV-EA) induction using Raji cells revealed a high order of activity compared to capsanthin, cranberry, red onion skin and short and long red bell peppers. An in vivo anti-tumor promoting activity evaluation against the mice skin and lung bioassays also revealed a significant tumor inhibitory effect. The combined findings suggest that beetroot ingestion can be a useful means to help prevent cancer.
In patients that had various forms of gastritis and gastric cancer, it was found that beet juice may inhibit or enhance N-nitrosodimethylamine (NDMA) formation depending on the gastric juice composition, pH in particular. In acid medium (pH-1.3-3.4) there was a trend to inhibition of NDMA synthesis, while in neutral and alkaline (pH = 7.4-8.5) medium NDMA synthesis is activated. N-nitrosodimethylamine is a nitrosamine, and is a suspected human carcinogen.
Glycemic Index of Beetroot
In a study to determine the estimated Glycemic Index of various foods, it was concluded that beetroot has a medium GI of 64.
Adverse Reactions from Beetroot
Beetroot and especially beet greens contain high levels of oxalate, and should be avoided by individuals with kidney stones containing oxalate
Beetroot contains nitrates and when they are cooked and left standing at room temperature, microorganisms that convert nitrates to nitrites begin to multiply, and the amount of nitrites in the beetroot rises. The nitrites combine with amines in the stomach to form nitrosamines, some of which are known carcinogens.
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