Now a new study (1) has found that after taking a small dose of inorganic nitrate for three days, healthy people consume less oxygen while riding an exercise bike (a sign of improved exercise performance). The study traces that improved performance to increased efficiency of the mitochondria that power our cells.

The study scientists are not recommending that anyone take inorganic nitrate supplements – what they point out is that their results may offer an explanation for the well-known health benefits of vegetables and fruits, especially green leafy vegetables.   In a press release one of the scientists said (2)  “We’re talking about an amount of nitrate equivalent to what is found in two or three red beets or a plate of spinach,” “We know that diets rich in fruits and vegetables can help prevent cardiovascular disease and diabetes but the active nutrients haven’t been clear. This shows inorganic nitrate as a candidate to explain those benefits.”

Until recently nitrate wasn’t thought to have any particular nutritional value and it had even been suggested that this component of vegetables might be toxic.  However, these researchers had previously found that dietary nitrate, with the help of friendly bacteria in the mouth, feeds into a pathway in the body that produces nitric oxide. Nitric oxide is known to be a physiologically important molecule e.g.  It helps to opens up blood vessels which helps to lower blood pressure in the body (2).

This new study (1) suggests another benefit of nitrate and the nitric oxides that stem from them.   It appears that the nitric oxide makes the ‘powerhouses’ in our cells, the mitochondria, more efficient (by means of a complex mechanism that lowers the levels of a specific protein which normally makes the mitochondrial powerhouse leaky and less effective).  The study (1) involved healthy people who were given nitrate – the equivalent of 200-300g of spinach or lettuce for three days, after which they were given a cycling task to perform. The researchers then analysed samples from their thigh muscles and compared them with similar samples from the same subjects when they had taken a placebo (no nitrite) instead. After nitrate ingestion, a significant improvement was seen in the efficiency of the mitochondria, which consumed less oxygen and produced more of the energy-rich substance ATP per consumed oxygen molecule.

The study results do show that increased dietary nitrite, from beetroot or spinach consumption, can have quite an immediate effect.  However, it is not known what might happen in individuals who consume high levels of these kinds of fruit and vegetables over long periods of time.  The scientists are already planning further research studies and also want to repeat the experiment in people with conditions linked to mitochondrial dysfunction, including diabetes and cardiovascular disease, to see if they too enjoy the benefits of nitrates.

The researchers conclude (1): “Among the more consistent findings from nutritional research are the beneficial effects of a high intake of fruit and vegetables in protection against major disorders such as cardiovascular disease and diabetes,”  ”However, the underlying mechanism(s) responsible for these effects is still unclear, and trials with single nutrients have generally failed. It is tempting to speculate that boosting of the nitrate-nitrite-NO pathway may be one mechanism by which vegetables exert their protective effects.”

As an interesting side note the researchers say that the benefits of dietary nitrates suggest that powerful mouthwashes may have a downside. “We need oral bacteria for the first step in nitrate reduction,” “You could block the effects of inorganic nitrate if you use a strong mouthwash or spit [instead of swallowing your saliva]. In our view, strong mouthwashes are not good if you want this system to work.” (2)

A healthy diet is one which includes an abundance of different vegetables and fruits.  Beetroot and spinach are a healthy addition to any eating plan.  Arginine supplements are available to buy and have been shown to be useful to increase nitric oxide levels in the body.  The amino acid, Arginine, is a powerful vasodilator (blood vessel relaxer) and may help to support and maintain healthy blood flow and circulation. Arginine is also an antioxidant and helps support healthy arteries.  Always check with a medical doctor prior to taking any supplement.  Beetroot drinks and supplements are also available to buy but it is important to remember that supplements should never be viewed as a substitute for a healthy balanced diet and lifestyle.  Beetroot is also rich source of vitamins, minerals, antioxidant bioflavonoids (bioactive plant compounds) and fibre. 

(1) Larsen FJ et al.  2011.  Dietary Inorganic Nitrate Improves Mitochondrial Efficiency in Humans.  Cell Metabolism.  13(2):149-159

(2)Press release.  Cell Press (2011, February 1). Want more efficient muscles? Eat your spinach. ScienceDaily. Retrieved February 2, 2011, from http://www.sciencedaily.com­ /releases/2011/02/110201122226.htm

Written by Ani Kowal

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A recent study (1) has found that drinking beetroot juice can increase blood flow to the brain in older adults, such a finding may be of great importance in research related dementia prevention and treatment.  The research paper (1) mentions that there have already been many past studies that have shown how drinking beetroot juice can lower blood pressure.  This new study aimed to look at whether drinking beetroot juice could increase blood flow to the brain as well as to the rest of the body. 

Poor blood flow contributes to many disease states and may also be a factor in the decline of physical and cognitive [brain] function in aging.  In a press release (2) one of the study authors,  Daniel Kim-Shapiro,  said “There are areas in the brain that become poorly perfused as you age, and that’s believed to be associated with dementia and poor cognition.”

In this small preliminary study (1), the first to find a link between consumption of nitrate-rich beetroot juice and increased blood flow to the brain, researchers looked at how dietary nitrates affected 14 adults age 70 and older over a period of four days. 

On the first day (1,2), after a 10hour fast, the study participants completed a health status report and consumed either a high- or low-nitrate breakfast.  The high-nitrate breakfast included beetroot juice.  The individuals taking part in the study then went home with lunch, dinner and snacks conforming to their assigned diets.  The next day, following another 10-hour fast, the subjects returned to the research centre, where they ate their assigned breakfasts.  One hour after breakfast, an MRI [magnetic resonance imaging] scan recorded the blood flow in each subject’s brain.  Blood tests before and after breakfast were used to confirm nitrite levels in the body.  For the third and fourth days of the study, the researchers switched the diets and repeated the process for each subject.

The MRI scans showed that after eating a high-nitrate diet, the older adults had increased blood flow to the white matter of the frontal lobes in their brains.  These are the areas of the brain commonly associated with degeneration that leads to dementia and other cognitive conditions.  One of the study authors, Gary Miller, said in the press release (2) “I think these results are consistent and encouraging — that good diet consisting of a lot of fruits and vegetables can contribute to overall good health,”

The authors conclude (1) “These results suggest that dietary nitrate may be useful in improving regional brain perfusion in older adults in critical brain areas known to be involved in executive functioning”.

Beetroot drinks and supplements are available to buy but it is important to remember that supplements should not be viewed as a substitute for a healthy balanced diet and lifestyle.  Beetroot is also rich source of vitamins, minerals, antioxidant bioflavonoids (bioactive plant compounds) and fibre and would certainly be a good vegetable to include as part of a varied and balanced diet.  As mentioned in previous posts a plant based diet may well be helpful to keeping the brain healthy

(1)Presley TD et al.  2010.  Acute effect of a high nitrate diet on brain perfusion in older adults. Nitric Oxide.  DOI: 10.1016/j.niox.2010.10.002

(2)Press Release.  Wake Forest University (2010, November 2). Daily dose of beet juice promotes brain health in older adults. ScienceDaily. Retrieved November 3, 2010, from http://www.sciencedaily.com­ /releases/2010/11/101102130957.htm

Written by Ani Kowal

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