The impact of nutritional supplements on brain and cognitive function. Part 2

Herbal products and herbal extracts

A whole range of herbal products and herbal extracts is used to improve performance and speed up recovery after exercise. Among them the most popular are: polyphenols, ginseng, ginkgo biloba, flavonoids, cocoa flavonols, beetroot juice, Rhodiola rosea, sage, and guarana seeds. Extracted from fruits, vegetables and roots, these dietary supplements have effects on the central nervous system. Many of them improve cognitive function and slow down central level fatigue.

Polyphenols

Polyphenols are plant-based foods with powerful antioxidant properties. The main sources of polyphenols are tea, red wine, cocoa, and coffee. Polyphenols are divided into two large groups: flavonoids and non-flavonoids.

The non-flavonoid group is divided into two classes:

•  phenolic acids (ester of quinic and chlorogenic acids) found in blueberries, plums, kiwi, and apples;
•  hydroxycinnamic acids and stilbenes; the main stilbene is resperatrol, which is found in grapes, wine, and peanuts.

But the largest group of polyphenols is the group of flavonoids. There are six defined dietary groups of flavonoids:

•  flavones (apigenin, luteolin) are found in parsley, and celery;
•  flavanones/flavanonols (hesperetin, naringenin/astilbin, engeletin) found in citrus fruits, oregano, and wine;
•  isoflavones (daidzein, genistein) are found in soy;
•  flavonols (kaempferol, kvartsetin) found in onions, leeks, and broccoli;
•  flavanols (catechin, epicatechin, epigallocatechin, epigallocatechin gallate) are found in green tea, red wine, and chocolate;
•  anthocyanides (pelargonidin, cyanidin, malvidin) are found in red wine, and berries.

An interesting study by Francis et al., 2006; Scholey et al., 2008, shows that consumption of cocoa flavanols increases brain oxygenation during cognitive tasks. Consumption of tea and fruits rich in polyphenols and flavonoids slows down the progress of cerebrovascular diseases such as stroke, dementia, and other cognitive impairments. In a study by Einöther & Martens, 2013, consumption of black tea was shown to improve attention during complex tasks and to increase alertness.

One can consume polyphenols by consciously focusing on foods high in polyphenols, or by using supplements that have a much higher content of active substances. The effects of dietary polyphenols on the body include:

•  protection of neurons from damage caused by neurotoxins;
•  suppression of neuroinflammatory reactions;
•  improvement of memory and learning;
•  increase in cognitive functions;
•  improvement of working memory.

Studies examining the effects of polyphenols have shown a positive impact on athletic performance (Somerville et al., 2017), as well as a reduction in the risk of dementia and improved cognitive function.

Beetroot juice

Inorganic nitrate (NO3-) contained in beetroot juice, when taken into the body, is reduced through nitrite to nitric oxide. Due to this, beetroot juice has the following effects:

•  improves the function of vascular endothelium, including cerebral vessels;
•  lowers blood pressure;
•  reduces the use of oxygen during intense physical exercise;
•  prevents cognitive decline (Thompson et al., 2015);
•  improves cerebral blood flow, which in turn has a positive effect on cognitive functions (Wightman et al., 2015).

Ginseng

Ginseng is a well-known herb often used as a biostimulant for chronic fatigue, low mood, and decreased motivation. A study by Gorby et al., 2010, found that ginseng reduced fatigue and improved motor skills.

Ginkgo biloba (biloba)

The extract of this plant is widely used in oriental medicine as a means of improving memory and cognitive functions.

Gurana seeds

This plant is native to the Amazon, and its seeds are high in theophylline, theobromine, and caffeine. Theobromine, like caffeine, is an adenosine receptor antagonist and has cognitive enhancing properties. Authors Haskell et al., 2007; Kennedy et al., 2004, found that the use of guarana seeds improved mood, memory during attentional tasks, reduced mental fatigue, and increased performance on cognitive tasks.

Rhodiola rosea

Studies by De Bock et al., 2004, noted that Rhodiola rosea effects endurance. So, for example, taking 3 mg per 1 kg of body weight reduces the heart rate in response to maximum exercise by reducing the perception of the effort.

Sage

Kennedy et al., 2006, Tildesley et al., 2003, 2005, note that sage improves attention and memory.

The brain uses a record amount of energy compared to other organs and systems of the human body. A constant search of chemical substances, food products, and herbal supplements which, on the one hand, protect the brain, and, on the other hand, stimulate its functions, demands for more and more research. The role of nutritional supplements and herbal products in populations with Alzheimer's disease, dementia, and cognitive decline is still not well understood. This requires more of widely randomized trials with well-defined outcome measures before supplements can be said to have an undeniably beneficial effect on brain function. But with a rational attitude to our diet, with the right emphasis on certain groups of herbal and nutritional supplements, we can achieve a balanced, sparing attitude to our health, prolongation of life in conditions of wear and tear, and aging of the body.