L-Theanine and the Brain

Posted on March 21, 2024 by Robert Barrington

L-theanine (N-ethyl-L-glutamine) is a non-proteinaceous amino acid that is found in high amounts almost exclusively in tea (Camellia sinensis). In fact, L-theanine accounts for around 50 % of the amino acids in tea leaves. L-theanine is structurally similar to glutamic acid. L-theanine is of interest nutritionally because it appears to have an ability to increase calmness and focus in humans and this relates to the way it interacts with the brain. L-theanine is able to cross the blood brain barrier and here it can interact with neurones such as the N-methyl-D-aspartate (NMDA) receptor to antagonise its activity. This reduces the excitability of the brain and therefore explains the calming effects of the amino acid. L-theanine also appears to be able to increase synthesis of a number of neurotransmitters including GABA, serotonin and dopamine, and this may have particular mood-elevating effects. Drinking tea has been shown to have these effects, but L-theamine can also be taken as a supplement in powder form.  

Eat Well, Stay Healthy, Protect Yourself

RdB 

Nathan, P.J., Lu, K., Gray, M. and Oliver, C. 2006. The neuropharmacology of L-theanine (N-ethyl-L-glutamine) a possible neuroprotective and cognitive enhancing agent. Journal of Herbal Pharmacotherapy. 6(2): 21-30
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Glycine

Posted on March 20, 2024 by Robert Barrington

Glycine is the simplest and smallest amino acid and is the only amino acid in human nutrition that does not show chirality. Glycine plays a number of important roles in human metabolism, including as a substrate for the cellular antioxidant glutathione. Glycine has a number of physiological effects that include anti-inflammatory, cytoprotective and immunomodulatory effects, and as such it can affect a number of physiological systems and modulate the course of a number of diseases. One important brain function of glycine is its ability to bind partially to the N-methyl D-aspartate (NMDA) receptor. This may be important in reducing the excitability of the brain, and by binding in this way, glycine may protect NMDA receipts from becoming overstimulated by other agonists. Normal blood levels of glycine in humans are around 300 micromolar, but ingesting glycine can increase blood levels to 900 micromolar. Studies suggest that high intakes of glycine are safe, but it is not clear how much is required to benefit health. 

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RdB

Pérez-Torres, I., María Zuniga-Munoz, A. and Guarner-Lans, V. 2017. Beneficial effects of the amino acid glycine. Mini reviews in medicinal chemistry. 17(1): 15-32
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Lutein and Zeaxanthin in Foods: Eye Health

Posted on March 19, 2024 by Robert Barrington

Lutein and zeaxanthin are carotenoids that have a particular role to play in human health. Both compounds accumulate in the macula of the eye, and here they protect the retina and other parts from free radicals through their antioxidant activity. A diet high in lutein and zeaxanthin is therefore beneficial to eye health and can significantly reduce the risk of specific eye disorders related to free radical damage. Dietary sources of lutein and zeaxanthin tend to have strong yellow colours as these pigments reflect the light waves necessary to be visualised as yellow. Foods such as egg yolks and yellow flower petals are often rich sources of lutein and zeaxanthin. However, lutein and zeaxanthin can also be found in green leafy vegetables such as kale, parsley and spinach, with the green chlorophyll pigment masking the yellow colour of the carotenoids. Generally, plant diets are high in both lutein and zeaxanthin, but eating foods that contain higher amounts can be a good strategy to optimise eye health and protect eyesight. 

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RdB

Abdel-Aal, E.S.M., Akhtar, H., Zaheer, K. and Ali, R. 2013 Dietary Sources of Lutein and Zeaxanthin Carotenoids and Their Role in Eye Health. Nutrients. 5: 1169-1185
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Chlorophyll in Human Nutrition

Posted on March 18, 2024 by Robert Barrington

Chlorophyll is one of the most ubiquitous chemicals in the human diet and makes up a considerable amount of the micronutrient intake when a high plant food diet is eaten. Chlorophyll is a pigment in plants that is structurally similar to human haemoglobin apart from the presence of magnesium ions rather than iron ions. Chlorophyll may have a number of health effects in humans and in particular it may be able to modify the process that can lead to the formation of cancers. One way this may occur is through the modification of oxidative stress through an antioxidant process that is present in certain chlorophyll metabolites. Of course one of the major benefits of eating more chlorophyll from plants is that with the chlorophyll many other useful and health giving nutrients are consumed. High chlorophyll diets therefore tend to be high in many beneficial phytochemicals, many of which possess antioxidant, anti-cancer, cardioprotective and anti-inflammatory effects. 

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RdB

Hayes, M. and Ferruzzi, M.G. 2020. Update on the bioavailability and chemopreventative mechanisms of dietary chlorophyll derivatives. Nutrition Research. 81: 19-37
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The Functions of Glycine

Posted on March 15, 2024 by Robert Barrington

Glycine represents around 11.5 % of the total amino acids in humans and roughly 20 % of the nitrogen from amino acids in proteins. However, glycine is not essential because it can be synthesised from other chemicals including choline, glyoxylate and the amino acid threonine. Glycine is used by the body for a number of functions and the wide variety of its uses means that the body has a high requirement to synthesise it. For example glycine is required for the formation of collagen, where it forms every third residue in the triple helical structure. Glycine is also required for the formation of the cellular antioxidant glutathione. The energy system of the body relies on glycine because it is needed for the synthesis of creatine, which forms the high energy creatine phosphate compound in cells. Purine in the form of DNA and RNA both require glycine, as does the oxygen carrying compound haem. Another highly important function of glycine is the formation of bile acids, which are pivotal in the digestion and absorption of lipids. 

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RdB

Wang, W., Wu, Z., Dai, Z., Yang, Y., Wang, J. and Wu, G. 2013. Glycine metabolism in animals and humans: implications for nutrition and health. Amino Acids. 45(3): 463-477
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The Temporal Component of Food

Posted on March 14, 2024 by Robert Barrington

Unless considerable time and effort is spent learning about nutrition, the superficial viewpoint will never fully uncover the secrets it possesses. One great example of this is how the nutritional component within foods change over time. Looking at a particular food at time point A can give a different picture of the same frood at time point B. Bananas for example when unripe and high in starch. As the banana ripens the starch is converted to sugar and therefore the nutritional quality of the banana changes. This can have significant effects on the consumer as not only are the macronutrients they ingest different, but those macronutrients affect metabolism in different ways. Another great example of this are fatty acids, that slowly degrade over time and become rancid. A healthy food at time point A, can therefore become an unhealthy food at time point B. Understanding the changing nutrition of foods is part of understanding nutrition, and without this knowledge, the one-size fits all advice will likely mislead the consumer to ill health. 

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RdB

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Edible Flowers

Posted on March 13, 2024 by Robert Barrington

Flower petals are brightly coloured as the purpose of the petals is to attract insects that can pollinate the plant. The plant uses a variety of phytochemicals to colour its petals and some of these have interesting nutritional properties. Two of the most commonly used phytochemicals that plants accumulate in petals include anthocyanins, which have a red, blue or purple colour, and carotenoids, which can be red, yellow or orange. Traditional Japanese, Chinese and Indian medicine all incorporate flowers from plants as part of their medical treatments in certain forms, and teas such as jasmine tea (Jasminum), made from Jasmine flowers, has become popular in the West for its calming effects.  In Europe, marigold (Calendula officinalis), geranium (Geranium macrorrhizum), bougainvillaea (Bougainvillaea spectabilis) and Jerusalem artichoke (Helianthus tuberosus) are all edible and have a traditional culinary use. Health effects of flowers generally derive from their high antioxidant content. 

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RdB

Petrova, I., Petkova, N. and Ivanov, I. 2016. Five edible flowers–valuable source of antioxidants in human nutrition. International Journal of Pharmacognosy and Phytochemical Research. 8(4): 604-610
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How Costly is Chicken and Fish Farming?

Posted on March 12, 2024 by Robert Barrington

Chicken and salmon farming both have considerable environmental impacts when compared to more sustainable plant based practices of agriculture. Studies show that chicken farming is more efficient when compared to salmon farming and also cod fishing with a trawler. This likely relates to the fact that chickens are easy to feed and house and grow quickly. Salmon is more intensive as a method of farming, particularly as salmon farming requires a high use of chemicals in order to prevent the fish becoming ill. Cod fishing is also energy intensive because of the requirement to use a trawler, which necessitates the use of expensive equipment. Another factor is the huge area required for fishing compared to the small area required for growing chickens. However, compared to plants, all animal protein is significantly more costly in terms of time, energy and resources, with planting, harvesting and storing taking up most of the energy needs.  

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RdB

Ellingsen, H. and Aanondsen, S.A. 2006. Environmental impacts of wild caught cod and farmed Salmon-a comparison with chicken (7 pp). The International Journal of Life Cycle Assessment. 11(1): 60-65
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The Best Antioxidant for Your Brain?

Posted on March 11, 2024 by Robert Barrington

The human brain is composed of a high concentration of lipids, many of which are phospholipids and their derivatives. Diets rich in essential fatty acids improve brain function and efficiency. However, the essential fatty acids are polyunsaturated, and this increases the susceptibility of the brain to free radical damage. Free radical damage is highly detrimental to the long term health of the brain and a significant factor in the development of dementia and mood disorders. Because the brain is composed of high amounts of fat, the best antioxidants are those that protect fats. Of these the most useful is perhaps the vitamin E vitamers that are composed of the tocotrienols and the tocopherols. These vitamins accumulate in cell membranes and protect the fatty acids for free radicals which lower the risk of lipid peroxidation and disease. Nature has cleverly packages polyunsaturated fatty acids with vitamin E in the most common source, nuts and seeds, and so consumption of these foods negates the necessity to consume additional vitamin E. 

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RdB

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Why Honey is Not The Same as Sugar

Posted on March 8, 2024 by Robert Barrington

Evidence shows that refined crystalline sugars, including sucrose and fructose are detrimental to the health. This relates to the way the fructose molecule is able to decrease the insulin sensitivity of cells, something that causes metabolic dysfunction, weight gain and fatty liver disease. Honey contains sucrose and fructose in high amounts, and yet studies consistently show that honey does not have the same negative effects. It is not fully understood why this might be so, but a number of lines of evidence exist. In particular, honey contains high amounts of antioxidants in the form of polyphenols, and these may protect the consumer from the negative effects of the sucrose and fructose by reducing the risk of insulin resistance developing. This may be because for insulin resistance to develop a free radical process must happen, but the polyphenols interfere with the generation of free radicals and therefore prevent the negative effects. However, as with all foods honey should still be moderated if consumed as part of a healthy diet. 

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RdB

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