The amino acid score is a good reflection of the digestibility of proteins and amino acids in our diet.Read More
A previous post discussed the harmful effects exposure to sunlight has on your skin, but there are also many positive effects of the sun.
1. Sunlight improves our mood – You will notice that more people are out, with smiles on their faces as the sun stimulates the brain to produce tryptamines that improve our mood.
2. Sunlight helps you make Vitamin D – Spending just 10 – 20 minutes a day in the sun enables us to produce Vitamin D, important for several reasons including strengthen bones, muscles and our immune system. Vitamin D may also lower the risk of certain cancers such as colon cancer. Low levels of Vitamin D can cause diseases such as osteoporosis and rickets in children.
3. Sunlight can improve your sleep – Sunlight that hits our eyes helps to reset our biological clocks thus improving quality of our sleep. In the morning, cortisol, a key steroid hormone for normal health, is at highest, and exposure to bright light in the morning can help regulate its levels. During the day, we release serotonin, a hormone required for calming and focusing the mind. And at night, our bodies are triggered into releasing melatonin to help us go to sleep.
Low levels of serotonin, such as when there is a decrease in sun exposure, can lead to a higher risks of seasonal affective disorder (SAD), common through the winter months when the days are shorter and the nights longer. Patients with SAD are treated with phototherapy in the form of a special light box to stimulate the brain to make more serotonin and less melatonin.
4. Sunlight can treat skin conditions – Gradual exposure to sunlight can also be used to treat various conditions such as psoriasis jaundice, eczema, and acne, however, the benefits of this form of therapy will vary from person to person.
5. Sunlight can act as a natural disinfectant – As UV rays can damage our cells, they can also damage bacteria and other microorganisms. UV lamps are regularly used to disinfect and sterilise instruments.
Being out and enjoying the sunlight has many positive effects including boasting your mood, reducing depression, strengthening our bones and treating certain skin conditions. So when the sun is out, enjoy the benefits.
You know that wonderful feeling of having the sun on your skin; it signals the beginning of summer, and you go about your day with a smile on your face and sense of wellbeing.
Though the sun has other wonderful benefits, it can unfortunately also lead to skin damage ranging from sunburn and premature skin ageing, to potentially causing skin cancers. It is the ultraviolet (UV) light that actually causes these effects on your skin. There are three types of UV light that are classified according to their wavelength; UVA, UVB and UVC.
As sunlight passes through the atmosphere, all of the UVC (short wavelength; 100-280nm) is absorbed by the ozone, so we can affectively ignore this type (see Figure 1).
Most of the UVB (medium wavelength; 280-315nm) is also absorbed before it can reach your skin, however, with the depletion of the ozone, we are exposed to higher levels of UV radiation, particularly UVB. UVB results in the immediate effect of being in the sun, such as tanning. This is caused by the production of melanin by melanocytes (the pigment producing cells) providing your skin with natural protection against UV radiation.
Sunburn, that develops into peeling of skin and inflammation, is due to more UVB rays absorbed than the level of melanin in the skin can protect you from. UVB rays also slows down the production of collagen, required for structural support of our skin with elastin. This results in some of the long term effects of repeated sun exposure, such as premature skin ageing with the appearance of wrinkles, sagging of the skin, sun spots, and a rough and leathery skin texture. Though it cannot penetrate beyond the superficial layers of the skin, eventually UVB exposure will significantly increase the risk of developing skin cancer (see Figure 2).
UVA, with the longest wavelength (315-400nm) and accounting for ~95% of UV radiation, is not significantly stopped by the atmosphere (see Figure 1). As with UVB, UVA will induce the production of melanin and also contribute to premature skin ageing and wrinkling. But because UVA rays can penetrate deeper into the layers of the skin, it can also cause DNA damage that can ultimately lead to cancer.
It’s worth noting that using a sun-bed, which uses UV light, will also have these effects on your skin. If you do use one, maybe use it less often if you can’t stop completely.
Look out for the next few posts on how to protect you skin while still enjoying the benefits of being in the sun.
This week, doctors in the UK have been granted permission to use the ‘three-parent’ technique to prevent the inheritance of incurable genetic diseases.
This method was first used last year to help a Jordanian couple, whose first two children died of Leigh Syndrome, have a healthy child. Leigh syndrome is a severe neurological disorder that affects the central nervous system, occurring in about 1 in 40,000 newborns. There are several different mutations that can cause this disease found in both nuclear DNA, the main genetic information of cells found in the nucleus, and mitochondrial DNA, that only has about 37 genes. Mitochondria are organelles within our cells that regulate the production of energy, and are inherited only from the mother.
The aim of this procedure is to prevent the mother’s affected mitochondria, carrying mutations for any mitochondrial disease, of being passes on to her children.
The method approved in the UK, is the fertilization of both the mother’s and donor’s eggs with the father’s sperm first. The nucleus is then removed before they divide into early-stage embryos. The mother’s nucleus is then placed into the donor’s egg, while the nucleus of the donor is destroyed. The resulting egg has the nucleus of the mother, but importantly the healthy mitochondrial DNA of the donor. Unfortunately, this requires that one of the embryo’s is destroyed, which some parents may be opposed to, as with the aforementioned Jordanian couple.
In the second method, the nucleus of the mother is removed and inserted into the egg of a donor, which had its own nucleus removed. The resulting egg is then fertilised with the sperm of the father. This method was successfully used in 2016, resulting in the birth of a healthy baby boy.
There is still controversy over the three-parent baby technique. This technique does have the potential of helping many couples have a healthy child, and reducing the risk of these mitochondria diseases being passed on to future generations. However, there is the possibility that mitochondria carrying the mutation could still be carried over, replicate and increase in number over time, and thus potentially cause the disease to appear at a later date. But with one in 5,000 children being born with a mitochondrial disease that are often fatal, this reproductive choice is welcomed by many affected parents.
The simple act of chewing for longer and eating slowly has many benefits, and all it takes is a few extra minutes to start gaining these amazing effects:
1. Lose weight. Studies have shown that you consume 88 fewer calories when eating your food slowly compared to eating it fast. In addition, eating slower increases the feeling of fullness for longer. This is due to a variety of hormones and feedback loops. Leptin, for example, is a hormone secreted by the adipocytes in direct proportion to high calorie intake. Leptin triggers the release of melanocortin from the hypothalamus, and melanocortin then acts to decreases the appetite, preventing overeating and giving you the feeling of fullness. This feedback loop takes about 20 minutes, so eating fast doesn’t give the body enough time for this process to work, and we continue to eat.
2. Improve digestion. Digestion begins in the mouth through the process of mastication (chewing), and by the digestive enzymes in the saliva. Chewing for longer breaks the food into smaller particles, while the saliva lubricates and soften the food particles making them easier to digest, and therefore more nutrients are taken up by the cells.
3. Less stress. Leptin has also been shown to interact with the neurotransmitter dopamine to regulate food intake and mood behaviours. Leptin raises dopamine levels and thus the rewarding effects and pleasure of eating the food. Not giving enough time for this response to occur by eating fast, means that more food is consumed to feel better.
4. Reduces the risk of diabetes. Chewing for longer (number of chews), or chewing slower, and thereby eating slower, has also been shown to prevent the occurrence of diabetes. This can be associated to a lower tendency to be overweight because of the feeling of fullness, making it less likely to eat unless you are actually hungry.
5. Enjoy good food. Taking your time and being mindful of what you eat will enable you to really enjoy and savour the complex flavours of foods. Processed foods that rely on tasting great when eaten quickly, will taste rather bland when you eat them slower. You will find yourself making better meal choices and enjoying the higher quality foods more by simply chewing for longer.
Taking your time to chew your food and eating slow is not easy when you are used to eating fast, but shouldn’t the benefits of adopting this simple act into your lifestyle make it worth a try?
The Maillard reaction, first described in 1912, is a complex network of reactions, that starts with a reducing sugar, such as glucose, and an amino residue with a protein.
Step 1: Condensation of an aldose reducing sugar, such as glucose, with an amino group within the R-group an amino residue of a protein, for example a lysine residue.
Step 2: The product of the glycation reaction in Step 1 is an unstable aldimine that will spontaneously rearrange into a more stable ketoamine, also known as the Amadori product. If the starting reducing sugar is glucose, the Amadori product is fructoselysine.
Step 3: The Amadori products can then degraded by different pathways that can depend on the pH (acidic pH favours formation of furfurals while a basic pH results in the formation of reductones), or can be oxidatively decomposed to a wide range of reactive carbonyl and dicarbonyl compounds.
Step 4: The Strecker degradation of these reactive carbonyl and dicarbonyl compounds result in Strecker aldehydes, and aminoketones that condense to form pyrazines. It is the Strecker aldehydes and the pyrazines that contribute to the aroma of food as they are heated.
Step 5: Aldol condensation of the furfurals, reductones, and Strecker aldehydes formed from Step 3 & 4 then occurs with or without amino compounds resulting in polymers called melanoidins. It is these that contribute to the colour of food (browning).
The Maillard reaction products can lead to the formation of the carcinogen acrylamide. The amount of these depends on the way the food is processes and pH. It also can depend on the amino acid and reducing sugar. For example, condensation of asparagine with glucose results in an N-glycoside, and decarboxylation and heterolytic cleavage of the nitrogen-carbon bond produces acrylamide.
Rydberg, P., Eriksson, S., Tareke, E., Karlsson, P., Ehrenberg, L., Rornqvist, M. (2005). Factors that influence the acrylamide content of heated foods. Adv Exp Med Biol. 561, pp. 317-328. PubMed Abstract
Stadler, RH., Blank, I., Varga, N., Robert, F., Hau, J., Guy, PA., Rober, MC., Riediker, S. (2002). Acrylamide from Maillard reaction products. Nature, 3; 419 (6906), pp. 449-50. PubMed Abstract
Zhang, Q., Ames, JM., Smith, RD., Baynes, JW., Metz, TO. (2009). A Perspective on the Maillard Reaction and the Analysis of Protein Glycation by Mass Spectrometry: Probing the Pathogenesis of Chronic Disease. J Protemome Res. 6; 8(2): pp. 754-769. PubMed Article
A recent campaign from the UK Food Standards Agency (FSA) issued a warning about eating starchy foods, such as potatoes, bread, pasta, rice and cereals, that are too brown or crispy. Basically anything that has been toasted, roasted, baked, fried or grilled at high temperatures for a long period is not good for you! I wanted to know why I was told I should no longer enjoy having crispy roast potatoes or browned toast, when there are probably a lot more dangerous health hazards I should be worried about.
The chemical reaction that occurs when we cook our food is called the Maillard Reaction; named after the scientist that first described this reaction in 1912. As we cook or heat our food, the aroma and colour change, or browning, of the food is due to some of the Maillard reaction products (MRP).
The MRP also have beneficial effects on our health included antioxidants, that help prevent damage to cells, and bactericidal, preventing the growth of bacteria.
Unfortunately, the MRP can lead to the production of acrylamide. Acrylamide is a known carcinogen, which means that exposure to this chemical can lead and contribute to an increased risk to cancer.
The FSA's slogan “Go for Gold” tell us what we should aim for. So instead of roasting your potatoes etc. until they are crispy and browned, go for a light gold colour. After all, it is the colour of champions! But if that’s the only way you will have them, enjoy them in moderation.