Health Myths

Dr Thanh-Tam Pham - 08/01/2023

Dr Roger Seheult gave an interesting talk about the common health myths based on scientific reviews.

       1. If you take Vitamin D supplement you do not need sunlight

Sunlight has many other benefits than just the production of Vitamin D.

Sunlight hit the retina of our eyes and stimulate the photosensitive neural ganglion cells and the signals go to:

Sunlight penetrates our skin up to 8cm deep to activate the receptors in mitochondria to produce melatonin. Mitochondria is the powerhouse of the cell and in the process of energy production, by- products are produced, the reactive oxygen species ROS, that in turn can damage the mitochondria. This can lead to less optimal health such as inflammation, cancer, dementia, diabetes and learning disabilities. The body has a system to counteract these ROS causing oxidative stress. At night, the pineal gland secretes melatonin and at daytime light exposure shut down the secretion of melatonin from the pineal gland. The body has another system to produce melatonin: the near infrared radiation (NIR) stimulates the production of melatonin in the mitochondria where it is needed. Melatonin is a powerful antioxidant to protect the body against damage.

       2. Take melatonin will give you the full benefit

Firstly, supplements are not regulated, and we do not know what amounts of ingredients we get in the supplements. Melatonin is the signal that it is time to sleep, and it will start to increase at around 9pm. Bright light exposure suppresses melatonin secretion. We cannot take melatonin during the day as it signals it is time to sleep so supplements do not solve the problem at daytime.

It was found that Covid 19 viruses prevent the formation of antioxidant and ROS increase in the blood causing damage to the cells and forming blood clots and hypoxemia. Melatonin is an antioxidant that is twice as powerful as vitamin E and it upregulates the anti-oxidant glutathione. Melatonin will get rid of ROS and protect the body. So, it is very important to have maximal melatonin at night by avoiding light exposure late and go outside in the sun so the body can make melatonin from the action of near infra-red light penetrating our body. The near infrared light is not good at penetrating the new E-glass through a window.

     3. I get plenty of sunlight at work through my window:

There are some changes in the lights at home. LED lights (energy efficient) emit no NIR light at all comparing to the old incandescent bulbs.

Low-E glass will not allow NIR to pass through comparing to regular glass used in the past, so we cannot have the full benefit of sunlight exposure indoors through a window.

     4. It makes no difference when I eat, a calorie is a calorie

The body has different tasks to do at night and daytime. During the day, we are eating so the body is building up and stores energy. At night, the body must repair abnormal cells, cleaning up waste products from metabolism. A study in 2012 found that insulin sensitivity is highest at breakfast than at lunch or dinner. Research studies were conducted to compare the effects of early time restricted eating like eating at 8am to 2pm only, instead of eating from 8am to 8pm. After 4 days, it was found that not only light affects the circadian rhythm but when we eat also affects the circadian genes clock.

In the time restricted eating groups, there were improvement in glycaemic control by lowering the 24-hour glucose levels, improved cortisol amplitude in the morning and improved hormones and genes relating to longevity such as the BDNF gene, SIRT1 and LC3A.

The BDNF gene provides instructions to make brain derived neurotropic factor in the brain and spinal cord. The protein promotes the survival of neurons by playing a role in the growth, maturation, differentiation, and maintenance of these cells.

SIRT1 promotes insulin secretion and action, upregulates fat metabolism, protects against inflammation, oxidative stress, and DNA damage, increases telomere stability, and extends lifespan.

LC3A is a structural protein of autophagosomal membranes and is a biomarker of autophagy. Autophagy has been shown to play a major role in protecting against multiple chronic diseases such as diabetes, heart disease, cancer, and neurodegenerative diseases, by recycling damaged and used proteins and organelles. A calorie is the same at day or at night, that is true for energy perspective but the effect to the body is not the same. For example, if you are driving from A to B at peak hours or at night, the time or the fuel needed to travel is not the same for the same distance. Therefore, there is a better time to eat.

      5. A fever should be treated

The innate immune system is strong in young children and is responsible for creating fever. The adaptive immune system is stronger with age as the body takes some years to make antibodies against pathogens from previous exposures. Babies and children tend to have high fever whereas old people may not have fever even in serious infections. Studies showed fever enhances Interferon gamma synthesis and alters the peripheral lymphocyte population. At 39 degrees, there was a 10-fold increase of interferon. In mild disease, interferon activity is very high and vice versa.

Fever is the body’s natural way to fight the infection. A note of caution is high fever in some children can cause seizures and delirium and therefore needs to be treated.

      6. Being in the cold gives you a cold

Spending too much time in cold air does not make you sick or have a viral illness. Studies found cold exposure can improve immunity to fight infections.  In fact, you are more likely to get sick indoors, where germs are easily passed. There is an explanation for why people catch more colds in winter as we spend more time in close quarters indoors.

There was a study showing that natural killer cells increased activity with a short period of cold exposure.

     7. An all-nighter is OK to do occasionally

A study in 2018 revealed why all-nighters staying awake at night and sleeping during the day may be dangerous for your health. Blood tests were done 4 hourly and there were some changes in more than 100 proteins affecting blood sugar, immune function, and metabolism. Glucagon rose higher at night than would normally be at daytime leading to risk of diabetes. FGF19 normally boost calorie burning, was found to decrease and there was less calorie burning and leading to risk of weight gain. Over time, these biochemical changes in blood protein levels can elevate your risk for health issues such as diabetes, weight gain and even cancer.