Survival of the Sickest, Part III, Vitamin D and Race

This will be my last post about this very thought provoking book, but first, I want to tell you about sunlight and Vitamin D as this health information is important and it might be the missing puzzle piece you need to solve your own health issues. This probably should be two blog entries for brevity-Vitamin D and Genetic Race, but I figure if you intend to read it, you will, if you aren't interested, you won't.

Sunlight, specifically UVB rays, prompts the body to manufacture Vit D from the cholesterol in the blood. If we have low cholesterol and don't get enough sun, we may become Vit D deficient. Sunlight also, in the balance of things, destroys folic acid, or folates in the body. If our cholesterol is low, cell membranes won't be repaired and the brains' messages to the immune system get lost and we are not protected against cancer and disease. Cholesterol is important in the production of estrogen and progesterone as well as Vitamin D. The UVB rays in sunlight are strongest when the sun is directly overhead and to get enough Vit D, we need 15-20 minutes a day of sun over 40% of our bodies, which is nearly impossible to do year around. Additionally, we are advised to avoid the high noon sun, and to wear sunscreen to prohibit UVB rays from hitting our skin. In winter, our cholesterol levels rise because the sun does not get high enough or stay high enough long enough to convert cholesterol to Vit D. Vit D also plays a part in our metabolism. Almost 60% of diabetics are deficient in Vit D, as are the obese. It is unknown whether the afflictions cause the deficiency or visa versa, but there is a relationship.

We all know that skin color varies by the amount of melanin it contains. Darker skin protects against sunburn, but it also reduces the amount of UVB that reaches the skin and that can lead to a Vit D deficiency, high cholesterol levels, and low folic acid levels. Melanocytes make melanin, and pituitary hormones control how much is made based on information that arrives at the pituitary via the optic nerve. When you go out in the sun, the eye measures the strength of the rays and sends a message to the pituitary glad to produce hormones that boost melanin production, so the cells make massive amounts of melanin to protect the skin from harmful rays. HOWEVER, guess what happens if you, like everyone does, wears sunglasses. Yup, you trick the pituitary gland into thinking that the sun is not as bright or harmful, and therefore the gland does not send the chemical signal for the melanocytes to make melanin. The end result is a sunburn, maybe even skin cancer. Secondary result is a depletion of folic acid in the body. Dark skinned peoples may not always be Vit D deficient due to the evolution of a protein called Apolipoprotein E, which pumps extra cholesterol from the liver into the blood so that sunlight can more effectively convert the cholesterol into Vitamin D. That might explain why some African Americans suffer more from heart disease resultant from high cholesterol levels. Similarly, the protein is also found in light skinned peoples that originate in the far north-like me. They don't have melanin in their skin to block UVB, but they live so far north that their UVB exposure is minimized. It might be that neither of these groups of people would need cholesterol lowering drugs like statins for life. Perhaps, just perhaps, a daily dose of UVB would be of more benefit. I'd choose the tanning bed, or move closer to the equator. Fortifying milk with Vit D doesn't really work for people of my ancestry. http://tinyurl.com/nk9mjc

For more information about Vitamin D, where you can find it and how much exposure you will have at certain locations and times, read this:

http://ods.od.nih.gov/factsheets/vitamind.asp

More and more, science is learning about the importance of this vitamin in immune response, cancer prevention, and general well being. Have your levels monitored the next time you have bloodwork drawn by the lab. Chances are, you will be deficient.


Of course, the point of Moalem's book is that one generation's evolutionary adaptive solution is another generation's disease producing nightmare, as high levels of cholesterol in the blood lead to heart disease and high levels of sugar in the blood leads to diabetes. The problem becomes exaggerated when populations are removed from the area where the adaption took place. In my case, I no longer live north of the Arctic circle like my Sami ancestors, so my body is not really adapted to the increased amount of sun at this latitude. I burn because I don't have enough melanin to protect me.

I hate the word 'race'. Race is a label that humans use to create separation and distance where there may be none. Race is defined based on visual observations, not genetics, because when you look at genetics, the house of race cards come tumbling down. There are populations of dark skinned North Africans who are genetically closer to fair skinned Europeans than other dark-skinned Africans. Race is a convention, and when it comes to evolution and adaptions, it doesn't always match the ethnic markers seen in certain populations. Dr. Moalem shares the case of Cohanim Jews who claim to be descendants of Moses' brother Aaron. DNA was collected from Cohanites from all corners of the globe. Their appearance was a spectrum of color, in skin and hair and eyes, yet they all shared very rare and distinct Y chromosome markers that date back to the time of Aaron 3180 years ago. It takes less than 10000 years for skin color to change in a population, and again, race is just a temporary convention-a way to group people, that should never be set in concrete because at best it points to a snapshot in time. Everyday, groups of people are adapting to their environment. People are getting influenza, sunburn, etc. For other people, their environments are climate and light controlled, or perhaps they are on supplements or medications that have changed their body functions. I feel that my ancestors left Africa early and headed towards modern day Iran. Interactions with the Mongul and Persians drove them northward into Russia, into Siberia. Eventually my ancestors were pushed westward to the Baltic and Arctic. Less sun exposure during those centuries slowed the melanin production, except for the melanocyte that controls freckles, that one went awry, I think.

Humans have been walking around for a million years, and we have been essentially the same for the last 100,000 years. Natural disasters and diseases have reduced our numbers, but evolution marches on and each human adapts to his environment. It is a dynamic process, not a static one. During the last 500 years, since Columbus 'discovered' America, the world has gotten smaller in the sense that there is more trade, more cultural exchange, and more interbreeding between peoples from different areas of the globe. In fact, there has been far more gene mixing than people realize. Discrimination based on what we refer to as race is simply idiotic. It makes about as much sense as discriminating based on where someone was born. Of course, there will always be people who discriminate because they have to find a way to make themselves more important than others.

Seriously, we are who we are, and that is a changing organism. When it comes to genetic predispositions and markers, it is not enough just to have a marker, but how many times that marker is present is also important. For example a gene call CYP2D6 affects drug metabolism. People who have only a few of these genes are slow metabolizers (maybe 10% of Caucasians) and it is even rarer in Asians (1%), however, Ethiopians often have as many as 13 copies of the gene, meaning that they metabolize drugs very quickly. Only 1% of Caucasians fall into that category. We can't just look at someone and say this person will metabolize drugs quickly based on their skin color. You NEED that gene study, and even with that, you still can't make assumptions, because the individual might have moved away from the location in which the original mutation occurred. An African living in NYC instead of equatorial Africa will probably have too much cholesterol in his blood and still be Vit D deficient. The CYP2D6 gene probably came into being because of polluted environments. The more toxins in an environment, that faster the body needs to process them through.

In the 20th century, there has been a correlation between sunspot peaks and flu epidemics. 6/9 sunspot peaks occurred in tandem with massive flu outbreaks. The worst outbreaks of the century, killing millions in 1918 and 1919, which followed the sunspot peak in 1917. Epidemics are thought to be causes by antigenic drift, when a mutation occurs in the DNA of a virus or a antigenic shift, when a virus acquires new genes from a related strain. It the virus changes or mutates a lot, our bodies will find it dissimilar to previous viruses and we will not have immunity to it, leading to pandemic conditions. These mutations, while not proven, could be a result of increased radiation from the sun.

There is a gene, CCR5-Delta 32, that blocks HIV from entering cells. One copy hampers the virus' ability to replicate, and if a person has more than one copy of this gene, it is like an immunity to HIV. It is estimated that 5-10% of Caucasians are immune, but sadly, Africans are not. It is unknown why this particular gene came into being, what the adaptive stimulus was.

Mitochondria might have originated as a bacteria that our cells married and integrated. Many viruses and bacteria not only shape our adaptive process, but we may be a result of integration of those microbes. Viruses that we may have incorporated into our DNA and that co-evolved with us are called "persisting viruses". If you think about this stuff long enough, it will creep you out to the point that you will start writing sci-fi horror books!