Sunlight and the Microbiome
By now, we all know the importance of having a robust microbiome, there being almost no area of health not influenced by our mix of gut bacteria. (If you find this material somewhat uninteresting, I suggest you read to the end, where we take an interesting detour.)
Thus, many studies have been done exploring the influence of a wide variety of variables which might impact the structure of the microbiome, improving or worsening its functionality. Such studies have looked at age, behaviour, diet, diseases, ethnicity, and gender.
One aspect that is understudied is the effect of sunlight on microbiome composition, and recently (Oct, 2019) a study used artificial sunlight to examine this variable. This Canadian study, done in Vancouver, “investigated whether repeated exposure of the skin to NB-UVB light would alter the gut microbiota composition of healthy female volunteers in a clinical pilot study.”
This UVB exposure did indeed have a significant effect on the composition of the subject’s microbiome (after repeated exposures) improving the diversity of their microbiota. The broadest benefits occurred among those who took no vitamin D supplements, and were D-deficient prior to beginning the study.
The vitamin D deficient participants started the study with significantly lower microbial diversity, compared to the group which had sufficient vitamin D levels, but after repeated UVB exposure, their diversity increased to the same level as the group with sufficient stores of vitamin D.
This was no real surprise to the researchers who observed that, “vitamin D deficiency has been previously correlated with microbial dysbiosis in both mice and humans”.
They concluded that “UVB light can rapidly modulate the gut microbiome without any dietary changes of the participants”.
Since the microbiome of those with sufficient vitamin D did not change much, already being at a healthy level, it was clear that seasonal variations in sunlight probably won’t have any obvious effects on healthy individuals. However, that is not true for those with immune dysfunction.
They noted that, “several chronic inflammatory diseases display seasonal patterns in the severity of disease (Watad et al., 2017). Specifically, the relapsing and remitting nature of IBD and MS are strongly associated with vitamin D levels (Munger et al., 2006; Abreu-Delgado et al., 2016; Watad et al., 2017). Exacerbations in IBD activity are commonly reported when serum vitamin D levels are low, with our data raising the question of whether these changes in disease activity could be precipitated by concurrent changes in microbiome composition.” (Study)
Based on the findings of this Canadian study, other researchers “revisited our data on a hunter-gatherer gut microbiome” (Yanomami, who inhabit the Amazon region). The Canadian study showed “an increase of biodiversity, Firmicutes and Proteobacteria, and a decrease of Bacteroidetes,” which was similar to the gut microbiome of the Yanomami people.
The review of the Yanomami study looked at the high amount of Proteobacteria they had, which at the time was considered to be a unique feature. However, once these scientists looked at the Canadian study, and found a similar abundance of Proteobacteria, they realized this was a feature of the high amount of sunlight the tribe was exposed to on a regular basis.
They concluded their review with this: “In this commentary, we would like to point out that the human lifestyle concerning sunlight exposure should be considered as one force modulating the gut microbiome, highlighting...a novel skin-gut axis which is associated with health and disease.” (Study)
A Whole Other Perspective
Now this material is all interesting, and none too surprising, but there is one other angle that has been overlooked by the aforementioned research.
My friend and coworker told me a story about sunlight and the microbiome, and was kind enough to find the video from which he derived this material (thanks Carmine).
Jeff Leach did microbiome research on an equatorial tribe called the Hadza. (The Hadza are a modern hunter-gatherer people living in northern Tanzania, one of the last hunter-gatherer tribes in Africa.) He gave them junk food, soda pop, and even antibiotics, in an attempt to alter their microbiome (they were willing participants in the experiment). However, this high sugar, low quality diet had virtually no impact on their microbiome.
This material is discussed by health expert, and neurosurgeon, Dr. Jack Kruse in this video: Jack Kruse on How Light sculpts Your Microbiome & Implications for Gut Health and Mental Illness - (Video Link) (If you wish to cut to the chase, go to around the 19 minute mark.)
According to Dr. Kruse, “When you put people in nature under the power of the sun, the microbiome doesn’t change with diet.”
However, it does change with the seasons, and with migration. Why does it change with migration? Because the latitude changes, and thus the amount of sunlight received.
According to Dr. Kruse, “every single cell on the planet, animal or plant releases a frequency of light” (extremely low frequency UV light), and “the microbiome is sculpted using light, water, and magnetism.”
(By magnetism he is referring to the Earth’s frequency, the Schumann resonance, which supports good health, and a healthy microbiome. Conversely, bad electromagnetic frequencies from cell phone antennae, wireless transmitters, smart meters, and other forms of electromagnetic pollution, disrupt the microbiome, and impede good health. I have covered this subject in detail in my new book, Health Secrets for the 21st Century: Volume Two.)
What all this implies is that our need for sunlight goes beyond its ability to produce vitamin D. We need sunlight to feed information to our cells, and the microbiome, and Dr. Kruse has gone so far as to suggest that sunglasses can actually impede the ideal functioning of the microbiome.
Sunglasses and Cancer?
I will end with a post about sunglasses, from Dr. Kruse’s facebook page:
“Still think sunglasses are OK? Possible carcinogenic effects from filtering natural light were found accidentally in a conversation Dr. John Ott had with Dr. Albert Schweitzer’s daughter. The conversation pertained to her experiences with her father at Lambarene, on the west coast of Africa, and the rate of cancer found among those people. She said that when her father had started the hospital, there was no cancer at all, but now it was a problem. She said that their simple surroundings had not changed or modernized.
The only thing different was that natives all wore sunglasses as a status symbol of the civilized world. They could always be found wearing them “even when paddling their dugout canoes wearing no more than a loin cloth. Sunglasses were so prized that these new adornments carried a higher barter value than beads or other trinkets.”