010: How to Know if Your Genetics Contribute to Your Sensitivity to Blue Light and Poor Sleep, and What to Do About it
Mastering Nutrition Episode 10
Originally published May 20, 2016.
In this episode, I answer a listener’s question about whether I am worried about my phosphorus intake and whether a high phosphorus intake is ok as long as it is balanced by calcium. I describe the biochemistry and physiology of the system that regulates calcium and phosphorus, their distribution in foods, how to determine the right balance in the diet, and how to use parathyroid hormone (PTH) as a blood measurement to assess whether the dietary balance is working for an individual.
In this episode, I show you how you can determine whether your genetics are contributing to your sensitivity to blue light, poor sleep, and poor daytime alertness, and what you can do about it. Specifically, I look at the research showing that variations in the gene for the vitamin A-dependent protein melanopsin underlie sensitivity to blue light and I teach you how to figure out your own genetics for this protein using a 23andMe account (they don’t have a health report for it, but the hack around that is easy).
This podcast is also available as a corresponding blog post. Read that post if you prefer to read the material rather than listen, or if you want to follow up the references.
Also check out my original post on melanopsin from a few months ago.
For my own sleep-optimization routine, check out Episode 5.
Since this episode is over an hour long, here is a guide to navigate through it more effectively:
0:00:30 cliff notes for people who want the take-home points in a few mintues
0:04:54 updates on meditation and chicken stock
0:11:20 how to navigate through this podcast and the two related blog posts
0:13:00 background on melanopsin and the other vitamin A-dependent opsins, and their roles in vision, pupillary constriction, and circadian rhythm
0:25:20 entrainment of the circadian rhythm vs. the acute response to light and darkness
0:29:45 the i394T polymorphism in the melanopsin gene
0:33:35 role of the C allele in greater light sensitivity: research methods
0:39:25 role of the C allele in greater light sensitivity: results
0:41:33 practical implications of having the C allele
0:48:50 how to figure out if you have the C allele
0:51:30 how to properly construct a light exposure routine
1:02:20 the importance of temperature and psychological wind-down routines
1:03:45 nutritional factors: A, B6, B12, folate, choline, betaine, protein, carbohydrate, timing
At 31:25, I apologize for the loud sirens. These were crazy loud when I was recording but I don’t hear them when listening to my podcast. Do you? If not, that says something good about my recording equipment.
To find your own melanopsin genetics, follow these instructions or use the video below:
In the upper right corner of the home screen, click on the drop-down arrow by your name, and select “browse raw data.”
Midway down the new page, you will see two text boxes, “Jump to a
gene” and “Jump to an SNP.” Copy and paste “rs1079610” (without the
quotes) into the text box to the right of “Jump to an SNP.”
You should see a new page that says “OPN4” on the left and says your
name and genotype on the right. Under your name, see whether it says
TT, CT, or CC.
If you have one or more C alleles, this indicates increased
sensitivity to disruptions of the natural light cycle caused by the use
of artificial lighting.
If you want extra help doing this, use this video, and skip to the 4 minute 15 second mark:
If you want to prioritize your light exposure to hack your sleep, here are links to the products I’ve found most useful and use myself:
For the computer screen, f.lux
Nightshift on the iphone 6 or later
If you learn your melanopsin genetics and have a story to share about whether optimizing your light exposure has or hasn’t helped your sleep and alertness, please share your story below! It would be great to use the comments as an easy way to initially crowdsource an inquiry into how strongly the genetics and the anecdotes correlate.
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