MAHA Report Recognizes the Impact of Light on Health
Join me in designing a large-scale intervention study on Healthy Light Exposure in Children
On May 21st in this newsletter, I raised my concerns that the Make America Healthy Again (MAHA) Commission would focus on ultra-processed foods, and might not address the problem of daylight deprivation and evening blue-rich light exposure.
Then on May 22nd MAHA published the first draft of its report “Making Our Children Healthy Again (Assessment),” and I was delighted to find that the issue of light and health was addressed.
Criticism in the media has questioned the rigorousness of the science, and challenged the accuracy of some of the citations on which the MAHA report relies. This led to the release of an updated MAHA report on May 30th. But I will just focus on my area of expertise - the impact of light on health.
MAHA Report is Correct on the Impact of Light on Health
The statements in the revised MAHA report on the adverse impact of daylight deprivation and artificial light exposure at night on health, while limited, are fundamentally correct as shown in the extracts below.
The MAHA report does not specifically flag the problem with evening use of narrow spectrum blue-rich LED lights, or the loss of infrared light indoors, but it does place the issue of light and health on the agenda. One could also quibble with the scientific citations they chose to use - but my book THE LIGHT DOCTOR1 provides 247 scientific citations for those who want to access the broader literature on this topic.
MAHA Recommendations
The recommendations in this MAHA assessment report are focused on children’s health, although they would also be very relevant to adult health. The importance of studying light exposure was recognized as show in the extract below:
Design of Large Scale Intervention Studies on Children’s Light Exposure
The science-based recommendations for healthy lighting are straightforward, but they require changes to lifestyle behavior and the choice of lights. For optimal health, children should be exposed during the day to natural unfiltered daylight, or to circadian blue-enriched artificial light when indoors. And during the evening they should be exposed to blue-free light, and then sleep in the dark at night.
MAHA calls for large-scale intervention studies that embed real-world randomized controlled trials. These will be valuable in helping to convince the lighting industry, and the purchasers and users of lighting, of the health, wellness, and productivity benefits of circadian lighting.
The challenge is to develop data that supports a meaningful and convincing return on investment (ROI). The leading scientists working on the intersection of light and health agree that all lighting should support circadian health2, but light fixtures and light bulbs that modulate day versus night exposure to the critical circadian blue wavelengths are currently more expensive than conventional static, but harmful, blue-rich LED lights.
I invite my readers to collaborate in the conception of the most effective randomized controlled trials that could be undertaken under real-world conditions to address this challenge. Here are some initial ideas to start a discussion.
Study population and environment
During a typical day or week, children are exposed to a wide variety of lighting conditions in their homes, their bedrooms, their schools, their sports and extracurricular activities, and their play dates and overnight sleepovers. This makes control of lighting exposure and its spectral content very challenging.
To reduce this variability, one could envisage recruiting multiple boarding schools, some of which would serve as controls, and some would implement circadian lighting. During the school term, the lighting exposure across each 24/7 week for that potential study population of children is relatively consistent and predictable. Furthermore, the daily schedule, nutrition, and other aspects of the environment are relatively well controlled.
Unlike hospitals, or other places where children are in a controlled environment, boarding school children represent a relatively healthy population. The downside is that children who attend boarding school are not a representative sample of all children, but in terms of collecting data in well-defined conditions essential for reaching statistically valid conclusions, the boarding school population is hard to beat.
Lighting Interventions
Any circadian lighting evaluated in these trials must meet well-defined, scientifically validated standards, such as providing less than 2% 440 to 495 nm blue light after sunset and providing greater than 20% 440 to 495 nm blue light during daytime hours. Lighting vendors have been very loose, and somewhat unscrupulous, in claiming that their lighting products are “circadian”, when in fact many of these products just vary the CCT (coordinated color temperature) of the lights. Even when changing from 6000 K to 2700 K CCT, the relative change in circadian blue (440-495 nm) content can be relatively minimal. Changing color is not enough; the spectral content and intensity of the light falling at eye level are critical for the physiological effects and health benefits.
Lighting Exposure Measurements
Even in a boarding school environment, the exposure of each child to light across the 24-hour day will vary depending on their activities. It will be vital to continuously document the spectral composition and the intensity of the light falling on each child across each 24-hour day, as was done by Sean Cain and his colleagues in the chart below3.
Just measuring lux is not enough. Lux predominately measures the green and yellow content of the light that determines visual brightness, but does not take into account the other critical wavelengths, such as ultraviolet, violet, blue, red, and infrared light.
Because of the recognized importance of near ultraviolet and near infrared light the maximum value to these studies would be gained by using portable spectrophotometers that measure not only the visible wavelengths but also the invisible spectrum to which the children are exposed. One such device is the BLE spectral radiometer from NanoLambda. For example, the W1 type XL-500 can continuously measure light wavelengths from 340 nm to 1010 nm. Another device is the MiEye from Circadian Health Innovators which captures just the visible spectral range from 400 to 720nm. I would be interested to learn from my readers what other continuously measuring portable spectrophotometers are available and what spectral ranges they track.
Other outcome measures
In terms of health measurements, we have to consider which metrics would be the least stressful for the children involved in the studies.
Continuous tracking of activity and sleep can be provided by a wide range of potable technologies, and numerous studies have evaluated the relative reliability of these devices.
It would also be helpful to track body temperature to estimate circadian phase and synchronization to the light-dark cycle. Again, there are several devices that can gain this data noninvasively.
Body weight and height can easily be obtained by monthly measurements, and from these, the body mass index can be calculated.
The rising epidemic of myopia (short-sightedness) in children has been linked to insufficient exposure to natural full spectrum daylight. Hence eye exams at the beginning and end of each school term should be obtained under different lighting conditions
Metabolic disorders are a well-known consequence of artificial LED lighting. For obvious reasons, blood sampling should be minimized. However, there are some tests that could be done only at the beginning and end of each school term to evaluate specific lighting conditions. For example, the hemoglobin A1c test is a blood test that assesses the average level of blood sugar over the past 2-3 months.
Other Parallel Studies
I have outlined here just one of the issues that should be addressed in large scale inventions studies. The use of circadian blue blocking glasses, the most effective time of day for near infrared exposure, the spectral characteristics that reduce the risk of myopia. and other related issues should also be considered.
Further Resources
For more remarkable insights into what we have done to ourselves by moving indoors and switching on narrow spectrum blue-rich LED lights, see my book THE LIGHT DOCTOR.
Remember the light we see is as important our health as the food we eat, the water we drink, and the air we breathe.
Sources
Moore-Ede M, (2024) THE LIGHT DOCTOR: Using Light to Boost Health, Improve Sleep and Live Longer, CIRCADIAN Books
Moore-Ede M et al (2023) Lights should support circadian rhythms: evidence-based scientific consensus. Front. Photon 4: https://doi.org/10.3389/fphot.2023.1272934
Cain S. et al (2020) Evening home lighting adversely impacts the circadian system and sleep Scientific Reports 10:19110 | https://doi.org/10.1038/s41598-020-75622-4