Dr. Richard Harris
Shift work is essential to modern life; however, it is not without health risks. I experienced a dramatic worsening of my mental and physical health after switching to an exclusively night 12-hour shift. Long-term shift work is associated with cardiovascular diseases and mental health disorders. Shift work is also associated with unhealthy lifestyles. This study aimed to examine the association of shift work with anxiety and depression and the potential role lifestyle factors play in mediating shift work-associated anxiety and depression.
After following participants for up to 9 years, shift work was associated with a 22% increased risk of depression and a 16% increased risk of anxiety. When examining the mediation effects of lifestyle factors, four factors explained 31.3% of the association with depression, and three factors explained 21.2% of the association with anxiety. Those factors were smoking, sleep duration, sedentary time (depression only), and BMI. Of those factors, BMI was the strongest mediating factor.
An interesting finding was that the longer a person did shift work, the lower the risk of anxiety and depression, pointing towards adaptation to the new environment. This study lends evidence to something I've long advocated for. If you are working shift work, it's essential to try and optimize other lifestyle factors to minimize the health risks associated with shift work.
We have talked about BDNF before, but as a quick refresher, BDNF is an important brain growth factor. Previous trials have associated increases in BDNF with cognitive and behavioral performance increases. BDNF also seems to play a role in energy balance, appetite, and glucose and insulin signaling. Evidence suggests that lower levels of BDNF are associated with type 2 diabetes, obesity, cardiovascular disease, and neurocognitive diseases like Alzheimer's.
This study of studies found that BDNF levels were considerably higher in those who took omega-3 supplementation compared to control groups, especially when it was taken for 10 weeks or more. The authors also saw a more significant effect in doses less than 1500 mg per day, but this may be due to people with certain health conditions associated with lower BDNF levels taking higher doses of omega-3 supplementation. Also, some of the studies included used a placebo, while others used different oils as the control, which may impact comparisons.
However, this study adds to the evidence supporting omega-3 supplementation for brain health. I take 2g of fish oil daily because I don't particularly like oily fish. I also add crushed flax seeds to my Greek yogurt every morning. Not everyone needs to supplement with fish oil. I take a higher amount (the normal starting supplementation amount is 1g) because there is some evidence to support that those with the APOE4 allele may need higher doses of omega-3 fatty acids to decrease brain levels (PMID: 32690472).