Separating Fact from Fiction

Here’s part two of our Coronavirus Myth Buster series and two more common ‘myths’ that are currently in circulation, reviewed from the perspective of scientific evidence.

1. Does staying indoors impact your immunity?

We’ve all done our part during the pandemic by staying at home and only stepping out for essential supplies. While this greatly reduced our chances of exposing ourselves and others, it unfortunately has led us to be more vulnerable in other ways. 

Being outdoors enables our body to produce vitamin D in response to sun exposure.  While the major natural source of vitamin D is from the sun, it can also be absorbed through nutritional supplementation. There are already numerous reported health benefits of vitamin D in boosting immunity, including this randomized trial of vitamin D supplementation to prevent seasonal influenza in schoolchildren.

Vitamin D enables our lungs to activate immune cells and to produce an antimicrobial peptide called cathelicidin, killing bacteria and viruses. Recent studies are indicating that people with low levels of vitamin D are at greater risk of complications due to COVID-19. Also, in Spain and Italy, the highest death rates from COVID-19 were from patients with the lowest levels of vitamin D. Many of the ‘at risk’ like the elderly spent most of their time indoors inspite of the sunny climates of these countries.

Although there is no published evidence proving that exercise protects us from COVID-19, this recently published study shows the importance of staying active during the pandemic as exercise training has been shown to improve immune responses to viral infections. Also, exercise reduces stress and increases the number and activity of our natural killer cells. 

Furthermore, if you can do that by exercising in your backyard, a park or forest, then so much the better. Studies have shown the health benefits of exercising and being outdoors but here is a systematic review of the health outcomes of greenspace exposure. 

My advice – Vitamin D supplementation should be monitored through lab results so ask your clinican about getting blood work done to determine how to optimize them. I get mine checked once a year and often supplement as I’m not spending enough time outdoors to obtain adequate levels. And with “stay at home” restrictions easing, you may want to venture out to your local park or trail/forest to get some hiking/biking and exposure to the great outdoors (within the social distancing guidelines, of course).

2. Should I be ‘fasting or dieting’ during the pandemic?

In one of my previous blogs, I wrote about the benefits of intermittent fasting (IF), which restricts eating times to certain periods of the day or certain days of the week. There are several published studies on the impact of fasting on metablic health and obesity/weight loss.

I’ve been a fan of IF myself and over time, worked up to a 14-15 hour fast (for example, I finish eating by 7pm and will delay breakfast until 9-10am). However, when I feel run down or tired, I do not stick to this self-imposed guideline and for good reason. According to Dr. Peter Attia, Chief Medical Officer of the fasting app Zero, he recommends not starting a fasting protocol during this time nor doing multi-day fasts as it will cause a cortisol spike and depress your immune system. If you’re already on an IF plan like me, he suggests that sticking to that schedule shouldn’t be a problem but let your body guide you. During the pandemic, I have shortened my fasting window to 13-14 hours because my body felt it needed nutrition earlier in the morning.

The same applies for dieting – extreme restriction of calories or limiting categories of food can make you feel fatigued, disrupt sleep and cause irritability. None of this seems like a good way to boost our immune system. When I joke to my family that I’m starting a ‘diet’ the next day, that means going back to my usual healthy eating (i.e., cutting out the desserts and the non-stop snacking), NOT actually going on a fast or some popular restricted eating program.

My advice – Focus on eating healthy with lots of greens and low-sugar fruits, complex carbohydrates and good proteins like grass-fed meat, organic poultry and clean fish (I’ll talk more about clean fish in a later post). Try to avoid the snacking and the temptation to ‘go all out’ – but if you do, start the next day on a clean slate and refuel your body with all the good stuff. Remember that it’s the journey (not the destination) that will create good habits which will become second-nature to you. It took me years to optimize a clean eating program that works for my body with lots of missteps and re-starts. So don’t beat yourself up for yesterday but start today on a clean slate.


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