Ah yes, good old nontoxicity and psychological balance, I’ll go buy a load of that from target right away.

Poor health in many demographics in Europe is caused by environmental and cultural factors, changing biology (giving people drugs) is much quicker than changing people’s behavior and their cultural environment.

If that was not the case, there wouldn’t be a market in the hundreds of billions for insulin, statins and 5-HT reuptake inhibitor.

And let’s be bloody honest here, early deaths from CVD, diabetes, NAFLD and a host of other metabolic disease kill more people in an hour around US and Europe than covid-19 has all year…. and those are fully (or almost fully) metabolic disease as far as we understand them and can be prevented and reverted (in the case of diabetes and NAFLD) with change in lifestyle and diet.

But people don’t want to change their lifestyle and diet.

Not to mention, the changes will take years to occur. You don’t just skip a budlight, eat a salad and run 1km and then “Bam, now all your cells have working MHC-2 again and your T-cell signaling mechanism are the same as that of a newborn”.

Can healthy lifestyle improve your immune system as a function of improving overall health ? Yeah

Is it the kind of fast-paced or easy to follow intervention that would put a dent in covid-19 deaths if physicians started advising it ? I would say the only sane answer to that is no (Unless you want to argue doctors have been sitting on the cure for 4 out of the top 5 causes of deaths in the US and most of Europe but are just refusing to act on it).