Lectins
Lectins are an aggravating factor here. It often does not hit people too hard if they are young, but not always. These lectins have the potential to disrupt all sorts of things in the body including, but not restricted to, arthritis, eyesight, intestinal problems, inflamation, virus proliferation and chronic illness. This subject has been covered by
(opens in new tab) Dr Gundry in his excellent book, The Plant Paradox.
(opens in new tab) I would not say that these pesky lectins have nothing to do with Fibromyalgia!

D3 is a hormone,
So D3 needs a mention because one may have a compromised immune system, and like all hormones they are messengers. Some hormones, although essential for immediate survival like cortisol can have a negative effect if they are called upon too much. Others like D3 seem to possess an almost magical opposite
(new tab)possitive effect.
Here this study is also going further by suggesting it possibly has even an
(open new tab) endochrine and cardiovascular benefit too.
(new tab) So D3 has anti viral properties. Especailly respiratory.
(new tab) Also it seems lectins are implicated in viral outbreaks.

https://www.risagrouxnutrition.com/post/how-does-the-keto-diet-affect-insulin-and-blood-glucose here experts believe keto should be the first port of call for dealing with diabetes.