I hope that one reason for us to have gardens is to help us have healthy diets. Nutritionists tell us again and again that this means plenty of fruits and vegetables.
There are a lot of reasons to have a vegetable garden, with nutrition being just one of them. There is much to be said about growing the vegetables & varieties we choose, controlling what is - and is not - in them, and consuming them at peak flavor fresh from the garden.
But please forgive me
@digitS' if I go momentarily off topic, because as much as it pains me to do so, I have to add one caveat:
Despite our best efforts, home-grown vegetables are not
automatically healthier than store bought produce.
Those of us who garden organically assume that our vegetables are relatively free of contaminants, That might not be the case (especially in urban environments) because contaminant-free vegetables can only be grown from contaminant-free soil. Lead (from paint, and from the years of leaded gasoline) may be present, as may other contaminants from the years before we became environmentally aware. The soil may contain toxins from previous agricultural use, from contaminated soil brought in, or from reckless backyard dumping. Just because land appears to be open & unused now, does not mean it has always been so.
Some personal examples:
In the 80's, when I was in the Navy, I was allowed to plant a garden in a vacant field, in exchange for mowing that field. My tiller kept jumping at one point, and I finally dug down with a pick hoe, expecting to dig up a big rock. It was a deeply buried asphalt sidewalk, running from the road to about 10' into the garden. Obviously there had once been a building there, despite the lack of any visual evidence.
In my present rural garden, I dug up large quantities of nails, bolts, hooks, and other iron hardware. There were even a few blobs of molten aluminum. So apparently that site had either been a burn pit (which were & are common in rural areas), or a structure which had burned down long ago. The present owner (who has lived there for over 25 years) said it was just lawn from the time they moved in, and knows nothing about its history.
And there are concrete blocks peeking out of some portions of my present lawn, which are evidence of rather indiscriminate dumping at some point. Even our own homes & properties can be shrouded in mystery.