I learned many years ago that eating a healthy diet is really not complicated. If 80% of your diet comes from raw, unprocessed fruits & vegetables, you're eating a healthy diet.Vit D is useful if you're like me and stay out of the sun. Wayyyy out of the sun, and have for decades.
For bone density I take chelated calcium-magnesium. Also for decades, ever since I became allergic to milk at age 20.
When I finally managed to wrangle a bone density test out of my HMO at age 57, I was congratulated on having the bone density of a 23 yr old.
My elder sister had asked me to get a bone density test as she was diagnosed with osteoporosis that was apparently caused by malfunctioning parathyroids. Like me she took cal-mag supplements, but in her case the glandular malfunction caused calcium to just circulate around in her blood, rather than deposit it into the bones.
No one had any idea anything was wrong (no symptoms, obviously) until bones started breaking in her feet - she was an ICU nurse. As she weighs maybe 85 lbs soaking wet they had to search for a cause for almost two years before finally doing the surgery!
It's always best to eat a healthy diet. But very few people DO eat a completely healthy diet, day in and day out. And as you age, you eat less and less. This does not even take into consideration your digestive process slows down and becomes less efficient at getting nutrients out of the food you are eating.
I watched my MIL as she aged and her diet was atrocious. All she concentrated on was salt and portion size. She was the perfect weight for her height, but nutritionally she was a disaster. Finally one day she fainted from low blood sugar (she wasn't diabetic) and I had to insist she start drinking a liquid protein supplement every day.