need for calcium supplement

Serum levels don't reveal adquate intake for bone health. In order to maintain serum levels of calcium, when intake is too low calcium is absorbed from the bone and serum levels are maintained.
It is a struggle to know how much calcium is in a diet because so many high calcium foods contain lectins or phosphates that hinder absorption.
Vtamin d3 increases absorption and vitamin k2 directs the absorbed calcium away from soft tissue and to the bone. It is said that your body can't absorb more than 500mg in a two hour period.
I have adequate intake from food, but can only guess at absorption. So I take a cautionary Citracal 250mg twice a day.
I think the asnwer to the question is yes.

If you don't get enough calcium from food, yes. If you get enough from food, you don't want to over-supplement either!

I agree with windyshores, food is what your body deals with best! And supplements are not checked for potency, contamination, etc. Lastly, my osteo doc prefers I get my calcium from food sources. Thankfully, Lactaid milk works well for me.

Do not use serum calcium to determine whether you need to eat more or less calcium. Instead go by your typical food intake. If you are not getting enough calcium in your diet then you either change your diet or add supplemental calcium. As a general rule it's probably almost always ideal to get nutrients from food rather than supplements but I think it's nuts to not get recommended amounts of calcium because your diet doesn't have enough and you've heard supplements are not as good or maybe dangerous. Very little evidence of that. If you need them just take the supplements to get you up to the recommended daily amount.
It's best to look up the calcium content of the foods you eat and add up what you are likely getting per day. Also a good idea for some foods to take some percentage off the total amount in those foods due to anti-nutrients in those foods.
Due to extreme food sensitivities I eat a rather unusual diet and I found out I was getting only a couple of hundred mg of calcium a day. Maybe the source of my problem? Anyway I sure as heck take calcium supplements now.
Oh, a pet peeve of mine is the insanity of recommending foods with calcium added and calling those natural food sources of calcium. If you add calcium to some nut milk or juice or other that's alright but it's not calcium in the food, it's just the same as you taking a calcium powder and stirring it a drink. It's supplemental calcium.

Bioavailability and bioabsorbability are not the same,
https://workshops.americanbonehealth.org/wp-content/uploads/2021/04/122b-calcium_bioavailability.pdf
which makes it difficult to calculate intake from food.

I was just diagnosed with osteopenia of the lumbar spine. Last year's test were fine. I did have a lumbar laminectomy in 2019. However, I do take Pepcid in the AM and PM. I don't know which calcium is best for me- citrate or carbonate. Also, should this be taken along with another for absorption? Is there a one-pill-a-day regimen and how much is safe? Could anyone make a suggestion. I do take D3 K2 now.

@mresnick664 the only thing I am able to say here is that calcium supplements need to be split up. The body does not absorb more than 400mg at a time, I was told. Others can chime in wiht the brands they use.