The 3 supplements every woman should consider taking, according to a registered dietitian

Possibly the most confusing part of healthy eating: supplements. Fish oil, zinc, magnesium, potassium…how do you know what you really need and what isn’t worth shelling out for? (Because no joke, supplements aren’t cheap.)

The best way to know, of course, it to talk to your MD, who will likely do blood work to actually see what nutrients you need more of, and then you can go from there. But in general, there are typically three big vitamins women should be consuming on the regular, registered dietitian Tracy Lockwood Beckerman said in the latest episode of You Versus Food. They are (drum roll please): calcium, vitamin D, and iron.

Why those three particular supplements for women? Beckerman says that vitamin D helps with calcium absorption, and it also plays a crucial role in brain and reproductive health. Calcium keeps bones strong and helps support the thyroid, which is responsible for regulating the menstrual cycle.

As for iron, you how you can feel more tired on your period? Beckerman says that’s because you’re often lower in iron, the third crucial vitamin on her list. Simply put, iron provides energy and helps the blood carry oxygen throughout the body. She adds that if you’re vegan or vegetarian, you especially need to be conscious that you’re getting enough (since iron is harder to come by from plant-based sources).

So what if one wanted to get those above-mentioned vitamins without going a supplement route? Beckerman shares some of the richest whole-food sources of calcium, vitamin D, and iron…but you’re going to have to watch the video to find out what they are. Sorry, not sorry.

Ideally, everyone would get all the nutrients they need from food. But we’re all human, and eating a wide variety of healthy foods is easier said than done. “Although you should try hard every day to eat a balanced diet, it’s a good idea for women to take a multivitamin daily to ensure she’s still getting the full gamut of macro and micro nutrients,” Beckerman says. Consider it your nutritional insurance policy.

Here’s how to make sure you’re buying legit supplements and not wasting your money. And here are some guidelines on what supplements to take, based on your age.