Most toddlers are notoriously picky eaters. They snub new textures, colors, aromas and especially anything green. They may even flat out refuse to eat.

Even if your toddler is an adventurous eater, you may still worry that he’s not getting enough of the nutrition he needs to grow healthy.

Read on for the 5 key nutrients experts say are essential for toddlers and easy ways to add them into their diet.

1. Potassium
Potassium is a key nutrient for keeping blood pressure low but most kids don’t get enough, especially those who are at risk for being overweight or obese, said Sarah Krieger, a registered dietitian and spokesperson for the Academy of Nutrition and Dietetics.

Most fruits and vegetables have potassium and the best sources include bananas, cantaloupe, strawberries, watermelon, broccoli, peas, and potatoes.  Try adding pureed butternut squash to pasta sauce, put fruit on skewers, make a smoothie, or let your toddler dip cut-up red bell pepper into hummus as a snack.

2. DHA
“DHA is an important building block for the growing brain,” said Dr. Scott Cohen, a pediatrician, spokesperson for Enfagrow and author of “Eat, Sleep, Poop.”

Yet toddlers are only getting about 25 percent of the recommended amount of this omega-3 fatty acid. The brain grows rapidly during the first three years of life and DHA can help with cognition and vision. It may even decrease colds and allergies and help your child sleep better, found a recent study in the Journal of Sleep Research.

Good sources of DHA include eggs (yolks), fortified milk and fish. Try making your own salmon fish patties or fish sticks or mashing sardines into tomato sauce.

“If it doesn’t smell fishy, most kids will eat it,” Krieger said.

3. Calcium
Necessary for strong bones, muscles and teeth, calcium is a vital nutrient for growing toddlers. Aim for 16 to 24 ounces of milk or yogurt a day, closer to 16 ounces if they also eat cheese. Other options include calcium-fortified foods like cereal, applesauce or granola bars. Fortified orange juice is ok, but limit it to 4 to 6 ounces a day.

4. Iron
Iron is a mineral that’s necessary to make hemoglobin, a part of the red blood cells that transfers oxygen from the lungs to the body’s tissues. Iron is also important for your child’s metabolism, growth and development.Without enough, kids can become anemic. The number one reason for deficiencies? Drinking too much milk—calcium trumps iron for space in the blood, Krieger said.

Limit milk to two cups a day and try fortified cereals with an 80 to 90 percent daily value of iron. Other toddler-friendly sources of iron include eggs, chicken, lean beef, and enriched rice and breads.

5. Fiber
Getting enough fiber is part of a healthy diet, but it’s especially important for toddlers who are frequently constipated or are potty training, which can make constipation worse. Fill your toddler’s plate half full of fruits and vegetables and include a new variety alongside his favorites and see if he tries it.

Whole grains are another great source of fiber, so make sure at least half of his diet is made up of them.

“It doesn’t have to be all or none—it’s ok to balance the refined with some of the whole grains,” Krieger said.  

You can also add flax meal to muffins, pancakes or oatmeal for an extra boost of fiber.

Julie Revelant is a health journalist and a consultant who provides content marketing and copywriting services for the healthcare industry. She's also a mom of two. Learn more about Julie at revelantwriting.com.