Tweens and teens may bristle at the notion of taking supplements, so the wise parent knows when to keep things simple and not create a battleground. That said, during this key growth stage, dietary supplements can help build bones and tissues, maintain healthy moods and brain function, and reduce the risk of health problems now and much later in life—so it’s worth the effort if you think your child’s diet could use a boost. Here are the top supplements to consider, in order of importance.

Multivitamins.Think of multis as a stand-alone foundation to prevent basic nutritional deficiencies—or as a starting point for a more comprehensive supplement regimen. Each essential vitamin and mineral plays myriad roles in the body and mind, and too little of any single nutrient can have wide-ranging negative health effects; a zinc deficiency, for example, can impair growth. Most multivitamin formulas contain all essential vitamins and at least a smattering of minerals. (Calcium and magnesium are bulky, so it’s impossible to add enough into one capsule.) For tweens, opt for products formulated specifically for children. Early teens can take half the dose of adult multis (for example, one capsule instead of two), and older teens can simply start with an adult dose. Menstruating girls need about 15 mg iron per day, so make sure it’s in her supplement. Dose: daily, according to label directions.

Vitamin D.Unfortunately, typical multis don’t provide enough vitamin D. Most kids (and adults) are deficient, and children especially need this vitamin to build strong bones for later years. Vitamin D also helps manage blood sugar, protect against the flu and other upper respiratory infections, and might even fight wintertime depression. Dose: 1,000– 2,000 IU daily year-round.

Omega-3s.Sourced from either fish oralgae, omega-3s are the ultimate brain nutrients. Docosahexaenoic acid (DHA) is essential for brain development, and a recent study found that omega-3 supplements improved children’s learning and moods. Still more research shows that combining eicosapentaenoic acid (EPA) with gamma-linolenic acid (GLA), an omega-6 plant oil, reduces impulsive and hyperactive behavior in children. Look for a supplement with roughly a 5:1 DHA to EPA ratio. Dose: 300–1,000 mg total DHA-EPA daily, 50 mg GLA if desired.

Calcium and magnesium.You know that calcium is critical for normal bone strength, but so is magnesium. In a Yale University study, magnesium supplements increased bone density in tween and teen girls. Calcium also works hand in hand with vitamin D to regulate blood sugar, and magnesium can reduce asthma symptoms. Too much magnesium may have a laxative effect, so cut back if necessary. Dose: 700–1,300 mg calcium and 80–420 mg magnesium daily.

Probiotics.Tweens and teens often take antibiotics to treat various types of infections, but the drugs cause diarrhea. During and for four weeks after a round of antibiotics, teens should take probiotics containing Lactobacillusrhamnosus GG and Saccharomycesboulardii, which restore normal gut bacteria and bowel function. General-use probiotics also reduce inflammation and enhance immunity. Recent research suggests they might even improve moods. Dose: Follow label directions.