Walnut

Around 6 months, when your baby is ready for solids, you can offer walnut as a very finely ground powder or as walnut butter stirred into other foods. Whole walnuts, chopped walnuts and thick walnut butter are choking hazards.

Walnuts are seeds of broadleaf trees that grow across the temperate world, in places as far apart as China, Iran and the US. Two kinds dominate the table. One is the American black walnut. The other is the English or Persian walnut from Southwest Asia, now a favorite nut around the world.

Walnuts supply healthy fats that help brain growth and heart health. Few whole foods contain as much ALA, a plant omega-3. They also provide fiber, folate, zinc and iron, which makes them useful in plant-based diets.

Grinding and thinning

Look for smooth walnut butter with no honey, or process walnuts until no big bits are left. Without a processor, pound them in a cloth with a mortar, hammer or bottle base. Sprinkle the powder over warm porridge or slippery fruit. Thin the butter with applesauce, water, breast milk or formula. Then smear a very thin coat on strips of bread. A drink from an open cup helps wash down sticky bits.

Whole walnuts

After 24 months, a child who chews well can start learning to eat whole walnuts. Medical bodies treat nuts and pieces as a choking risk until age 4 and beyond. Seat your child upright, attentive to the meal, and do not serve nuts while they talk, shout or sing. Skip nuts in the car, a stroller or when on the move. Model a small bite and chew first. Next, hold the nut firmly yourself and let your child bite it, without putting it in their mouth. Offer one or two at a time. If your child does not bite, try again in a few weeks. Make sure the mouth is empty at the end of the meal.

Walnut milk

Before 12 months, walnut milk is not a drink, though it can be an ingredient in food. After the first birthday, remember that most nut milks provide too little energy, fat and protein for a toddler. You will get more nutrition from fortified soy or pea milk.

Babies and young children can choke on whole walnuts, nut pieces and thick walnut butter. Grind the nut finely or thin the butter. Stay close during meals.

The World Health Organization lists walnut as a global priority allergen. It counts as a tree nut, though it is technically a seed. About 70 percent of children allergic to walnut are also allergic to pecan. An allergy to tree nuts affects 0.5 to 1.2 percent of people. It usually stays for life, and just about 9 percent of children outgrow it.

Walnut reactions can be severe. Walnut also causes oral allergy syndrome, especially in people allergic to birch pollen, which usually means brief itching, tingling or burning in the mouth.

A child allergic to walnut can cross-react to other tree nuts and seeds. That does not mean all nuts must go. Work with an allergist.

Most babies do not need allergy testing before trying walnut. If your baby has severe eczema, has reacted to food before, or may have a nut allergy, check with your pediatrician or an allergist before the first taste. Evidence for protection from early introduction keeps growing, so do not delay longer than needed.