Pine nuts

Whole pine nuts are a choking hazard: they're small and can block a child's airway. The AAP advises keeping nuts and seeds from children until about 4 years, depending on the child, and the NHS says no whole nuts under 5. Serve pine nuts finely ground, blended completely smooth into a dish, or as a smooth paste thinned or spread very thinly. Never offer thick lumps or spoonfuls of pine nut paste. Check salads, pasta dishes and baked goods for whole pine nuts.

Pine nuts are seeds botanically, but the FDA counts them as a tree nut, one of the most common food allergens. Current guidance is to introduce common allergens, including nut products, from around 6 months once your baby has started solids, then keep offering them regularly. Start with a small amount when your baby is well and watch for signs of a reaction. The AAAAI says people with a tree nut allergy can often tolerate pine nuts, but the ACAAI says allergists usually advise people allergic to one tree nut to avoid all nuts. If your child has a tree nut allergy, never try pine nuts at home unless your allergist has cleared them. Tree nut allergy usually lasts for life: fewer than 1 in 10 people outgrow it. Between 25% and 40% of people with a peanut allergy also react to at least one tree nut.

A source of fat, magnesium, zinc, manganese and vitamin E. Pine nuts have some iron (about 5.5 mg per 100 g), but a teaspoon of ground pine nuts gives well under 1 mg.

Not until at least 4 years in the US (the AAP says 4 years or older, depending on the child) and 5 years in the UK. Until then, keep them finely ground or blended smooth.

Homemade pesto, blended completely smooth and made without salt, is fine from about 12 months once pine nuts have been introduced on their own. Add cheese only if it's pasteurized and dairy is already in your baby's diet.

Some people notice a bitter or metallic taste 1 to 3 days after eating certain pine nuts. A medical review links the affected nuts to a Chinese pine (Pinus armandii), and says nuts from other species could be involved too. It fades on its own once you stop eating them. It's different from an allergic reaction, which usually starts within a few minutes and can take up to 2 hours. Your child may not be able to tell you, so if they suddenly go off their food after pine nuts, stop them and mention it to your pediatrician.

Ask your allergist first, and never try them at home unless your allergist has cleared them. Pine nuts are botanically seeds, and the AAAAI says people with a tree nut allergy can often tolerate them, but the ACAAI says allergists usually advise people allergic to one tree nut to avoid all nuts. Your allergist will decide based on your child's test results and past reactions.